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 83 matching · 2723 totalSort: id ↑
No.ProblemDifficulty
- 0001Two SumEasy
- 0002Add Two NumbersMed
- 0003Longest Substring Without Repeating CharactersMed
- 0005Longest Palindromic SubstringMed
- 0006Zigzag ConversionMed
- 00153SumMed
- 0017Letter Combinations of a Phone NumberMed
- 0020Valid ParenthesesEasy
- 0023Merge k Sorted ListsHard
- 0026Remove Duplicates from Sorted ArrayEasy
- 0042Trapping Rain WaterHard
- 0046PermutationsMed
- 0048Rotate ImageMed
- 0049Group AnagramsMed
- 0053Maximum SubarrayMed
- 0054Spiral MatrixMed
- 0055Jump GameMed
- 0056Merge IntervalsMed
- 0062Unique PathsMed
- 0063Unique Paths IIMed
Showing 20 of 83