DSA Fundamentals Roadmap

A beginner-to-job path: arrays → hashing → trees → graphs → DP.

1. 1.Arrays & hashing

   Two Sum, Contains Duplicate, Group Anagrams

   #	Title	Difficulty	Topics
   1	Two Sum	Easy	hash table
   217	Contains Duplicate	Easy	hash table
   49	Group Anagrams	Medium	hash table

2. 2.Two pointers & windows

   3Sum, Container With Most Water, Longest Substring

   #	Title	Difficulty	Topics
   15	3 Sum	Medium	two pointers
   11	Container With Most Water	Medium	greedy
   3	Longest Substring Without Repeating Characters	Medium	hash table

3. 3.Trees & graphs

   Traversals, BST, islands, courses

   #	Title	Difficulty	Topics
   226	Invert Binary Tree	Easy	tree
   98	Validate Binary Search Tree	Medium	recursion
   200	Number of Islands	Medium	depth first search
   207	Course Schedule	Medium	breadth first search

4. 4.Dynamic programming

   Climbing Stairs through classic DP

   #	Title	Difficulty	Topics
   70	Climbing Stairs	Easy	dynamic programming
   198	House Robber	Easy	dynamic programming
   322	Coin Change	Medium	dynamic programming