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
10 of 10 matching · 2723 totalSort: id ↑
No.ProblemDifficulty
- 0003Longest Substring Without Repeating CharactersMed
- 0020Valid ParenthesesEasy
- 0031Next PermutationMed
- 0053Maximum SubarrayMed
- 0122Best Time to Buy and Sell Stock IIMed
- 0155Min StackMed
- 0190Happy NumberEasy
- 0485Diagonal TraverseMed
- 0571Can Place FlowersEasy
- 2402Design Graph With Shortest Path CalculatorHard
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