Backtracking Interview Questions

Explore-and-prune search for combinations and permutations.

60 problems

#	Title	Difficulty	Topics
17	Letter Combinations of a Phone Number	Medium	backtracking
22	Generate Parentheses	Medium	backtracking
37	Sudoku Solver	Hard	backtracking
39	Combination Sum	Medium	backtracking
40	Combination Sum II	Medium	backtracking
46	Permutations	Medium	backtracking
47	Permutations II	Medium	backtracking
51	N-Queens	Hard	backtracking
52	N-Queens-II	Hard	backtracking
77	Combinations	Medium	backtracking
78	Subsets	Medium	backtracking
79	Word Search	Medium	backtracking
90	Subsets II	Medium	backtracking
93	Restore IP Addresses	Medium	backtracking
126	Word Ladder II	Hard	backtracking
131	Palindrome Partitioning	Medium	backtracking
140	Word Break II	Hard	backtracking
212	Word Search II	Hard	backtracking
216	Combination Sum III	Medium	backtracking
254	Factor Combinations	Medium	backtracking
267	Palindrome Permutation II	Medium	backtracking
291	Word Pattern II	Hard	backtracking
294	Flip Game II	Medium	backtracking
320	Generalized Abbreviation	Medium	backtracking
425	Word Squares	Hard	backtracking
488	Zuma Game	Hard	backtracking
491	Increasing Subsequences	Medium	backtracking
526	Beautiful Arrangement	Medium	backtracking
676	Implement Magic Dictionary	Medium	backtracking
679	24 Game	Hard	backtracking
698	Partition to K Equal Sum Subsets	Medium	backtracking
718	Maximum Length of Repeated Subarray	Medium	backtracking
784	Letter Case Permutation	Easy	backtracking
996	Number of Squareful Arrays	Hard	backtracking
1087	Brace Expansion	Medium	backtracking
1096	Brace Expansion II	Hard	backtracking
1219	Path with Maximum Gold	Medium	backtracking
1240	Tiling a Rectangle with the Fewest Squares	Hard	backtracking
1255	Maximum Score Words Formed by Letters	Hard	backtracking
1258	Synonymous Sentences	Medium	backtracking
1307	Verbal Arithmetic Puzzle	Hard	backtracking
1379	Find a Corresponding Node of a Binary Tree in a Clone of That Tree	Medium	backtracking
1593	Split a String Into the Max Number of Unique Substrings	Medium	backtracking
1659	Maximize Grid Happiness	Hard	backtracking
1718	Construct the Lexicographically Largest Valid Sequence	Medium	backtracking
1723	Find Minimum Time to Finish All Jobs	Hard	backtracking
1849	Splitting a String Into Descending Consecutive Values	Medium	backtracking
1999	Smallest Greater Multiple Made of Two Digits	Medium	backtracking
2014	Longest Subsequence Repeated k Times	Hard	backtracking
2056	Number of Valid Move Combinations On Chessboard	Hard	backtracking
2094	Finding 3-Digit Even Numbers	Easy	backtracking
2443	Sum of Number and Its Reverse	Medium	backtracking
2664	The Knight’s Tour	Medium	backtracking
2698	Find the Punishment Number of an Integer	Medium	backtracking
2741	Special Permutations	Medium	backtracking
3211	Generate Binary Strings Without Adjacent Zeros	Medium	backtracking
3437	Permutations III	Medium	backtracking
3565	Sequential Grid Path Cover	Medium	backtracking
3669	Balanced K-Factor Decomposition	Medium	backtracking
3955	Valid Binary Strings With Cost Limit	Medium	backtracking