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 22 matching · 2723 totalSort: id ↑
No.ProblemDifficulty
- 0001Two SumEasy
- 0003Longest Substring Without Repeating CharactersMed
- 0004Median of Two Sorted ArraysHard
- 0007Reverse IntegerMed
- 0009Palindrome NumberEasy
- 0013Roman to IntegerEasy
- 0020Valid ParenthesesEasy
- 0026Remove Duplicates from Sorted ArrayEasy
- 0049Group AnagramsMed
- 0055Jump GameMed
- 0070Climbing StairsEasy
- 0088Merge Sorted ArrayEasy
- 0125Valid PalindromeEasy
- 0141Linked List CycleEasy
- 0179Rotate ArrayMed
- 0192Count PrimesMed
- 0203Kth Largest Element in an ArrayMed
- 0219Power of TwoEasy
- 0230Valid AnagramEasy
- 0438Sort Characters By FrequencyMed
Showing 20 of 22