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
16 of 16 matching · 2723 totalSort: id ↑
No.ProblemDifficulty
- 0001Two SumEasy
- 0003Longest Substring Without Repeating CharactersMed
- 0005Longest Palindromic SubstringMed
- 0011Container With Most WaterMed
- 0014Longest Common PrefixEasy
- 0020Valid ParenthesesEasy
- 0033Search in Rotated Sorted ArrayMed
- 0042Trapping Rain WaterHard
- 0070Climbing StairsEasy
- 0080Remove Duplicates from Sorted Array IIMed
- 0121Best Time to Buy and Sell StockEasy
- 0187Binary Tree Right Side ViewMed
- 0332Reverse Vowels of a StringEasy
- 0689Asteroid CollisionMed
- 1076Longest Common SubsequenceMed
- 1152Replace the Substring for Balanced StringMed
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