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 31 matching · 2723 totalSort: id ↑
No.ProblemDifficulty
- 0004Median of Two Sorted ArraysHard
- 0005Longest Palindromic SubstringMed
- 00153SumMed
- 0017Letter Combinations of a Phone NumberMed
- 0020Valid ParenthesesEasy
- 0025Reverse Nodes in k-GroupHard
- 0033Search in Rotated Sorted ArrayMed
- 0036Valid SudokuMed
- 0039Combination SumMed
- 0049Group AnagramsMed
- 0053Maximum SubarrayMed
- 0073Set Matrix ZeroesMed
- 0075Sort ColorsMed
- 0093Restore IP AddressesMed
- 0141Linked List CycleEasy
- 0146LRU CacheMed
- 0169Majority ElementEasy
- 0197Minimum Size Subarray SumMed
- 0226Product of Array Except SelfMed
- 0227Sliding Window MaximumHard
Showing 20 of 31