Practice Problems

Curated problems organized by pattern, difficulty, and company. Exactly what you need — nothing you don't.

Easy

Medium

Hard

Total

Patterns

Companies

Problem	Difficulty	Companies
1 30. Substring With Concatenation Of All Words
2 17. Letter Combinations Of A Phone Number
3 3. Longest Substring Without Repeating Characters
4 19. Remove Nth Node From End Of List
5 14. Longest Common Prefix
6 25. Reverse Nodes In K-group
7 15. 3sum
8 22. Generate Parentheses
9 23. Merge K Sorted Lists
10 136. Single Number	Easy