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 31 matching problems in NeetCode 150.

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Array80Dynamic Programming35String33

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

Title	Difficulty	Topics
79. Word Search Open source	Medium	ArrayStringBacktracking+2 more
98. Validate Binary Search Tree Open source	Medium	TreeDepth-First SearchBinary Search Tree+1 more
100. Same Tree Open source	Easy	TreeDepth-First SearchBreadth-First Search+1 more
104. Maximum Depth of Binary Tree Open source	Easy	TreeDepth-First SearchBreadth-First Search+1 more
110. Balanced Binary Tree Open source	Easy	TreeDepth-First SearchBinary Tree
124. Binary Tree Maximum Path Sum Open source	Hard	Dynamic ProgrammingTreeDepth-First Search+2 more
130. Surrounded Regions Open source	Medium	ArrayDepth-First SearchBreadth-First Search+2 more
133. Clone Graph Open source	Medium	Hash TableDepth-First SearchBreadth-First Search+1 more
199. Binary Tree Right Side View Open source	Medium	TreeDepth-First SearchBreadth-First Search+1 more
200. Number of Islands Open source	Medium	ArrayDepth-First SearchBreadth-First Search+2 more
207. Course Schedule Open source	Medium	Depth-First SearchBreadth-First SearchGraph Theory+2 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
226. Invert Binary Tree Open source	Easy	TreeDepth-First SearchBreadth-First Search+1 more
230. Kth Smallest Element in a BST Open source	Medium	TreeDepth-First SearchBinary Search Tree+1 more
235. Lowest Common Ancestor of a Binary Search Tree Open source	Medium	TreeDepth-First SearchBinary Search Tree+3 more
261. Graph Valid Tree Open sourcePremium	Medium	Depth-First SearchBreadth-First SearchUnion-Find+1 more
269. Alien Dictionary Open sourcePremium	Hard	ArrayStringDepth-First Search+4 more
297. Serialize and Deserialize Binary Tree Open source	Hard	StringTreeDepth-First Search+3 more
323. Number of Connected Components in an Undirected Graph Open sourcePremium	Medium	Depth-First SearchBreadth-First SearchUnion-Find+1 more
329. Longest Increasing Path in a Matrix Open source	Hard	ArrayDynamic ProgrammingDepth-First Search+6 more
332. Reconstruct Itinerary Open source	Hard	ArrayStringDepth-First Search+6 more
417. Pacific Atlantic Water Flow Open source	Medium	ArrayDepth-First SearchBreadth-First Search+1 more
543. Diameter of Binary Tree Open source	Easy	TreeDepth-First SearchBinary Tree+1 more
572. Subtree of Another Tree Open source	Easy	TreeDepth-First SearchString Matching+2 more