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 28 matching · 2723 totalSort: id ↑
No.ProblemDifficulty
- 0020Valid ParenthesesEasy
- 0023Merge k Sorted ListsHard
- 0033Search in Rotated Sorted ArrayMed
- 0049Group AnagramsMed
- 0054Spiral MatrixMed
- 0056Merge IntervalsMed
- 0114Flatten Binary Tree to Linked ListMed
- 0188Number of IslandsMed
- 0195Course ScheduleMed
- 0198Course Schedule IIMed
- 0212Basic CalculatorHard
- 0215Basic Calculator IIMed
- 0270Move ZeroesEasy
- 0274Find the Duplicate NumberMed
- 0276Game of LifeMed
- 0282Find Median from Data StreamHard
- 0462HeatersMed
- 0514MinesweeperMed
- 0693Daily TemperaturesMed
- 0772Race CarHard
Showing 20 of 28