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 201-225 of 250 matching problems.

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All topics Algorithm X Array Backtracking Bidirectional Search Binary Indexed Tree Binary Lifting Binary Search Binary Search Tree Binary Tree Bit Manipulation Boyer–Moore Majority Vote Algorithm Boyer–Moore String-Search Algorithm Bracket Sequences Breadth-First Search Brute-Force Search Bubble Sort Bucket Sort Combinatorics

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

Title	Difficulty	Topics
201. Bitwise AND of Numbers Range Open source	Medium	Bit Manipulation
202. Happy Number Open source	Easy	Hash TableMathTwo Pointers+1 more
203. Remove Linked List Elements Open source	Easy	Linked ListRecursion
204. Count Primes Open source	Medium	ArrayMathEnumeration+4 more
205. Isomorphic Strings Open source	Easy	Hash TableString
206. Reverse Linked List Open source	Easy	Linked ListRecursion
207. Course Schedule Open source	Medium	Depth-First SearchBreadth-First SearchGraph Theory+2 more
208. Implement Trie (Prefix Tree)Open source	Medium	Hash TableStringDesign+1 more
209. Minimum Size Subarray Sum Open source	Medium	ArrayBinary SearchSliding Window+1 more
210. Course Schedule II Open source	Medium	Depth-First SearchBreadth-First SearchGraph Theory+1 more
211. Design Add and Search Words Data Structure Open source	Medium	StringDepth-First SearchDesign+1 more
212. Word Search II Open source	Hard	ArrayStringBacktracking+2 more
213. House Robber II Open source	Medium	ArrayDynamic Programming
214. Shortest Palindrome Open source	Hard	StringRolling HashString Matching+4 more
215. Kth Largest Element in an Array Open source	Medium	ArrayDivide and ConquerSorting+2 more
216. Combination Sum III Open source	Medium	ArrayBacktracking
217. Contains Duplicate Open source	Easy	ArrayHash TableSorting
218. The Skyline Problem Open source	Hard	ArrayDivide and ConquerBinary Indexed Tree+5 more
219. Contains Duplicate II Open source	Easy	ArrayHash TableSliding Window
220. Contains Duplicate III Open source	Hard	ArraySliding WindowSorting+2 more
221. Maximal Square Open source	Medium	ArrayDynamic ProgrammingMatrix
222. Count Complete Tree Nodes Open source	Medium	Binary SearchBit ManipulationTree+1 more
223. Rectangle Area Open source	Medium	MathGeometry
224. Basic Calculator Open source	Hard	MathStringStack+1 more
225. Implement Stack using Queues Open source	Easy	StackDesignQueue