Problem Library

Master these coding challenges to ace your next technical interview. Handpicked problems with personalized spaced repetition.

All tracks Blind 75 NeetCode 150 NeetCode 250 Striver A to Z SDE Sheet

Showing 1-25 of 150 matching problems in NeetCode 150.

Topic filter

All topics 0-1 Knapsack Algorithm X Array Backtracking Bidirectional Search Binary Lifting Binary Search Binary Search Tree Binary Tree Bit Manipulation Borůvka's Algorithm Bracket Sequences Breadth-First Search Brute-Force Search Bucket Sort Combinatorics Complete Knapsack Counting

Topic focus

Array80Dynamic Programming35String33

These are the topics showing up most often in your current queue.

Title	Difficulty	Topics
1. Two Sum Open source	Easy	ArrayHash Table
2. Add Two Numbers Open source	Medium	Linked ListMathRecursion
3. Longest Substring Without Repeating Characters Open source	Medium	Hash TableStringSliding Window
4. Median of Two Sorted Arrays Open source	Hard	ArrayBinary SearchDivide and Conquer
5. Longest Palindromic Substring Open source	Medium	Two PointersStringDynamic Programming+1 more
7. Reverse Integer Open source	Medium	Math
10. Regular Expression Matching Open source	Hard	StringDynamic ProgrammingRecursion
11. Container With Most Water Open source	Medium	ArrayTwo PointersGreedy
15. 3Sum Open source	Medium	ArrayTwo PointersSorting
17. Letter Combinations of a Phone Number Open source	Medium	Hash TableStringBacktracking
19. Remove Nth Node From End of List Open source	Medium	Linked ListTwo Pointers
20. Valid Parentheses Open source	Easy	StringStackBracket Sequences
21. Merge Two Sorted Lists Open source	Easy	Linked ListRecursion
22. Generate Parentheses Open source	Medium	StringDynamic ProgrammingBacktracking+1 more
23. Merge k Sorted Lists Open source	Hard	Linked ListDivide and ConquerHeap (Priority Queue)+2 more
25. Reverse Nodes in k-Group Open source	Hard	Linked ListRecursion
33. Search in Rotated Sorted Array Open source	Medium	ArrayBinary Search
36. Valid Sudoku Open source	Medium	ArrayHash TableMatrix
39. Combination Sum Open source	Medium	ArrayBacktracking
40. Combination Sum II Open source	Medium	ArrayBacktracking
42. Trapping Rain Water Open source	Hard	ArrayTwo PointersDynamic Programming+2 more
43. Multiply Strings Open source	Medium	MathStringSimulation
45. Jump Game II Open source	Medium	ArrayDynamic ProgrammingGreedy
46. Permutations Open source	Medium	ArrayBacktracking
48. Rotate Image Open source	Medium	ArrayMathMatrix