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 94 matching · 2723 totalSort: id ↑
No.ProblemDifficulty
- 0001Two SumEasy
- 0002Add Two NumbersMed
- 0003Longest Substring Without Repeating CharactersMed
- 0007Reverse IntegerMed
- 0008String to Integer (atoi)Med
- 0014Longest Common PrefixEasy
- 00153SumMed
- 0019Remove Nth Node From End of ListMed
- 0020Valid ParenthesesEasy
- 0022Generate ParenthesesMed
- 0023Merge k Sorted ListsHard
- 0033Search in Rotated Sorted ArrayMed
- 0036Valid SudokuMed
- 0042Trapping Rain WaterHard
- 0048Rotate ImageMed
- 0049Group AnagramsMed
- 0053Maximum SubarrayMed
- 0054Spiral MatrixMed
- 0056Merge IntervalsMed
- 0070Climbing StairsEasy
Showing 20 of 94