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 40 matching · 2723 totalSort: id ↑
No.ProblemDifficulty
- 0003Longest Substring Without Repeating CharactersMed
- 0005Longest Palindromic SubstringMed
- 0010Regular Expression MatchingHard
- 0014Longest Common PrefixEasy
- 00153SumMed
- 0020Valid ParenthesesEasy
- 0034Find First and Last Position of Element in Sorted ArrayMed
- 0049Group AnagramsMed
- 0053Maximum SubarrayMed
- 0054Spiral MatrixMed
- 0055Jump GameMed
- 0056Merge IntervalsMed
- 0070Climbing StairsEasy
- 0121Best Time to Buy and Sell StockEasy
- 0125Valid PalindromeEasy
- 0128Longest Consecutive SequenceMed
- 0186House RobberMed
- 0188Number of IslandsMed
- 0203Kth Largest Element in an ArrayMed
- 0226Product of Array Except SelfMed
Showing 20 of 40