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
15 of 15 matching · 2723 totalSort: id ↑
No.ProblemDifficulty
- 0030Substring with Concatenation of All WordsHard
- 0043Multiply StringsMed
- 0071Simplify PathMed
- 0146LRU CacheMed
- 0227Sliding Window MaximumHard
- 0334Top K Frequent ElementsMed
- 0381Decode StringMed
- 0582Maximum Product of Three NumbersEasy
- 0632Valid Parenthesis StringMed
- 063324 GameHard
- 0634Valid Palindrome IIEasy
- 0689Asteroid CollisionMed
- 0798Backspace String CompareEasy
- 0818Shortest Path to Get All KeysHard
- 0958Max Consecutive Ones IIIMed
All 15 matching problems loaded