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 82 matching · 2723 totalSort: id ↑
No.ProblemDifficulty
- 0004Median of Two Sorted ArraysHard
- 0021Merge Two Sorted ListsEasy
- 0036Valid SudokuMed
- 0037Sudoku SolverHard
- 0039Combination SumMed
- 0040Combination Sum IIMed
- 0044Wildcard MatchingHard
- 0049Group AnagramsMed
- 0053Maximum SubarrayMed
- 0056Merge IntervalsMed
- 0072Edit DistanceMed
- 0074Search a 2D MatrixMed
- 0076Minimum Window SubstringHard
- 0079Word SearchMed
- 0091Decode WaysMed
- 0096Unique Binary Search TreesMed
- 0121Best Time to Buy and Sell StockEasy
- 0123Best Time to Buy and Sell Stock IIIHard
- 0124Binary Tree Maximum Path SumHard
- 0127Word LadderHard
Showing 20 of 82