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 71 matching · 2723 totalSort: id ↑
No.ProblemDifficulty
- 0001Two SumEasy
- 0002Add Two NumbersMed
- 0005Longest Palindromic SubstringMed
- 0007Reverse IntegerMed
- 0009Palindrome NumberEasy
- 0011Container With Most WaterMed
- 0014Longest Common PrefixEasy
- 00153SumMed
- 00184SumMed
- 0020Valid ParenthesesEasy
- 0023Merge k Sorted ListsHard
- 0030Substring with Concatenation of All WordsHard
- 0033Search in Rotated Sorted ArrayMed
- 0041First Missing PositiveHard
- 0042Trapping Rain WaterHard
- 0045Jump Game IIMed
- 0051N-QueensHard
- 0053Maximum SubarrayMed
- 0056Merge IntervalsMed
- 0069Sqrt(x)Easy
Showing 20 of 71