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 34 matching · 2723 totalSort: id ↑
No.ProblemDifficulty
- 0003Longest Substring Without Repeating CharactersMed
- 0020Valid ParenthesesEasy
- 0022Generate ParenthesesMed
- 0033Search in Rotated Sorted ArrayMed
- 0041First Missing PositiveHard
- 0048Rotate ImageMed
- 0054Spiral MatrixMed
- 0056Merge IntervalsMed
- 0068Text JustificationHard
- 0079Word SearchMed
- 0088Merge Sorted ArrayEasy
- 0121Best Time to Buy and Sell StockEasy
- 0139Word BreakMed
- 0146LRU CacheMed
- 0179Rotate ArrayMed
- 0198Course Schedule IIMed
- 0205Contains DuplicateEasy
- 0207Contains Duplicate IIEasy
- 0208Contains Duplicate IIIHard
- 0216Summary RangesEasy
Showing 20 of 34