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 21 matching · 2723 totalSort: id ↑
No.ProblemDifficulty
- 0001Two SumEasy
- 0003Longest Substring Without Repeating CharactersMed
- 0005Longest Palindromic SubstringMed
- 0007Reverse IntegerMed
- 0009Palindrome NumberEasy
- 0011Container With Most WaterMed
- 0014Longest Common PrefixEasy
- 0020Valid ParenthesesEasy
- 0023Merge k Sorted ListsHard
- 0056Merge IntervalsMed
- 0070Climbing StairsEasy
- 0072Edit DistanceMed
- 0118Pascal's TriangleEasy
- 0121Best Time to Buy and Sell StockEasy
- 0151Reverse Words in a StringMed
- 0169Majority ElementEasy
- 0194Reverse Linked ListEasy
- 0203Kth Largest Element in an ArrayMed
- 0309Coin ChangeMed
- 0472Max Consecutive OnesEasy
Showing 20 of 21