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 195 matching · 2723 totalSort: id ↑
No.ProblemDifficulty
- 0100Same TreeEasy
- 0101Symmetric TreeEasy
- 0102Binary Tree Level Order TraversalMed
- 0103Binary Tree Zigzag Level Order TraversalMed
- 0104Maximum Depth of Binary TreeEasy
- 0107Binary Tree Level Order Traversal IIMed
- 0111Minimum Depth of Binary TreeEasy
- 0112Path SumEasy
- 0116Populating Next Right Pointers in Each NodeMed
- 0117Populating Next Right Pointers in Each Node IIMed
- 0126Word Ladder IIHard
- 0127Word LadderHard
- 0130Surrounded RegionsMed
- 0133Clone GraphMed
- 0187Binary Tree Right Side ViewMed
- 0188Number of IslandsMed
- 0195Course ScheduleMed
- 0198Course Schedule IIMed
- 0214Invert Binary TreeEasy
- 0266Perfect SquaresMed
Showing 20 of 195