Problems

3,987 problems with original AlgoForge explanations and reference solutions. Filter via topics, patterns, companies, or search.

#	Title	Difficulty	Topics
1	Two Sum	Easy	hash table
2	Add Two Numbers	Medium	linked list
3	Longest Substring Without Repeating Characters	Medium	hash table
4	Median of Two Sorted Arrays	Hard	binary search
5	Longest Palindromic Substring	Medium	string
6	ZigZag Conversion	Easy	string
7	Reverse Integer	Easy	math
8	String to Integer (atoi)	Easy	string
9	Palindrome Number	Easy	math
10	Regular Expression Matching	Hard	dynamic programming
11	Container With Most Water	Medium	greedy
12	Integer to Roman	Medium	math
13	Roman to Integer	Easy	math
14	Longest Common Prefix	Easy	string
15	3 Sum	Medium	two pointers
16	3 Sum Closest	Medium	two pointers
17	Letter Combinations of a Phone Number	Medium	backtracking
18	4 Sum	Medium	two pointers
19	Remove Nth Node From End of List	Medium	two pointers
20	Valid Parentheses	Easy	stack
21	Merge Two Sorted Lists	Easy	linked list
22	Generate Parentheses	Medium	backtracking
23	Merge k Sorted Lists	Hard	linked list
24	Swap Nodes in Pairs	Easy	linked list
25	Reverse Nodes in k-Group	Hard	linked list
26	Remove Duplicates from Sorted Array	Easy	array
27	Remove Element	Easy	array
28	Implement strStr()	Easy	string
29	Divide Two Integers	Medium	math
30	Substring with Concatenation of All Words	Hard	hash table
31	Next Permutation	Medium	array
32	Longest Valid Parentheses	Hard	stack
33	Search in Rotated Sorted Array	Medium	binary search
34	Find First and Last Position of Element in Sorted Array	Medium	binary search
35	Search Insert Position	Medium	binary search
36	Valid Sudoku	Easy	hash table
37	Sudoku Solver	Hard	backtracking
38	Count and Say	Easy	string
39	Combination Sum	Medium	backtracking
40	Combination Sum II	Medium	backtracking
41	First Missing Positive	Hard	array
42	Trapping Rain Water	Hard	greedy
43	Multiply Strings	Medium	string
44	Wildcard Matching	Hard	dynamic programming
45	Jump Game II	Hard	greedy
46	Permutations	Medium	backtracking
47	Permutations II	Medium	backtracking
48	Rotate Image	Medium	array
49	Group Anagrams	Medium	hash table
50	Pow(x, n)	Medium	math
51	N-Queens	Hard	backtracking
52	N-Queens-II	Hard	backtracking
53	Maximum Subarray	Easy	dynamic programming
54	Spiral Matrix	Medium	array
55	Jump Game	Medium	greedy
56	Merge Intervals	Hard	sort
57	Insert Interval	Hard	sort
58	Length of Last Word	Easy	string
59	Spiral Matrix II	Medium	array
60	Permutation Sequence	Medium	math
61	Rotate List	Medium	linked list
62	Unique Paths	Medium	dynamic programming
63	Unique Paths II	Medium	dynamic programming
64	Minimum Path Sum	Medium	dynamic programming
65	Valid Number	Hard	math
66	Plus One	Easy	array
67	Add Binary	Easy	string
68	Text Justification	Hard	string
69	Sqrt(x)	Medium	binary search
70	Climbing Stairs	Easy	dynamic programming
71	Simplify Path	Medium	stack
72	Edit Distance	Hard	dynamic programming
73	Set Matrix Zeroes	Medium	array
74	Search a 2D Matrix	Medium	binary search
75	Sort Colors	Medium	sort
76	Minimum Window Substring	Hard	hash table
77	Combinations	Medium	backtracking
78	Subsets	Medium	backtracking
79	Word Search	Medium	backtracking
80	Remove Duplicates from Sorted Array II	Medium	array
81	Search in Rotated Sorted Array II	Medium	binary search
82	Remove Duplicates from Sorted List II	Medium	linked list
83	Remove Duplicates from Sorted List	Easy	linked list
84	Largest Rectangle in Histogram	Hard	stack
85	Maximal Rectangle	Hard	stack
86	Partition List	Medium	two pointers
87	Scramble String	Hard	dynamic programming
88	Merge Sorted Array	Easy	sort
89	Gray Code	Medium	math
90	Subsets II	Medium	backtracking
91	Decode Ways	Medium	dynamic programming
92	Reverse Linked List II	Medium	linked list
93	Restore IP Addresses	Medium	backtracking
94	Binary Tree Inorder Traversal	Medium	tree
95	Unique Binary Search Trees II	Medium	recursion
96	Unique Binary Search Trees	Medium	dynamic programming
97	Interleaving String	Hard	dynamic programming
98	Validate Binary Search Tree	Medium	recursion
99	Recover Binary Search Tree	Hard	tree
100	Same Tree	Easy	recursion
101	Symmetric Tree	Easy	stack
102	Binary Tree Level Order Traversal	Easy	breadth first search
103	Binary Tree Zigzag Level Order Traversal	Medium	breadth first search
104	Maximum Depth of Binary Tree	Easy	recursion
105	Construct Binary Tree from Preorder and Inorder Traversal	Medium	recursion
106	Construct Binary Tree from Inorder and Postorder Traversal	Medium	recursion
107	Binary Tree Level Order Traversal II	Easy	breadth first search
108	Convert Sorted Array to Binary Search Tree	Medium	recursion
109	Convert Sorted List to Binary Search Tree	Medium	recursion
110	Balanced Binary Tree	Easy	recursion
111	Minimum Depth of Binary Tree	Easy	recursion
112	Path Sum	Easy	depth first search
113	Path Sum II	Medium	depth first search
114	Flatten Binary Tree to Linked List	Medium	recursion
115	Distinct Subsequences	Hard	dynamic programming
116	Populating Next Right Pointers in Each Node	Medium	recursion
117	Populating Next Right Pointers in Each Node II	Hard	breadth first search
118	Pascal's Triangle	Easy	array
119	Pascal's Triangle II	Easy	array
120	Triangle	Medium	dynamic programming
121	Best Time to Buy and Sell Stock	Easy	array
122	Best Time to Buy and Sell Stock II	Easy	greedy
123	Best Time to Buy and Sell Stock III	Hard	dynamic programming
124	Binary Tree Maximum Path Sum	Hard	recursion
125	Valid Palindrome	Easy	string
126	Word Ladder II	Hard	backtracking
127	Word Ladder	Medium	breadth first search
128	Longest Consecutive Sequence	Hard	array
129	Sum Root to Leaf Numbers	Medium	recursion
130	Surrounded Regions	Medium	breadth first search
131	Palindrome Partitioning	Medium	backtracking
132	Palindrome Partitioning II	Hard	dynamic programming
133	Clone Graph	Medium	breadth first search
134	Gas Station	Medium	greedy
135	Candy	Hard	greedy
136	Single Number	Easy	bit manipulation
137	Single Number II	Medium	bit manipulation
138	Copy List with Random Pointer	Medium	linked list
139	Word Break	Medium	dynamic programming
140	Word Break II	Hard	backtracking
141	Linked List Cycle	Easy	two pointers
142	Linked List Cycle II	Medium	two pointers
143	Reorder List	Medium	two pointers
144	Binary Tree Preorder Traversal	Medium	tree
145	Binary Tree Postorder Traversal	Hard	tree
146	LRU Cache	Hard	design
147	Insertion Sort List	Medium	sort
148	Sort List	Medium	sort
149	Max Points on a Line	Hard	hash table
150	Evaluate Reverse Polish Notation	Medium	stack
151	Reverse Words in a String	Medium	string
152	Maximum Product Subarray	Medium	dynamic programming
153	Find Minimum in Rotated Sorted Array	Medium	binary search
154	Find Minimum in Rotated Sorted Array II	Hard	binary search
155	Min Stack	Easy	stack
156	Binary Tree Upside Down	Medium	recursion
157	Read N Characters Given Read4	Easy	array
158	Read N Characters Given Read4 II - Call multiple times	Hard	array
159	Longest Substring with At Most Two Distinct Characters	Hard	hash table
160	Intersection of Two Linked Lists	Easy	linked list
161	One Edit Distance	Medium	string
162	Find Peak Element	Medium	binary search
163	Missing Ranges	Medium	array
164	Maximum Gap	Hard	sort
165	Compare Version Numbers	Easy	string
166	Fraction to Recurring Decimal	Medium	math
167	Two Sum II - Input array is sorted	Medium	two pointers
168	Excel Sheet Column Title	Easy	math
169	Majority Element	Easy	array
170	Two Sum III - Data structure design	Easy	hash table
171	Excel Sheet Column Number	Easy	math
172	Factorial Trailing Zeroes	Easy	math
173	Binary Search Tree Iterator	Medium	design
174	Dungeon Game	Hard	dynamic programming
175	Combine Two Tables	Easy	sql
176	Second Highest Salary	Easy	sql
177	Nth Highest Salary	Medium	sql
178	Rank Scores	Medium	sql
179	Largest Number	Medium	sort
180	Consecutive Numbers	Medium	sql
181	Employees Earning More Than Their Managers	Easy	sql
182	Duplicate Emails	Easy	sql
183	Customers Who Never Order	Easy	sql
184	Department Highest Salary	Medium	sql
185	Department Top Three Salaries	Hard	sql
186	Reverse Words in a String II	Medium	string
187	Repeated DNA Sequences	Medium	hash table
188	Best Time to Buy and Sell Stock IV	Hard	dynamic programming
189	Rotate Array	Easy	array
190	Reverse Bits	Easy	bit manipulation
191	Number of 1 Bits	Easy	bit manipulation
192	Word Frequency	Medium	sql
193	Valid Phone Numbers	Easy	sql
194	Transpose File	Medium	sql
195	Tenth Line	Easy	sql
196	Delete Duplicate Emails	Easy	sql
197	Rising Temperature	Easy	sql
198	House Robber	Easy	dynamic programming
199	Binary Tree Right Side View	Medium	depth first search
200	Number of Islands	Medium	depth first search
201	Bitwise AND of Numbers Range	Medium	bit manipulation
202	Happy Number	Easy	hash table
203	Remove Linked List Elements	Easy	linked list
204	Count Primes	Easy	hash table
205	Isomorphic Strings	Easy	hash table
206	Reverse Linked List	Easy	linked list
207	Course Schedule	Medium	breadth first search
208	Implement Trie (Prefix Tree)	Medium	tree
209	Minimum Size Subarray Sum	Medium	two pointers
210	Course Schedule II	Medium	breadth first search
211	Add and Search Word - Data structure design	Medium	tree
212	Word Search II	Hard	backtracking
213	House Robber II	Medium	dynamic programming
214	Shortest Palindrome	Hard	string
215	Kth Largest Element in an Array	Medium	array
216	Combination Sum III	Medium	backtracking
217	Contains Duplicate	Easy	hash table
218	The Skyline Problem	Hard	sort
219	Contains Duplicate II	Easy	hash table
220	Contains Duplicate III	Medium	binary search tree
221	Maximal Square	Medium	dynamic programming
222	Count Complete Tree Nodes	Medium	binary search
223	Rectangle Area	Easy	math
224	Basic Calculator	Hard	stack
225	Implement Stack using Queues	Easy	design
226	Invert Binary Tree	Easy	tree
227	Basic Calculator II	Medium	stack
228	Summary Ranges	Medium	array
229	Majority Element II	Medium	array
230	Kth Smallest Element in a BST	Medium	binary search tree
231	Power of Two	Easy	bit manipulation
232	Implement Queue using Stacks	Easy	stack
233	Number of Digit One	Hard	math
234	Palindrome Linked List	Easy	linked list
235	Lowest Common Ancestor of a Binary Search Tree	Easy	binary search tree
236	Lowest Common Ancestor of a Binary Tree	Medium	depth first search
237	Delete Node in a Linked List	Easy	linked list
238	Product of Array Except Self	Medium	array
239	Sliding Window Maximum	Hard	queue
240	Search a 2D Matrix II	Medium	array
241	Different Ways to Add Parentheses	Medium	recursion
242	Valid Anagram	Easy	string
243	Shortest Word Distance	Easy	array
244	Shortest Word Distance II	Medium	hash table
245	Shortest Word Distance III	Medium	array
246	Strobogrammatic Number	Easy	hash table
247	Strobogrammatic Number II	Medium	depth first search
248	Strobogrammatic Number III	Hard	math
249	Group Shifted Strings	Easy	hash table
250	Count Univalue Subtrees	Medium	depth first search
251	Flatten 2D Vector	Medium	array
252	Meeting Rooms	Easy	sort
253	Meeting Rooms II	Medium	sort
254	Factor Combinations	Medium	backtracking
255	Verify Preorder Sequence in Binary Search Tree	Medium	stack
256	Paint House	Medium	dynamic programming
257	Binary Tree Paths	Easy	depth first search
258	Add Digits	Easy	math
259	3Sum Smaller	Medium	two pointers
260	Single Number III	Medium	bit manipulation
261	Graph Valid Tree	Medium	breadth first search
262	Trips and Users	Hard	sql
263	Ugly Number	Easy	math
264	Ugly Number II	Medium	binary heap
265	Paint House II	Hard	dynamic programming
266	Palindrome Permutation	Easy	hash table
267	Palindrome Permutation II	Medium	backtracking
268	Missing Number	Medium	bit manipulation
269	Alien Dictionary	Hard	breadth first search
270	Closest Binary Search Tree Value	Easy	binary search tree
271	Encode and Decode Strings	Medium	string
272	Closest Binary Search Tree Value II	Hard	stack
273	Integer to English Words	Hard	string
274	H-Index	Medium	sort
275	H-Index II	Medium	binary search
276	Paint Fence	Easy	dynamic programming
277	Find the Celebrity	Medium	array
278	First Bad Version	Easy	binary search
279	Perfect Squares	Medium	dynamic programming
280	Wiggle Sort	Medium	sort
281	Zigzag Iterator	Medium	queue
282	Expression Add Operators	Hard	depth first search
283	Move Zeroes	Easy	two pointers
284	Peeking Iterator	Medium	design
285	Inorder Successor in BST	Medium	binary search tree
286	Walls and Gates	Medium	breadth first search
287	Find the Duplicate Number	Hard	two pointers
288	Unique Word Abbreviation	Easy	hash table
289	Game of Life	Medium	array
290	Word Pattern	Easy	hash table
291	Word Pattern II	Hard	backtracking
292	Nim Game	Easy	math
293	Flip Game	Easy	array
294	Flip Game II	Medium	backtracking
295	Find Median from Data Stream	Hard	binary heap
296	Best Meeting Point	Hard	array
297	Serialize and Deserialize Binary Tree	Hard	tree
298	Binary Tree Longest Consecutive Sequence	Medium	recursion
299	Bulls and Cows	Easy	hash table
300	Longest Increasing Subsequence	Medium	binary search
301	Remove Invalid Parentheses	Hard	depth first search
302	Smallest Rectangle Enclosing Black Pixels	Hard	binary search
303	Range Sum Query - Immutable	Easy	dynamic programming
304	Range Sum Query 2D - Immutable	Medium	dynamic programming
305	Number of Islands II	Hard	hash table
306	Addictive Number	Medium	string
307	Range Sum Query - Mutable	Medium	tree
308	Range Sum Query 2D - Mutable	Hard	tree
309	Best Time to Buy and Sell Stock with Cooldown	Medium	dynamic programming
310	Minimum Height Trees	Medium	breadth first search
311	Sparse Matrix Multiplication	Medium	array
312	Burst Balloons	Hard	dynamic programming
313	Super Ugly Number	Medium	binary heap
314	Binary Tree Vertical Order Traversal	Medium	hash table
315	Count of Smaller Numbers After Self	Hard	tree
316	Remove Duplicate Letters	Hard	greedy
317	Shortest Distance from All Buildings	Hard	breadth first search
318	Maximum Product of Word Lengths	Medium	bit manipulation
319	Bulb Switcher	Medium	math
320	Generalized Abbreviation	Medium	backtracking
321	Create Maximum Number	Hard	greedy
322	Coin Change	Medium	dynamic programming
323	Number of Connected Components in an Undirected Graph	Medium	hash table
324	Wiggle Sort II	Medium	sort
325	Maximum Size Subarray Sum Equals k	Medium	hash table
326	Power of Three	Easy	math
327	Count of Range Sum	Hard	recursion
328	Odd Even Linked List	Medium	linked list
329	Longest Increasing Path in a Matrix	Hard	depth first search
330	Patching Array	Hard	greedy
331	Verify Preorder Serialization of a Binary Tree	Medium	stack
332	Reconstruct Itinerary	Medium	graph
333	Largest BST Subtree	Medium	recursion
334	Increasing Triplet Subsequence	Medium	array
335	Self Crossing	Hard	math
336	Palindrome Pairs	Hard	hash table
337	House Robber III	Medium	recursion
338	Counting Bits	Medium	math
339	Nested List Weight Sum	Easy	depth first search
340	Longest Substring with At Most K Distinct Characters	Hard	hash table
341	Flatten Nested List Iterator	Medium	stack
342	Power of Four	Easy	bit manipulation
343	Integer Break	Medium	math
344	Reverse String	Easy	two pointers
345	Reverse Vowels of a String	Easy	two pointers
346	Moving Average from Data Stream	Easy	queue
347	Top K Frequent Elements	Medium	sort
348	Design Tic-Tac-Toe	Medium	design
349	Intersection of Two Arrays	Easy	two pointers
350	Intersection of Two Arrays II	Easy	two pointers
351	Android Unlock Patterns	Medium	dynamic programming
352	Data Stream as Disjoint Intervals	Hard	binary search tree
353	Design Snake Game	Medium	design
354	Russian Doll Envelopes	Hard	binary search
355	Design Twitter	Medium	design
356	Line Reflection	Medium	hash table
357	Count Numbers with Unique Digits	Medium	dynamic programming
358	Rearrange String k Distance Apart	Hard	binary heap
359	Logger Rate Limiter	Easy	design
360	Sort Transformed Array	Medium	two pointers
361	Bomb Enemy	Medium	dynamic programming
362	Design Hit Counter	Medium	design
363	Max Sum of Rectangle No Larger Than K	Hard	binary search
364	Nested List Weight Sum II	Medium	depth first search
365	Water and Jug Problem	Medium	math
366	Find Leaves of Binary Tree	Medium	depth first search
367	Valid Perfect Square	Medium	binary search
368	Largest Divisible Subset	Medium	dynamic programming
369	Plus One Linked List	Medium	linked list
370	Range Addition	Medium	array
371	Sum of Two Integers	Easy	bit manipulation
372	Super Pow	Medium	math
373	Find K Pairs with Smallest Sums	Medium	binary heap
374	Guess Number Higher or Lower	Easy	binary search
375	Guess Number Higher or Lower II	Medium	dynamic programming
376	Wiggle Subsequence	Medium	greedy
377	Combination Sum IV	Medium	dynamic programming
378	Kth Smallest Element in a Sorted Matrix	Medium	binary heap
379	Design Phone Directory	Medium	design
380	Insert Delete GetRandom O(1)	Hard	design
381	Insert Delete GetRandom O(1) - Duplicates allowed	Hard	design
382	Linked List Random Node	Medium	math
383	Ransom Note	Easy	string
384	Shuffle an Array	Medium	array
385	Mini Parser	Medium	stack
386	Lexicographical Numbers	Medium	math
387	First Unique Character in a String	Easy	hash table
388	Longest Absolute File Path	Medium	hash table
389	Find the Difference	Easy	bit manipulation
390	Elimination Game	Medium	math
391	Perfect Rectangle	Hard	math
392	Is Subsequence	Medium	greedy
393	UTF-8 Validation	Medium	bit manipulation
394	Decode String	Medium	stack
395	Longest Substring with At Least K Repeating Characters	Medium	recursion
396	Rotate Function	Easy	array
397	Integer Replacement	Medium	greedy
398	Random Pick Index	Medium	math
399	Evaluate Division	Medium	graph
400	Nth Digit	Easy	math
401	Binary Watch	Easy	bit manipulation
402	Remove K Digits	Medium	greedy
403	Frog Jump	Hard	dynamic programming
404	Sum of Left Leaves	Easy	recursion
405	Convert a Number to Hexadecimal	Easy	string
406	Queue Reconstruction by Height	Medium	sort
407	Trapping Rain Water II	Hard	binary heap
408	Valid Word Abbreviation	Easy	string
409	Longest Palindrome	Easy	hash table
410	Split Array Largest Sum	Hard	binary search
411	Minimum Unique Word Abbreviation	Hard	bit manipulation
412	Fizz Buzz	Easy	array
413	Arithmetic Slices	Medium	math
414	Third Maximum Number	Easy	array
415	Add Strings	Easy	string
416	Partition Equal Subset Sum	Medium	dynamic programming
417	Pacific Atlantic Water Flow	Medium	depth first search
418	Sentence Screen Fitting	Medium	dynamic programming
419	Battleships in a Board	Medium	array
420	Strong Password Checker	Hard	string
421	Maximum XOR of Two Numbers in an Array	Medium	bit manipulation
422	Valid Word Square	Easy	array
423	Reconstruct Original Digits from English	Medium	math
424	Longest Repeating Character Replacement	Medium	two pointers
425	Word Squares	Hard	backtracking
426	Convert Binary Search Tree to Sorted Doubly Linked List	Medium	tree
427	Construct Quad Tree	Medium	tree
428	Serialize and Deserialize N-ary Tree	Hard	tree
429	N-ary Tree Level Order Traversal	Medium	tree
430	Flatten a Multilevel Doubly Linked List	Medium	tree
431	Encode N-ary Tree to Binary Tree	Hard	tree
432	All O\`one Data Structure	Hard	design
433	Minimum Genetic Mutation	Medium	breadth first search
434	Number of Segments in a String	Easy	string
435	Non-overlapping Intervals	Medium	greedy
436	Find Right Interval	Medium	binary search
437	Path Sum III	Easy	recursion
438	Find All Anagrams in a String	Easy	hash table
439	Ternary Expression Parser	Medium	stack
440	K-th Smallest in Lexicographical Order	Hard	depth first search
441	Arranging Coins	Easy	math
442	Find All Duplicates in an Array	Medium	array
443	String Compression	Easy	string
444	Sequence Reconstruction	Medium	breadth first search
445	Add Two Numbers II	Medium	linked list
446	Arithmetic Slices II - Subsequence	Hard	dynamic programming
447	Number of Boomerangs	Easy	hash table
448	Find All Numbers Disappeared in an Array	Easy	array
449	Serialize and Deserialize BST	Medium	binary search tree
450	Delete Node in a BST	Medium	binary search tree
451	Sort Characters By Frequency	Medium	sort
452	Minimum Number of Arrows to Burst Balloons	Medium	greedy
453	Minimum Moves to Equal Array Elements	Easy	math
454	4Sum II	Medium	hash table
455	Assign Cookies	Easy	greedy
456	132 Pattern	Medium	stack
457	Circular Array Loop	Medium	two pointers
458	Poor Pigs	Easy	math
459	Repeated Substring Pattern	Easy	string
460	LFU Cache	Hard	design
461	Hamming Distance	Easy	bit manipulation
462	Minimum Moves to Equal Array Elements II	Medium	array
463	Island Perimeter	Easy	array
464	Can I Win	Medium	depth first search
465	Optimal Account Balancing	Hard	dynamic programming
466	Count The Repetitions	Hard	dynamic programming
467	Unique Substrings in Wraparound String	Medium	dynamic programming
468	Validate IP Address	Medium	string
469	Convex Polygon	Medium	math
470	Implement Rand10() Using Rand7()	Medium	math
471	Encode String with Shortest Length	Medium	dynamic programming
472	Concatenated Words	Medium	dynamic programming
473	Matchsticks to Square	Medium	hash table
474	Ones and Zeroes	Medium	dynamic programming
475	Heaters	Easy	binary search
476	Number Complement	Easy	bit manipulation
477	Total Hamming Distance	Medium	bit manipulation
478	Generate Random Point in a Circle	Medium	math
479	Largest Palindrome Product	Hard	math
480	Sliding Window Median	Hard	binary heap
481	Magical String	Medium	string
482	License Key Formatting	Easy	string
483	Smallest Good Base	Hard	math
484	Find Permutation	Medium	greedy
485	Max Consecutive Ones	Easy	array
486	Predict the Winner	Medium	dynamic programming
487	Max Consecutive Ones II	Medium	array
488	Zuma Game	Hard	backtracking
489	Robot Room Cleaner	Hard	design
490	The Maze	Medium	breadth first search
491	Increasing Subsequences	Medium	backtracking
492	Construct the Rectangle	Easy	math
493	Reverse Pairs	Hard	sort
494	Target Sum	Medium	dynamic programming
495	Teemo Attacking	Easy	array
496	Next Greater Element I	Easy	stack
497	Random Point in Non-overlapping Rectangles	Medium	math
498	Diagonal Traverse	Medium	array
499	The Maze III	Hard	breadth first search
500	Keyboard Row	Easy	string
501	Find Mode in Binary Search Tree	Easy	tree
502	IPO	Hard	binary heap
503	Next Greater Element II	Medium	stack
504	Base 7	Easy	math
505	The Maze II	Medium	breadth first search
506	Relative Ranks	Easy	array
507	Perfect Number	Easy	math
508	Most Frequent Subtree Sum	Medium	tree
509	Fibonacci Number	Easy	dynamic programming
510	Inorder Successor in BST II	Medium	binary search tree
511	Game Play Analysis I	Easy	sql
512	Game Play Analysis II	Easy	sql
513	Find Bottom Left Tree Value	Medium	tree
514	Freedom Trail	Hard	dynamic programming
515	Find Largest Value in Each Tree Row	Medium	depth first search
516	Longest Palindromic Subsequence	Medium	dynamic programming
517	Super Washing Machines	Hard	math
518	Coin Change 2	Medium	dynamic programming
519	Random Flip Matrix	Medium	math
520	Detect Capital	Easy	string
521	Longest Uncommon Subsequence I	Easy	string
522	Longest Uncommon Subsequence II	Medium	string
523	Continuous Subarray Sum	Medium	hash table
524	Longest Word in Dictionary through Deleting	Medium	string
525	Contiguous Array	Medium	hash table
526	Beautiful Arrangement	Medium	backtracking
527	Word Abbreviation	Hard	string
528	Random Pick with Weight	Medium	math
529	Minesweeper	Medium	tree
530	Minimum Absolute Difference in BST	Easy	binary search tree
531	Lonely Pixel I	Medium	array
532	K-diff Pairs in an Array	Easy	hash table
533	Lonely Pixel II	Medium	array
534	Game Play Analysis III	Medium	sql
535	Encode and Decode TinyURL	Medium	design
536	Construct Binary Tree from String	Medium	tree
537	Complex Number Multiplication	Medium	math
538	Convert BST to Greater Tree	Easy	tree
539	Minimum Time Difference	Medium	string
540	Single Element in a Sorted Array	Medium	binary search
541	Reverse String II	Easy	string
542	01 Matrix	Medium	breadth first search
543	Diameter of Binary Tree	Easy	tree
544	Output Contest Matches	Medium	recursion
545	Boundary of Binary Tree	Medium	tree
546	Remove Boxes	Hard	dynamic programming
547	Friend Circles	Medium	depth first search
548	Split Array with Equal Sum	Medium	tree
549	Binary Tree Longest Consecutive Sequence II	Medium	recursion
550	Game Play Analysis IV	Medium	sql
551	Student Attendance Record I	Easy	string
552	Student Attendance Record II	Hard	dynamic programming
553	Optimal Division	Medium	math
554	Brick Wall	Medium	hash table
555	Split Concatenated Strings	Medium	string
556	Next Greater Element III	Medium	string
557	Reverse Words in a String III	Easy	string
558	Logical OR of Two Binary Grids Represented as Quad-Trees	Medium	tree
559	Max Consecutive Ones	Easy	tree
560	Subarray Sum Equals K	Medium	hash table
561	Array Partition I	Easy	hash table
562	Longest Line of Consecutive One in Matrix	Medium	dynamic programming
563	Binary Tree Tilt	Easy	tree
564	Find the Closest Palindrome	Hard	string
565	Array Nesting	Medium	array
566	Reshape the Matrix	Easy	array
567	Permutation in String	Medium	two pointers
568	Maximum Vacation Days	Hard	dynamic programming
569	Median Employee Salary	Hard	sql
570	Managers with at Least 5 Direct Reports	Medium	sql
571	Find Median Given Frequency of Numbers	Hard	sql
572	Subtree of Another Tree	Easy	tree
573	Squirrel Simulation	Medium	math
574	Winning Candidate	Medium	sql
575	Distribute Candies	Easy	hash table
576	Out of Boundary Paths	Medium	dynamic programming
577	Employee Bonus	Easy	sql
578	Get Highest Answer Rate Question	Medium	sql
579	Find Cumulative Salary of an Employee	Hard	sql
580	Count Student Number in Departments	Medium	sql
581	Shortest Unsorted Continuous Subarray	Easy	array
582	Kill Process	Medium	depth first search
583	Delete Operation for Two Strings	Medium	dynamic programming
584	Find Customer Referee	Easy	sql
585	Investments in 2016	Medium	sql
586	Customer Placing the Largest Number of Orders	Easy	sql
587	Erect the Fence	Hard	geometry
588	Design In-Memory File System	Hard	design
589	N-ary Tree Preorder Traversal	Easy	tree
590	N-ary Tree Postorder Traversal	Medium	tree
591	Tag Validator	Hard	string
592	Fraction Addition and Subtraction	Medium	math
593	Valid Square	Medium	math
594	Longest Harmonious Subsequence	Easy	hash table
595	Big Countries	Easy	sql
596	Classes More Than 5 Students	Easy	sql
597	Friend Requests I: Overall Acceptance Rate	Easy	sql
598	Range Addition II	Easy	math
599	Minimum Index Sum of Two Lists	Easy	hash table
600	Non-negative Integers without Consecutive Ones	Hard	dynamic programming
601	Human Traffic of Stadium	Hard	sql
602	Friend Requests II: Who Has the Most Friends	Medium	sql
603	Consecutive Available Seats	Easy	sql
604	Design Compressed String Iterator	Easy	design
605	Can Place Flowers	Easy	array
606	Construct String from Binary Tree	Easy	tree
607	Sales Person	Easy	sql
608	Tree Node	Medium	sql
609	Find Duplicate File in System	Medium	hash table
610	Triangle Judgement	Easy	sql
611	Valid Triangle Number	Medium	two pointers
612	Shortest Distance in a Plane	Medium	sql
613	Shortest Distance in a Line	Easy	sql
614	Second Degree Follower	Medium	sql
615	Average Salary: Departments VS Company	Hard	sql
616	Add Bold Tag in String	Medium	string
617	Merge Two Binary Trees	Easy	tree
618	Students Report By Geography	Hard	sql
619	Biggest Single Number	Easy	sql
620	Not Boring Movies	Easy	sql
621	Task Scheduler	Medium	greedy
622	Design Circular Queue	Medium	design
623	Add One Row to Tree	Medium	tree
624	Maximum Distance in Arrays	Easy	array
625	Minimum Factorization	Medium	math
626	Exchange Seats	Medium	sql
627	Swap Salary	Easy	sql
628	Maximum Product of Three Numbers	Easy	math
629	K Inverse Pairs Array	Hard	dynamic programming
630	Course Schedule III	Hard	greedy
631	Design Excel Sum Formula	Hard	design
632	Smallest Range	Hard	binary heap
633	Sum of Square Numbers	Easy	math
634	Find the Derangement of An Array	Medium	math
635	Design Log Storage System	Medium	design
636	Exclusive Time of Functions	Medium	stack
637	Average of Levels in Binary Tree	Easy	tree
638	Shopping Offers	Medium	depth first search
639	Decode Ways II	Hard	dynamic programming
640	Solve the Equation	Medium	math
641	Design Circular Deque	Medium	design
642	Design Search Autocomplete System	Hard	design
643	Maximum Average Subarray I	Easy	array
644	Maximum Average Subarray II	Hard	array
645	Set Mismatch	Easy	bit manipulation
646	Maximum Length of Pair Chain	Medium	greedy
647	Palindromic Substrings	Medium	string
648	Replace Words	Medium	string
649	Dota2 Senate	Medium	greedy
650	2 Keys Keyboard	Medium	dynamic programming
651	4 Keys Keyboard	Medium	math
652	Find Duplicate Subtrees	Medium	tree
653	Two Sum IV - Input is a BST	Easy	tree
654	Maximum Binary Tree	Medium	tree
655	Print Binary Tree	Medium	tree
656	Coin Path	Hard	dynamic programming
657	Robot Return to Origin	Easy	string
658	Find K Closest Elements	Medium	binary search
659	Split Array into Consecutive Subsequences	Medium	greedy
660	Remove 9	Hard	math
661	Image Smoother	Easy	array
662	Maximum Width of Binary Tree	Medium	tree
663	Equal Tree Partition	Medium	tree
664	Strange Printer	Hard	dynamic programming
665	Non-decreasing Array	Easy	array
666	Path Sum IV	Medium	breadth first search
667	Beautiful Arrangement II	Medium	array
668	Kth Smallest Number in Multiplication Table	Hard	binary search
669	Trim a Binary Search Tree	Easy	recursion
670	Maximum Swap	Medium	array
671	Second Minimum Node In a Binary Tree	Easy	recursion
672	Bulb Switcher II	Medium	math
673	Number of Longest Increasing Subsequence	Medium	dynamic programming
674	Longest Continuous Increasing Subsequence	Easy	array
675	Cut Off Trees for Golf Event	Hard	breadth first search
676	Implement Magic Dictionary	Medium	backtracking
677	Map Sum Pairs	Medium	tree
678	Valid Parenthesis String	Medium	string
679	24 Game	Hard	backtracking
680	Valid Palindrome II	Easy	string
681	Next Closest Time	Medium	string
682	Baseball Game	Easy	stack
683	K Empty Slots	Hard	array
684	Redundant Connection	Medium	tree
685	Redundant Connection II	Hard	tree
686	Repeated String Match	Easy	string
687	Longest Univalue Path	Easy	tree
688	Knight Probability in Chessboard	Medium	dynamic programming
689	Maximum Sum of 3 Non-Overlapping Subarrays	Hard	dynamic programming
690	Employee Importance	Easy	depth first search
691	Stickers to Spell Word	Hard	dynamic programming
692	Top K Frequent Words	Medium	sort
693	Binary Number with Alternating Bits	Easy	bit manipulation
694	Number of Distinct Islands	Medium	depth first search
695	Max Area of Island	Easy	depth first search
696	Count Binary Substrings	Easy	string
697	Degree of an Array	Easy	array
698	Partition to K Equal Sum Subsets	Medium	backtracking
699	Falling Squares	Hard	tree
700	Search in a Binary Search Tree	Easy	tree
701	Insert into a Binary Search Tree	Medium	tree
702	Search in a Sorted Array of Unknown Size	Medium	binary search
703	Kth Largest Element in a Stream	Easy	binary heap
704	Binary Search	Easy	binary search
705	Design HashSet	Easy	design
706	Design HashMap	Easy	design
707	Design Linked List	Medium	design
708	Insert into a Sorted Circular Linked List	Medium	linked list
709	To Lower Case	Easy	string
710	Random Pick with Blacklist	Hard	binary search
711	Number of Distinct Islands II	Hard	depth first search
712	Minimum ASCII Delete Sum for Two Strings	Medium	dynamic programming
713	Subarray Product Less Than K	Medium	array
714	Best Time to Buy and Sell Stock with Transaction Fee	Medium	dynamic programming
715	Range Module	Hard	design
716	Max Stack	Easy	design
717	1-bit and 2-bit Characters	Easy	array
718	Maximum Length of Repeated Subarray	Medium	backtracking
719	Find K-th Smallest Pair Distance	Hard	binary search
720	Longest Word in Dictionary	Easy	string
721	Accounts Merge	Medium	hash table
722	Remove Comments	Medium	string
723	Candy Crush	Medium	array
724	Find Pivot Index	Easy	array
725	Split Linked List in Parts	Medium	linked list
726	Number of Atoms	Hard	stack
727	Minimum Window Subsequence	Hard	dynamic programming
728	Self Dividing Numbers	Medium	math
729	My Calendar I	Medium	array
730	Count Different Palindromic Subsequences	Hard	dynamic programming
731	My Calendar II	Medium	array
732	My Calendar III	Hard	array
733	Max Area of Island	Easy	depth first search
734	Sentence Similarity	Easy	hash table
735	Asteroid Collision	Medium	stack
736	Parse Lisp Expression	Hard	stack
737	Sentence Similarity II	Medium	hash table
738	Monotone Increasing Digits	Medium	greedy
739	Daily Temperatures	Medium	stack
740	Delete and Earn	Medium	dynamic programming
741	Cherry Pickup	Hard	dynamic programming
742	Closest Leaf in a Binary Tree	Medium	breadth first search
743	Network Delay Time	Medium	breadth first search
744	Find Smallest Letter Greater Than Target	Easy	binary search
745	Prefix and Suffix Search	Hard	design
746	Min Cost Climbing Stairs	Easy	dynamic programming
747	Largest Number At Least Twice of Others	Easy	array
748	Shortest Completing Word	Easy	hash table
749	Contain Virus	Hard	depth first search
750	Number Of Corner Rectangles	Medium	dynamic programming
751	IP to CIDR	Medium	string
752	Open the Lock	Medium	breadth first search
753	Cracking the Safe	Hard	depth first search
754	Reach a Number	Medium	math
755	Pour Water	Medium	array
756	Pyramid Transition Matrix	Medium	depth first search
757	Set Intersection Size At Least Two	Hard	greedy
758	Bold Words in String	Easy	string
759	Employee Free Time	Hard	greedy
760	Find Anagram Mappings	Easy	hash table
761	Special Binary String	Hard	recursion
762	Prime Number of Set Bits in Binary Representation	Easy	bit manipulation
763	Partition Labels	Medium	greedy
764	Largest Plus Sign	Medium	dynamic programming
765	Couples Holding Hands	Hard	graph
766	Toeplitz Matrix	Easy	array
767	Reorganize String	Medium	greedy
768	Max Chunks To Make Sorted II	Hard	array
769	Max Chunks To Make Sorted	Medium	array
770	Basic Calculator IV	Hard	stack
771	Jewels and Stones	Easy	hash table
772	Basic Calculator III	Hard	stack
773	Sliding Puzzle	Hard	breadth first search
774	Minimize Max Distance to Gas Station	Hard	binary search
775	Global and Local Inversions	Medium	math
776	Split BST	Medium	binary search tree
777	Swap Adjacent in LR String	Medium	two pointers
778	Swim in Rising Water	Hard	array
779	K-th Symbol in Grammar	Medium	math
780	Reaching Points	Hard	math
781	Rabbits in Forest	Medium	math
782	Transform to Chessboard	Hard	math
783	Minimum Distance Between BST Nodes	Easy	binary search tree
784	Letter Case Permutation	Easy	backtracking
785	Is Graph Bipartite?	Medium	depth first search
786	K-th Smallest Prime Fraction	Hard	binary search
787	Cheapest Flights Within K Stops	Medium	breadth first search
788	Rotated Digits	Easy	dynamic programming
789	Escape The Ghosts	Medium	math
790	Domino and Tromino Tiling	Medium	dynamic programming
791	Custom Sort String	Medium	string
792	Number of Matching Subsequences	Medium	array
793	Preimage Size of Factorial Zeroes Function	Hard	binary search
794	Valid Tic-Tac-Toe State	Medium	array
795	Number of Subarrays with Bounded Maximum	Medium	array
796	Rotate String	Easy	string
797	All Paths From Source to Target	Medium	depth first search
798	Smallest Rotation with Highest Score	Hard	greedy
799	Champagne Tower	Medium	dynamic programming
800	Similar RGB Color	Easy	math
801	Minimum Swaps To Make Sequences Increasing	Medium	dynamic programming
802	Find Eventual Safe States	Medium	depth first search
803	Bricks Falling When Hit	Hard	array
804	Unique Morse Code Words	Easy	string
805	Split Array With Same Average	Hard	dynamic programming
806	Number of Lines To Write String	Easy	string
807	Max Increase to Keep City Skyline	Medium	array
808	Soup Servings	Medium	dynamic programming
809	Expressive Words	Medium	string
810	Chalkboard XOR Game	Hard	math
811	Subdomain Visit Count	Easy	hash table
812	Largest Triangle Area	Easy	math
813	Largest Sum of Averages	Medium	dynamic programming
814	Binary Tree Pruning	Medium	tree
815	Bus Routes	Medium	breadth first search
816	Ambiguous Coordinates	Medium	string
817	Linked List Components	Medium	linked list
818	Race Car	Hard	dynamic programming
819	Most Common Word	Easy	string
820	Short Encoding of Words	Medium	string
821	Shortest Distance to a Character	Easy	array
822	Card Flipping Game	Medium	hash table
823	Binary Trees With Factors	Medium	dynamic programming
824	Goat Latin	Easy	string
825	Friends Of Appropriate Ages	Medium	hash table
826	Most Profit Assigning Work	Medium	two pointers
827	Making A Large Island	Hard	depth first search
828	Count Unique Characters of All Substrings of a Given String	Hard	two pointers
829	Consecutive Numbers Sum	Hard	math
830	Positions of Large Groups	Easy	array
831	Masking Personal Information	Medium	string
832	Flipping an Image	Easy	array
833	Find And Replace in String	Medium	string
834	Sum of Distances in Tree	Hard	depth first search
835	Image Overlap	Medium	array
836	Rectangle Overlap	Easy	math
837	New 21 Game	Medium	dynamic programming
838	Push Dominoes	Medium	dynamic programming
839	Similar String Groups	Hard	string
840	Magic Squares In Grid	Easy	array
841	Keys and Rooms	Medium	depth first search
842	Split Array into Fibonacci Sequence	Medium	array
843	Guess the Word	Hard	greedy
844	Backspace String Compare	Easy	two pointers
845	Longest Mountain in Array	Medium	array
846	Hand of Straights	Medium	binary heap
847	Shortest Path Visiting All Nodes	Hard	dynamic programming
848	Shifting Letters	Medium	string
849	Maximize Distance to Closest Person	Easy	array
850	Rectangle Area II	Hard	tree
851	Loud and Rich	Medium	depth first search
852	Peak Index in a Mountain Array	Easy	binary search
853	Car Fleet	Medium	stack
854	K-Similar Strings	Hard	breadth first search
855	Exam Room	Medium	binary heap
856	Score of Parentheses	Medium	stack
857	Minimum Cost to Hire K Workers	Hard	binary heap
858	Mirror Reflection	Medium	math
859	Buddy Strings	Easy	string
860	Lemonade Change	Easy	array
861	Score After Flipping Matrix	Medium	greedy
862	Shortest Subarray with Sum at Least K	Hard	two pointers
863	All Nodes Distance K in Binary Tree	Medium	tree
864	Shortest Path to Get All Keys	Hard	breadth first search
865	Smallest Subtree with all the Deepest Nodes	Medium	tree
866	Prime Palindrome	Medium	math
867	Transpose Matrix	Easy	array
868	Binary Gap	Easy	bit manipulation
869	Reordered Power of 2	Medium	hash table
870	Advantage Shuffle	Medium	greedy
871	Minimum Number of Refueling Stops	Hard	binary heap
872	Leaf-Similar Trees	Easy	stack
873	Length of Longest Fibonacci Subsequence	Medium	hash table
874	Walking Robot Simulation	Easy	simulation
875	Koko Eating Bananas	Medium	binary search
876	Middle of the Linked List	Easy	two pointers
877	Stone Game	Medium	dynamic programming
878	Nth Magical Number	Hard	binary search
879	Profitable Schemes	Hard	dynamic programming
880	Decoded String at Index	Medium	string
881	Boats to Save People	Medium	greedy
882	Reachable Nodes In Subdivided Graph	Medium	breadth first search
883	Projection Area of 3D Shapes	Easy	math
884	Uncommon Words from Two Sentences	Easy	string
885	Spiral Matrix III	Medium	array
886	Possible Bipartition	Medium	breadth first search
887	Super Egg Drop	Hard	math
888	Fair Candy Swap	Easy	array
889	Construct Binary Tree from Preorder and Postorder Traversal	Medium	tree
890	Find and Replace Pattern	Medium	string
891	Sum of Subsequence Widths	Hard	math
892	Surface Area of 3D Shapes	Easy	geometry
893	Groups of Special-Equivalent Strings	Easy	string
894	All Possible Full Binary Trees	Medium	binary search
895	Maximum Frequency Stack	Hard	stack
896	Monotonic Array	Easy	array
897	Increasing Order Search Tree	Easy	tree
898	Bitwise ORs of Subarrays	Medium	bit manipulation
899	Orderly Queue	Hard	math
900	RLE Iterator	Medium	design
901	Online Stock Span	Medium	stack
902	Numbers At Most N Given Digit Set	Hard	math
903	Valid Permutations for DI Sequence	Hard	dynamic programming
904	Fruit Into Baskets	Medium	two pointers
905	Sort Array By Parity	Easy	array
906	Super Palindromes	Hard	math
907	Sum of Subarray Minimums	Medium	math
908	Smallest Range I	Easy	math
909	Snakes and Ladders	Medium	array
910	Smallest Range II	Medium	math
911	Online Election	Medium	binary search
912	Sort an Array	Medium	sort
913	Cat and Mouse	Hard	breadth first search
914	X of a Kind in a Deck of Cards	Easy	math
915	Partition Array into Disjoint Intervals	Medium	array
916	Word Subsets	Medium	string
917	Reverse Only Letters	Easy	string
918	Maximum Sum Circular Subarray	Medium	array
919	Complete Binary Tree Inserter	Medium	tree
920	Number of Music Playlists	Hard	dynamic programming
921	Minimum Add to Make Parentheses Valid	Medium	stack
922	Sort Array By Parity II	Easy	array
923	3Sum With Multiplicity	Medium	array
924	Minimize Malware Spread	Hard	graph
925	Long Pressed Name	Easy	string
926	Flip String to Monotone Increasing	Medium	dynamic programming
927	Three Equal Parts	Hard	array
928	Minimize Malware Spread II	Hard	graph
929	Unique Email Addresses	Easy	string
930	Binary Subarrays With Sum	Medium	two pointers
931	Minimum Falling Path Sum	Medium	dynamic programming
932	Beautiful Array	Medium	array
933	Number of Recent Calls	Easy	queue
934	Shortest Bridge	Medium	breadth first search
935	Knight Dialer	Medium	dynamic programming
936	Stamping The Sequence	Hard	greedy
937	Reorder Log Files	Easy	sort
938	Range Sum of BST	Medium	tree
939	Minimum Area Rectangle	Medium	string
940	Distinct Subsequences II	Hard	dynamic programming
941	Valid Mountain Array	Easy	array
942	DI String Match	Easy	string
943	Find the Shortest Superstring	Hard	dynamic programming
944	Delete Columns to Make Sorted	Medium	string
945	Minimum Increment to Make Array Unique	Medium	array
946	Validate Stack Sequences	Medium	stack
947	Most Stones Removed with Same Row or Column	Medium	array
948	Bag of Tokens	Medium	greedy
949	Largest Time for Given Digits	Easy	array
950	Reveal Cards In Increasing Order	Medium	array
951	Flip Equivalent Binary Trees	Medium	tree
952	Largest Component Size by Common Factor	Hard	array
953	Verifying an Alien Dictionary	Easy	string
954	Array of Doubled Pairs	Medium	array
955	Delete Columns to Make Sorted II	Medium	string
956	Tallest Billboard	Hard	dynamic programming
957	Prison Cells After N Days	Medium	hash table
958	Check Completeness of a Binary Tree	Medium	tree
959	Regions Cut By Slashes	Medium	graph
960	Delete Columns to Make Sorted III	Hard	dynamic programming
961	N-Repeated Element in Size 2N Array	Easy	array
962	Maximum Width Ramp	Medium	greedy
963	Minimum Area Rectangle II	Medium	math
964	Least Operators to Express Number	Hard	dynamic programming
965	Univalued Binary Tree	Easy	tree
966	Vowel Spellchecker	Medium	hash table
967	Numbers With Same Consecutive Differences	Medium	breadth first search
968	Binary Tree Cameras	Hard	greedy
969	Pancake Sorting	Medium	sort
970	Powerful Integers	Easy	math
971	Flip Binary Tree To Match Preorder Traversal	Medium	tree
972	Equal Rational Numbers	Hard	math
973	K Closest Points to Origin	Easy	sort
974	Subarray Sums Divisible by K	Medium	hash table
975	Odd Even Jump	Hard	dynamic programming
976	Largest Perimeter Triangle	Easy	sort
977	Squares of a Sorted Array	Easy	two pointers
978	Longest Turbulent Subarray	Medium	array
979	Distribute Coins in Binary Tree	Medium	tree
980	Unique Paths III	Hard	dynamic programming
981	Time Based Key-Value Store	Medium	binary search
982	Triples with Bitwise AND Equal To Zero	Hard	hash table
983	Minimum Cost For Tickets	Medium	dynamic programming
984	String Without AAA or BBB	Easy	greedy
985	Sum of Even Numbers After Queries	Easy	array
986	Interval List Intersections	Medium	linked list
987	Vertical Order Traversal of a Binary Tree	Medium	tree
988	Smallest String Starting From Leaf	Medium	tree
989	Add to Array-Form of Integer	Easy	array
990	Satisfiability of Equality Equations	Medium	graph
991	Broken Calculator	Medium	greedy
992	Subarrays with K Different Integers	Hard	two pointers
993	Cousins in Binary Tree	Easy	tree
994	Rotting Oranges	Easy	breadth first search
995	Minimum Number of K Consecutive Bit Flips	Hard	greedy
996	Number of Squareful Arrays	Hard	backtracking
997	Find the Town Judge	Easy	array
998	Maximum Binary Tree II	Medium	tree
999	Available Captures for Rook	Easy	array
1000	Minimum Cost to Merge Stones	Hard	dynamic programming
1001	Grid Illumination	Hard	hash table
1002	Find Common Characters	Easy	array
1003	Check If Word Is Valid After Substitutions	Medium	stack
1004	Max Consecutive Ones III	Medium	two pointers
1005	Maximize Sum Of Array After K Negations	Easy	greedy
1006	Clumsy Factorial	Medium	math
1007	Minimum Domino Rotations For Equal Row	Medium	array
1008	Construct Binary Search Tree from Preorder Traversal	Medium	tree
1009	Complement of Base 10 Integer	Easy	math
1010	Pairs of Songs With Total Durations Divisible by 60	Easy	array
1011	Capacity To Ship Packages Within D Days	Medium	binary search
1012	Numbers With Repeated Digits	Hard	math
1013	Partition Array Into Three Parts With Equal Sum	Easy	array
1014	Best Sightseeing Pair	Medium	array
1015	Smallest Integer Divisible by K	Medium	math
1016	Binary String With Substrings Representing 1 To N	Medium	string
1017	Convert to Base -2	Medium	math
1018	Binary Prefix Divisible By 5	Easy	array
1019	Next Greater Node In Linked List	Medium	stack
1020	Number of Enclaves	Medium	depth first search
1021	Remove Outermost Parentheses	Easy	stack
1022	Sum of Root To Leaf Binary Numbers	Easy	tree
1023	Camelcase Matching	Medium	string
1024	Video Stitching	Medium	greedy
1025	Divisor Game	Easy	math
1026	Maximum Difference Between Node and Ancestor	Medium	tree
1027	Longest Arithmetic Sequence	Medium	dynamic programming
1028	Recover a Tree From Preorder Traversal	Hard	tree
1029	Two City Scheduling	Easy	greedy
1030	Matrix Cells in Distance Order	Easy	array
1031	Maximum Sum of Two Non-Overlapping Subarrays	Medium	array
1032	Stream of Characters	Hard	tree
1033	Moving Stones Until Consecutive	Easy	two pointers
1034	Coloring A Border	Medium	breadth first search
1035	Uncrossed Lines	Medium	dynamic programming
1036	Escape a Large Maze	Hard	breadth first search
1037	Valid Boomerang	Easy	math
1038	Binary Search Tree to Greater Sum Tree	Medium	tree
1039	Minimum Score Triangulation of Polygon	Medium	dynamic programming
1040	Moving Stones Until Consecutive II	Medium	two pointers
1041	Robot Bounded In Circle	Medium	math
1042	Flower Planting With No Adjacent	Easy	graph
1043	Partition Array for Maximum Sum	Medium	dynamic programming
1044	Longest Duplicate Substring	Hard	binary search
1045	Customers Who Bought All Products	Medium	sql
1046	Last Stone Weight	Easy	binary heap
1047	Remove All Adjacent Duplicates In String	Easy	stack
1048	Longest String Chain	Medium	dynamic programming
1049	Last Stone Weight II	Medium	dynamic programming
1050	Actors and Directors Who Cooperated At Least Three Times	Easy	sql
1051	Height Checker	Easy	array
1052	Grumpy Bookstore Owner	Medium	array
1053	Previous Permutation With One Swap	Medium	greedy
1054	Distant Barcodes	Medium	sort
1055	Shortest Way to Form String	Medium	greedy
1056	Confusing Number	Easy	string
1057	Campus Bikes	Medium	binary heap
1058	Minimize Rounding Error to Meet Target	Medium	greedy
1059	All Paths from Source Lead to Destination	Medium	depth first search
1060	Missing Element in Sorted Array	Medium	binary search
1061	Lexicographically Smallest Equivalent String	Medium	string
1062	Longest Repeating Substring	Medium	binary search
1063	Number of Valid Subarrays	Hard	stack
1064	Fixed Point	Easy	binary search
1065	Index Pairs of a String	Easy	tree
1066	Campus Bikes II	Medium	dynamic programming
1067	Digit Count in Range	Hard	math
1068	Product Sales Analysis I	Easy	sql
1069	Product Sales Analysis II	Easy	sql
1070	Product Sales Analysis III	Medium	sql
1071	Greatest Common Divisor of Strings	Easy	string
1072	Flip Columns For Maximum Number of Equal Rows	Medium	array
1073	Adding Two Negabinary Numbers	Medium	math
1074	Number of Submatrices That Sum to Target	Hard	array
1075	Project Employees I	Easy	sql
1076	Project Employees II	Easy	sql
1077	Project Employees III	Medium	sql
1078	Occurrences After Bigram	Easy	string
1079	Letter Tile Possibilities	Medium	math
1080	Insufficient Nodes in Root to Leaf Paths	Medium	tree
1081	Smallest Subsequence of Distinct Characters	Medium	greedy
1082	Sales Analysis I	Easy	sql
1083	Sales Analysis II	Easy	sql
1084	Sales Analysis III	Easy	sql
1085	Sum of Digits in the Minimum Number	Easy	array
1086	High Five	Easy	sort
1087	Brace Expansion	Medium	backtracking
1088	Confusing Number II	Hard	math
1089	Duplicate Zeros	Easy	array
1090	Largest Values From Labels	Medium	greedy
1091	Shortest Path in Binary Matrix	Medium	breadth first search
1092	Shortest Common Supersequence	Hard	dynamic programming
1093	Statistics from a Large Sample	Medium	array
1094	Car Pooling	Medium	sort
1095	Find in Mountain Array	Hard	binary search
1096	Brace Expansion II	Hard	backtracking
1097	Game Play Analysis V	Hard	sql
1098	Unpopular Books	Medium	sql
1099	Two Sum Less Than K	Easy	array
1100	Find K-Length Substrings With No Repeated Characters	Medium	string
1101	The Earliest Moment When Everyone Become Friends	Medium	graph
1102	Path With Maximum Minimum Value	Medium	breadth first search
1103	Distribute Candies to People	Easy	math
1104	Path In Zigzag Labelled Binary Tree	Easy	tree
1105	Filling Bookcase Shelves	Medium	dynamic programming
1106	Parsing A Boolean Expression	Hard	recursion
1107	New Users Daily Count	Medium	sql
1108	Defanging an IP Address	Easy	string
1109	Corporate Flight Bookings	Medium	array
1110	Delete Nodes And Return Forest	Medium	binary search
1111	Maximum Nesting Depth of Two Valid Parentheses Strings	Medium	greedy
1112	Highest Grade For Each Student	Medium	sql
1113	Reported Posts	Easy	sql
1114	Print in Order	Easy	concurrency
1115	Print FooBar Alternately	Medium	concurrency
1116	Print Zero Even Odd	Medium	concurrency
1117	Building H2O	Hard	concurrency
1118	Number of Days in a Month	Easy	math
1119	Remove Vowels from a String	Easy	string
1120	Maximum Average Subtree	Easy	tree
1121	Divide Array Into Increasing Sequences	Hard	math
1122	Relative Sort Array	Easy	sort
1123	Lowest Common Ancestor of Deepest Leaves	Medium	tree
1124	Longest Well-Performing Interval	Medium	hash table
1125	Smallest Sufficient Team	Hard	dynamic programming
1126	Active Businesses	Medium	sql
1127	User Purchase Platform	Hard	sql
1128	Number of Equivalent Domino Pairs	Easy	math
1129	Shortest Path with Alternating Colors	Medium	breadth first search
1130	Minimum Cost Tree From Leaf Values	Medium	stack
1131	Maximum of Absolute Value Expression	Medium	math
1132	Reported Posts II	Medium	sql
1133	Largest Unique Number	Easy	hash table
1134	Armstrong Number	Easy	math
1135	Connecting Cities With Minimum Cost	Medium	graph
1136	Parallel Courses	Medium	breadth first search
1137	N-th Tribonacci Number	Easy	dynamic programming
1138	Alphabet Board Path	Medium	simulation
1139	Largest 1-Bordered Square	Medium	dynamic programming
1140	Stone Game II	Medium	dynamic programming
1141	User Activity for the Past 30 Days I	Easy	sql
1142	User Activity for the Past 30 Days II	Easy	sql
1143	Longest Common Subsequence	Medium	dynamic programming
1144	Decrease Elements To Make Array Zigzag	Medium	array
1145	Binary Tree Coloring Game	Medium	tree
1146	Snapshot Array	Medium	design
1147	Longest Chunked Palindrome Decomposition	Hard	string
1148	Article Views I	Easy	sql
1149	Article Views II	Medium	sql
1150	Check If a Number Is Majority Element in a Sorted Array	Easy	math
1151	Minimum Swaps to Group All 1's Together	Medium	two pointers
1152	Analyze User Website Visit Pattern	Medium	hash table
1153	String Transforms Into Another String	Hard	hash table
1154	Day of the Year	Easy	math
1155	Number of Dice Rolls With Target Sum	Medium	dynamic programming
1156	Swap For Longest Repeated Character Substring	Medium	two pointers
1157	Online Majority Element In Subarray	Hard	math
1158	Market Analysis I	Medium	sql
1159	Market Analysis II	Hard	sql
1160	Find Words That Can Be Formed by Characters	Easy	hash table
1161	Maximum Level Sum of a Binary Tree	Medium	breadth first search
1162	As Far from Land as Possible	Medium	breadth first search
1163	Last Substring in Lexicographical Order	Hard	greedy
1164	Product Price at a Given Date	Medium	sql
1165	Single-Row Keyboard	Easy	hash table
1166	Design File System	Medium	design
1167	Minimum Cost to Connect Sticks	Medium	greedy
1168	Optimize Water Distribution in a Village	Hard	graph
1169	Invalid Transactions	Medium	two pointers
1170	Compare Strings by Frequency of the Smallest Character	Easy	binary search
1171	Remove Zero Sum Consecutive Nodes from Linked List	Medium	linked list
1172	Dinner Plate Stacks	Hard	design
1173	Immediate Food Delivery I	Easy	sql
1174	Immediate Food Delivery II	Medium	sql
1175	Prime Arrangements	Easy	math
1176	Diet Plan Performance	Easy	two pointers
1177	Can Make Palindrome from Substring	Medium	string
1178	Number of Valid Words for Each Puzzle	Hard	string
1179	Reformat Department Table	Easy	sql
1180	Count Substrings with Only One Distinct Letter	Easy	linked list
1181	Before and After Puzzle	Medium	linked list
1182	Shortest Distance to Target Color	Medium	dynamic programming
1183	Maximum Number of Ones	Hard	greedy
1184	Distance Between Bus Stops	Easy	array
1185	Day of the Week	Easy	math
1186	Maximum Subarray Sum with One Deletion	Medium	dynamic programming
1187	Make Array Strictly Increasing	Hard	dynamic programming
1188	Design Bounded Blocking Queue	Medium	concurrency
1189	Maximum Number of Balloons	Easy	string
1190	Reverse Substrings Between Each Pair of Parentheses	Medium	stack
1191	K-Concatenation Maximum Sum	Medium	dynamic programming
1192	Critical Connections in a Network	Medium	depth first search
1193	Monthly Transactions I	Medium	sql
1194	Tournament Winners	Hard	sql
1195	Fizz Buzz Multithreaded	Medium	concurrency
1196	How Many Apples Can You Put into the Basket	Easy	greedy
1197	Minimum Knight Moves	Medium	math
1198	Find Smallest Common Element in All Rows	Medium	hash table
1199	Minimum Time to Build Blocks	Hard	greedy
1200	Minimum Absolute Difference	Easy	array
1201	Ugly Number III	Medium	binary search
1202	Smallest String With Swaps	Medium	depth first search
1203	Sort Items by Groups Respecting Dependencies	Hard	breadth first search
1204	Last Person to Fit in the Elevator	Medium	sql
1205	Monthly Transactions II	Medium	sql
1206	Design Skiplist	Hard	design
1207	Unique Number of Occurrences	Easy	hash table
1208	Get Equal Substrings Within Budget	Medium	two pointers
1209	Remove All Adjacent Duplicates in String II	Medium	stack
1210	Minimum Moves to Reach Target with Rotations	Hard	breadth first search
1211	Queries Quality and Percentage	Easy	sql
1212	Team Scores in Football Tournament	Medium	sql
1213	Intersection of Three Sorted Arrays	Easy	two pointers
1214	Two Sum BSTs	Medium	two pointers
1215	Stepping Numbers	Medium	breadth first search
1216	Valid Palindrome III	Hard	dynamic programming
1217	Play with Chips	Medium	math
1218	Longest Arithmetic Subsequence of Given Difference	Medium	dynamic programming
1219	Path with Maximum Gold	Medium	backtracking
1220	Count Vowels Permutation	Hard	dynamic programming
1221	Split a String in Balanced Strings	Easy	greedy
1222	Queens That Can Attack the King	Medium	array
1223	Dice Roll Simulation	Medium	dynamic programming
1224	Maximum Equal Frequency	Hard	hash table
1225	Report Contiguous Dates	Hard	sql
1226	The Dining Philosophers	Medium	concurrency
1227	Airplane Seat Assignment Probability	Medium	math
1228	Missing Number In Arithmetic Progression	Easy	binary search
1229	Meeting Scheduler	Medium	sort
1230	Toss Strange Coins	Medium	dynamic programming
1231	Divide Chocolate	Hard	binary search
1232	Check If It Is a Straight Line	Easy	math
1233	Remove Sub-Folders from the Filesystem	Medium	string
1234	Replace the Substring for Balanced String	Medium	two pointers
1235	Maximum Profit in Job Scheduling	Hard	dynamic programming
1236	Web Crawler	Medium	design
1237	Find Positive Integer Solution for a Given Equation	Easy	math
1238	Circular Permutation in Binary Representation	Medium	math
1239	Maximum Length of a Concatenated String with Unique Characters	Medium	dynamic programming
1240	Tiling a Rectangle with the Fewest Squares	Hard	backtracking
1241	Number of Comments per Post	Easy	sql
1242	Web Crawler Multithreaded	Medium	concurrency
1243	Array Transformation	Easy	simulation
1244	Design A Leaderboard	Medium	design
1245	Tree Diameter	Medium	breadth first search
1246	Palindrome Removal	Hard	dynamic programming
1247	Minimum Swaps to Make Strings Equal	Easy	greedy
1248	Count Number of Nice Subarrays	Medium	two pointers
1249	Minimum Remove to Make Valid Parentheses	Medium	greedy
1250	Check If It Is a Good Array	Hard	math
1251	Average Selling Price	Easy	sql
1252	Cells with Odd Values in a Matrix	Easy	array
1253	Reconstruct a 2-Row Binary Matrix	Medium	greedy
1254	Number of Closed Islands	Medium	depth first search
1255	Maximum Score Words Formed by Letters	Hard	backtracking
1256	Encode Number	Medium	math
1257	Smallest Common Region	Medium	tree
1258	Synonymous Sentences	Medium	backtracking
1259	Handshakes That Don't Cross	Hard	math
1260	Shift 2D Grid	Easy	array
1261	Find Elements in a Contaminated Binary Tree	Medium	tree
1262	Greatest Sum Divisible by Three	Medium	dynamic programming
1263	Minimum Moves to Move a Box to Their Target Location	Hard	breadth first search
1264	Page Recommendations	Medium	sql
1265	Print Immutable Linked List in Reverse	Medium	linked list
1266	Minimum Time Visiting All Points	Easy	math
1267	Count Servers that Communicate	Medium	array
1268	Search Suggestions System	Medium	design
1269	Number of Ways to Stay in the Same Place After Some Steps	Hard	dynamic programming
1270	All People Report to the Given Manager	Medium	sql
1271	Hexspeak	Easy	string
1272	Remove Interval	Medium	greedy
1273	Delete Tree Nodes	Medium	depth first search
1274	Number of Ships in a Rectangle	Hard	binary search
1275	Find Winner on a Tic Tac Toe Game	Easy	array
1276	Number of Burgers with No Waste of Ingredients	Medium	math
1277	Count Square Submatrices with All Ones	Medium	dynamic programming
1278	Palindrome Partitioning III	Hard	dynamic programming
1279	Traffic Light Controlled Intersection	Easy	concurrency
1280	Students and Examinations	Easy	sql
1281	Subtract the Product and Sum of Digits of an Integer	Easy	math
1282	Group the People Given the Group Size They Belong To	Medium	greedy
1283	Find the Smallest Divisor Given a Threshold	Medium	binary search
1284	Minimum Number of Flips to Convert Binary Matrix to Zero Matrix	Hard	breadth first search
1285	Find the Start and End Number of Continuous Ranges	Medium	sql
1286	Iterator for Combination	Medium	design
1287	Element Appearing More Than 25% In Sorted Array	Easy	binary search
1288	Remove Covered Intervals	Medium	greedy
1289	Minimum Falling Path Sum II	Hard	dynamic programming
1290	Convert Binary Number in a Linked List to Integer	Easy	linked list
1291	Sequential Digits	Medium	breadth first search
1292	Maximum Side Length of a Square with Sum Less than or Equal to Threshold	Medium	dynamic programming
1293	Shortest Path in a Grid with Obstacles Elimination	Hard	breadth first search
1294	Weather Type in Each Country	Easy	sql
1295	Find Numbers with Even Number of Digits	Easy	array
1296	Divide Array in Sets of K Consecutive Numbers	Medium	greedy
1297	Maximum Number of Occurrences of a Substring	Medium	two pointers
1298	Maximum Candies You Can Get from Boxes	Hard	breadth first search
1299	Replace Elements with Greatest Element on Right Side	Easy	array
1300	Sum of Mutated Array Closest to Target	Medium	math
1301	Number of Paths with Max Score	Hard	dynamic programming
1302	Deepest Leaves Sum	Medium	breadth first search
1303	Find the Team Size	Easy	sql
1304	Find N Unique Integers Sum up to Zero	Easy	array
1305	All Elements in Two Binary Search Trees	Medium	two pointers
1306	Jump Game III	Medium	breadth first search
1307	Verbal Arithmetic Puzzle	Hard	backtracking
1308	Running Total for Different Genders	Medium	sql
1309	Decrypt String from Alphabet to Integer Mapping	Easy	string
1310	XOR Queries of a Subarray	Medium	bit manipulation
1311	Get Watched Videos by Your Friends	Medium	breadth first search
1312	Minimum Insertion Steps to Make a String Palindrome	Hard	dynamic programming
1313	Decompress Run-Length Encoded List	Easy	array
1314	Matrix Block Sum	Medium	dynamic programming
1315	Sum of Nodes with Even-Valued Grandparent	Medium	depth first search
1316	Distinct Echo Substrings	Hard	two pointers
1317	Convert Integer to the Sum of Two No-Zero Integers	Easy	math
1318	Minimum Flips to Make a OR b Equal to c	Medium	bit manipulation
1319	Number of Operations to Make Network Connected	Medium	depth first search
1320	Minimum Distance to Type a Word Using Two Fingers	Hard	dynamic programming
1321	Restaurant Growth	Medium	sql
1322	Ads Performance	Easy	sql
1323	Maximum 69 Number	Easy	math
1324	Print Words Vertically	Medium	string
1325	Delete Leaves With a Given Value	Medium	tree
1326	Minimum Number of Taps to Open to Water a Garden	Hard	greedy
1327	List the Products Ordered in a Period	Easy	sql
1328	Break a Palindrome	Medium	string
1329	Sort the Matrix Diagonally	Medium	array
1330	Reverse Subarray To Maximize Array Value	Hard	math
1331	Rank Transform of an Array	Easy	array
1332	Remove Palindromic Subsequences	Easy	string
1333	Filter Restaurants by Vegan-Friendly, Price and Distance	Medium	array
1334	Find the City With the Smallest Number of Neighbors at a Threshold Distance	Medium	graph
1335	Minimum Difficulty of a Job Schedule	Hard	dynamic programming
1336	Number of Transactions per Visit	Medium	sql
1337	The K Weakest Rows in a Matrix	Easy	array
1338	Reduce Array Size to The Half	Medium	greedy
1339	Maximum Product of Splitted Binary Tree	Medium	tree
1340	Jump Game V	Hard	dynamic programming
1341	Movie Rating	Medium	sql
1342	Number of Steps to Reduce a Number to Zero	Easy	bit manipulation
1343	Number of Sub-arrays of Size K and Average Greater than or Equal to Threshold	Medium	array
1344	Angle Between Hands of a Clock	Medium	math
1345	Jump Game IV	Hard	breadth first search
1346	Check If N and Its Double Exist	Easy	array
1347	Minimum Number of Steps to Make Two Strings Anagram	Medium	string
1348	Tweet Counts Per Frequency	Medium	design
1349	Maximum Students Taking Exam	Hard	graph
1350	Students With Invalid Departments	Easy	sql
1351	Count Negative Numbers in a Sorted Matrix	Easy	array
1352	Product of the Last K Numbers	Medium	design
1353	Maximum Number of Events That Can Be Attended	Medium	greedy
1354	Construct Target Array With Multiple Sums	Hard	greedy
1355	Activity Participants	Medium	sql
1356	Sort Integers by The Number of 1 Bits	Easy	sort
1357	Apply Discount Every n Orders	Medium	design
1358	Number of Substrings Containing All Three Characters	Medium	two pointers
1359	Count All Valid Pickup and Delivery Options	Hard	math
1360	Number of Days Between Two Dates	Easy	math
1361	Validate Binary Tree Nodes	Medium	graph
1362	Closest Divisors	Medium	math
1363	Largest Multiple of Three	Hard	math
1364	Number of Trusted Contacts of a Customer	Medium	sql
1365	How Many Numbers Are Smaller Than the Current Number	Easy	sort
1366	Rank Teams by Votes	Medium	sort
1367	Linked List in Binary Tree	Medium	depth first search
1368	Minimum Cost to Make at Least One Valid Path in a Grid	Hard	breadth first search
1369	Get the Second Most Recent Activity	Hard	sql
1370	Increasing Decreasing String	Easy	string
1371	Find the Longest Substring Containing Vowels in Even Counts	Medium	string
1372	Longest ZigZag Path in a Binary Tree	Medium	depth first search
1373	Maximum Sum BST in Binary Tree	Hard	binary search tree
1374	Generate a String With Characters That Have Odd Count	Easy	string
1375	Bulb Switcher III	Medium	array
1376	Time Needed to Inform All Employees	Medium	depth first search
1377	Frog Position After T Seconds	Hard	depth first search
1378	Replace Employee ID With The Unique Identifier	Easy	sql
1379	Find a Corresponding Node of a Binary Tree in a Clone of That Tree	Medium	backtracking
1380	Lucky Numbers in a Matrix	Easy	array
1381	Design a Stack With Increment Operation	Medium	design
1382	Balance a Binary Search Tree	Medium	binary search tree
1383	Maximum Performance of a Team	Hard	greedy
1384	Total Sales Amount by Year	Hard	sql
1385	Find the Distance Value Between Two Arrays	Easy	binary search
1386	Cinema Seat Allocation	Medium	greedy
1387	Sort Integers by The Power Value	Medium	dynamic programming
1388	Pizza With 3n Slices	Hard	dynamic programming
1389	Create Target Array in the Given Order	Easy	array
1390	Four Divisors	Medium	math
1391	Check if There is a Valid Path in a Grid	Medium	depth first search
1392	Longest Happy Prefix	Hard	string
1393	Capital Gain/Loss	Medium	sql
1394	Find Lucky Integer in an Array	Easy	array
1395	Count Number of Teams	Medium	dynamic programming
1396	Design Underground System	Medium	design
1397	Find All Good Strings	Hard	dynamic programming
1398	Customers Who Bought Products A and B but Not C	Medium	sql
1399	Count Largest Group	Easy	array
1400	Construct K Palindrome Strings	Medium	greedy
1401	Circle and Rectangle Overlapping	Medium	math
1402	Reducing Dishes	Hard	greedy
1403	Minimum Subsequence in Non-Increasing Order	Easy	greedy
1404	Number of Steps to Reduce a Number in Binary Representation to One	Medium	array
1405	Longest Happy String	Medium	greedy
1406	Stone Game III	Hard	dynamic programming
1407	Top Travellers	Easy	sql
1408	String Matching in an Array	Easy	string
1409	Queries on a Permutation With Key	Medium	tree
1410	HTML Entity Parser	Medium	string
1411	Number of Ways to Paint N × 3 Grid	Hard	dynamic programming
1412	Find the Quiet Students in All Exams	Hard	sql
1413	Minimum Value to Get Positive Step by Step Sum	Easy	array
1414	Find the Minimum Number of Fibonacci Numbers Whose Sum Is K	Medium	greedy
1415	The k-th Lexicographical String of All Happy Strings of Length n	Medium	math
1416	Restore The Array	Hard	dynamic programming
1417	Reformat The String	Easy	string
1418	Display Table of Food Orders in a Restaurant	Medium	hash table
1419	Minimum Number of Frogs Croaking	Medium	greedy
1420	Build Array Where You Can Find The Maximum Exactly K Comparisons	Hard	dynamic programming
1421	NPV Queries	Medium	sql
1422	Maximum Score After Splitting a String	Easy	string
1423	Maximum Points You Can Obtain from Cards	Medium	two pointers
1424	Diagonal Traverse II	Medium	queue
1425	Constrained Subset Sum	Hard	two pointers
1426	Counting Elements	Easy	array
1427	Perform String Shifts	Easy	array
1428	Leftmost Column with at Least a One	Medium	array
1429	First Unique Number	Medium	design
1430	Check If a String Is a Valid Sequence from Root to Leaves Path in a Binary Tree	Medium	tree
1431	Kids With the Greatest Number of Candies	Easy	array
1432	Max Difference You Can Get From Changing an Integer	Medium	greedy
1433	Check If a String Can Break Another String	Medium	greedy
1434	Number of Ways to Wear Different Hats to Each Other	Hard	dynamic programming
1435	Create a Session Bar Chart	Easy	sql
1436	Destination City	Easy	string
1437	Check If All 1's Are at Least Length K Places Away	Medium	array
1438	Longest Continuous Subarray With Absolute Diff Less Than or Equal to Limit	Hard	queue
1439	Find the Kth Smallest Sum of a Matrix With Sorted Rows	Hard	binary heap
1440	Evaluate Boolean Expression	Medium	sql
1441	Build an Array With Stack Operations	Easy	stack
1442	Count Triplets That Can Form Two Arrays of Equal XOR	Medium	math
1443	Minimum Time to Collect All Apples in a Tree	Medium	tree
1444	Number of Ways of Cutting a Pizza	Hard	dynamic programming
1445	Apples & Oranges	Medium	sql
1446	Consecutive Characters	Easy	string
1447	Simplified Fractions	Medium	math
1448	Count Good Nodes in Binary Tree	Medium	tree
1449	Form Largest Integer With Digits That Add up to Target	Hard	dynamic programming
1450	Number of Students Doing Homework at a Given Time	Easy	array
1451	Rearrange Words in a Sentence	Medium	sort
1452	People Whose List of Favorite Companies Is Not a Subset of Another List	Medium	hash table
1453	Maximum Number of Darts Inside of a Circular Dartboard	Hard	geometry
1454	Active Users	Medium	sql
1455	Check If a Word Occurs As a Prefix of Any Word in a Sentence	Easy	string
1456	Maximum Number of Vowels in a Substring of Given Length	Medium	two pointers
1457	Pseudo-Palindromic Paths in a Binary Tree	Medium	tree
1458	Max Dot Product of Two Subsequences	Hard	dynamic programming
1459	Rectangles Area	Medium	sql
1460	Make Two Arrays Equal by Reversing Sub-arrays	Easy	array
1461	Check If a String Contains All Binary Codes of Size K	Medium	string
1462	Course Schedule IV	Medium	graph
1463	Cherry Pickup II	Hard	dynamic programming
1464	Maximum Product of Two Elements in an Array	Easy	array
1465	Maximum Area of a Piece of Cake After Horizontal and Vertical Cuts	Medium	array
1466	Reorder Routes to Make All Paths Lead to the City Zero	Medium	depth first search
1467	Probability of a Two Boxes Having The Same Number of Distinct Balls	Hard	dynamic programming
1468	Calculate Salaries	Easy	sql
1469	Find All The Lonely Nodes	Easy	tree
1470	Shuffle the Array	Easy	array
1471	The k Strongest Values in an Array	Medium	array
1472	Design Browser History	Medium	design
1473	Paint House III	Hard	dynamic programming
1474	Delete N Nodes After M Nodes of a Linked List	Easy	linked list
1475	Final Prices With a Special Discount in a Shop	Easy	array
1476	Subrectangle Queries	Medium	design
1477	Find Two Non-overlapping Sub-arrays Each With Target Sum	Medium	dynamic programming
1478	Allocate Mailboxes	Hard	dynamic programming
1479	Sales by Day of the Week	Hard	sql
1480	Running Sum of 1d Array	Easy	array
1481	Least Number of Unique Integers after K Removals	Medium	sort
1482	Minimum Number of Days to Make m Bouquets	Medium	binary search
1483	Kth Ancestor of a Tree Node	Hard	design
1484	Group Sold Products By The Date	Easy	sql
1485	Clone Binary Tree With Random Pointer	Medium	depth first search
1486	XOR Operation in an Array	Easy	math
1487	Making File Names Unique	Medium	hash table
1488	Avoid Flood in The City	Medium	greedy
1489	Find Critical and Pseudo-Critical Edges in Minimum Spanning Tree	Hard	graph
1490	Clone N-ary Tree	Medium	tree
1491	Average Salary Excluding the Minimum and Maximum Salary	Easy	array
1492	The kth Factor of n	Medium	math
1493	Longest Subarray of 1's After Deleting One Element	Medium	two pointers
1494	Parallel Courses II	Hard	dynamic programming
1495	Friendly Movies Streamed Last Month	Easy	sql
1496	Path Crossing	Easy	string
1497	Check If Array Pairs Are Divisible by k	Medium	math
1498	Number of Subsequences That Satisfy the Given Sum Condition	Medium	two pointers
1499	Max Value of Equation	Hard	queue
1500	Design a File Sharing System	Medium	design
1501	Countries You Can Safely Invest In	Medium	sql
1502	Can Make Arithmetic Progression From Sequence	Easy	array
1503	Last Moment Before All Ants Fall Out of a Plank	Medium	array
1504	Count Submatrices With All Ones	Medium	dynamic programming
1505	Minimum Possible Integer After at Most K Adjacent Swaps On Digits	Hard	tree
1506	Find Root of N-Ary Tree	Medium	tree
1507	Reformat Date	Easy	string
1508	Range Sum of Sorted Subarray Sums	Medium	two pointers
1509	Minimum Difference Between Largest and Smallest Value in Three Moves	Medium	sort
1510	Stone Game IV	Hard	dynamic programming
1511	Customer Order Frequency	Easy	sql
1512	Number of Good Pairs	Easy	math
1513	Number of Substrings With Only 1s	Medium	math
1514	Path with Maximum Probability	Medium	breadth first search
1515	Best Position for a Service Centre	Hard	geometry
1516	Move Sub-Tree of N-Ary Tree	Hard	tree
1517	Find Users With Valid E-Mails	Easy	sql
1518	Water Bottles	Easy	greedy
1519	Number of Nodes in the Sub-Tree With the Same Label	Medium	tree
1520	Maximum Number of Non-Overlapping Substrings	Medium	greedy
1521	Find a Value of a Mysterious Function Closest to Target	Hard	two pointers
1522	Diameter of N-Ary Tree	Medium	tree
1523	Count Odd Numbers in an Interval Range	Easy	sort
1524	Number of Sub-arrays With Odd Sum	Medium	dynamic programming
1525	Number of Good Ways to Split a String	Medium	math
1526	Minimum Number of Increments on Subarrays to Form a Target Array	Hard	greedy
1527	Patients With a Condition	Easy	sql
1528	Shuffle String	Easy	string
1529	Bulb Switcher IV	Medium	string
1530	Number of Good Leaf Nodes Pairs	Medium	tree
1531	String Compression II	Hard	dynamic programming
1532	The Most Recent Three Orders	Medium	sql
1533	Find the Index of the Large Integer	Medium	binary search
1534	Count Good Triplets	Easy	array
1535	Find the Winner of an Array Game	Medium	array
1536	Minimum Swaps to Arrange a Binary Grid	Medium	greedy
1537	Get the Maximum Score	Hard	math
1538	Guess the Majority in a Hidden Array	Medium	array
1539	Kth Missing Positive Number	Easy	binary search
1540	Can Convert String in K Moves	Medium	string
1541	Minimum Insertions to Balance a Parentheses String	Medium	stack
1542	Find Longest Awesome Substring	Hard	string
1543	Fix Product Name Format	Easy	sql
1544	Make The String Great	Easy	string
1545	Find Kth Bit in Nth Binary String	Medium	string
1546	Maximum Number of Non-Overlapping Subarrays With Sum Equals Target	Medium	greedy
1547	Minimum Cost to Cut a Stick	Hard	dynamic programming
1548	The Most Similar Path in a Graph	Hard	dynamic programming
1549	The Most Recent Orders for Each Product	Medium	sql
1550	Three Consecutive Odds	Easy	array
1551	Minimum Operations to Make Array Equal	Medium	math
1552	Magnetic Force Between Two Balls	Medium	binary search
1553	Minimum Number of Days to Eat N Oranges	Hard	dynamic programming
1554	Strings Differ by One Character	Medium	string
1555	Bank Account Summary	Medium	sql
1556	Thousand Separator	Easy	string
1557	Minimum Number of Vertices to Reach All Nodes	Medium	graph
1558	Minimum Numbers of Function Calls to Make Target Array	Medium	bit manipulation
1559	Detect Cycles in 2D Grid	Hard	array
1560	Most Visited Sector in a Circular Track	Easy	array
1561	Maximum Number of Coins You Can Get	Medium	sort
1562	Find Latest Group of Size M	Medium	array
1563	Stone Game V	Hard	dynamic programming
1564	Put Boxes Into the Warehouse I	Medium	greedy
1565	Unique Orders and Customers Per Month	Easy	sql
1566	Detect Pattern of Length M Repeated K or More Times	Easy	array
1567	Maximum Length of Subarray With Positive Product	Medium	greedy
1568	Minimum Number of Days to Disconnect Island	Medium	graph
1570	Dot Product of Two Sparse Vectors	Medium	design
1571	Warehouse Manager	Medium	sql
1572	Matrix Diagonal Sum	Easy	array
1573	Number of Ways to Split a String	Medium	string
1574	Shortest Subarray to be Removed to Make Array Sorted	Medium	array
1575	Count All Possible Routes	Hard	dynamic programming
1576	Replace All ?'s to Avoid Consecutive Repeating Characters	Easy	string
1577	Number of Ways Where Square of Number Is Equal to Product of Two Numbers	Medium	hash table
1578	Minimum Deletion Cost to Avoid Repeating Letters	Medium	greedy
1579	Remove Max Number of Edges to Keep Graph Fully Traversable	Hard	graph
1580	Put Boxes Into the Warehouse II	Medium	greedy
1581	Customer Who Visited but Did Not Make Any Transactions	Easy	sql
1582	Special Positions in a Binary Matrix	Easy	array
1583	Count Unhappy Friends	Medium	array
1584	Min Cost to Connect All Points	Medium	graph
1585	Check If String Is Transformable With Substring Sort Operations	Hard	greedy
1586	Binary Search Tree Iterator II	Medium	design
1587	Bank Account Summary II	Easy	sql
1588	Sum of All Odd Length Subarrays	Easy	sort
1589	Maximum Sum Obtained of Any Permutation	Medium	greedy
1590	Make Sum Divisible by P	Medium	hash table
1591	Strange Printer II	Hard	greedy
1592	Rearrange Spaces Between Words	Easy	string
1593	Split a String Into the Max Number of Unique Substrings	Medium	backtracking
1594	Maximum Non Negative Product in a Matrix	Medium	dynamic programming
1595	Minimum Cost to Connect Two Groups of Points	Hard	dynamic programming
1596	The Most Frequently Ordered Products for Each Customer	Medium	sql
1597	Build Binary Expression Tree From Infix Expression	Medium	stack
1598	Crawler Log Folder	Easy	string
1599	Maximum Profit of Operating a Centennial Wheel	Medium	greedy
1600	Throne Inheritance	Medium	design
1601	Maximum Number of Achievable Transfer Requests	Hard	graph
1602	Find Nearest Right Node in Binary Tree	Medium	breadth first search
1603	Design Parking System	Easy	design
1604	Alert Using Same Key-Card Three or More Times in a One Hour Period	Medium	two pointers
1605	Find Valid Matrix Given Row and Column Sums	Medium	greedy
1606	Find Servers That Handled Most Number of Requests	Hard	binary heap
1607	Sellers With No Sales	Medium	sql
1608	Special Array With X Elements Greater Than or Equal X	Easy	sort
1609	Even Odd Tree	Medium	breadth first search
1610	Maximum Number of Visible Points	Hard	geometry
1611	Minimum One Bit Operations to Make Integers Zero	Hard	math
1612	Check If Two Expression Trees are Equivalent	Medium	tree
1613	Find the Missing IDs	Medium	sql
1614	Maximum Nesting Depth of the Parentheses	Easy	string
1615	Maximal Network Rank	Medium	graph
1616	Split Two Strings to Make Palindrome	Medium	greedy
1617	Count Subtrees With Max Distance Between Cities	Hard	dynamic programming
1618	Maximum Font to Fit a Sentence in a Screen	Medium	binary search
1619	Mean of Array After Removing Some Elements	Easy	array
1620	Coordinate With Maximum Network Quality	Medium	sort
1621	Number of Sets of K Non-Overlapping Line Segments	Medium	sort
1622	Fancy Sequence	Hard	design
1623	All Valid Triplets That Can Represent a Country	Easy	sql
1624	Largest Substring Between Two Equal Characters	Easy	string
1625	Lexicographically Smallest String After Applying Operations	Medium	breadth first search
1626	Best Team With No Conflicts	Medium	dynamic programming
1627	Graph Connectivity With Threshold	Hard	graph
1628	Design an Expression Tree With Evaluate Function	Medium	design
1629	Slowest Key	Easy	array
1630	Arithmetic Subarrays	Medium	sort
1631	Path With Minimum Effort	Medium	graph
1632	Rank Transform of a Matrix	Hard	greedy
1633	Percentage of Users Attended a Contest	Easy	sql
1634	Add Two Polynomials Represented as Linked Lists	Medium	linked list
1635	Hopper Company Queries I	Hard	sql
1636	Sort Array by Increasing Frequency	Easy	sort
1637	Widest Vertical Area Between Two Points Containing No Points	Medium	sort
1638	Count Substrings That Differ by One Character	Medium	string
1639	Number of Ways to Form a Target String Given a Dictionary	Hard	dynamic programming
1640	Check Array Formation Through Concatenation	Easy	hash table
1641	Count Sorted Vowel Strings	Medium	math
1642	Furthest Building You Can Reach	Medium	binary heap
1643	Kth Smallest Instructions	Hard	math
1644	Lowest Common Ancestor of a Binary Tree II	Medium	depth first search
1645	Hopper Company Queries II	Hard	sql
1646	Get Maximum in Generated Array	Easy	array
1647	Minimum Deletions to Make Character Frequencies Unique	Medium	greedy
1648	Sell Diminishing-Valued Colored Balls	Medium	binary search
1649	Create Sorted Array through Instructions	Hard	tree
1650	Lowest Common Ancestor of a Binary Tree III	Medium	linked list
1651	Hopper Company Queries III	Hard	sql
1652	Defuse the Bomb	Easy	array
1653	Minimum Deletions to Make String Balanced	Medium	greedy
1654	Minimum Jumps to Reach Home	Medium	breadth first search
1655	Distribute Repeating Integers	Hard	dynamic programming
1656	Design an Ordered Stream	Easy	design
1657	Determine if Two Strings Are Close	Medium	hash table
1658	Minimum Operations to Reduce X to Zero	Medium	two pointers
1659	Maximize Grid Happiness	Hard	backtracking
1660	Correct a Binary Tree	Medium	breadth first search
1661	Average Time of Process per Machine	Easy	sql
1662	Check If Two String Arrays are Equivalent	Easy	string
1663	Smallest String With A Given Numeric Value	Medium	greedy
1664	Ways to Make a Fair Array	Medium	dynamic programming
1665	Minimum Initial Energy to Finish Tasks	Hard	greedy
1666	Change the Root of a Binary Tree	Medium	tree
1667	Fix Names in a Table	Easy	sql
1668	Maximum Repeating Substring	Easy	string
1669	Merge In Between Linked Lists	Medium	linked list
1670	Design Front Middle Back Queue	Medium	design
1671	Minimum Number of Removals to Make Mountain Array	Medium	binary search
1672	Richest Customer Wealth	Easy	array
1673	Find the Most Competitive Subsequence	Medium	greedy
1674	Minimum Moves to Make Array Complementary	Medium	greedy
1675	Minimize Deviation in Array	Hard	binary heap
1676	Lowest Common Ancestor of a Binary Tree IV	Medium	depth first search
1677	Product's Worth Over Invoices	Easy	sql
1678	Goal Parser Interpretation	Easy	string
1679	Max Number of K-Sum Pairs	Medium	hash table
1680	Concatenation of Consecutive Binary Numbers	Medium	sort
1681	Minimum Incompatibility	Hard	dynamic programming
1682	Longest Palindromic Subsequence II	Medium	dynamic programming
1683	Invalid Tweets	Easy	sql
1684	Count the Number of Consistent Strings	Easy	string
1685	Sum of Absolute Differences in a Sorted Array	Medium	sort
1686	Stone Game VI	Medium	greedy
1687	Delivering Boxes from Storage to Ports	Hard	two pointers
1688	Count of Matches in Tournament	Easy	sort
1689	Partitioning Into Minimum Number Of Deci-Binary Numbers	Medium	greedy
1690	Stone Game VII	Medium	dynamic programming
1691	Maximum Height by Stacking Cuboids	Hard	dynamic programming
1692	Count Ways to Distribute Candies	Hard	dynamic programming
1693	Daily Leads and Partners	Easy	sql
1694	Reformat Phone Number	Easy	string
1695	Maximum Erasure Value	Medium	two pointers
1696	Jump Game VI	Medium	queue
1697	Checking Existence of Edge Length Limited Paths	Hard	graph
1698	Number of Distinct Substrings in a String	Medium	string
1699	Number of Calls Between Two Persons	Medium	sql
1700	Number of Students Unable to Eat Lunch	Easy	array
1701	Average Waiting Time	Medium	array
1702	Maximum Binary String After Change	Medium	greedy
1703	Minimum Adjacent Swaps for K Consecutive Ones	Hard	sort
1704	Determine if String Halves Are Alike	Easy	string
1705	Maximum Number of Eaten Apples	Medium	greedy
1706	Where Will the Ball Fall	Medium	array
1707	Maximum XOR With an Element From Array	Hard	bit manipulation
1708	Largest Subarray Length K	Easy	greedy
1709	Biggest Window Between Visits	Medium	sql
1710	Maximum Units on a Truck	Easy	greedy
1711	Count Good Meals	Medium	hash table
1712	Ways to Split Array Into Three Subarrays	Medium	two pointers
1713	Minimum Operations to Make a Subsequence	Hard	binary search
1714	Sum Of Special Evenly-Spaced Elements In Array	Hard	array
1715	Count Apples and Oranges	Medium	sql
1716	Calculate Money in Leetcode Bank	Easy	sort
1717	Maximum Score From Removing Substrings	Medium	greedy
1718	Construct the Lexicographically Largest Valid Sequence	Medium	backtracking
1719	Number Of Ways To Reconstruct A Tree	Hard	graph
1720	Decode XORed Array	Easy	bit manipulation
1721	Swapping Nodes in a Linked List	Medium	linked list
1722	Minimize Hamming Distance After Swap Operations	Medium	depth first search
1723	Find Minimum Time to Finish All Jobs	Hard	backtracking
1724	Checking Existence of Edge Length Limited Paths II	Hard	graph
1725	Number Of Rectangles That Can Form The Largest Square	Easy	greedy
1726	Tuple with Same Product	Medium	array
1727	Largest Submatrix With Rearrangements	Medium	greedy
1728	Cat and Mouse II	Hard	breadth first search
1729	Find Followers Count	Easy	sql
1730	Shortest Path to Get Food	Medium	breadth first search
1731	The Number of Employees Which Report to Each Employee	Easy	sql
1732	Find the Highest Altitude	Medium	array
1733	Minimum Number of People to Teach	Medium	greedy
1734	Decode XORed Permutation	Medium	bit manipulation
1735	Count Ways to Make Array With Product	Hard	math
1736	Latest Time by Replacing Hidden Digits	Easy	greedy
1737	Change Minimum Characters to Satisfy One of Three Conditions	Medium	greedy
1738	Find Kth Largest XOR Coordinate Value	Medium	array
1739	Building Boxes	Hard	math
1740	Find Distance in a Binary Tree	Medium	depth first search
1741	Find Total Time Spent by Each Employee	Easy	sql
1742	Maximum Number of Balls in a Box	Easy	array
1743	Restore the Array From Adjacent Pairs	Medium	graph
1744	Can You Eat Your Favorite Candy on Your Favorite Day?	Medium	math
1745	Palindrome Partitioning IV	Hard	dynamic programming
1746	Maximum Subarray Sum After One Operation	Medium	dynamic programming
1747	Leetflex Banned Accounts	Medium	sql
1748	Sum of Unique Elements	Easy	hash table
1749	Maximum Absolute Sum of Any Subarray	Medium	greedy
1750	Minimum Length of String After Deleting Similar Ends	Medium	two pointers
1751	Maximum Number of Events That Can Be Attended II	Hard	dynamic programming
1752	Check if Array Is Sorted and Rotated	Easy	array
1753	Maximum Score From Removing Stones	Medium	math
1754	Largest Merge Of Two Strings	Medium	greedy
1755	Closest Subsequence Sum	Hard	array
1756	Design Most Recently Used Queue	Medium	design
1757	Recyclable and Low Fat Products	Easy	sql
1758	Minimum Changes To Make Alternating Binary String	Easy	greedy
1759	Count Number of Homogenous Substrings	Medium	greedy
1760	Minimum Limit of Balls in a Bag	Medium	binary search
1761	Minimum Degree of a Connected Trio in a Graph	Hard	graph
1762	Buildings With an Ocean View	Medium	greedy
1763	Longest Nice Substring	Easy	string
1764	Form Array by Concatenating Subarrays of Another Array	Medium	greedy
1765	Map of Highest Peak	Medium	breadth first search
1766	Tree of Coprimes	Hard	depth first search
1767	Find the Subtasks That Did Not Execute	Hard	sql
1768	Merge Strings Alternately	Easy	string
1769	Minimum Number of Operations to Move All Balls to Each Box	Medium	greedy
1770	Maximum Score from Performing Multiplication Operations	Medium	dynamic programming
1771	Maximize Palindrome Length From Subsequences	Hard	dynamic programming
1772	Sort Features by Popularity	Medium	sort
1773	Count Items Matching a Rule	Easy	array
1774	Closest Dessert Cost	Medium	dynamic programming
1775	Equal Sum Arrays With Minimum Number of Operations	Medium	greedy
1776	Car Fleet II	Hard	math
1777	Product's Price for Each Store	Easy	sql
1778	Shortest Path in a Hidden Grid	Medium	graph
1779	Find Nearest Point That Has the Same X or Y Coordinate	Easy	array
1780	Check if Number is a Sum of Powers of Three	Medium	math
1781	Sum of Beauty of All Substrings	Medium	hash table
1782	Count Pairs Of Nodes	Hard	graph
1783	Grand Slam Titles	Medium	sql
1784	Check if Binary String Has at Most One Segment of Ones	Easy	string
1785	Minimum Elements to Add to Form a Given Sum	Medium	greedy
1786	Number of Restricted Paths From First to Last Node	Medium	graph
1787	Make the XOR of All Segments Equal to Zero	Hard	dynamic programming
1788	Maximize the Beauty of the Garden	Hard	greedy
1789	Primary Department for Each Employee	Easy	sql
1790	Check if One String Swap Can Make Strings Equal	Easy	string
1791	Find Center of Star Graph	Medium	graph
1792	Maximum Average Pass Ratio	Medium	binary heap
1793	Maximum Score of a Good Subarray	Hard	greedy
1794	Count Pairs of Equal Substrings With Minimum Difference	Medium	greedy
1795	Rearrange Products Table	Easy	sql
1796	Second Largest Digit in a String	Easy	string
1797	Design Authentication Manager	Medium	design
1798	Maximum Number of Consecutive Values You Can Make	Medium	greedy
1799	Maximize Score After N Operations	Hard	dynamic programming
1800	Maximum Ascending Subarray Sum	Easy	array
1801	Number of Orders in the Backlog	Medium	greedy
1802	Maximum Value at a Given Index in a Bounded Array	Medium	binary search
1803	Count Pairs With XOR in a Range	Hard	dynamic programming
1804	Implement Trie II (Prefix Tree)	Medium	design
1805	Number of Different Integers in a String	Easy	string
1806	Minimum Number of Operations to Reinitialize a Permutation	Medium	math
1807	Evaluate the Bracket Pairs of a String	Medium	hash table
1808	Maximize Number of Nice Divisors	Medium	math
1809	Ad-Free Sessions	Easy	sql
1810	Minimum Path Cost in a Hidden Grid	Medium	graph
1811	Find Interview Candidates	Medium	sql
1812	Determine Color of a Chessboard Square	Easy	math
1813	Sentence Similarity III	Medium	string
1814	Count Nice Pairs in an Array	Medium	hash table
1815	Maximum Number of Groups Getting Fresh Donuts	Hard	greedy
1816	Truncate Sentence	Easy	string
1817	Finding the Users Active Minutes	Medium	hash table
1818	Minimum Absolute Sum Difference	Medium	binary search
1819	Number of Different Subsequences GCDs	Hard	math
1820	Maximum Number of Accepted Invitations	Medium	graph
1821	Find Customers With Positive Revenue this Year	Easy	sql
1822	Sign of the Product of an Array	Easy	math
1823	Find the Winner of the Circular Game	Medium	math
1824	Minimum Sideway Jumps	Medium	greedy
1825	Finding MK Average	Hard	design
1826	Faulty Sensor	Easy	array
1827	Minimum Operations to Make the Array Increasing	Easy	greedy
1828	Queries on Number of Points Inside a Circle	Medium	math
1829	Maximum XOR for Each Query	Medium	bit manipulation
1830	Minimum Number of Operations to Make String Sorted	Hard	math
1831	Maximum Transaction Each Day	Medium	sql
1832	Check if the Sentence Is Pangram	Easy	string
1833	Maximum Ice Cream Bars	Medium	greedy
1834	Single-Threaded CPU	Medium	tree
1835	Find XOR Sum of All Pairs Bitwise AND	Hard	math
1836	Remove Duplicates From an Unsorted Linked List	Medium	linked list
1837	Sum of Digits in Base K	Easy	math
1838	Frequency of the Most Frequent Element	Medium	two pointers
1839	Longest Substring Of All Vowels in Order	Medium	string
1840	Maximum Building Height	Hard	greedy
1841	League Statistics	Medium	sql
1842	Next Palindrome Using Same Digits	Hard	greedy
1843	Suspicious Bank Accounts	Medium	sql
1844	Replace All Digits with Characters	Easy	string
1845	Seat Reservation Manager	Medium	design
1846	Maximum Element After Decreasing and Rearranging	Medium	greedy
1847	Closest Room	Hard	sort
1848	Minimum Distance to the Target Element	Easy	array
1849	Splitting a String Into Descending Consecutive Values	Medium	backtracking
1850	Minimum Adjacent Swaps to Reach the Kth Smallest Number	Medium	greedy
1851	Minimum Interval to Include Each Query	Hard	sort
1852	Distinct Numbers in Each Subarray	Medium	two pointers
1853	Convert Date Format	Easy	sql
1854	Maximum Population Year	Easy	string
1855	Maximum Distance Between a Pair of Values	Medium	two pointers
1856	Maximum Subarray Min-Product	Medium	stack
1857	Largest Color Value in a Directed Graph	Hard	dynamic programming
1858	Longest Word With All Prefixes	Medium	string
1859	Sorting the Sentence	Easy	sort
1860	Incremental Memory Leak	Medium	math
1861	Rotating the Box	Medium	array
1862	Sum of Floored Pairs	Hard	math
1863	Sum of All Subset XOR Totals	Easy	math
1864	Minimum Number of Swaps to Make the Binary String Alternating	Medium	greedy
1865	Finding Pairs With a Certain Sum	Medium	design
1866	Number of Ways to Rearrange Sticks With K Sticks Visible	Hard	dynamic programming
1867	Orders With Maximum Quantity Above Average	Easy	sql
1868	Product of Two Run-Length Encoded Arrays	Medium	two pointers
1869	Longer Contiguous Segments of Ones than Zeros	Easy	array
1870	Minimum Speed to Arrive on Time	Medium	binary search
1871	Jump Game VII	Medium	dynamic programming
1872	Stone Game VIII	Hard	dynamic programming
1873	Calculate Special Bonus	Easy	sql
1874	Minimize Product Sum of Two Arrays	Medium	greedy
1875	Group Employees of the Same Salary	Medium	sql
1876	Substrings of Size Three with Distinct Characters	Easy	string
1877	Minimize Maximum Pair Sum in Array	Medium	greedy
1878	Get Biggest Three Rhombus Sums in a Grid	Easy	array
1879	Minimum XOR Sum of Two Arrays	Hard	graph
1880	Check if Word Equals Summation of Two Words	Easy	string
1881	Maximum Value after Insertion	Medium	greedy
1882	Process Tasks Using Servers	Medium	binary heap
1883	Minimum Skips to Arrive at Meeting On Time	Hard	dynamic programming
1884	Egg Drop With 2 Eggs and N Floors	Medium	math
1885	Count Pairs in Two Arrays	Medium	two pointers
1886	Determine Whether Matrix Can Be Obtained By Rotation	Easy	array
1887	Reduction Operations to Make the Array Elements Equal	Medium	greedy
1888	Minimum Number of Flips to Make the Binary String Alternatings	Medium	two pointers
1889	Minimum Space Wasted From Packaging	Hard	binary search
1890	The Latest Login in 2020	Easy	sql
1891	Cutting Ribbons	Medium	binary search
1892	Page Recommendations II	Hard	sql
1893	Check if All the Integers in a Range Are Covered	Easy	greedy
1894	Find the Student that Will Replace the Chalk	Medium	greedy
1895	Largest Magic Square	Medium	array
1896	Minimum Cost to Change the Final Value of Expression	Hard	dynamic programming
1897	Redistribute Characters to Make All Strings Equal	Easy	greedy
1898	Maximum Number of Removable Characters	Medium	binary search
1899	Merge Triplets to Form Target Triplet	Medium	greedy
1900	The Earliest and Latest Rounds Where Players Compete	Hard	dynamic programming
1901	Find a Peak Element II	Medium	binary search
1902	Depth of BST Given Insertion Order	Medium	binary search tree
1903	Largest Odd Number in String	Easy	string
1904	The Number of Full Rounds You Have Played	Medium	math
1905	Count Sub Islands	Medium	depth first search
1906	Minimum Absolute Difference Queries	Medium	array
1907	Count Salary Categories	Medium	sql
1908	Game of Nim	Medium	dynamic programming
1909	Remove One Element to Make the Array Strictly Increasing	Easy	array
1910	Remove All Occurrences of a Substring	Medium	string
1911	Maximum Alternating Subsequence Sum	Medium	greedy
1912	Design Movie Rental System	Hard	design
1913	Maximum Product Difference Between Two Pairs	Medium	greedy
1914	Cyclically Rotating a Grid	Medium	array
1915	Number of Wonderful Substrings	Medium	hash table
1916	Count Ways to Build Rooms in an Ant Colony	Hard	math
1917	Leetcodify Friends Recommendations	Hard	sql
1918	Kth Smallest Subarray Sum	Medium	binary search
1919	Leetcodify Similar Friends	Hard	sql
1920	Build Array from Permutation	Easy	array
1921	Eliminate Maximum Number of Monsters	Medium	greedy
1922	Count Good Numbers	Medium	math
1923	Longest Common Subpath	Hard	hash table
1924	Erect the Fence II	Hard	geometry
1925	Count Square Sum Triples	Easy	hash table
1926	Nearest Exit from Entrance in Maze	Medium	breadth first search
1927	Sum Game	Medium	greedy
1928	Minimum Cost to Reach Destination in Time	Medium	breadth first search
1929	Concatenation of Array	Easy	array
1930	Unique Length-3 Palindromic Subsequences	Medium	hash table
1931	Painting a Grid With Three Different Colors	Hard	dynamic programming
1932	Merge BSTs to Create Single BST	Hard	binary search tree
1933	Check if String Is Decomposable Into Value-Equal Substrings	Easy	string
1934	Confirmation Rate	Medium	sql
1935	Maximum Number of Words You Can Type	Easy	string
1936	Add Minimum Number of Rungs	Medium	greedy
1937	Maximum Number of Points with Cost	Medium	dynamic programming
1938	Maximum Genetic Difference Query	Hard	tree
1939	Users That Actively Request Confirmation Messages	Easy	sql
1940	Longest Common Subsequence Between Sorted Arrays	Medium	array
1941	Check if All Characters Have Equal Number of Occurrences	Easy	hash table
1942	The Number of the Smallest Unoccupied Chair	Medium	sort
1943	Describe the Painting	Medium	sort
1944	Number of Visible People in a Queue	Hard	stack
1945	Sum of Digits of String After Convert	Easy	math
1946	Largest Number After Mutating Substring	Medium	greedy
1947	Maximum Compatibility Score Sum	Medium	graph
1948	Delete Duplicate Folders in System	Hard	tree
1949	Strong Friendship	Medium	sql
1950	Maximum of Minimum Values in All Subarrays	Medium	stack
1951	All the Pairs With the Maximum Number of Common Followers	Medium	sql
1952	Three Divisors	Easy	math
1953	Maximum Number of Weeks for Which You Can Work	Medium	greedy
1954	Minimum Garden Perimeter to Collect Enough Apples	Medium	math
1955	Count Number of Special Subsequences	Hard	dynamic programming
1956	Minimum Time For K Virus Variants to Spread	Hard	geometry
1957	Delete Characters to Make Fancy String	Easy	string
1958	Check if Move is Legal	Medium	array
1959	Minimum Total Space Wasted With K Resizing Operations	Medium	dynamic programming
1960	Maximum Product of the Length of Two Palindromic Substrings	Hard	dynamic programming
1961	Check If String Is a Prefix of Array	Easy	string
1962	Remove Stones to Minimize the Total	Medium	binary heap
1963	Minimum Number of Swaps to Make the String Balanced	Medium	string
1964	Find the Longest Valid Obstacle Course at Each Position	Hard	binary search
1965	Employees With Missing Information	Easy	sql
1966	Binary Searchable Numbers in an Unsorted Array	Medium	array
1967	Number of Strings That Appear as Substrings in Word	Easy	string
1968	Array With Elements Not Equal to Average of Neighbors	Medium	sort
1969	Minimum Non-Zero Product of the Array Elements	Medium	math
1970	Last Day Where You Can Still Cross	Hard	array
1971	Find if Path Exists in Graph	Medium	graph
1972	First and Last Call On the Same Day	Hard	sql
1973	Count Nodes Equal to Sum of Descendants	Medium	depth first search
1974	Minimum Time to Type Word Using Special Typewriter	Easy	string
1975	Maximum Matrix Sum	Medium	greedy
1976	Number of Ways to Arrive at Destination	Medium	graph
1977	Number of Ways to Separate Numbers	Hard	dynamic programming
1978	Employees Whose Manager Left the Company	Easy	sql
1979	Find Greatest Common Divisor of Array	Easy	math
1980	Find Unique Binary String	Medium	math
1981	Minimize the Difference Between Target and Chosen Elements	Medium	dynamic programming
1982	Find Array Given Subset Sums	Hard	math
1983	Widest Pair of Indices With Equal Range Sum	Medium	array
1984	Minimum Difference Between Highest and Lowest of K Scores	Easy	two pointers
1985	Find the Kth Largest Integer in the Array	Medium	sort
1986	Minimum Number of Work Sessions to Finish the Tasks	Medium	dynamic programming
1987	Number of Unique Good Subsequences	Hard	dynamic programming
1988	Find Cutoff Score for Each School	Medium	sql
1989	Maximum Number of People That Can Be Caught in Tag	Medium	two pointers
1990	Count the Number of Experiments	Easy	sql
1991	Find the Middle Index in Array	Easy	array
1992	Find All Groups of Farmland	Medium	array
1993	Operations on Tree	Medium	design
1994	The Number of Good Subsets	Hard	dynamic programming
1995	Count Special Quadruplets	Easy	hash table
1996	The Number of Weak Characters in the Game	Medium	sort
1997	First Day Where You Have Been in All the Rooms	Medium	dynamic programming
1998	GCD Sort of an Array	Hard	array
1999	Smallest Greater Multiple Made of Two Digits	Medium	backtracking
2000	Reverse Prefix of Word	Easy	string
2001	Number of Pairs of Interchangeable Rectangles	Medium	math
2002	Maximum Product of the Length of Two Palindromic Subsequences	Medium	dynamic programming
2003	Smallest Missing Genetic Value in Each Subtree	Hard	tree
2004	The Number of Seniors and Juniors to Join the Company	Hard	sql
2005	Subtree Removal Game with Fibonacci Tree	Hard	math
2006	Count Number of Pairs With Absolute Difference K	Easy	hash table
2007	Find Original Array From Doubled Array	Medium	array
2008	Maximum Earnings From Taxi	Medium	dynamic programming
2009	Minimum Number of Operations to Make Array Continuous	Hard	two pointers
2011	Final Value of Variable After Performing Operations	Easy	array
2012	Sum of Beauty in the Array	Medium	array
2013	Detect Squares	Medium	design
2014	Longest Subsequence Repeated k Times	Hard	backtracking
2015	Average Height of Buildings in Each Segment	Medium	sort
2016	Maximum Difference Between Increasing Elements	Easy	array
2017	Grid Game	Medium	array
2018	Check if Word Can Be Placed In Crossword	Medium	array
2019	The Score of Students Solving Math Expression	Hard	dynamic programming
2020	Number of Accounts That Did Not Stream	Medium	sql
2021	Brightest Position on Street	Medium	sort
2022	Convert 1D Array Into 2D Array	Easy	array
2023	Number of Pairs of Strings With Concatenation Equal to Target	Medium	hash table
2024	Maximize the Confusion of an Exam	Medium	two pointers
2025	Maximum Number of Ways to Partition an Array	Hard	hash table
2026	Low-Quality Problems	Easy	sql
2027	Minimum Moves to Convert String	Easy	greedy
2028	Find Missing Observations	Medium	math
2029	Stone Game IX	Medium	math
2030	Smallest K-Length Subsequence With Occurrences of a Letter	Hard	greedy
2031	Count Subarrays With More Ones Than Zeros	Medium	dynamic programming
2032	Two Out of Three	Easy	hash table
2033	Minimum Operations to Make a Uni-Value Grid	Medium	array
2034	Stock Price Fluctuation	Medium	design
2035	Partition Array Into Two Arrays to Minimize Sum Difference	Hard	array
2036	Maximum Alternating Subarray Sum	Medium	greedy
2037	Minimum Number of Moves to Seat Everyone	Easy	greedy
2038	Remove Colored Pieces if Both Neighbors are the Same Color	Medium	array
2039	The Time When the Network Becomes Idle	Medium	breadth first search
2040	Kth Smallest Product of Two Sorted Arrays	Hard	two pointers
2041	Accepted Candidates From the Interviews	Medium	sql
2042	Check if Numbers Are Ascending in a Sentence	Easy	string
2043	Simple Bank System	Medium	design
2044	Count Number of Maximum Bitwise-OR Subsets	Medium	dynamic programming
2045	Second Minimum Time to Reach Destination	Medium	breadth first search
2046	Sort Linked List Already Sorted Using Absolute Values	Medium	two pointers
2047	Number of Valid Words in a Sentence	Easy	string
2048	Next Greater Numerically Balanced Number	Medium	string
2049	Count Nodes With the Highest Score	Medium	depth first search
2050	Parallel Courses III	Medium	breadth first search
2051	The Category of Each Member in the Store	Medium	sql
2052	Minimum Cost to Separate Sentence Into Rows	Medium	dynamic programming
2053	Kth Distinct String in an Array	Easy	hash table
2054	Two Best Non-Overlapping Events	Medium	binary heap
2055	Plates Between Candles	Medium	array
2056	Number of Valid Move Combinations On Chessboard	Hard	backtracking
2057	Smallest Index With Equal Value	Easy	array
2058	Find the Minimum and Maximum Number of Nodes Between Critical Points	Medium	linked list
2059	Minimum Operations to Convert Number	Medium	breadth first search
2060	Check if an Original String Exists Given Two Encoded Strings	Hard	dynamic programming
2061	Number of Spaces Cleaning Robot Cleaned	Medium	simulation
2062	Count Vowel Substrings of a String	Easy	two pointers
2063	Vowels of All Substrings	Medium	math
2064	Minimized Maximum of Products Distributed to Any Store	Medium	binary search
2065	Maximum Path Quality of a Graph	Medium	depth first search
2066	Account Balance	Medium	sql
2067	Number of Equal Count Substrings	Medium	two pointers
2068	Check Whether Two Strings are Almost Equivalent	Easy	hash table
2069	Walking Robot Simulation II	Medium	design
2070	Most Beautiful Item for Each Query	Medium	sort
2071	Maximum Number of Tasks You Can Assign	Hard	greedy
2072	The Winner University	Easy	sql
2073	Time Needed to Buy Tickets	Easy	math
2074	Reverse Nodes in Even Length Groups	Medium	linked list
2075	Decode the Slanted Ciphertext	Medium	array
2076	Process Restricted Friend Requests	Hard	graph
2077	Paths in Maze That Lead to Same Room	Medium	graph
2078	Two Furthest Houses With Different Colors	Easy	array
2079	Watering Plants	Medium	array
2080	Range Frequency Queries	Medium	design
2081	Sum of k-Mirror Numbers	Hard	string
2082	The Number of Rich Customers	Easy	sql
2083	Substrings That Begin and End With the Same Letter	Medium	math
2084	Drop Type 1 Orders for Customers With Type 0 Orders	Medium	sql
2085	Count Common Words With One Occurrence	Easy	hash table
2086	Minimum Number of Buckets Required to Collect Rainwater from Houses	Medium	greedy
2087	Minimum Cost Homecoming of a Robot in a Grid	Medium	greedy
2088	Count Fertile Pyramids in a Land	Hard	dynamic programming
2089	Find Target Indices After Sorting Array	Easy	sort
2090	K Radius Subarray Averages	Medium	two pointers
2091	Removing Minimum and Maximum From Array	Medium	math
2092	Find All People With Secret	Hard	graph
2093	Minimum Path Cost in a Hidden Grid	Medium	graph
2094	Finding 3-Digit Even Numbers	Easy	backtracking
2095	Delete the Middle Node of a Linked List	Medium	linked list
2096	Step-By-Step Directions From a Binary Tree Node to Another	Medium	tree
2097	Valid Arrangement of Pairs	Medium	graph
2098	Subsequence of Size K With the Largest Even Sum	Medium	array
2099	Find Subsequence of Length K With the Largest Sum	Easy	array
2100	Find Good Days to Rob the Bank	Medium	array
2101	Detonate the Maximum Bombs	Medium	geometry
2102	Sequentially Ordinal Rank Tracker	Hard	design
2103	Rings and Rods	Easy	string
2104	Sum of Subarray Ranges	Medium	stack
2105	Watering Plants II	Medium	two pointers
2106	Maximum Fruits Harvested After at Most K Steps	Hard	array
2107	Number of Unique Flavors After Sharing K Candies	Medium	two pointers
2108	Find First Palindromic String in the Array	Easy	string
2109	Adding Spaces to a String	Medium	string
2110	Number of Smooth Descent Periods of a Stock	Medium	math
2111	Minimum Operations to Make the Array K-Increasing	Hard	binary search
2112	The Airport With the Most Traffic	Medium	sql
2113	Elements in Array After Removing and Replacing Elements	Medium	array
2114	Maximum Number of Words Found in Sentences	Easy	string
2115	Find All Possible Recipes from Given Supplies	Medium	breadth first search
2116	Check if a Parentheses String Can Be Valid	Medium	string
2117	Abbreviating the Product of a Range	Hard	math
2118	Build the Equation	Hard	sql
2119	A Number After a Double Reversal	Easy	math
2120	Execution of All Suffix Instructions Staying in a Grid	Medium	hash table
2121	Intervals Between Identical Elements	Medium	array
2122	Recover the Original Array	Hard	array
2123	Minimum Operations to Remove Adjacent Ones in Matrix	Hard	graph
2124	Check if All A's Appears Before All B's	Easy	string
2125	Number of Laser Beams in a Bank	Medium	math
2126	Destroying Asteroids	Medium	greedy
2127	Maximum Employees to Be Invited to a Meeting	Hard	graph
2128	Remove All Ones With Row and Column Flips	Medium	array
2129	Capitalize the Title	Easy	string
2130	Maximum Twin Sum of a Linked List	Medium	linked list
2131	Longest Palindrome by Concatenating Two Letter Words	Medium	string
2132	Stamping the Grid	Hard	array
2133	Check if Every Row and Column Contains All Numbers	Easy	math
2134	Minimum Swaps to Group All 1's Together II	Medium	two pointers
2135	Count Words Obtained After Adding a Letter	Medium	string
2136	Earliest Possible Day of Full Bloom	Hard	greedy
2137	Pour Water Between Buckets to Make Water Levels Equal	Medium	binary search
2138	Divide a String Into Groups of Size k	Easy	string
2139	Minimum Moves to Reach Target Score	Medium	greedy
2140	Solving Questions With Brainpower	Medium	dynamic programming
2141	Maximum Running Time of N Computers	Hard	greedy
2142	The Number of Passengers in Each Bus I	Medium	sql
2143	Choose Numbers From Two Arrays in Range	Hard	dynamic programming
2144	Minimum Cost of Buying Candies With Discount	Easy	greedy
2145	Count the Hidden Sequences	Medium	math
2146	K Highest Ranked Items Within a Price Range	Medium	breadth first search
2147	Number of Ways to Divide a Long Corridor	Hard	greedy
2148	Count Elements With Strictly Smaller and Greater Elements	Easy	math
2149	Rearrange Array Elements by Sign	Medium	two pointers
2150	Find All Lonely Numbers in the Array	Medium	hash table
2151	Maximum Good People Based on Statements	Hard	bit manipulation
2152	Minimum Number of Lines to Cover Points	Medium	math
2153	The Number of Passengers in Each Bus II	Hard	sql
2154	Keep Multiplying Found Values by Two	Easy	hash table
2155	All Divisions With the Highest Score of a Binary Array	Medium	array
2156	Find Substring With Given Hash Value	Medium	string
2157	Groups of Strings	Hard	string
2158	Amount of New Area Painted Each Day	Hard	sort
2159	Order Two Columns Independently	Medium	sql
2160	Minimum Sum of Four Digit Number After Splitting Digits	Easy	greedy
2161	Partition Array According to Given Pivot	Medium	two pointers
2162	Minimum Cost to Set Cooking Time	Medium	simulation
2163	Minimum Difference in Sums After Removal of Elements	Hard	binary heap
2164	Sort Even and Odd Indices Independently	Easy	sort
2165	Smallest Value of the Rearranged Number	Medium	greedy
2166	Design Bitset	Medium	design
2167	Minimum Time to Remove All Cars Containing Illegal Goods	Hard	dynamic programming
2168	Unique Substrings With Equal Digit Frequency	Medium	string
2169	Count Operations to Obtain Zero	Easy	math
2170	Minimum Operations to Make the Array Alternating	Medium	hash table
2171	Removing Minimum Number of Magic Beans	Medium	math
2172	Maximum AND Sum of Array	Hard	graph
2173	Longest Winning Streak	Hard	sql
2174	Remove All Ones With Row and Column Flips II	Medium	dynamic programming
2175	The Change in Global Rankings	Medium	sql
2176	Count Equal and Divisible Pairs in an Array	Easy	math
2177	Find Three Consecutive Integers That Sum to a Given Number	Medium	math
2178	Maximum Split of Positive Even Integers	Medium	greedy
2179	Count Good Triplets in an Array	Hard	tree
2180	Count Integers With Even Digit Sum	Easy	math
2181	Merge Nodes in Between Zeros	Medium	linked list
2182	Construct String With Repeat Limit	Medium	greedy
2183	Count Array Pairs Divisible by K	Hard	math
2184	Number of Ways to Build Sturdy Brick Wall	Medium	dynamic programming
2185	Counting Words With a Given Prefix	Easy	string
2186	Minimum Number of Steps to Make Two Strings Anagram II	Medium	string
2187	Minimum Time to Complete Trips	Medium	binary search
2188	Minimum Time to Finish the Race	Hard	dynamic programming
2189	Number of Ways to Build House of Cards	Medium	dynamic programming
2190	Most Frequent Number Following Key In an Array	Easy	hash table
2191	Sort the Jumbled Numbers	Medium	sort
2192	All Ancestors of a Node in a Directed Acyclic Graph	Medium	depth first search
2193	Minimum Number of Moves to Make Palindrome	Hard	greedy
2194	Cells in a Range on an Excel Sheet	Easy	array
2195	Append K Integers With Minimal Sum	Medium	greedy
2196	Create Binary Tree From Descriptions	Medium	tree
2197	Replace Non-Coprime Numbers in Array	Hard	stack
2198	Number of Single Divisor Triplets	Medium	math
2199	Finding the Topic of Each Post	Hard	sql
2200	Find All K-Distant Indices in an Array	Easy	two pointers
2201	Count Artifacts That Can Be Extracted	Medium	hash table
2202	Maximize the Topmost Element After K Moves	Medium	constructive algorithms
2203	Minimum Weighted Subgraph With the Required Paths	Medium	graph
2204	Distance to a Cycle in Undirected Graph	Medium	graph
2205	The Number of Users That Are Eligible for Discount	Easy	sql
2206	Divide Array Into Equal Pairs	Easy	hash table
2207	Maximize Number of Subsequences in a String	Medium	greedy
2208	Minimum Operations to Halve Array Sum	Medium	binary heap
2209	Minimum White Tiles After Covering With Carpets	Hard	dynamic programming
2210	Count Hills and Valleys in an Array	Easy	array
2211	Count Collisions on a Road	Medium	string
2212	Maximum Points in an Archery Competition	Medium	bit manipulation
2213	Longest Substring of One Repeating Character	Hard	string
2214	Minimum Health to Beat Game	Medium	greedy
2215	Find the Difference of Two Arrays	Easy	hash table
2216	Minimum Deletions to Make Array Beautiful	Medium	greedy
2217	Find Palindrome With Fixed Length	Medium	math
2218	Maximum Value of K Coins From Piles	Hard	dynamic programming
2219	Maximum Sum Score of Array	Medium	array
2220	Minimum Bit Flips to Convert Number	Easy	bit manipulation
2221	Find Triangular Sum of an Array	Medium	math
2222	Number of Ways to Select Buildings	Medium	dynamic programming
2223	Sum of Scores of Built Strings	Hard	string
2224	Minimum Number of Operations to Convert Time	Easy	greedy
2225	Find Players With Zero or One Losses	Medium	hash table
2226	Maximum Candies Allocated to K Children	Medium	binary search
2227	Encrypt and Decrypt Strings	Hard	design
2228	Users With Two Purchases Within Seven Days	Medium	sql
2229	Check if an Array Is Consecutive	Easy	hash table
2230	The Users That Are Eligible for Discount	Easy	sql
2231	Largest Number After Digit Swaps by Parity	Easy	sort
2232	Minimize Result by Adding Parentheses to Expression	Medium	string
2233	Maximum Product After K Increments	Medium	sort
2234	Maximum Total Beauty of the Gardens	Hard	two pointers
2235	Add Two Integers	Easy	math
2236	Root Equals Sum of Children	Easy	tree
2237	Count Positions on Street With Required Brightness	Medium	array
2238	Number of Times a Driver Was a Passenger	Medium	sql
2239	Find Closest Number to Zero	Easy	array
2240	Number of Ways to Buy Pens and Pencils	Medium	math
2241	Design an ATM Machine	Medium	design
2242	Maximum Score of a Node Sequence	Medium	graph
2243	Calculate Digit Sum of a String	Easy	string
2244	Minimum Rounds to Complete All Tasks	Medium	math
2245	Maximum Trailing Zeros in a Cornered Path	Medium	array
2246	Longest Path With Different Adjacent Characters	Hard	depth first search
2247	Maximum Cost of Trip With K Highways	Hard	dynamic programming
2248	Intersection of Multiple Arrays	Easy	sort
2249	Count Lattice Points Inside a Circle	Medium	math
2250	Count Number of Rectangles Containing Each Point	Medium	binary search
2251	Number of Flowers in Full Bloom	Hard	sort
2252	Dynamic Pivoting of a Table	Hard	sql
2253	Dynamic Unpivoting of a Table	Hard	sql
2254	Design Video Sharing Platform	Hard	design
2255	Count Prefixes of a Given String	Easy	string
2256	Minimum Average Difference	Medium	array
2257	Count Unguarded Cells in the Grid	Medium	simulation
2258	Escape the Spreading Fire	Hard	breadth first search
2259	Remove Digit From Number to Maximize Result	Easy	greedy
2260	Minimum Consecutive Cards to Pick Up	Medium	hash table
2261	K Divisible Elements Subarrays	Medium	hash table
2262	Total Appeal of A String	Hard	math
2263	Make Array Non-decreasing or Non-increasing	Hard	greedy
2264	Largest 3-Same-Digit Number in String	Easy	string
2265	Count Nodes Equal to Average of Subtree	Medium	depth first search
2266	Count Number of Texts	Medium	dynamic programming
2267	Check if There Is a Valid Parentheses String Path	Hard	dynamic programming
2268	Minimum Number of Keypresses	Medium	greedy
2269	Find the K-Beauty of a Number	Easy	string
2270	Number of Ways to Split Array	Medium	array
2271	Maximum White Tiles Covered by a Carpet	Medium	array
2272	Substring With Largest Variance	Hard	string
2273	Find Resultant Array After Removing Anagrams	Easy	string
2274	Maximum Consecutive Floors Without Special Floors	Medium	array
2275	Largest Combination With Bitwise AND Greater Than Zero	Medium	bit manipulation
2276	Count Integers in Intervals	Hard	design
2277	Closest Node to Path in Tree	Hard	tree
2278	Percentage of Letter in String	Easy	string
2279	Maximum Bags With Full Capacity of Rocks	Medium	greedy
2280	Minimum Lines to Represent a Line Chart	Medium	math
2281	Sum of Total Strength of Wizards	Hard	stack
2282	Number of People That Can Be Seen in a Grid	Medium	stack
2283	Check if Number Has Equal Digit Count and Digit Value	Easy	hash table
2284	Sender With Largest Word Count	Medium	hash table
2285	Maximum Total Importance of Roads	Medium	greedy
2286	Booking Concert Tickets in Groups	Hard	design
2287	Rearrange Characters to Make Target String	Easy	hash table
2288	Apply Discount to Prices	Medium	string
2289	Steps to Make Array Non-decreasing	Hard	dynamic programming
2290	Minimum Obstacle Removal to Reach Corner	Hard	breadth first search
2291	Maximum Profit From Trading Stocks	Medium	dynamic programming
2292	Products With Three or More Orders in Two Consecutive Years	Medium	sql
2293	Min Max Game	Medium	array
2294	Partition Array Such That Maximum Difference Is K	Medium	greedy
2295	Replace Elements in an Array	Medium	hash table
2296	Design a Text Editor	Hard	design
2297	Jump Game VIII	Medium	dynamic programming
2298	Tasks Count in the Weekend	Medium	sql
2299	Strong Password Checker II	Easy	string
2300	Successful Pairs of Spells and Potions	Medium	binary search
2301	Match Substring After Replacement	Hard	string
2302	Count Subarrays With Score Less Than K	Hard	two pointers
2303	Calculate Amount Paid in Taxes	Easy	simulation
2304	Minimum Path Cost in a Grid	Medium	dynamic programming
2305	Fair Distribution of Cookies	Medium	dynamic programming
2306	Naming a Company	Hard	hash table
2307	Check for Contradictions in Equations	Hard	graph
2308	Arrange Table by Gender	Medium	sql
2309	Greatest English Letter in Upper and Lower Case	Easy	hash table
2310	Sum of Numbers With Units Digit K	Medium	math
2311	Longest Binary Subsequence Less Than or Equal to K	Medium	greedy
2312	Selling Pieces of Wood	Hard	dynamic programming
2313	Minimum Flips in Binary Tree to Get Result	Hard	dynamic programming
2314	The First Day of the Maximum Recorded Degree in Each City	Medium	sql
2315	Count Asterisks	Easy	string
2316	Count Unreachable Pairs of Nodes in an Undirected Graph	Medium	breadth first search
2317	Maximum XOR After Operations	Medium	bit manipulation
2318	Number of Distinct Roll Sequences	Hard	dynamic programming
2319	Check if Matrix Is X-Matrix	Easy	array
2320	Count Number of Ways to Place Houses	Medium	dynamic programming
2321	Maximum Score Of Spliced Array	Hard	greedy
2322	Minimum Score After Removals on a Tree	Hard	depth first search
2323	Find Minimum Time to Finish All Jobs II	Medium	greedy
2324	Product Sales Analysis IV	Medium	sql
2325	Decode the Message	Easy	hash table
2326	Spiral Matrix IV	Medium	array
2327	Number of People Aware of a Secret	Medium	dynamic programming
2328	Number of Increasing Paths in a Grid	Hard	dynamic programming
2329	Product Sales Analysis V	Medium	sql
2330	Valid Palindrome IV	Medium	two pointers
2331	Evaluate Boolean Binary Tree	Easy	depth first search
2332	The Latest Time to Catch a Bus	Medium	two pointers
2333	Minimum Sum of Squared Difference	Medium	binary search
2334	Subarray With Elements Greater Than Varying Threshold	Hard	stack
2335	Minimum Amount of Time to Fill Cups	Easy	constructive algorithms
2336	Smallest Number in Infinite Set	Medium	design
2337	Move Pieces to Obtain a String	Medium	two pointers
2338	Count the Number of Ideal Arrays	Hard	math
2339	All the Matches of the League	Easy	sql
2340	Minimum Adjacent Swaps to Make a Valid Array	Medium	greedy
2341	Maximum Number of Pairs in Array	Easy	hash table
2342	Max Sum of a Pair With Equal Sum of Digits	Medium	hash table
2343	Query Kth Smallest Trimmed Number	Medium	sort
2344	Minimum Deletions to Make Array Divisible	Hard	math
2345	Finding the Number of Visible Mountains	Medium	math
2346	Compute the Rank as a Percentage	Medium	sql
2347	Best Poker Hand	Easy	hash table
2348	Number of Zero-Filled Subarrays	Medium	two pointers
2349	Design a Number Container System	Medium	design
2350	Shortest Impossible Sequence of Rolls	Hard	constructive algorithms
2351	First Letter to Appear Twice	Easy	hash table
2352	Equal Row and Column Pairs	Medium	hash table
2353	Design a Food Rating System	Medium	design
2354	Number of Excellent Pairs	Hard	hash table
2355	Maximum Number of Books You Can Take	Hard	stack
2356	Number of Unique Subjects Taught by Each Teacher	Easy	sql
2357	Make Array Zero by Subtracting Equal Amounts	Easy	hash table
2358	Maximum Number of Groups Entering a Competition	Medium	constructive algorithms
2359	Find Closest Node to Given Two Nodes	Medium	graph
2360	Longest Cycle in a Graph	Hard	graph
2361	Minimum Costs Using the Train Line	Hard	dynamic programming
2362	Generate the Invoice	Hard	sql
2363	Merge Similar Items	Easy	hash table
2364	Count Number of Bad Pairs	Medium	hash table
2365	Task Scheduler II	Medium	hash table
2366	Minimum Replacements to Sort the Array	Hard	greedy
2367	Number of Arithmetic Triplets	Easy	hash table
2368	Reachable Nodes With Restrictions	Medium	breadth first search
2369	Check if There is a Valid Partition For The Array	Medium	dynamic programming
2370	Longest Ideal Subsequence	Medium	dynamic programming
2371	Minimize Maximum Value in a Grid	Hard	greedy
2372	Calculate the Influence of Each Salesperson	Medium	sql
2373	Largest Local Values in a Matrix	Easy	array
2374	Node With Highest Edge Score	Medium	hash table
2375	Construct Smallest Number From DI String	Medium	greedy
2376	Count Special Integers	Hard	math
2377	Sort the Olympic Table	Easy	sql
2378	Choose Edges to Maximize Score in a Tree	Medium	dynamic programming
2379	Minimum Recolors to Get K Consecutive Black Blocks	Easy	two pointers
2380	Time Needed to Rearrange a Binary String	Medium	dynamic programming
2381	Shifting Letters II	Medium	string
2382	Maximum Segment Sum After Removals	Hard	array
2383	Minimum Hours of Training to Win a Competition	Easy	greedy
2384	Largest Palindromic Number	Medium	greedy
2385	Amount of Time for Binary Tree to Be Infected	Medium	depth first search
2386	Find the K-Sum of an Array	Hard	binary heap
2387	Median of a Row Wise Sorted Matrix	Medium	binary search
2388	Change Null Values in a Table to the Previous Value	Medium	sql
2389	Longest Subsequence With Limited Sum	Easy	binary search
2390	Removing Stars From a String	Medium	string
2391	Minimum Amount of Time to Collect Garbage	Medium	array
2392	Build a Matrix With Conditions	Hard	graph
2393	Count Strictly Increasing Subarrays	Medium	two pointers
2394	Employees With Deductions	Medium	sql
2395	Find Subarrays With Equal Sum	Easy	hash table
2396	Strictly Palindromic Number	Medium	math
2397	Maximum Rows Covered by Columns	Medium	bit manipulation
2398	Maximum Number of Robots Within Budget	Hard	queue
2399	Check Distances Between Same Letters	Easy	hash table
2400	Number of Ways to Reach a Position After Exactly k Steps	Medium	math
2401	Longest Nice Subarray	Medium	two pointers
2402	Meeting Rooms III	Hard	binary heap
2403	Minimum Time to Kill All Monsters	Hard	dynamic programming
2404	Most Frequent Even Element	Easy	hash table
2405	Optimal Partition of String	Medium	greedy
2406	Divide Intervals Into Minimum Number of Groups	Medium	array
2407	Longest Increasing Subsequence II	Hard	array
2408	Design SQL	Medium	design
2409	Count Days Spent Together	Easy	math
2410	Maximum Matching of Players With Trainers	Medium	greedy
2411	Smallest Subarrays With Maximum Bitwise OR	Medium	bit manipulation
2412	Minimum Money Required Before Transactions	Hard	greedy
2413	Smallest Even Multiple	Easy	math
2414	Length of the Longest Alphabetical Continuous Substring	Medium	string
2415	Reverse Odd Levels of Binary Tree	Medium	breadth first search
2416	Sum of Prefix Scores of Strings	Hard	string
2417	Closest Fair Integer	Medium	greedy
2418	Sort the People	Easy	sort
2419	Longest Subarray With Maximum Bitwise AND	Medium	bit manipulation
2420	Find All Good Indices	Medium	dynamic programming
2421	Number of Good Paths	Hard	tree
2422	Merge Operations to Turn Array Into a Palindrome	Medium	greedy
2423	Remove Letter To Equalize Frequency	Easy	hash table
2424	Longest Uploaded Prefix	Medium	design
2425	Bitwise XOR of All Pairings	Medium	bit manipulation
2426	Number of Pairs Satisfying Inequality	Hard	binary search tree
2427	Number of Common Factors	Easy	math
2428	Maximum Sum of an Hourglass	Medium	array
2429	Minimize XOR	Medium	bit manipulation
2430	Maximum Deletions on a String	Hard	dynamic programming
2431	Maximize Total Tastiness of Purchased Fruits	Medium	dynamic programming
2432	The Employee That Worked on the Longest Task	Easy	array
2433	Find The Original Array of Prefix Xor	Medium	array
2434	Using a Robot to Print the Lexicographically Smallest String	Medium	greedy
2435	Paths in Matrix Whose Sum Is Divisible by K	Hard	dynamic programming
2436	Minimum Split Into Subarrays With GCD Greater Than One	Medium	greedy
2437	Number of Valid Clock Times	Easy	math
2438	Range Product Queries of Powers	Medium	array
2439	Minimize Maximum of Array	Medium	greedy
2440	Create Components With Same Value	Hard	greedy
2441	Largest Positive Integer That Exists With Its Negative	Easy	hash table
2442	Count Number of Distinct Integers After Reverse Operations	Medium	hash table
2443	Sum of Number and Its Reverse	Medium	backtracking
2444	Count Subarrays With Fixed Bounds	Hard	two pointers
2445	Number of Nodes With Value One	Medium	depth first search
2446	Determine if Two Events Have Conflict	Easy	array
2447	Number of Subarrays With GCD Equal to K	Medium	dynamic programming
2448	Minimum Cost to Make Array Equal	Hard	binary search
2449	Minimum Number of Operations to Make Arrays Similar	Hard	greedy
2450	Number of Distinct Binary Strings After Applying Operations	Medium	math
2451	Odd String Difference	Easy	hash table
2452	Words Within Two Edits of Dictionary	Medium	hash table
2453	Destroy Sequential Targets	Medium	hash table
2454	Next Greater Element IV	Hard	stack
2455	Average Value of Even Numbers That Are Divisible by Three	Easy	math
2456	Most Popular Video Creator	Medium	hash table
2457	Minimum Addition to Make Integer Beautiful	Medium	greedy
2458	Height of Binary Tree After Subtree Removal Queries	Hard	depth first search
2459	Sort Array by Moving Items to Empty Space	Hard	greedy
2460	Apply Operations to an Array	Easy	array
2461	Maximum Sum of Distinct Subarrays With Length K	Medium	two pointers
2462	Total Cost to Hire K Workers	Medium	binary heap
2463	Minimum Total Distance Traveled	Hard	dynamic programming
2464	Minimum Subarrays in a Valid Split	Medium	dynamic programming
2465	Number of Distinct Averages	Easy	two pointers
2466	Count Ways To Build Good Strings	Medium	dynamic programming
2467	Most Profitable Path in a Tree	Medium	depth first search
2468	Split Message Based on Limit	Hard	math
2469	Convert the Temperature	Easy	math
2470	Number of Subarrays With LCM Equal to K	Medium	dynamic programming
2471	Minimum Number of Operations to Sort a Binary Tree by Level	Medium	breadth first search
2472	Maximum Number of Non-overlapping Palindrome Substrings	Hard	greedy
2473	Minimum Cost to Buy Apples	Medium	graph
2474	Customers With Strictly Increasing Purchases	Hard	sql
2475	Number of Unequal Triplets in Array	Easy	dynamic programming
2476	Closest Nodes Queries in a Binary Search Tree	Hard	binary search
2477	Minimum Fuel Cost to Report to the Capital	Medium	depth first search
2478	Number of Beautiful Partitions	Hard	dynamic programming
2479	Maximum XOR of Two Non-Overlapping Subtrees	Hard	greedy
2480	Form a Chemical Bond	Easy	sql
2481	Minimum Cuts to Divide a Circle	Easy	math
2482	Difference Between Ones and Zeros in Row and Column	Medium	array
2483	Minimum Penalty for a Shop	Medium	greedy
2484	Count Palindromic Subsequences	Hard	hash table
2485	Find the Pivot Integer	Easy	math
2486	Append Characters to String to Make Subsequence	Medium	greedy
2487	Remove Nodes From Linked List	Medium	linked list
2488	Count Subarrays With Median K	Hard	hash table
2489	Number of Substrings With Fixed Ratio	Medium	hash table
2490	Circular Sentence	Easy	string
2491	Divide Players Into Teams of Equal Skill	Medium	hash table
2492	Minimum Score of a Path Between Two Cities	Medium	breadth first search
2493	Divide Nodes Into the Maximum Number of Groups	Medium	breadth first search
2494	Merge Overlapping Events in the Same Hall	Hard	sql
2495	Number of Subarrays Having Even Product	Medium	dynamic programming
2496	Maximum Value of a String in an Array	Easy	string
2497	Maximum Star Sum of a Graph	Medium	sort
2498	Frog Jump II	Medium	greedy
2499	Minimum Total Cost to Make Arrays Unequal	Hard	greedy
2500	Delete Greatest Value in Each Row	Easy	array
2501	Longest Square Streak in an Array	Medium	hash table
2502	Design Memory Allocator	Medium	design
2503	Maximum Number of Points From Grid Queries	Hard	breadth first search
2504	Concatenate the Name and the Profession	Easy	sql
2505	Bitwise OR of All Subsequence Sums	Medium	bit manipulation
2506	Count Pairs Of Similar Strings	Easy	hash table
2507	Smallest Value After Replacing With Sum of Prime Factors	Medium	simulation
2508	Add Edges to Make Degrees of All Nodes Even	Hard	graph
2509	Cycle Length Queries in a Tree	Hard	tree
2510	Check if There is a Path With Equal Number of 0's And 1's	Medium	dynamic programming
2511	Maximum Enemy Forts That Can Be Captured	Easy	two pointers
2512	Reward Top K Students	Medium	sort
2513	Minimize the Maximum of Two Arrays	Medium	binary search
2514	Count Anagrams	Hard	math
2515	Shortest Distance to Target String in a Circular Array	Easy	array
2516	Take K of Each Character From Left and Right	Medium	two pointers
2517	Maximum Tastiness of Candy Basket	Medium	binary search
2518	Number of Great Partitions	Hard	dynamic programming
2519	Count the Number of K-Big Indices	Hard	binary heap
2520	Count the Digits That Divide a Number	Easy	math
2521	Distinct Prime Factors of Product of Array	Medium	math
2522	Partition String Into Substrings With Values at Most K	Medium	greedy
2523	Closest Prime Numbers in Range	Medium	math
2524	Maximum Frequency Score of a Subarray	Hard	two pointers
2525	Categorize Box According to Criteria	Easy	math
2526	Find Consecutive Integers from a Data Stream	Medium	design
2527	Find Xor-Beauty of Array	Medium	bit manipulation
2528	Maximize the Minimum Powered City	Hard	binary search
2529	Maximum Count of Positive Integer and Negative Integer	Easy	binary search
2530	Maximal Score After Applying K Operations	Medium	binary heap
2531	Make Number of Distinct Characters Equal	Medium	hash table
2532	Time to Cross a Bridge	Hard	simulation
2533	Number of Good Binary Strings	Medium	dynamic programming
2534	Time Taken to Cross the Door	Hard	simulation
2535	Difference Between Element Sum and Digit Sum of an Array	Easy	array
2536	Increment Submatrices by One	Medium	array
2537	Count the Number of Good Subarrays	Medium	two pointers
2538	Difference Between Maximum and Minimum Price Sum	Hard	dynamic programming
2539	Count the Number of Good Subsequences	Medium	math
2540	Minimum Common Value	Easy	two pointers
2541	Minimum Operations to Make Array Equal II	Medium	greedy
2542	Maximum Subsequence Score	Medium	greedy
2543	Check if Point Is Reachable	Hard	math
2544	Alternating Digit Sum	Easy	math
2545	Sort the Students by Their Kth Score	Medium	sort
2546	Apply Bitwise Operations to Make Strings Equal	Medium	constructive algorithms
2547	Minimum Cost to Split an Array	Hard	dynamic programming
2548	Maximum Price to Fill a Bag	Medium	greedy
2549	Count Distinct Numbers on Board	Easy	math
2550	Count Collisions of Monkeys on a Polygon	Medium	math
2551	Put Marbles in Bags	Hard	greedy
2552	Count Increasing Quadruplets	Hard	dynamic programming
2553	Separate the Digits in an Array	Easy	array
2554	Maximum Number of Integers to Choose From a Range I	Medium	binary search
2555	Maximize Win From Two Segments	Medium	two pointers
2556	Disconnect Path in a Binary Matrix by at Most One Flip	Medium	dynamic programming
2557	Maximum Number of Integers to Choose From a Range II	Medium	binary search
2558	Take Gifts From the Richest Pile	Easy	binary heap
2559	Count Vowel Strings in Ranges	Medium	array
2560	House Robber IV	Medium	binary search
2561	Rearranging Fruits	Hard	greedy
2562	Find the Array Concatenation Value	Easy	math
2563	Count the Number of Fair Pairs	Medium	two pointers
2564	Substring XOR Queries	Medium	hash table
2565	Subsequence With the Minimum Score	Hard	dynamic programming
2566	Maximum Difference by Remapping a Digit	Easy	greedy
2567	Minimum Score by Changing Two Elements	Medium	greedy
2568	Minimum Impossible OR	Medium	math
2569	Handling Sum Queries After Update	Hard	array
2570	Merge Two 2D Arrays by Summing Values	Easy	two pointers
2571	Minimum Operations to Reduce an Integer to 0	Medium	greedy
2572	Count the Number of Square-Free Subsets	Medium	dynamic programming
2573	Find the String with LCP	Hard	greedy
2574	Left and Right Sum Differences	Easy	array
2575	Find the Divisibility Array of a String	Medium	string
2576	Find the Maximum Number of Marked Indices	Medium	greedy
2577	Minimum Time to Visit a Cell In a Grid	Hard	breadth first search
2578	Split With Minimum Sum	Easy	greedy
2579	Count Total Number of Colored Cells	Medium	math
2580	Count Ways to Group Overlapping Ranges	Medium	array
2581	Count Number of Possible Root Nodes	Hard	depth first search
2582	Pass the Pillow	Medium	math
2583	Kth Largest Sum in a Binary Tree	Medium	breadth first search
2584	Split the Array to Make Coprime Products	Hard	math
2585	Number of Ways to Earn Points	Hard	dynamic programming
2586	Count the Number of Vowel Strings in Range	Medium	string
2587	Rearrange Array to Maximize Prefix Score	Medium	greedy
2588	Count the Number of Beautiful Subarrays	Medium	hash table
2589	Minimum Time to Complete All Tasks	Hard	greedy
2590	Design a Todo List	Medium	design
2591	Distribute Money to Maximum Children	Easy	greedy
2592	Maximize Greatness of an Array	Medium	hash table
2593	Find Score of an Array After Marking All Elements	Medium	simulation
2594	Minimum Time to Repair Cars	Medium	binary search
2595	Number of Even and Odd Bits	Easy	bit manipulation
2596	Check Knight Tour Configuration	Medium	simulation
2597	The Number of Beautiful Subsets	Medium	dynamic programming
2598	Smallest Missing Non-negative Integer After Operations	Medium	hash table
2599	Make the Prefix Sum Non-negative	Medium	greedy
2600	K Items With the Maximum Sum	Easy	greedy
2601	Prime Subtraction Operation	Medium	greedy
2602	Minimum Operations to Make All Array Elements Equal	Medium	binary search
2603	Collect Coins in a Tree	Hard	breadth first search
2604	Minimum Time to Eat All Grains	Hard	greedy
2605	Form Smallest Number From Two Digit Arrays	Easy	hash table
2606	Find the Substring With Maximum Cost	Medium	greedy
2607	Make K-Subarray Sums Equal	Medium	greedy
2608	Shortest Cycle in a Graph	Hard	graph
2609	Find the Longest Balanced Substring of a Binary String	Easy	two pointers
2610	Convert an Array Into a 2D Array With Conditions	Medium	constructive algorithms
2611	Mice and Cheese	Medium	greedy
2612	Minimum Reverse Operations	Hard	breadth first search
2613	Beautiful Pairs	Hard	recursion
2614	Prime In Diagonal	Easy	math
2615	Sum of Distances	Medium	hash table
2616	Minimize the Maximum Difference of Pairs	Medium	binary search
2617	Minimum Number of Visited Cells in a Grid	Hard	breadth first search
2618	Check if Object Instance of Class	Medium	design
2619	Array Prototype Last	Easy	design
2620	Counter	Easy	design
2621	Sleep	Easy	design
2622	Cache With Time Limit	Medium	design
2623	Memoize	Medium	design
2624	Snail traversal	Medium	design
2625	Flatten Deeply Nested Array	Medium	design
2626	Array Reduce Transformation	Easy	design
2627	Debounce	Medium	design
2628	JSON Deep Equal	Medium	design
2629	Function Composition	Easy	design
2630	Memoize II	Hard	design
2631	Group By	Medium	design
2632	Curry	Medium	design
2633	Convert Object to JSON String	Medium	design
2634	Filter Elements from Array	Easy	design
2635	Apply Transform Over Each Element in Array	Easy	design
2636	Promise Pool	Medium	design
2637	Promise Time Limit	Easy	design
2638	Count the Number of K-Free Subsets	Medium	dynamic programming
2639	Find the Width of Columns of a Grid	Easy	array
2640	Find the Score of All Prefixes of an Array	Medium	array
2641	Cousins in Binary Tree II	Medium	breadth first search
2642	Design Graph With Shortest Path Calculator	Medium	design
2643	Row With Maximum Ones	Easy	array
2644	Find the Maximum Divisibility Score	Easy	array
2645	Minimum Additions to Make Valid String	Medium	greedy
2646	Minimize the Total Price of the Trips	Hard	dynamic programming
2647	Color the Triangle Red	Hard	constructive algorithms
2648	Generate Fibonacci Sequence	Easy	design
2649	Nested Array Generator	Medium	design
2650	Design Cancellable Function	Hard	design
2651	Calculate Delayed Arrival Time	Easy	math
2652	Sum Multiples	Easy	math
2653	Sliding Subarray Beauty	Medium	two pointers
2654	Minimum Number of Operations to Make All Array Elements Equal to 1	Medium	constructive algorithms
2655	Find Maximal Uncovered Ranges	Medium	array
2656	Maximum Sum With Exactly K Elements	Easy	math
2657	Find the Prefix Common Array of Two Arrays	Medium	hash table
2658	Maximum Number of Fish in a Grid	Medium	breadth first search
2659	Make Array Empty	Hard	sort
2660	Determine the Winner of a Bowling Game	Medium	array
2661	First Completely Painted Row or Column	Medium	hash table
2662	Minimum Cost of a Path With Special Roads	Medium	graph
2663	Lexicographically Smallest Beautiful String	Hard	greedy
2664	The Knight’s Tour	Medium	backtracking
2665	Counter II	Easy	design
2666	Allow One Function Call	Easy	design
2667	Create Hello World Function	Easy	design
2668	Find Latest Salaries	Easy	sql
2669	Count Artist Occurrences On Spotify Ranking List	Easy	sql
2670	Find the Distinct Difference Array	Easy	hash table
2671	Frequency Tracker	Medium	design
2672	Number of Adjacent Elements With the Same Color	Medium	array
2673	Make Costs of Paths Equal in a Binary Tree	Medium	greedy
2674	Split a Circular Linked List	Medium	linked list
2675	Array of Objects to Matrix	Medium	design
2676	Throttle	Medium	design
2677	Chunk Array	Easy	design
2678	Number of Senior Citizens	Easy	string
2679	Sum in a Matrix	Medium	sort
2680	Maximum OR	Medium	greedy
2681	Power of Heroes	Hard	dynamic programming
2682	Find the Losers of the Circular Game	Easy	simulation
2683	Neighboring Bitwise XOR	Medium	array
2684	Maximum Number of Moves in a Grid	Medium	dynamic programming
2685	Count the Number of Complete Components	Medium	breadth first search
2686	Immediate Food Delivery III	Medium	sql
2687	Bikes Last Time Used	Easy	sql
2688	Find Active Users	Medium	sql
2689	Extract Kth Character From The Rope Tree	Medium	binary search tree
2690	Infinite Method Object	Medium	design
2691	Immutability Helper	Hard	design
2692	Make Object Immutable	Medium	design
2693	Call Function with Custom Context	Medium	design
2694	Event Emitter	Medium	design
2695	Array Wrapper	Easy	design
2696	Minimum String Length After Removing Substrings	Easy	stack
2697	Lexicographically Smallest Palindrome	Easy	greedy
2698	Find the Punishment Number of an Integer	Medium	backtracking
2699	Modify Graph Edge Weights	Medium	graph
2700	Differences Between Two Objects	Medium	design
2701	Consecutive Transactions with Increasing Amounts	Hard	sql
2702	Minimum Operations to Make Numbers Non-positive	Hard	binary search
2703	Return Length of Arguments Passed	Easy	design
2704	To Be Or Not To Be	Easy	design
2705	Compact Object	Medium	design
2706	Buy Two Chocolates	Easy	greedy
2707	Extra Characters in a String	Medium	dynamic programming
2708	Maximum Strength of a Group	Medium	greedy
2709	Greatest Common Divisor Traversal	Hard	breadth first search
2710	Remove Trailing Zeros From a String	Easy	string
2711	Difference of Number of Distinct Values on Diagonals	Medium	array
2712	Minimum Cost to Make All Characters Equal	Medium	greedy
2713	Maximum Strictly Increasing Cells in a Matrix	Hard	dynamic programming
2714	Find Shortest Path with K Hops	Hard	graph
2715	Execute Cancellable Function With Delay	Easy	design
2716	Minimize String Length	Easy	hash table
2717	Semi-Ordered Permutation	Easy	array
2718	Sum of Matrix After Queries	Medium	hash table
2719	Count of Integers	Hard	dynamic programming
2720	Popularity Percentage	Hard	sql
2721	Execute Asynchronous Functions in Parallel	Medium	design
2722	Join Two Arrays by ID	Medium	design
2723	Add Two Promises	Easy	design
2724	Sort By	Easy	design
2725	Interval Cancellation	Easy	design
2726	Calculator with Method Chaining	Easy	design
2727	Is Object Empty	Easy	design
2728	Count Houses in a Circular Street	Easy	constructive algorithms
2729	Check if The Number is Fascinating	Easy	string
2730	Find the Longest Semi-Repetitive Substring	Medium	two pointers
2731	Movement of Robots	Medium	math
2732	Find a Good Subset of the Matrix	Hard	constructive algorithms
2733	Neither Minimum nor Maximum	Easy	array
2734	Lexicographically Smallest String After Substring Operation	Medium	greedy
2735	Collecting Chocolates	Medium	stack
2736	Maximum Sum Queries	Hard	stack
2737	Find the Closest Marked Node	Medium	graph
2738	Count Occurrences in Text	Medium	sql
2739	Total Distance Traveled	Easy	math
2740	Find the Value of the Partition	Medium	sort
2741	Special Permutations	Medium	backtracking
2742	Painting the Walls	Hard	dynamic programming
2743	Count Substrings Without Repeating Character	Medium	two pointers
2744	Find Maximum Number of String Pairs	Easy	hash table
2745	Construct the Longest New String	Medium	constructive algorithms
2746	Decremental String Concatenation	Medium	dynamic programming
2747	Count Zero Request Servers	Hard	two pointers
2748	Number of Beautiful Pairs	Easy	hash table
2749	Minimum Operations to Make the Integer Zero	Medium	math
2750	Ways to Split Array Into Good Subarrays	Medium	math
2751	Robot Collisions	Hard	simulation
2752	Customers with Maximum Number of Transactions on Consecutive Days	Hard	sql
2753	Count Houses in a Circular Street II	Hard	constructive algorithms
2754	Bind Function to Context	Medium	design
2755	Deep Merge of Two Objects	Medium	design
2756	Query Batching	Hard	design
2757	Generate Circular Array Values	Medium	design
2758	Next Day	Easy	design
2759	Convert JSON String to Object	Hard	design
2760	Longest Even Odd Subarray With Threshold	Easy	array
2761	Prime Pairs With Target Sum	Medium	math
2762	Continuous Subarrays	Medium	two pointers
2763	Sum of Imbalance Numbers of All Subarrays	Hard	two pointers
2764	is Array a Preorder of Some ‌Binary Tree	Medium	stack
2765	Longest Alternating Subarray	Easy	array
2766	Relocate Marbles	Medium	hash table
2767	Partition String Into Minimum Beautiful Substrings	Medium	dynamic programming
2768	Number of Black Blocks	Medium	hash table
2769	Find the Maximum Achievable Number	Easy	greedy
2770	Maximum Number of Jumps to Reach the Last Index	Medium	dynamic programming
2771	Longest Non-decreasing Subarray From Two Arrays	Medium	dynamic programming
2772	Apply Operations to Make All Array Elements Equal to Zero	Medium	greedy
2773	Height of Special Binary Tree	Medium	depth first search
2774	Array Upper Bound	Easy	design
2775	Undefined to Null	Medium	design
2776	Convert Callback Based Function to Promise Based Function	Medium	design
2777	Date Range Generator	Medium	design
2778	Sum of Squares of Special Elements	Easy	math
2779	Maximum Beauty of an Array After Applying Operation	Medium	two pointers
2780	Minimum Index of a Valid Split	Medium	math
2781	Length of the Longest Valid Substring	Hard	two pointers
2782	Number of Unique Categories	Medium	array
2783	Flight Occupancy and Waitlist Analysis	Medium	sql
2784	Check if Array is Good	Easy	hash table
2785	Sort Vowels in a String	Medium	sort
2786	Visit Array Positions to Maximize Score	Medium	dynamic programming
2787	Ways to Express an Integer as Sum of Powers	Medium	dynamic programming
2788	Split Strings by Separator	Easy	string
2789	Largest Element in an Array after Merge Operations	Medium	greedy
2790	Maximum Number of Groups With Increasing Length	Hard	greedy
2791	Count Paths That Can Form a Palindrome in a Tree	Hard	depth first search
2792	Count Nodes That Are Great Enough	Hard	sort
2793	Status of Flight Tickets	Hard	sql
2794	Create Object from Two Arrays	Easy	design
2795	Parallel Execution of Promises for Individual Results Retrieval	Medium	design
2796	Repeat String	Easy	design
2797	Partial Function with Placeholders	Medium	design
2798	Number of Employees Who Met the Target	Easy	array
2799	Count Complete Subarrays in an Array	Medium	two pointers
2800	Shortest String That Contains Three Strings	Medium	string
2801	Count Stepping Numbers in Range	Hard	dynamic programming
2802	Find The K-th Lucky Number	Medium	math
2803	Factorial Generator	Easy	design
2804	Array Prototype ForEach	Easy	design
2805	Custom Interval	Medium	design
2806	Account Balance After Rounded Purchase	Easy	math
2807	Insert Greatest Common Divisors in Linked List	Medium	linked list
2808	Minimum Seconds to Equalize a Circular Array	Medium	hash table
2809	Minimum Time to Make Array Sum At Most x	Hard	dynamic programming
2810	Faulty Keyboard	Easy	string
2811	Check if it is Possible to Split Array	Medium	constructive algorithms
2812	Find the Safest Path in a Grid	Medium	breadth first search
2813	Maximum Elegance of a K-Length Subsequence	Hard	greedy
2814	Minimum Time Takes to Reach Destination Without Drowning	Hard	breadth first search
2815	Max Pair Sum in an Array	Easy	hash table
2816	Double a Number Represented as a Linked List	Medium	linked list
2817	Minimum Absolute Difference Between Elements With Constraint	Medium	binary search tree
2818	Apply Operations to Maximize Score	Hard	binary heap
2819	Minimum Relative Loss After Buying Chocolates	Hard	greedy
2820	Election Results	Medium	sql
2821	Delay the Resolution of Each Promise	Easy	design
2822	Inversion of Object	Easy	design
2823	Deep Object Filter	Medium	design
2824	Count Pairs Whose Sum is Less than Target	Easy	two pointers
2825	Make String a Subsequence Using Cyclic Increments	Medium	greedy
2826	Sorting Three Groups	Medium	dynamic programming
2827	Number of Beautiful Integers in the Range	Hard	dynamic programming
2828	Check if a String Is an Acronym of Words	Easy	string
2829	Determine the Minimum Sum of a k-avoiding Array	Medium	constructive algorithms
2830	Maximize the Profit as the Salesman	Medium	dynamic programming
2831	Find the Longest Equal Subarray	Medium	two pointers
2832	Maximal Range That Each Element Is Maximum in It	Medium	stack
2833	Furthest Point From Origin	Easy	math
2834	Find the Minimum Possible Sum of a Beautiful Array	Medium	constructive algorithms
2835	Minimum Operations to Form Subsequence With Target Sum	Hard	greedy
2836	Maximize Value of Function in a Ball Passing Game	Hard	graph
2837	Total Traveled Distance	Easy	sql
2838	Maximum Coins Heroes Can Collect	Medium	two pointers
2839	Check if Strings Can be Made Equal With Operations I	Easy	hash table
2840	Check if Strings Can be Made Equal With Operations II	Medium	hash table
2841	Maximum Sum of Almost Unique Subarray	Medium	two pointers
2842	Count K-Subsequences of a String With Maximum Beauty	Hard	greedy
2843	Count Symmetric Integers	Easy	string
2844	Minimum Operations to Make a Special Number	Medium	greedy
2845	Count of Interesting Subarrays	Medium	hash table
2846	Minimum Edge Weight Equilibrium Queries in a Tree	Hard	tree
2847	Smallest Number With Given Digit Product	Medium	greedy
2848	Points That Intersect With Cars	Easy	array
2849	Determine if a Cell Is Reachable at a Given Time	Medium	constructive algorithms
2850	Minimum Moves to Spread Stones Over Grid	Medium	graph
2851	String Transformation	Hard	string
2852	Sum of Remoteness of All Cells	Medium	breadth first search
2853	Highest Salaries Difference	Easy	sql
2854	Rolling Average Steps	Medium	sql
2855	Minimum Right Shifts to Sort the Array	Easy	array
2856	Minimum Array Length After Pair Removals	Medium	constructive algorithms
2857	Count Pairs of Points With Distance k	Medium	hash table
2858	Minimum Edge Reversals So Every Node Is Reachable	Hard	dynamic programming
2859	Sum of Values at Indices With K Set Bits	Easy	bit manipulation
2860	Happy Students	Medium	greedy
2861	Maximum Number of Alloys	Medium	math
2862	Maximum Element-Sum of a Complete Subset of Indices	Hard	math
2863	Maximum Length of Semi-Decreasing Subarrays	Medium	stack
2864	Maximum Odd Binary Number	Easy	greedy
2865	Beautiful Towers I	Medium	stack
2866	Beautiful Towers II	Medium	stack
2867	Count Valid Paths in a Tree	Hard	dynamic programming
2868	The Wording Game	Hard	greedy
2869	Minimum Operations to Collect Elements	Easy	hash table
2870	Minimum Number of Operations to Make Array Empty	Medium	greedy
2871	Split Array Into Maximum Number of Subarrays	Medium	greedy
2872	Maximum Number of K-Divisible Components	Hard	greedy
2873	Maximum Value of an Ordered Triplet I	Easy	array
2874	Maximum Value of an Ordered Triplet II	Easy	array
2875	Minimum Size Subarray in Infinite Array	Medium	two pointers
2876	Count Visited Nodes in a Directed Graph	Hard	graph
2877	Create a DataFrame from List	Easy	sql
2878	Get the Size of a DataFrame	Easy	sql
2879	Display the First Three Rows	Easy	sql
2880	Select Data	Easy	sql
2881	Create a New Column	Easy	sql
2882	Drop Duplicate Rows	Easy	sql
2883	Drop Missing Data	Easy	sql
2884	Modify Columns	Easy	sql
2885	Rename Columns	Easy	sql
2886	Change Data Type	Easy	sql
2887	Fill Missing Data	Easy	sql
2888	Reshape Data: Concatenate	Easy	sql
2889	Reshape Data: Pivot	Easy	sql
2890	Reshape Data: Melt	Easy	sql
2891	Method Chaining	Easy	sql
2892	Minimizing Array After Replacing Pairs With Their Product	Medium	greedy
2893	Calculate Orders Within Each Interval	Medium	sql
2894	Divisible and Non-divisible Sums Difference	Easy	math
2895	Minimum Processing Time	Medium	greedy
2896	Apply Operations to Make Two Strings Equal	Medium	dynamic programming
2897	Apply Operations on Array to Maximize Sum of Squares	Hard	greedy
2898	Maximum Linear Stock Score	Medium	math
2899	Last Visited Integers	Easy	stack
2900	Longest Unequal Adjacent Groups Subsequence I	Medium	greedy
2901	Longest Unequal Adjacent Groups Subsequence II	Medium	dynamic programming
2902	Count of Sub-Multisets With Bounded Sum	Hard	dynamic programming
2903	Find Indices With Index and Value Difference I	Easy	array
2904	Shortest and Lexicographically Smallest Beautiful String	Medium	two pointers
2905	Find Indices With Index and Value Difference II	Medium	array
2906	Construct Product Matrix	Medium	array
2907	Maximum Profitable Triplets With Increasing Prices I	Medium	binary search tree
2908	Minimum Sum of Mountain Triplets I	Easy	array
2909	Minimum Sum of Mountain Triplets II	Medium	array
2910	Minimum Number of Groups to Create a Valid Assignment	Medium	greedy
2911	Minimum Changes to Make K Semi-palindromes	Hard	dynamic programming
2912	Number of Ways to Reach Destination in the Grid	Hard	dynamic programming
2913	Subarrays Distinct Element Sum of Squares I	Easy	dynamic programming
2914	Minimum Number of Changes to Make Binary String Beautiful	Medium	greedy
2915	Length of the Longest Subsequence That Sums to Target	Medium	dynamic programming
2916	Subarrays Distinct Element Sum of Squares II	Easy	dynamic programming
2917	Find the K-or of an Array	Easy	bit manipulation
2918	Minimum Equal Sum of Two Arrays After Replacing Zeros	Medium	greedy
2919	Minimum Increment Operations to Make Array Beautiful	Medium	dynamic programming
2920	Maximum Points After Collecting Coins From All Nodes	Hard	dynamic programming
2921	Maximum Profitable Triplets With Increasing Prices II	Hard	binary search tree
2922	Market Analysis III	Medium	sql
2923	Find Champion I	Easy	array
2924	Find Champion II	Medium	graph
2925	Maximum Score After Applying Operations on a Tree	Medium	dynamic programming
2926	Maximum Balanced Subsequence Sum	Hard	binary search tree
2927	Distribute Candies Among Children III	Hard	math
2928	Distribute Candies Among Children I	Easy	math
2929	Distribute Candies Among Children II	Medium	math
2930	Number of Strings Which Can Be Rearranged to Contain Substring	Medium	math
2931	Minimum Equal Sum of Two Arrays After Replacing Zeros	Hard	greedy
2932	Maximum Strong Pair XOR I	Easy	bit manipulation
2933	High-Access Employees	Medium	two pointers
2934	Minimum Operations to Maximize Last Elements in Arrays	Medium	simulation
2935	Maximum Strong Pair XOR II	Hard	bit manipulation
2936	Number of Equal Numbers Blocks	Medium	binary search
2937	Make Three Strings Equal	Easy	string
2938	Separate Black and White Balls	Medium	two pointers
2939	Maximum Xor Product	Medium	greedy
2940	Find Building Where Alice and Bob Can Meet	Hard	binary search
2941	Maximum GCD-Sum of a Subarray	Hard	dynamic programming
2942	Find Words Containing Character	Easy	string
2943	Maximize Area of Square Hole in Grid	Medium	hash table
2944	Minimum Number of Coins for Fruits	Medium	dynamic programming
2945	Find Maximum Non-decreasing Array Length	Hard	dynamic programming
2946	Matrix Similarity After Cyclic Shifts	Easy	array
2947	Count Beautiful Substrings I	Medium	hash table
2948	Make Lexicographically Smallest Array by Swapping Elements	Medium	sort
2949	Count Beautiful Substrings II	Hard	hash table
2950	Number of Divisible Substrings	Medium	hash table
2951	Find the Peaks	Easy	array
2952	Minimum Number of Coins to be Added	Medium	greedy
2953	Count Complete Substrings	Medium	two pointers
2954	Count the Number of Infection Sequences	Hard	math
2955	Number of Same-End Substrings	Medium	hash table
2956	Find Common Elements Between Two Arrays	Easy	hash table
2957	Remove Adjacent Almost-Equal Characters	Medium	greedy
2958	Length of Longest Subarray With at Most K Frequency	Medium	two pointers
2959	Number of Possible Sets of Closing Branches	Medium	graph
2960	Count Tested Devices After Test Operations	Easy	simulation
2961	Double Modular Exponentiation	Medium	math
2962	Count Subarrays Where Max Element Appears at Least K Times	Medium	two pointers
2963	Count the Number of Good Partitions	Hard	math
2964	Number of Divisible Triplet Sums	Medium	hash table
2965	Find Missing and Repeated Values	Easy	array
2966	Divide Array Into Arrays With Max Difference	Medium	array
2967	Minimum Cost to Make Array Equalindromic	Medium	string
2968	Apply Operations to Maximize Frequency Score	Hard	two pointers
2969	Minimum Number of Coins for Fruits II	Hard	dynamic programming
2970	Count the Number of Incremovable Subarrays I	Easy	two pointers
2971	Find Polygon With the Largest Perimeter	Medium	greedy
2972	Count the Number of Incremovable Subarrays II	Hard	two pointers
2973	Find Number of Coins to Place in Tree Nodes	Hard	depth first search
2974	Minimum Number Game	Easy	sort
2975	Maximum Square Area by Removing Fences From a Field	Medium	hash table
2976	Minimum Cost to Convert String I	Medium	dynamic programming
2977	Minimum Cost to Convert String II	Hard	dynamic programming
2978	Symmetric Coordinates	Medium	sql
2979	Most Expensive Item That Can Not Be Bought	Medium	math
2980	Check if Bitwise OR Has Trailing Zeros	Easy	bit manipulation
2981	Find Longest Special Substring That Occurs Thrice I	Medium	hash table
2982	Find Longest Special Substring That Occurs Thrice II	Medium	hash table
2983	Palindrome Rearrangement Queries	Hard	hash table
2984	Find Peak Calling Hours for Each City	Medium	sql
2985	Calculate Compressed Mean	Easy	sql
2986	Find Third Transaction	Medium	sql
2987	Find Expensive Cities	Easy	sql
2988	Manager of the Largest Department	Medium	sql
2989	Class Performance	Medium	sql
2990	Loan Types	Easy	sql
2991	Top Three Wineries	Hard	sql
2992	Number of Self-Divisible Permutations	Medium	dynamic programming
2993	Friday Purchases I	Medium	sql
2994	Friday Purchases II	Hard	sql
2995	Viewers Turned Streamers	Hard	sql
2996	Smallest Missing Integer Greater Than Sequential Prefix Sum	Easy	hash table
2997	Minimum Number of Operations to Make Array XOR Equal to K	Medium	bit manipulation
2998	Minimum Number of Operations to Make X and Y Equal	Medium	dynamic programming
2999	Count the Number of Powerful Integers	Hard	math
3000	Maximum Area of Longest Diagonal Rectangle	Easy	array
3001	Minimum Moves to Capture The Queen	Medium	math
3002	Maximum Size of a Set After Removals	Medium	greedy
3003	Maximize the Number of Partitions After Operations	Hard	greedy
3004	Maximum Subtree of the Same Color	Medium	depth first search
3005	Count Elements With Maximum Frequency	Easy	hash table
3006	Find Beautiful Indices in the Given Array I	Medium	two pointers
3007	Maximum Number That Sum of the Prices Is Less Than or Equal to K	Medium	math
3008	Find Beautiful Indices in the Given Array II	Hard	two pointers
3009	Maximum Number of Intersections on the Chart	Hard	array
3010	Divide an Array Into Subarrays With Minimum Cost I	Easy	array
3011	Find if Array Can Be Sorted	Medium	sort
3012	Minimize Length of Array Using Operations	Medium	greedy
3013	Divide an Array Into Subarrays With Minimum Cost II	Hard	two pointers
3014	Minimum Number of Pushes to Type Word I	Easy	greedy
3015	Count the Number of Houses at a Certain Distance I	Medium	array
3016	Minimum Number of Pushes to Type Word II	Medium	greedy
3017	Count the Number of Houses at a Certain Distance II	Hard	array
3018	Maximum Number of Removal Queries That Can Be Processed I	Hard	dynamic programming
3019	Number of Changing Keys	Easy	string
3020	Find the Maximum Number of Elements in Subset	Medium	dynamic programming
3021	Alice and Bob Playing Flower Game	Medium	math
3022	Minimize OR of Remaining Elements Using Operations	Hard	greedy
3023	Find Pattern in Infinite Stream I	Medium	string
3024	Type of Triangle II	Easy	math
3025	Find the Number of Ways to Place People I	Medium	sort
3026	Maximum Good Subarray Sum	Medium	array
3027	Find the Number of Ways to Place People II	Hard	sort
3028	Ant on the Boundary	Easy	array
3029	Minimum Time to Revert Word to Initial State I	Medium	string
3030	Find the Grid of Region Average	Medium	array
3031	Minimum Time to Revert Word to Initial State II	Hard	string
3032	Count Numbers With Unique Digits II	Easy	math
3033	Modify the Matrix	Easy	array
3034	Number of Subarrays That Match a Pattern I	Medium	string
3035	Maximum Palindromes After Operations	Medium	greedy
3036	Number of Subarrays That Match a Pattern II	Hard	string
3037	Find Pattern in Infinite Stream II	Hard	string
3038	Maximum Number of Operations With the Same Score I	Easy	array
3039	Apply Operations to Make String Empty	Medium	hash table
3040	Maximum Number of Operations With the Same Score II	Medium	dynamic programming
3041	Maximize Consecutive Elements in an Array After Modification	Hard	dynamic programming
3042	Count Prefix and Suffix Pairs I	Easy	string
3043	Find the Length of the Longest Common Prefix	Medium	string
3044	Most Frequent Prime	Medium	hash table
3045	Count Prefix and Suffix Pairs II	Hard	string
3046	Split the Array	Easy	hash table
3047	Find the Largest Area of Square Inside Two Rectangles	Medium	math
3048	Earliest Second to Mark Indices I	Medium	binary search
3049	Earliest Second to Mark Indices II	Hard	binary search
3050	Pizza Toppings Cost Analysis	Medium	sql
3051	Find Candidates for Data Scientist Position	Easy	sql
3052	Maximize Items	Hard	sql
3053	Classifying Triangles by Lengths	Easy	sql
3054	Binary Tree Nodes	Medium	sql
3055	Top Percentile Fraud	Medium	sql
3056	Snaps Analysis	Medium	sql
3057	Employees Project Allocation	Hard	sql
3058	Friends With No Mutual Friends	Medium	sql
3059	Find All Unique Email Domains	Easy	sql
3060	User Activities within Time Bounds	Hard	sql
3061	Calculate Trapping Rain Water	Hard	sql
3062	Winner of the Linked List Game	Easy	linked list
3063	Linked List Frequency	Medium	linked list
3064	Guess the Number Using Bitwise Questions I	Medium	bit manipulation
3065	Minimum Operations to Exceed Threshold Value I	Easy	array
3066	Minimum Operations to Exceed Threshold Value II	Medium	binary heap
3067	Count Pairs of Connectable Servers in a Weighted Tree Network	Medium	depth first search
3068	Find the Maximum Sum of Node Values	Hard	greedy
3069	Distribute Elements Into Two Arrays I	Easy	array
3070	Count Submatrices with Top-Left Element and Sum Less Than k	Medium	array
3071	Minimum Operations to Write the Letter Y on a Grid	Medium	array
3072	Distribute Elements Into Two Arrays II	Hard	binary search tree
3073	Maximum Increasing Triplet Value	Medium	binary search tree
3074	Apple Redistribution into Boxes	Easy	greedy
3075	Maximize Happiness of Selected Children	Medium	greedy
3076	Shortest Uncommon Substring in an Array	Medium	string
3077	Maximum Strength of K Disjoint Subarrays	Hard	dynamic programming
3078	Match Alphanumerical Pattern in Matrix I	Medium	hash table
3079	Find the Sum of Encrypted Integers	Easy	array
3080	Mark Elements on Array by Performing Queries	Medium	binary heap
3081	Replace Question Marks in String to Minimize Its Value	Medium	sort
3082	Find the Sum of the Power of All Subsequences	Hard	dynamic programming
3083	Existence of a Substring in a String and Its Reverse	Easy	hash table
3084	Count Substrings Starting and Ending with Given Character	Medium	math
3085	Minimum Deletions to Make String K-Special	Medium	two pointers
3086	Minimum Moves to Pick K Ones	Hard	greedy
3087	Find Trending Hashtags	Medium	sql
3088	Make String Anti-palindrome	Hard	greedy
3089	Find Bursty Behavior	Medium	sql
3090	Maximum Length Substring With Two Occurrences	Easy	two pointers
3091	Apply Operations to Make Sum of Array Greater Than or Equal to k	Medium	math
3092	Most Frequent IDs	Medium	binary heap
3093	Longest Common Suffix Queries	Hard	string
3094	Guess the Number Using Bitwise Questions II	Medium	bit manipulation
3095	Shortest Subarray With OR at Least K I	Easy	two pointers
3096	Minimum Levels to Gain More Points	Medium	array
3097	Shortest Subarray With OR at Least K II	Medium	two pointers
3098	Find the Sum of Subsequence Powers	Hard	dynamic programming
3099	Harshad Number	Easy	math
3100	Water Bottles II	Medium	simulation
3101	Count Alternating Subarrays	Medium	dynamic programming
3102	Minimize Manhattan Distances	Hard	math
3103	Find Trending Hashtags II	Hard	sql
3104	Find Longest Self-Contained Substring	Hard	binary search
3105	Longest Strictly Increasing or Strictly Decreasing Subarray	Easy	array
3106	Lexicographically Smallest String After Operations With Constraint	Medium	greedy
3107	Minimum Operations to Make Median of Array Equal to K	Medium	greedy
3108	Minimum Cost Walk in Weighted Graph	Hard	graph
3109	Find the Index of Permutation	Medium	tree
3110	Score of a String	Easy	string
3111	Minimum Rectangles to Cover Points	Medium	greedy
3112	Minimum Time to Visit Disappearing Nodes	Medium	graph
3113	Find the Number of Subarrays Where Boundary Elements Are Maximum	Hard	stack
3114	Latest Time You Can Obtain After Replacing Characters	Easy	greedy
3115	Maximum Prime Difference	Medium	math
3116	Kth Smallest Amount With Single Denomination Combination	Hard	binary search
3117	Minimum Sum of Values by Dividing Array	Hard	dynamic programming
3118	Friday Purchase III	Medium	sql
3119	Maximum Number of Potholes That Can Be Fixed	Medium	greedy
3120	Count the Number of Special Characters I	Easy	hash table
3121	Count the Number of Special Characters II	Medium	hash table
3122	Minimum Number of Operations to Satisfy Conditions	Medium	dynamic programming
3123	Find Edges in Shortest Paths	Medium	graph
3124	Find Longest Calls	Medium	sql
3125	Maximum Number That Makes Result of Bitwise AND Zero	Medium	bit manipulation
3126	Server Utilization Time	Medium	sql
3127	Make a Square with the Same Color	Easy	array
3128	Right Triangles	Medium	math
3129	Find All Possible Stable Binary Arrays I	Medium	dynamic programming
3130	Find All Possible Stable Binary Arrays II	Hard	dynamic programming
3131	Find the Integer Added to Array I	Easy	array
3132	Find the Integer Added to Array II	Medium	sort
3133	Minimum Array End	Medium	bit manipulation
3134	Find the Median of the Uniqueness Array	Hard	binary search
3135	Equalize Strings by Adding or Removing Characters at Ends	Medium	binary search
3136	Valid Word	Easy	string
3137	Minimum Number of Operations to Make Word K-Periodic	Medium	hash table
3138	Minimum Length of Anagram Concatenation	Medium	hash table
3139	Minimum Cost to Equalize Array	Hard	constructive algorithms
3140	Consecutive Available Seats II	Medium	sql
3141	Maximum Hamming Distances	Hard	dynamic programming
3142	Check if Grid Satisfies Conditions	Easy	array
3143	Maximum Points Inside the Square	Medium	hash table
3144	Minimum Substring Partition of Equal Character Frequency	Medium	dynamic programming
3145	Find Products of Elements of Big Array	Hard	binary search
3146	Permutation Difference between Two Strings	Easy	hash table
3147	Taking Maximum Energy From the Mystic Dungeon	Medium	array
3148	Maximum Difference Score in a Grid	Medium	dynamic programming
3149	Find the Minimum Cost Array Permutation	Hard	dynamic programming
3150	Invalid Tweets II	Easy	sql
3151	Special Array I	Easy	array
3152	Special Array II	Medium	array
3153	Sum of Digit Differences of All Pairs	Medium	array
3154	Find Number of Ways to Reach the K-th Stair	Hard	math
3155	Maximum Number of Upgradable Servers	Medium	math
3156	Employee Task Duration and Concurrent Tasks	Hard	sql
3157	Find the Level of Tree with Minimum Sum	Medium	breadth first search
3158	Find the XOR of Numbers Which Appear Twice	Easy	hash table
3159	Find Occurrences of an Element in an Array	Medium	array
3160	Find the Number of Distinct Colors Among the Balls	Medium	hash table
3161	Block Placement Queries	Hard	binary search tree
3162	Find the Number of Good Pairs I	Easy	math
3163	String Compression III	Medium	string
3164	Find the Number of Good Pairs II	Medium	math
3165	Maximum Sum of Subsequence With Non-adjacent Elements	Hard	binary search tree
3166	Calculate Parking Fees and Duration	Medium	sql
3167	Better Compression of String	Medium	hash table
3168	Minimum Number of Chairs in a Waiting Room	Easy	simulation
3169	Count Days Without Meetings	Medium	sort
3170	Lexicographically Minimum String After Removing Stars	Medium	greedy
3171	Find Subarray With Bitwise OR Closest to K	Hard	two pointers
3172	Second Day Verification	Easy	sql
3173	Bitwise OR of Adjacent Elements	Easy	array
3174	Clear Digits	Easy	stack
3175	Find The First Player to win K Games in a Row	Medium	simulation
3176	Find the Maximum Length of a Good Subsequence I	Medium	dynamic programming
3177	Find the Maximum Length of a Good Subsequence II	Hard	dynamic programming
3178	Find the Child Who Has the Ball After K Seconds	Easy	math
3179	Find the N-th Value After K Seconds	Medium	math
3180	Maximum Total Reward Using Operations I	Medium	dynamic programming
3181	Maximum Total Reward Using Operations II	Hard	dynamic programming
3182	Find Top Scoring Students	Medium	sql
3183	The Number of Ways to Make the Sum	Medium	math
3184	Count Pairs That Form a Complete Day I	Easy	hash table
3185	Count Pairs That Form a Complete Day II	Medium	hash table
3186	Maximum Total Damage With Spell Casting	Medium	dynamic programming
3187	Peaks in Array	Hard	array
3188	Find Top Scoring Students II	Hard	sql
3189	Minimum Moves to Get a Peaceful Board	Medium	greedy
3190	Find Minimum Operations to Make All Elements Divisible by Three	Easy	math
3191	Minimum Operations to Make Binary Array Elements Equal to One I	Medium	greedy
3192	Minimum Operations to Make Binary Array Elements Equal to One II	Medium	greedy
3193	Count the Number of Inversions	Hard	dynamic programming
3194	Minimum Average of Smallest and Largest Elements	Easy	sort
3195	Find the Minimum Area to Cover All Ones I	Medium	array
3196	Maximize Total Cost of Alternating Subarrays	Medium	dynamic programming
3197	Find the Minimum Area to Cover All Ones II	Hard	dynamic programming
3198	Find Cities in Each State	Easy	sql
3199	Count Triplets with Even XOR Set Bits I	Easy	bit manipulation
3200	Maximum Height of a Triangle	Easy	math
3201	Find the Maximum Length of Valid Subsequence I	Medium	dynamic programming
3202	Find the Maximum Length of Valid Subsequence II	Medium	dynamic programming
3203	Find Minimum Diameter After Merging Two Trees	Hard	depth first search
3204	Bitwise User Permissions Analysis	Medium	sql
3205	Maximum Array Hopping Score I	Medium	greedy
3206	Alternating Groups I	Easy	two pointers
3207	Maximum Points After Enemy Battles	Medium	greedy
3208	Alternating Groups II	Medium	two pointers
3209	Number of Subarrays With AND Value of K	Hard	dynamic programming
3210	Find the Encrypted String	Medium	string
3211	Generate Binary Strings Without Adjacent Zeros	Medium	backtracking
3212	Count Submatrices With Equal Frequency of X and Y	Medium	dynamic programming
3213	Construct String with Minimum Cost	Hard	dynamic programming
3214	Year on Year Growth Rate	Hard	sql
3215	Count Triplets with Even XOR Set Bits II	Medium	bit manipulation
3216	Lexicographically Smallest String After a Swap	Easy	greedy
3217	Delete Nodes From Linked List Present in Array	Medium	linked list
3218	Minimum Cost for Cutting Cake I	Medium	greedy
3219	Minimum Cost for Cutting Cake II	Hard	greedy
3220	Odd and Even Transactions	Medium	sql
3221	Maximum Array Hopping Score II	Medium	greedy
3222	Find the Winning Player in Coin Game	Easy	math
3223	Minimum Length of String After Operations	Medium	hash table
3224	Minimum Array Changes to Make Differences Equal	Medium	array
3225	Maximum Score From Grid Operations	Hard	dynamic programming
3226	Number of Bit Changes to Make Two Integers Equal	Easy	bit manipulation
3227	Vowels Game in a String	Medium	math
3228	Maximum Number of Operations to Move Ones to the End	Medium	greedy
3229	Minimum Operations to Make Array Equal to Target	Hard	greedy
3230	Customer Purchasing Behavior Analysis	Medium	sql
3231	Minimum Number of Increasing Subsequence to Be Removed	Hard	binary search
3232	Find if Digit Game Can Be Won	Easy	math
3233	Find the Count of Numbers Which Are Not Special	Medium	binary search
3234	Count the Number of Substrings With Dominant Ones	Medium	two pointers
3235	Check if the Rectangle Corner Is Reachable	Hard	graph
3236	CEO Subordinate Hierarchy	Hard	sql
3237	Alt and Tab Simulation	Medium	hash table
3238	Find the Number of Winning Players	Easy	hash table
3239	Minimum Number of Flips to Make Binary Grid Palindromic I	Medium	greedy
3240	Minimum Number of Flips to Make Binary Grid Palindromic II	Medium	greedy
3241	Time Taken to Mark All Nodes	Hard	dynamic programming
3242	Design Neighbor Sum Service	Easy	design
3243	Shortest Distance After Road Addition Queries I	Medium	graph
3244	Shortest Distance After Road Addition Queries II	Hard	graph
3245	Alternating Groups III	Hard	hash table
3246	Premier League Table Ranking	Easy	sql
3247	Number of Subsequences with Odd Sum	Medium	math
3248	Snake in Matrix	Medium	simulation
3249	Count the Number of Good Nodes	Medium	depth first search
3250	Find the Count of Monotonic Pairs I	Hard	math
3251	Find the Count of Monotonic Pairs II	Hard	math
3252	Premier League Table Ranking II	Medium	sql
3253	Construct String with Minimum Cost (Easy)	Medium	dynamic programming
3254	Find the Power of K-Size Subarrays I	Medium	two pointers
3255	Find the Power of K-Size Subarrays II	Medium	two pointers
3256	Maximum Value Sum by Placing Three Rooks I	Hard	binary heap
3257	Maximum Value Sum by Placing Three Rooks II	Hard	binary heap
3258	Count Substrings That Satisfy K-Constraint I	Easy	two pointers
3259	Maximum Energy Boost From Two Drinks	Medium	dynamic programming
3260	Find the Largest Palindrome Divisible by K	Hard	constructive algorithms
3261	Count Substrings That Satisfy K-Constraint II	Hard	two pointers
3262	Find Overlapping Shifts	Medium	sql
3263	Convert Doubly Linked List to Array I	Easy	linked list
3264	Final Array State After K Multiplication Operations I	Easy	two pointers
3265	Count Almost Equal Pairs I	Medium	graph
3266	Final Array State After K Multiplication Operations II	Hard	two pointers
3267	Count Almost Equal Pairs II	Hard	graph
3268	Find Overlapping Shifts II	Hard	sql
3269	Constructing Two Increasing Arrays	Hard	dynamic programming
3270	Find the Key of the Numbers	Easy	math
3271	Hash Divided String	Medium	string
3272	Find the Count of Good Integers	Hard	math
3273	Minimum Amount of Damage Dealt to Bob	Hard	greedy
3274	Check if Two Chessboard Squares Have the Same Color	Easy	math
3275	K-th Nearest Obstacle Queries	Medium	binary heap
3276	Select Cells in Grid With Maximum Score	Hard	graph
3277	Maximum XOR Score Subarray Queries	Hard	dynamic programming
3278	Find Candidates for Data Scientist Position II	Medium	sql
3279	Maximum Total Area Occupied by Pistons	Hard	array
3280	Convert Date to Binary	Easy	string
3281	Maximize Score of Numbers in Ranges	Medium	binary search
3282	Reach End of Array With Max Score	Medium	greedy
3283	Maximum Number of Moves to Kill All Pawns	Hard	dynamic programming
3284	Sum of Consecutive Subarrays	Medium	math
3285	Find Indices of Stable Mountains	Easy	array
3286	Find a Safe Walk Through a Grid	Medium	breadth first search
3287	Find the Maximum Sequence Value of Array	Hard	dynamic programming
3288	Length of the Longest Increasing Path	Hard	binary search
3289	The Two Sneaky Numbers of Digitville	Easy	bit manipulation
3290	Maximum Multiplication Score	Medium	dynamic programming
3291	Minimum Number of Valid Strings to Form Target I	Medium	dynamic programming
3292	Minimum Number of Valid Strings to Form Target II	Hard	dynamic programming
3293	Calculate Product Final Price	Medium	sql
3294	Convert Doubly Linked List to Array II	Medium	linked list
3295	Report Spam Message	Medium	hash table
3296	Minimum Number of Seconds to Make Mountain Height Zero	Medium	binary search
3297	Count Substrings That Can Be Rearranged to Contain a String I	Medium	two pointers
3298	Count Substrings That Can Be Rearranged to Contain a String II	Hard	two pointers
3299	Sum of Consecutive Subsequences	Hard	math
3300	Minimum Element After Replacement With Digit Sum	Easy	array
3301	Maximize the Total Height of Unique Towers	Medium	greedy
3302	Find the Lexicographically Smallest Valid Sequence	Medium	greedy
3303	Find the Occurrence of First Almost Equal Substring	Hard	string
3304	Find the K-th Character in String Game I	Easy	bit manipulation
3305	Count of Substrings Containing Every Vowel and K Consonants I	Medium	two pointers
3306	Count of Substrings Containing Every Vowel and K Consonants II	Medium	two pointers
3307	Find the K-th Character in String Game II	Hard	bit manipulation
3308	Find Top Performing Driver	Medium	sql
3309	Maximum Possible Number by Binary Concatenation	Medium	sort
3310	Remove Methods From Project	Medium	graph
3311	Construct 2D Grid Matching Graph Layout	Hard	constructive algorithms
3312	Sorted GCD Pair Queries	Hard	math
3313	Find the Last Marked Nodes in Tree	Hard	dynamic programming
3314	Construct the Minimum Bitwise Array I	Easy	bit manipulation
3315	Construct the Minimum Bitwise Array II	Medium	bit manipulation
3316	Find Maximum Removals From Source String	Medium	dynamic programming
3317	Find the Number of Possible Ways for an Event	Hard	math
3318	Find X-Sum of All K-Long Subarrays I	Easy	two pointers
3319	K-th Largest Perfect Subtree Size in Binary Tree	Medium	depth first search
3320	Count The Number of Winning Sequences	Hard	dynamic programming
3321	Find X-Sum of All K-Long Subarrays II	Hard	two pointers
3322	Premier League Table Ranking III	Medium	sql
3323	Minimize Connected Groups by Inserting Interval	Medium	two pointers
3324	Find the Sequence of Strings Appeared on the Screen	Medium	string
3325	Count Substrings With K-Frequency Characters I	Medium	two pointers
3326	Minimum Division Operations to Make Array Non Decreasing	Medium	math
3327	Check if DFS Strings Are Palindromes	Hard	depth first search
3328	Find Cities in Each State II	Medium	sql
3329	Count Substrings With K-Frequency Characters II	Hard	two pointers
3330	Find the Original Typed String I	Easy	array
3331	Find Subtree Sizes After Changes	Medium	depth first search
3332	Maximum Points Tourist Can Earn	Hard	dynamic programming
3333	Find the Original Typed String II	Hard	dynamic programming
3334	Find the Maximum Factor Score of Array	Medium	array
3335	Total Characters in String After Transformations I	Medium	dynamic programming
3336	Find the Number of Subsequences With Equal GCD	Hard	dynamic programming
3337	Total Characters in String After Transformations II	Hard	dynamic programming
3338	Second Highest Salary II	Medium	sql
3339	Find the Number of K-Even Arrays	Medium	math
3340	Check Balanced String	Easy	string
3341	Find Minimum Time to Reach Last Room I	Medium	graph
3342	Find Minimum Time to Reach Last Room II	Medium	graph
3343	Count Number of Balanced Permutations	Hard	dynamic programming
3344	Maximum Sized Array	Medium	bit manipulation
3345	Smallest Divisible Digit Product I	Easy	math
3346	Maximum Frequency of an Element After Performing Operations I	Medium	two pointers
3347	Maximum Frequency of an Element After Performing Operations II	Hard	two pointers
3348	Smallest Divisible Digit Product II	Hard	math
3349	Adjacent Increasing Subarrays Detection I	Easy	array
3350	Adjacent Increasing Subarrays Detection II	Medium	array
3351	Sum of Good Subsequences	Hard	dynamic programming
3352	Count K-Reducible Numbers Less Than N	Hard	dynamic programming
3353	Minimum Total Operations	Easy	array
3354	Make Array Elements Equal to Zero	Easy	array
3355	Zero Array Transformation I	Medium	array
3356	Zero Array Transformation II	Medium	binary search
3357	Minimize the Maximum Adjacent Element Difference	Hard	binary search
3358	Books with NULL Ratings	Easy	sql
3359	Find Sorted Submatrices With Maximum Element at Most K	Hard	dynamic programming
3360	Stone Removal Game	Easy	math
3361	Shift Distance Between Two Strings	Medium	array
3362	Zero Array Transformation III	Medium	greedy
3363	Find the Maximum Number of Fruits Collected	Hard	dynamic programming
3364	Minimum Positive Sum Subarray	Easy	two pointers
3365	Rearrange K Substrings to Form Target String	Medium	hash table
3366	Minimum Array Sum	Medium	dynamic programming
3367	Maximize Sum of Weights after Edge Removals	Hard	depth first search
3368	First Letter Capitalization	Hard	sql
3369	Design an Array Statistics Tracker	Hard	design
3370	Smallest Number With All Set Bits	Easy	bit manipulation
3371	Identify the Largest Outlier in an Array	Medium	hash table
3372	Maximize the Number of Target Nodes After Connecting Trees I	Medium	dynamic programming
3373	Maximize the Number of Target Nodes After Connecting Trees II	Hard	breadth first search
3374	First Letter Capitalization II	Hard	sql
3375	Minimum Operations to Make Array Values Equal to K	Easy	constructive algorithms
3376	Minimum Time to Break Locks I	Medium	graph
3377	Digit Operations to Make Two Integers Equal	Medium	graph
3378	Count Connected Components in LCM Graph	Hard	graph
3379	Transformed Array	Easy	array
3380	Maximum Area Rectangle With Point Constraints I	Medium	array
3381	Maximum Subarray Sum With Length Divisible by K	Medium	dynamic programming
3382	Maximum Area Rectangle With Point Constraints II	Hard	array
3383	Minimum Runes to Add to Cast Spell	Hard	graph
3384	Team Dominance by Pass Success	Hard	sql
3385	Minimum Time to Break Locks II	Hard	graph
3386	Button with Longest Push Time	Easy	array
3387	Maximize Amount After Two Days of Conversions	Medium	graph
3388	Count Beautiful Splits in an Array	Medium	dynamic programming
3389	Minimum Operations to Make Character Frequencies Equal	Hard	dynamic programming
3390	Longest Team Pass Streak	Hard	sql
3391	Design a 3D Binary Matrix with Efficient Layer Tracking	Medium	design
3392	Count Subarrays of Length Three With a Condition	Easy	array
3393	Count Paths With the Given XOR Value	Medium	dynamic programming
3394	Check if Grid can be Cut into Sections	Medium	sort
3395	Subsequences with a Unique Middle Mode I	Hard	math
3396	Minimum Number of Operations to Make Elements in Array Distinct	Easy	hash table
3397	Maximum Number of Distinct Elements After Operations	Medium	greedy
3398	Smallest Substring With Identical Characters I	Hard	binary search
3399	Smallest Substring With Identical Characters II	Hard	binary search
3400	Maximum Number of Matching Indices After Right Shifts	Medium	array
3401	Find Circular Gift Exchange Chains	Hard	sql
3402	Minimum Operations to Make Columns Strictly Increasing	Easy	greedy
3403	Find the Lexicographically Largest String From the Box I	Medium	greedy
3404	Count Special Subsequences	Medium	hash table
3405	Count the Number of Arrays with K Matching Adjacent Elements	Hard	math
3406	Find the Lexicographically Largest String From the Box II	Hard	greedy
3407	Substring Matching Pattern	Easy	string
3408	Design Task Manager	Medium	design
3409	Longest Subsequence With Decreasing Adjacent Difference	Medium	dynamic programming
3410	Maximize Subarray Sum After Removing All Occurrences of One Element	Hard	greedy
3411	Maximum Subarray With Equal Products	Easy	math
3412	Find Mirror Score of a String	Medium	simulation
3413	Maximum Coins From K Consecutive Bags	Medium	two pointers
3414	Maximum Score of Non-overlapping Intervals	Hard	dynamic programming
3415	Find Products with Three Consecutive Digits	Easy	sql
3416	Subsequences with a Unique Middle Mode II	Hard	math
3417	Zigzag Grid Traversal With Skip	Easy	array
3418	Maximum Amount of Money Robot Can Earn	Medium	dynamic programming
3419	Minimize the Maximum Edge Weight of Graph	Medium	graph
3420	Count Non-Decreasing Subarrays After K Operations	Hard	two pointers
3421	Find Students Who Improved	Medium	sql
3422	Minimum Operations to Make Subarray Elements Equal	Medium	two pointers
3423	Maximum Difference Between Adjacent Elements in a Circular Array	Easy	array
3424	Minimum Cost to Make Arrays Identical	Medium	greedy
3425	Longest Special Path	Hard	two pointers
3426	Manhattan Distances of All Arrangements of Pieces	Hard	math
3427	Sum of Variable Length Subarrays	Easy	array
3428	Maximum and Minimum Sums of at Most Size K Subsequences	Medium	math
3429	Paint House IV	Medium	dynamic programming
3430	Maximum and Minimum Sums of at Most Size K Subarrays	Hard	two pointers
3431	Minimum Unlocked Indices to Sort Nums	Medium	sort
3432	Count Partitions with Even Sum Difference	Easy	array
3433	Count Mentions Per User	Medium	simulation
3434	Maximum Frequency After Subarray Operation	Medium	dynamic programming
3435	Frequencies of Shortest Supersequences	Hard	graph
3436	Find Valid Emails	Easy	sql
3437	Permutations III	Medium	backtracking
3438	Find Valid Pair of Adjacent Digits in String	Easy	hash table
3439	Reschedule Meetings for Maximum Free Time I	Medium	two pointers
3440	Reschedule Meetings for Maximum Free Time II	Medium	array
3441	Minimum Cost Good Caption	Hard	dynamic programming
3442	Maximum Difference Between Even and Odd Frequency I	Easy	hash table
3443	Maximum Manhattan Distance After K Changes	Medium	greedy
3444	Minimum Increments for Target Multiples in an Array	Hard	dynamic programming
3445	Maximum Difference Between Even and Odd Frequency II	Hard	two pointers
3446	Sort Matrix by Diagonals	Medium	array
3447	Assign Elements to Groups with Constraints	Medium	math
3448	Count Substrings Divisible By Last Digit	Hard	math
3449	Maximize the Minimum Game Score	Hard	binary search
3450	Maximum Students on a Single Bench	Easy	hash table
3451	Find Invalid IP Addresses	Hard	sql
3452	Sum of Good Numbers	Easy	array
3453	Separate Squares I	Medium	geometry
3454	Separate Squares II	Hard	geometry
3455	Shortest Matching Substring	Hard	string
3456	Find Special Substring of Length K	Easy	string
3457	Eat Pizzas!	Medium	greedy
3458	Select K Disjoint Special Substrings	Medium	greedy
3459	Length of Longest V-Shaped Diagonal Segment	Hard	dynamic programming
3460	Longest Common Prefix After at Most One Removal	Medium	two pointers
3461	Check If Digits Are Equal in String After Operations I	Easy	math
3462	Maximum Sum With at Most K Elements	Medium	greedy
3463	Check If Digits Are Equal in String After Operations II	Hard	math
3464	Maximize the Distance Between Points on a Square	Hard	binary search
3465	Find Products with Valid Serial Numbers	Easy	sql
3466	Maximum Coin Collection	Medium	dynamic programming
3467	Transform Array by Parity	Easy	array
3468	Find the Number of Copy Arrays	Medium	greedy
3469	Find Minimum Cost to Remove Array Elements	Medium	dynamic programming
3470	Permutations IV	Hard	math
3471	Find the Largest Almost Missing Integer	Easy	hash table
3472	Longest Palindromic Subsequence After at Most K Operations	Medium	dynamic programming
3473	Sum of K Subarrays With Length at Least M	Medium	dynamic programming
3474	Lexicographically Smallest Generated String	Hard	greedy
3475	DNA Pattern Recognition	Medium	sql
3476	Maximize Profit from Task Assignment	Medium	greedy
3477	Fruits Into Baskets II	Easy	binary search
3478	Choose K Elements With Maximum Sum	Medium	greedy
3479	Fruits Into Baskets III	Medium	binary search
3480	Maximize Subarrays After Removing One Conflicting Pair	Hard	greedy
3481	Apply Substitutions	Medium	graph
3482	Analyze Organization Hierarchy	Hard	sql
3483	Unique 3-Digit Even Numbers	Easy	math
3484	Design Spreadsheet	Medium	design
3485	Longest Common Prefix of K Strings After Removal	Hard	two pointers
3486	Longest Special Path II	Hard	two pointers
3487	Maximum Unique Subarray Sum After Deletion	Easy	hash table
3488	Closest Equal Element Queries	Medium	hash table
3489	Zero Array Transformation IV	Medium	dynamic programming
3490	Count Beautiful Numbers	Hard	dynamic programming
3491	Phone Number Prefix	Easy	string
3492	Maximum Containers on a Ship	Easy	math
3493	Properties Graph	Medium	graph
3494	Find the Minimum Amount of Time to Brew Potions	Medium	greedy
3495	Minimum Operations to Make Array Elements Zero	Hard	greedy
3496	Maximize Score After Pair Deletions	Medium	greedy
3497	Analyze Subscription Conversion	Medium	sql
3498	Reverse Degree of a String	Easy	string
3499	Maximize Active Section with Trade I	Medium	greedy
3500	Minimum Cost to Divide Array Into Subarrays	Hard	dynamic programming
3501	Maximize Active Section with Trade II	Hard	greedy
3502	Minimum Cost to Reach Every Position	Easy	array
3503	Longest Palindrome After Substring Concatenation I	Medium	dynamic programming
3504	Longest Palindrome After Substring Concatenation II	Hard	dynamic programming
3505	Minimum Operations to Make Elements Within K Subarrays Equal	Hard	dynamic programming
3506	Find Time Required to Eliminate Bacterial Strains	Hard	greedy
3507	Minimum Pair Removal to Sort Array I	Easy	simulation
3508	Implement Router	Medium	design
3509	Maximum Product of Subsequences With an Alternating Sum Equal to K	Hard	dynamic programming
3510	Minimum Pair Removal to Sort Array II	Hard	simulation
3511	Make a Positive Array	Medium	greedy
3512	Minimum Operations to Make Array Sum Divisible by K	Easy	math
3513	Number of Unique XOR Triplets I	Medium	math
3514	Number of Unique XOR Triplets II	Medium	array
3515	Shortest Path in a Weighted Tree	Hard	tree
3516	Find Closest Person	Easy	math
3517	Smallest Palindromic Rearrangement I	Medium	greedy
3518	Smallest Palindromic Rearrangement II	Hard	greedy
3519	Count Numbers with Non-Decreasing Digits	Hard	math
3520	Minimum Threshold for Inversion Pairs Count	Medium	binary search
3521	Find Product Recommendation Pairs	Medium	sql
3522	Calculate Score After Performing Instructions	Medium	simulation
3523	Make Array Non-decreasing	Medium	greedy
3524	Find X Value of Array I	Medium	dynamic programming
3525	Find X Value of Array II	Hard	dynamic programming
3526	Range XOR Queries with Subarray Reversals	Hard	binary search tree
3527	Find the Most Common Response	Medium	hash table
3528	Unit Conversion I	Medium	breadth first search
3529	Count Cells in Overlapping Horizontal and Vertical Substrings	Medium	string
3530	Maximum Profit from Valid Topological Order in DAG	Hard	dynamic programming
3531	Count Covered Buildings	Medium	array
3532	Path Existence Queries in a Graph I	Medium	graph
3533	Concatenated Divisibility	Hard	dynamic programming
3534	Path Existence Queries in a Graph II	Hard	graph
3535	Unit Conversion II	Medium	breadth first search
3536	Maximum Product of Two Digits	Easy	graph
3537	Fill a Special Grid	Medium	array
3538	Merge Operations for Minimum Travel Time	Hard	dynamic programming
3539	Find Sum of Array Product of Magical Sequences	Hard	dynamic programming
3540	Minimum Time to Visit All Houses	Medium	array
3541	Find Most Frequent Vowel and Consonant	Easy	hash table
3542	Minimum Operations to Convert All Elements to Zero	Medium	greedy
3543	Maximum Weighted K-Edge Path	Medium	dynamic programming
3544	Subtree Inversion Sum	Hard	dynamic programming
3545	Minimum Deletions for At Most K Distinct Characters	Easy	greedy
3546	Equal Sum Grid Partition I	Medium	array
3547	Maximum Sum of Edge Values in a Graph	Hard	graph
3548	Equal Sum Grid Partition II	Hard	array
3549	Multiply Two Polynomials	Hard	array
3550	Smallest Index With Digit Sum Equal to Index	Easy	array
3551	Minimum Swaps to Sort by Digit Sum	Medium	sort
3552	Grid Teleportation Traversal	Medium	breadth first search
3553	Minimum Weighted Subgraph With the Required Paths II	Hard	tree
3554	Find Category Recommendation Pairs	Hard	sql
3555	Smallest Subarray to Sort in Every Sliding Window	Medium	two pointers
3556	Sum of Largest Prime Substrings	Medium	math
3557	Find Maximum Number of Non Intersecting Substrings	Medium	greedy
3558	Number of Ways to Assign Edge Weights I	Medium	tree
3559	Number of Ways to Assign Edge Weights II	Medium	tree
3560	Find Minimum Log Transportation Cost	Easy	math
3561	Resulting String After Adjacent Removals	Medium	simulation
3562	Maximum Profit from Trading Stocks with Discounts	Hard	dynamic programming
3563	Lexicographically Smallest String After Adjacent Removals	Hard	dynamic programming
3564	Seasonal Sales Analysis	Medium	sql
3565	Sequential Grid Path Cover	Medium	backtracking
3566	Partition Array into Two Equal Product Subsets	Medium	bit manipulation
3567	Minimum Absolute Difference in Sliding Submatrix	Medium	two pointers
3568	Minimum Moves to Clean the Classroom	Medium	breadth first search
3569	Maximize Count of Distinct Primes After Split	Medium	array
3570	Find Books with No Available Copies	Easy	sql
3571	Find the Shortest Superstring II	Easy	string
3572	Maximize Y‑Sum by Picking a Triplet of Distinct X‑Values	Medium	hash table
3573	Best Time to Buy and Sell Stock V	Medium	dynamic programming
3574	Maximize Subarray GCD Score	Hard	dynamic programming
3575	Maximum Good Subtree Score	Hard	dynamic programming
3576	Transform Array to All Equal Elements	Medium	greedy
3577	Count the Number of Computer Unlocking Permutations	Medium	math
3578	Count Partitions With Max-Min Difference at Most K	Medium	dynamic programming
3579	Minimum Steps to Convert String with Operations	Hard	dynamic programming
3580	Find Consistently Improving Employees	Medium	sql
3581	Count Odd Letters from Number	Easy	hash table
3582	Generate Tag for Video Caption	Easy	string
3583	Count Special Triplets	Medium	dynamic programming
3584	Maximum Product of First and Last Elements of a Subsequence	Medium	two pointers
3585	Find Weighted Median Node in Tree	Hard	tree
3586	Find COVID Recovery Patients	Medium	sql
3587	Minimum Adjacent Swaps to Alternate Parity	Medium	greedy
3588	Find Maximum Area of a Triangle	Medium	math
3589	Count Prime-Gap Balanced Subarrays	Medium	two pointers
3590	Kth Smallest Path XOR Sum	Hard	depth first search
3591	Check if Any Element Has Prime Frequency	Easy	hash table
3592	Inverse Coin Change	Medium	dynamic programming
3593	Minimum Increments to Equalize Leaf Paths	Medium	depth first search
3594	Minimum Time to Transport All Individuals	Hard	graph
3595	Once Twice	Medium	dynamic programming
3596	Minimum Cost Path with Alternating Directions I	Medium	math
3597	Partition String	Medium	simulation
3598	Longest Common Prefix Between Adjacent Strings After Removals	Medium	string
3599	Partition Array to Minimize XOR	Medium	dynamic programming
3600	Maximize Spanning Tree Stability with Upgrades	Hard	graph
3601	Find Drivers with Improved Fuel Efficiency	Medium	sql
3602	Hexadecimal and Hexatrigesimal Conversion	Easy	math
3603	Minimum Cost Path with Alternating Directions II	Medium	dynamic programming
3604	Minimum Time to Reach Destination in Directed Graph	Medium	graph
3605	Minimum Stability Factor of Array	Hard	binary search
3606	Coupon Code Validator	Easy	string
3607	Power Grid Maintenance	Medium	depth first search
3608	Minimum Time for K Connected Components	Medium	simulation
3609	Minimum Moves to Reach Target in Grid	Hard	simulation
3610	Minimum Number of Primes to Sum to Target	Medium	dynamic programming
3611	Find Overbooked Employees	Medium	sql
3612	Process String with Special Operations I	Medium	simulation
3613	Minimize Maximum Component Cost	Medium	simulation
3614	Process String with Special Operations II	Hard	simulation
3615	Longest Palindromic Path in Graph	Hard	dynamic programming
3616	Number of Student Replacements	Medium	simulation
3617	Find Students with Study Spiral Pattern	Hard	sql
3618	Split Array by Prime Indices	Medium	math
3619	Count Islands With Total Value Divisible by K	Medium	breadth first search
3620	Network Recovery Pathways	Hard	graph
3621	Number of Integers With Popcount-Depth Equal to K I	Hard	math
3622	Check Divisibility by Digit Sum and Product	Easy	math
3623	Count Number of Trapezoids I	Medium	math
3624	Number of Integers With Popcount-Depth Equal to K II	Hard	math
3625	Count Number of Trapezoids II	Hard	math
3626	Find Stores with Inventory Imbalance	Medium	sql
3627	Maximum Median Sum of Subsequences of Size 3	Medium	greedy
3628	Maximum Number of Subsequences After One Inserting	Medium	dynamic programming
3629	Minimum Jumps to Reach End via Prime Teleportation	Medium	breadth first search
3630	Partition Array for Maximum XOR and AND	Hard	greedy
3631	Sort Threats by Severity and Exploitability	Medium	sort
3632	Subarrays with XOR at Least K	Hard	bit manipulation
3633	Earliest Finish Time for Land and Water Rides I	Easy	greedy
3634	Minimum Removals to Balance Array	Medium	two pointers
3635	Earliest Finish Time for Land and Water Rides II	Medium	greedy
3636	Threshold Majority Queries	Hard	hash table
3637	Trionic Array I	Easy	array
3638	Maximum Balanced Shipments	Medium	greedy
3639	Minimum Time to Activate String	Medium	simulation
3640	Trionic Array II	Easy	two pointers
3641	Longest Semi-Repeating Subarray	Medium	two pointers
3642	Find Books with Polarized Opinions	Easy	sql
3643	Flip Square Submatrix Vertically	Easy	array
3644	Maximum K to Sort a Permutation	Medium	sort
3645	Maximum Total from Optimal Activation Order	Medium	greedy
3646	Next Special Palindrome Number	Hard	bit manipulation
3647	Maximum Weight in Two Bags	Medium	dynamic programming
3648	Minimum Sensors to Cover Grid	Medium	math
3649	Number of Perfect Pairs	Medium	two pointers
3650	Minimum Cost Path with Edge Reversals	Medium	graph
3651	Minimum Cost Path with Teleportations	Hard	dynamic programming
3652	Best Time to Buy and Sell Stock using Strategy	Medium	two pointers
3653	XOR After Range Multiplication Queries I	Medium	array
3654	Minimum Sum After Divisible Sum Deletions	Medium	dynamic programming
3655	XOR After Range Multiplication Queries II	Hard	array
3656	Determine if a Simple Graph Exists	Medium	graph
3657	Find Loyal Customers	Medium	sql
3658	GCD of Odd and Even Sums	Easy	math
3659	Partition Array Into K-Distinct Groups	Medium	math
3660	Jump Game IX	Medium	graph
3661	Maximum Walls Destroyed by Robots	Hard	dynamic programming
3662	Filter Characters by Frequency	Easy	hash table
3663	Find The Least Frequent Digit	Easy	hash table
3664	Two-Letter Card Game	Medium	math
3665	Twisted Mirror Path Count	Medium	dynamic programming
3666	Minimum Operations to Equalize Binary String	Hard	math
3667	Sort Array By Absolute Value	Easy	sort
3668	Restore Finishing Order	Easy	hash table
3669	Balanced K-Factor Decomposition	Medium	backtracking
3670	Maximum Product of Two Integers With No Common Bits	Medium	dynamic programming
3671	Sum of Beautiful Subsequences	Hard	math
3672	Sum of Weighted Modes in Subarrays	Medium	two pointers
3673	Find Zombie Sessions	Hard	sql
3674	Minimum Operations to Equalize Array	Easy	array
3675	Minimum Operations to Transform String	Medium	greedy
3676	Count Bowl Subarrays	Medium	stack
3677	Count Binary Palindromic Numbers	Hard	math
3678	Smallest Absent Positive Greater Than Average	Easy	hash table
3679	Minimum Discards to Balance Inventory	Medium	two pointers
3680	Generate Schedule	Medium	constructive algorithms
3681	Maximum XOR of Subsequences	Hard	greedy
3682	Minimum Index Sum of Common Elements	Medium	hash table
3683	Earliest Time to Finish One Task	Easy	array
3684	Maximize Sum of At Most K Distinct Elements	Easy	binary heap
3685	Subsequence Sum After Capping Elements	Medium	dynamic programming
3686	Number of Stable Subsequences	Hard	dynamic programming
3687	Library Late Fee Calculator	Easy	array
3688	Bitwise OR of Even Numbers in an Array	Easy	array
3689	Maximum Total Subarray Value I	Medium	greedy
3690	Split and Merge Array Transformation	Medium	breadth first search
3691	Maximum Total Subarray Value II	Hard	binary heap
3692	Majority Frequency Characters	Easy	hash table
3693	Climbing Stairs II	Medium	dynamic programming
3694	Distinct Points Reachable After Substring Removal	Medium	hash table
3695	Maximize Alternating Sum Using Swaps	Hard	breadth first search
3696	Maximum Distance Between Unequal Words in Array I	Easy	array
3697	Compute Decimal Representation	Easy	math
3698	Split Array With Minimum Difference	Medium	two pointers
3699	Number of ZigZag Arrays I	Hard	dynamic programming
3700	Number of ZigZag Arrays II	Hard	array
3701	Compute Alternating Sum	Easy	array
3702	Longest Subsequence With Non-Zero Bitwise XOR	Medium	bit manipulation
3703	Remove K-Balanced Substrings	Medium	stack
3704	Count No-Zero Pairs That Sum to N	Hard	dynamic programming
3705	Find Golden Hour Customers	Medium	sql
3706	Maximum Distance Between Unequal Words in Array II	Medium	array
3707	Equal Score Substrings	Easy	array
3708	Longest Fibonacci Subarray	Medium	array
3709	Design Exam Scores Tracker	Medium	design
3710	Maximum Partition Factor	Hard	graph
3711	Maximum Transactions Without Negative Balance	Medium	greedy
3712	Sum of Elements With Frequency Divisible by K	Easy	hash table
3713	Longest Balanced Substring I	Medium	hash table
3714	Longest Balanced Substring II	Medium	hash table
3715	Sum of Perfect Square Ancestors	Hard	tree
3716	Find Churn Risk Customers	Medium	sql
3717	Minimum Operations to Make the Array Beautiful	Medium	dynamic programming
3718	Smallest Missing Multiple of K	Easy	hash table
3719	Longest Balanced Subarray I	Medium	array
3720	Lexicographically Smallest Permutation Greater Than Target	Medium	greedy
3721	Longest Balanced Subarray II	Hard	array
3722	Lexicographically Smallest String After Reverse	Medium	binary search
3723	Maximize Sum of Squares of Digits	Medium	greedy
3724	Minimum Operations to Transform Array	Medium	greedy
3725	Count Ways to Choose Coprime Integers from Rows	Hard	dynamic programming
3726	Remove Zeros in Decimal Representation	Easy	math
3727	Maximum Alternating Sum of Squares	Medium	greedy
3728	Stable Subarrays With Equal Boundary and Interior Sum	Medium	hash table
3729	Count Distinct Subarrays Divisible by K in Sorted Array	Hard	hash table
3730	Maximum Calories Burnt from Jumps	Medium	greedy
3731	Find Missing Elements	Easy	math
3732	Maximum Product of Three Elements After One Replacement	Medium	greedy
3733	Minimum Time to Complete All Deliveries	Medium	binary search
3734	Lexicographically Smallest Palindromic Permutation Greater Than Target	Hard	greedy
3735	Lexicographically Smallest String After Reverse II	Hard	binary search
3736	Minimum Moves to Equal Array Elements III	Easy	array
3737	Count Subarrays With Majority Element I	Medium	array
3738	Longest Non-Decreasing Subarray After Replacing at Most One Element	Medium	array
3739	Count Subarrays With Majority Element II	Hard	array
3740	Minimum Distance Between Three Equal Elements I	Easy	two pointers
3741	Minimum Distance Between Three Equal Elements II	Medium	two pointers
3742	Maximum Path Score in a Grid	Medium	dynamic programming
3743	Maximize Cyclic Partition Score	Hard	dynamic programming
3744	Find Kth Character in Expanded String	Medium	string
3745	Maximize Expression of Three Elements	Easy	math
3746	Minimum String Length After Balanced Removals	Medium	string
3747	Count Distinct Integers After Removing Zeros	Medium	math
3748	Count Stable Subarrays	Hard	string
3749	Evaluate Valid Expressions	Hard	stack
3750	Minimum Number of Flips to Reverse Binary String	Easy	bit manipulation
3751	Total Waviness of Numbers in Range I	Medium	array
3752	Lexicographically Smallest Negated Permutation that Sums to Target	Medium	greedy
3753	Total Waviness of Numbers in Range II	Hard	dynamic programming
3754	Concatenate Non-Zero Digits and Multiply by Sum I	Easy	math
3755	Find Maximum Balanced XOR Subarray Length	Medium	hash table
3756	Concatenate Non-Zero Digits and Multiply by Sum II	Medium	array
3757	Number of Effective Subsequences	Hard	dynamic programming
3758	Convert Number Words to Digits	Medium	string
3759	Count Elements With at Least K Greater Values	Medium	sort
3760	Maximum Substrings With Distinct Start	Medium	hash table
3761	Minimum Absolute Distance Between Mirror Pairs	Medium	hash table
3762	Minimum Operations to Equalize Subarrays	Hard	array
3763	Maximum Total Sum with Threshold Constraints	Medium	greedy
3764	Most Common Course Pairs	Hard	sql
3765	Complete Prime Number	Medium	math
3766	Minimum Operations to Make Binary Palindrome	Medium	bit manipulation
3767	Maximize Points After Choosing K Tasks	Medium	greedy
3768	Minimum Inversion Count in Subarrays of Fixed Length	Hard	two pointers
3769	Sort Integers by Binary Reflection	Easy	bit manipulation
3770	Largest Prime from Consecutive Prime Sum	Medium	math
3771	Total Score of Dungeon Runs	Medium	binary search
3772	Maximum Subgraph Score in a Tree	Hard	dynamic programming
3773	Maximum Number of Equal Length Runs	Medium	hash table
3774	Absolute Difference Between Maximum and Minimum K Elements	Easy	array
3775	Reverse Words With Same Vowel Count	Medium	string
3776	Minimum Moves to Balance Circular Array	Medium	greedy
3777	Minimum Deletions to Make Alternating Substring	Hard	string
3778	Minimum Distance Excluding One Maximum Weighted Edge	Medium	graph
3779	Minimum Number of Operations to Have Distinct Elements	Medium	hash table
3780	Maximum Sum of Three Numbers Divisible by Three	Medium	sort
3781	Maximum Score After Binary Swaps	Medium	binary heap
3782	Last Remaining Integer After Alternating Deletion Operations	Hard	bit manipulation
3783	Mirror Distance of an Integer	Easy	math
3784	Minimum Deletion Cost to Make All Characters Equal	Medium	hash table
3785	Minimum Swaps to Avoid Forbidden Values	Hard	greedy
3786	Total Sum of Interaction Cost in Tree Groups	Hard	breadth first search
3787	Find Diameter Endpoints of a Tree	Medium	breadth first search
3788	Maximum Score of a Split	Medium	array
3789	Minimum Cost to Acquire Required Items	Medium	math
3790	Smallest All-Ones Multiple	Medium	math
3791	Number of Balanced Integers in a Range	Hard	dynamic programming
3792	Sum of Increasing Product Blocks	Medium	simulation
3793	Find Users with High Token Usage	Easy	sql
3794	Reverse String Prefix	Easy	string
3795	Minimum Subarray Length With Distinct Sum At Least K	Medium	two pointers
3796	Find Maximum Value in a Constrained Sequence	Medium	greedy
3797	Count Routes to Climb a Rectangular Grid	Hard	greedy
3798	Largest Even Number	Easy	math
3799	Word Squares II	Medium	sort
3800	Minimum Cost to Make Two Binary Strings Equal	Medium	math
3801	Minimum Cost to Merge Sorted Lists	Hard	dynamic programming
3802	Number of Ways to Paint Sheets	Hard	two pointers
3803	Count Residue Prefixes	Easy	hash table
3804	Number of Centered Subarrays	Medium	hash table
3805	Count Caesar Cipher Pairs	Medium	hash table
3806	Maximum Bitwise AND After Increment Operations	Hard	greedy
3807	Minimum Cost to Repair Edges to Traverse a Graph	Medium	binary search
3808	Find Emotionally Consistent Users	Medium	sql
3809	Best Reachable Tower	Medium	array
3810	Minimum Operations to Reach Target Array	Medium	hash table
3811	Number of Alternating XOR Partitions	Medium	dynamic programming
3812	Minimum Edge Toggles on a Tree	Hard	greedy
3813	Vowel-Consonant Score	Easy	string
3814	Maximum Capacity Within Budget	Medium	array
3815	Design Auction System	Medium	design
3816	Lexicographically Smallest String After Deleting Duplicate Characters	Hard	greedy
3817	Good Indices in a Digit String	Medium	math
3818	Minimum Prefix Removal to Make Array Strictly Increasing	Medium	array
3819	Rotate Non Negative Elements	Medium	array
3820	Pythagorean Distance Nodes in a Tree	Medium	breadth first search
3821	Find Nth Smallest Integer With K One Bits	Hard	math
3822	Design Order Management System	Medium	design
3823	Reverse Letters Then Special Characters in a String	Easy	string
3824	Minimum K to Reduce Array Within Limit	Medium	binary search
3825	Longest Strictly Increasing Subsequence With Non-Zero Bitwise AND	Medium	binary search
3826	Minimum Partition Score	Hard	binary search
3827	Count Monobit Integers	Easy	bit manipulation
3828	Final Element After Subarray Deletions	Medium	greedy
3829	Design Ride Sharing System	Medium	design
3830	Longest Alternating Subarray After Removing At Most One Element	Hard	dynamic programming
3831	Median of a Binary Search Tree Level	Medium	breadth first search
3832	Find Users with Persistent Behavior Patterns	Hard	sql
3833	Count Dominant Indices	Easy	array
3834	Merge Adjacent Equal Elements	Medium	stack
3835	Count Subarrays With Cost Less Than or Equal to K	Medium	two pointers
3836	Maximum Score Using Exactly K Pairs	Hard	dynamic programming
3837	Delayed Count of Equal Elements	Medium	hash table
3838	Weighted Word Mapping	Easy	string
3839	Number of Prefix Connected Groups	Medium	hash table
3840	House Robber V	Medium	dynamic programming
3841	Palindromic Path Queries in a Tree	Hard	tree
3842	Toggle Light Bulbs	Easy	hash table
3843	First Element with Unique Frequency	Medium	hash table
3844	Longest Almost-Palindromic Substring	Medium	two pointers
3845	Maximum Subarray XOR with Bounded Range	Hard	two pointers
3846	Total Distance to Type a String Using One Finger	Medium	hash table
3847	Find the Score Difference in a Game	Medium	simulation
3848	Check Digitorial Permutation	Medium	hash table
3849	Maximum Bitwise XOR After Rearrangement	Medium	greedy
3850	Count Sequences to K	Hard	dynamic programming
3851	Maximum Requests Without Violating the Limit	Medium	two pointers
3852	Smallest Pair With Different Frequencies	Easy	hash table
3853	Merge Close Characters	Medium	simulation
3854	Minimum Operations to Make Array Parity Alternating	Medium	greedy
3855	Sum of K-Digit Numbers in a Range	Hard	math
3856	Trim Trailing Vowels	Easy	string
3857	Minimum Cost to Split into Ones	Medium	math
3858	Minimum Bitwise OR From Grid	Medium	greedy
3859	Count Subarrays With K Distinct Integers	Hard	two pointers
3860	Unique Email Groups	Medium	string
3861	Minimum Capacity Box	Easy	array
3862	Find the Smallest Balanced Index	Medium	array
3863	Minimum Operations to Sort a String	Medium	greedy
3864	Minimum Cost to Partition a Binary String	Hard	dynamic programming
3865	Reverse K Subarrays	Medium	array
3866	First Unique Even Element	Easy	hash table
3867	Sum of GCD of Formed Pairs	Medium	simulation
3868	Minimum Cost to Equalize Arrays Using Swaps	Medium	greedy
3869	Count Fancy Numbers in a Range	Hard	dynamic programming
3870	Count Commas in Range	Easy	math
3871	Count Commas in Range II	Medium	math
3872	Longest Arithmetic Sequence After Changing At Most One Element	Medium	two pointers
3873	Maximum Points Activated with One Addition	Hard	graph
3874	Valid Subarrays With Exactly One Peak	Medium	two pointers
3875	Construct Uniform Parity Array I	Easy	constructive algorithms
3876	Construct Uniform Parity Array II	Medium	constructive algorithms
3877	Minimum Removals to Achieve Target XOR	Medium	dynamic programming
3878	Count Good Subarrays	Hard	stack
3879	Maximum Distinct Path Sum in a Binary Tree	Medium	tree
3880	Minimum Absolute Difference Between Two Values	Easy	array
3881	Direction Assignments with Exactly K Visible People	Medium	math
3882	Minimum XOR Path in a Grid	Medium	dynamic programming
3883	Count Non Decreasing Arrays With Given Digit Sums	Medium	dynamic programming
3884	First Matching Character From Both Ends	Medium	string
3885	Design Event Manager	Medium	design
3886	Sum of Sortable Integers	Hard	array
3887	Incremental Even-Weighted Cycle Queries	Hard	graph
3888	Minimum Operations to Make All Grid Elements Equal	Hard	greedy
3889	Mirror Frequency Distance	Medium	hash table
3890	Integers With Multiple Sum of Two Cubes	Medium	hash table
3891	Minimum Increase to Maximize Special Indices	Medium	dynamic programming
3892	Minimum Operations to Achieve At Least K Peaks	Hard	greedy
3893	Maximum Team Size with Overlapping Intervals	Medium	binary search
3894	Traffic Signal Color	Easy	simulation
3895	Count Digit Appearances	Medium	math
3896	Count Digit Appearances	Medium	math
3897	Maximum Value of Concatenated Binary Segments	Hard	greedy
3898	Find the Degree of Each Vertex	Easy	array
3899	Angles of a Triangle	Medium	math
3900	Longest Balanced Substring After One Swap	Medium	hash table
3901	Good Subsequence Queries	Medium	hash table
3902	Zigzag Level Sum of Binary Tree	Hard	breadth first search
3903	Smallest Stable Index I	Easy	array
3904	Smallest Stable Index II	Medium	array
3905	Multi Source Flood Fill	Medium	breadth first search
3906	Count Good Integers on a Grid Path	Hard	dynamic programming
3907	Count Smaller Elements With Opposite Parity	Medium	array
3908	Valid Digit Number	Easy	math
3909	Compare Sums of Bitonic Parts	Medium	array
3910	Count Connected Subgraphs with Even Node Sum	Hard	graph
3911	K-th Smallest Remaining Even Integer in Subarray Queries	Hard	binary search
3912	Valid Elements in an Array	Medium	array
3913	Sort Vowels by Frequency	Medium	hash table
3914	Minimum Operations to Make Array Non Decreasing	Medium	greedy
3916	Number of ZigZag Arrays III	Hard	dynamic programming
3917	Count Indices With Opposite Parity	Easy	hash table
3918	Sum of Primes Between Number and Its Reverse	Medium	array
3919	Minimum Cost to Move Between Indices	Medium	greedy
3920	Maximize Fixed Points After Deletions	Hard	binary search
3921	Score Validator	Easy	hash table
3922	Minimum Flips to Make Binary String Coherent	Medium	greedy
3923	Minimum Generations to Target Point	Medium	breadth first search
3924	Minimum Threshold Path With Limited Heavy Edges	Hard	binary search
3925	Concatenate Array With Reverse	Easy	array
3926	Count Valid Word Occurrences	Medium	hash table
3927	Minimize Array Sum Using Divisible Replacements	Medium	math
3928	Minimum Cost to Buy Apples II	Hard	graph
3929	Minimum Partition Score II	Hard	binary search
3930	Power Update After K-th Largest Insertion II	Hard	binary search tree
3931	Check Adjacent Digit Differences	Easy	string
3932	Count K-th Roots in a Range	Medium	binary search
3933	Largest Local Values in a Matrix II	Medium	array
3934	Smallest Unique Subarray	Hard	binary search
3936	Minimum Swaps to Move Zeros to End	Easy	array
3937	Minimum Operations to Make Array Modulo Alternating I	Medium	two pointers
3938	Maximum Path Intersection Sum in a Grid	Medium	array
3939	Count Non Adjacent Subsets in a Rooted Tree	Hard	dynamic programming
3940	Limit Occurrences in Sorted Array	Easy	array
3941	Password Strength	Medium	string
3942	Minimum Operations to Sort a Permutation	Medium	array
3943	Number of Pairs After Increment	Hard	array
3944	Minimum Operations to Make Array Modulo Alternating II	Hard	two pointers
3945	Digit Frequency Score	Easy	hash table
3946	Maximum Number of Items From Sale I	Medium	dynamic programming
3947	Maximum Number of Items From Sale II	Medium	greedy
3948	Lexicographically Maximum MEX Array	Hard	greedy
3949	Subtree Inversion Sum II	Hard	dynamic programming
3950	Exactly One Consecutive Set Bits Pair	Easy	bit manipulation
3951	Minimum Energy to Maintain Brightness	Medium	array
3952	Maximum Total Value of Covered Indices	Medium	greedy
3953	Maximum Score with Co-Prime Element	Hard	dynamic programming
3954	Sum of Compatible Numbers in Range I	Easy	math
3955	Valid Binary Strings With Cost Limit	Medium	backtracking
3956	Maximum Sum of M Non-Overlapping Subarrays I	Hard	binary search
3957	Maximum Sum of M Non-Overlapping Subarrays II	Hard	binary search
3958	Minimum Cost to Split into Ones II	Medium	math
3959	Check Good Integer	Easy	math
3960	Frequency Balance Subarray	Medium	hash table
3961	Maximize Sum of Device Ratings	Medium	greedy
3962	Maximum Subarray Sum After at Most K Swaps	Hard	binary heap
3963	Create Grid With Exactly One Path	Easy	array
3964	Minimum Lights to Illuminate a Road	Medium	greedy
3965	Finish Time of Tasks I	Medium	dynamic programming
3966	Count Good Integers in a Range	Hard	dynamic programming
3967	Finish Time of Tasks II	Hard	dynamic programming
3968	Maximum Manhattan Distance After All Moves	Medium	simulation
3969	Valid Subarrays With Matching Sum Digits I	Medium	two pointers
3970	Shortest Path With At Most K Consecutive Identical Characters	Medium	graph
3971	Maximum Total Value	Hard	binary search
3972	Valid Subarrays With Matching Sum Digits II	Hard	two pointers
3973	Distinct Gate Paths to LCA	Hard	tree
3974	Maximum Total Sum of K Selected Elements	Medium	greedy
3975	Filter Occupied Intervals	Medium	sort
3976	Maximum Subarray Sum After Multiplier	Medium	dynamic programming
3977	Minimum Time to Reach Target With Limited Power	Hard	graph
3978	Unique Middle Element	Easy	array
3979	Maximum Valid Pair Sum	Medium	array
3980	Minimum Operations to Transform Binary String	Medium	greedy
3981	Count Distinct Ways to Form Target from Two Strings	Hard	dynamic programming
3982	Sum of Integers with Maximum Digit Range	Easy	array
3983	Subsequence After One Replacement	Medium	dynamic programming
3984	Divisible Game	Medium	math
3985	Palindromic Subarray Sum	Hard	array
3986	Number of Elapsed Seconds Between Two Times	Easy	string
3987	Minimum Total Cost to Process All Elements	Medium	math
3988	Create Grid With Exactly K Paths I	Medium	constructive algorithms
3989	Maximum Consistent Columns in a Grid	Hard	dynamic programming
3990	Create Grid With Exactly K Paths II	Hard	constructive algorithms
3991	Sort Array Using Prefix Reversals	Medium	breadth first search