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
- 0001Two SumEasy
- 0003Longest Substring Without Repeating CharactersMed
- 0005Longest Palindromic SubstringMed
- 0012Integer to RomanMed
- 00153SumMed
- 0020Valid ParenthesesEasy
- 0045Jump Game IIMed
- 0049Group AnagramsMed
- 0056Merge IntervalsMed
- 0063Unique Paths IIMed
- 0066Plus OneEasy
- 0076Minimum Window SubstringHard
- 0088Merge Sorted ArrayEasy
- 0120TriangleMed
- 0121Best Time to Buy and Sell StockEasy
- 0122Best Time to Buy and Sell Stock IIMed
- 0186House RobberMed
- 0218Kth Smallest Element in a BSTMed
- 0270Move ZeroesEasy
- 0282Find Median from Data StreamHard
Showing 20 of 40