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 42 matching · 2723 totalSort: id ↑
No.ProblemDifficulty
- 0004Median of Two Sorted ArraysHard
- 0023Merge k Sorted ListsHard
- 0053Maximum SubarrayMed
- 0105Construct Binary Tree from Preorder and Inorder TraversalMed
- 0106Construct Binary Tree from Inorder and Postorder TraversalMed
- 0108Convert Sorted Array to Binary Search TreeEasy
- 0109Convert Sorted List to Binary Search TreeMed
- 0148Sort ListMed
- 0169Majority ElementEasy
- 0180Reverse BitsEasy
- 0181Number of 1 BitsEasy
- 0203Kth Largest Element in an ArrayMed
- 0206The Skyline ProblemHard
- 0228Search a 2D Matrix IIMed
- 0302Count of Smaller Numbers After SelfHard
- 0311Wiggle Sort IIMed
- 0314Count of Range SumHard
- 0334Top K Frequent ElementsMed
- 0359Super PowMed
- 0382Longest Substring with At Least K Repeating CharactersMed
Showing 20 of 42