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 49 matching · 2723 totalSort: id ↑
No.ProblemDifficulty
- 0001Two SumEasy
- 0003Longest Substring Without Repeating CharactersMed
- 0005Longest Palindromic SubstringMed
- 00153SumMed
- 0017Letter Combinations of a Phone NumberMed
- 0020Valid ParenthesesEasy
- 0022Generate ParenthesesMed
- 0026Remove Duplicates from Sorted ArrayEasy
- 0041First Missing PositiveHard
- 0049Group AnagramsMed
- 0053Maximum SubarrayMed
- 0055Jump GameMed
- 0056Merge IntervalsMed
- 0061Rotate ListMed
- 0075Sort ColorsMed
- 0079Word SearchMed
- 0091Decode WaysMed
- 0121Best Time to Buy and Sell StockEasy
- 0138Copy List with Random PointerMed
- 0146LRU CacheMed
Showing 20 of 49