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 63 matching · 2723 totalSort: id ↑
No.ProblemDifficulty
- 0001Two SumEasy
- 0002Add Two NumbersMed
- 0003Longest Substring Without Repeating CharactersMed
- 0005Longest Palindromic SubstringMed
- 0010Regular Expression MatchingHard
- 0011Container With Most WaterMed
- 0023Merge k Sorted ListsHard
- 0031Next PermutationMed
- 0033Search in Rotated Sorted ArrayMed
- 0039Combination SumMed
- 0040Combination Sum IIMed
- 0042Trapping Rain WaterHard
- 0050Pow(x, n)Med
- 0056Merge IntervalsMed
- 0062Unique PathsMed
- 0070Climbing StairsEasy
- 0076Minimum Window SubstringHard
- 0078SubsetsMed
- 0088Merge Sorted ArrayEasy
- 0103Binary Tree Zigzag Level Order TraversalMed
Showing 20 of 63