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 667 matching · 2723 totalSort: id ↑
No.ProblemDifficulty
- 0001Two SumEasy
- 0009Palindrome NumberEasy
- 0013Roman to IntegerEasy
- 0014Longest Common PrefixEasy
- 0020Valid ParenthesesEasy
- 0021Merge Two Sorted ListsEasy
- 0026Remove Duplicates from Sorted ArrayEasy
- 0027Remove ElementEasy
- 0028Find the Index of the First Occurrence in a StringEasy
- 0035Search Insert PositionEasy
- 0058Length of Last WordEasy
- 0066Plus OneEasy
- 0067Add BinaryEasy
- 0069Sqrt(x)Easy
- 0070Climbing StairsEasy
- 0083Remove Duplicates from Sorted ListEasy
- 0088Merge Sorted ArrayEasy
- 0094Binary Tree Inorder TraversalEasy
- 0100Same TreeEasy
- 0101Symmetric TreeEasy
Showing 20 of 667