DSA
Master the patterns
Search the bank, then filter by difficulty, pattern, data structure, or algorithm. Each problem includes approaches, solutions, and walkthroughs.
Active·2,723
Easy·667
Medium·1,394
Hard·662
Patterns
Recognize the move
Filter the bank by pattern — each card links into the problem index.
Problem index
Browse problems
Search by title, then refine with facets. Sorted by problem ID.
Difficulty
Facets
20 of 249 matching · 2723 totalSort: id ↑
No.ProblemDifficulty
- 0079Word SearchMed
- 0094Binary Tree Inorder TraversalEasy
- 0098Validate Binary Search TreeMed
- 0099Recover Binary Search TreeMed
- 0100Same TreeEasy
- 0101Symmetric TreeEasy
- 0104Maximum Depth of Binary TreeEasy
- 0110Balanced Binary TreeEasy
- 0111Minimum Depth of Binary TreeEasy
- 0112Path SumEasy
- 0113Path Sum IIMed
- 0114Flatten Binary Tree to Linked ListMed
- 0116Populating Next Right Pointers in Each NodeMed
- 0117Populating Next Right Pointers in Each Node IIMed
- 0124Binary Tree Maximum Path SumHard
- 0129Sum Root to Leaf NumbersMed
- 0130Surrounded RegionsMed
- 0133Clone GraphMed
- 0144Binary Tree Preorder TraversalEasy
- 0145Binary Tree Postorder TraversalEasy
Showing 20 of 249