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 35 of 35 problems in Blind 75.

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All topics Array Backtracking Binary Search Binary Search Tree Binary Tree Breadth-First Search Depth-First Search Design Divide and Conquer Dynamic Programming Graph Theory Greedy Hash Table Linked List Math Matrix Memoization Prefix Sum

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Array17Depth-First Search11Binary Tree9

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

Title	Difficulty	Topics
1. Two Sum	Easy	ArrayHash Table
5. Longest Palindromic Substring	Medium	Two PointersStringDynamic Programming
11. Container With Most Water	Medium	ArrayTwo PointersGreedy
15. 3Sum	Medium	ArrayTwo PointersSorting
19. Remove Nth Node From End of List	Medium	Linked ListTwo Pointers
21. Merge Two Sorted Lists	Easy	Linked ListRecursion
33. Search in Rotated Sorted Array	Medium	ArrayBinary Search
53. Maximum Subarray	Medium	ArrayDivide and ConquerDynamic Programming
56. Merge Intervals	Medium	ArraySorting
57. Insert Interval	Medium	Array
70. Climbing Stairs	Easy	MathDynamic ProgrammingMemoization
79. Word Search	Medium	ArrayStringBacktracking+2 more
98. Validate Binary Search Tree	Medium	TreeDepth-First SearchBinary Search Tree+1 more
100. Same Tree	Easy	TreeDepth-First SearchBreadth-First Search+1 more
102. Binary Tree Level Order Traversal	Medium	TreeBreadth-First SearchBinary Tree
104. Maximum Depth of Binary Tree	Easy	TreeDepth-First SearchBreadth-First Search+1 more
105. Construct Binary Tree from Preorder and Inorder Traversal	Medium	ArrayHash TableDivide and Conquer+2 more
110. Balanced Binary Tree	Easy	TreeDepth-First SearchBinary Tree
121. Best Time to Buy and Sell Stock	Easy	ArrayDynamic Programming
133. Clone Graph	Medium	Hash TableDepth-First SearchBreadth-First Search+1 more
141. Linked List Cycle	Easy	Hash TableLinked ListTwo Pointers
143. Reorder List	Medium	Linked ListTwo PointersStack+1 more
152. Maximum Product Subarray	Medium	ArrayDynamic Programming
153. Find Minimum in Rotated Sorted Array	Medium	ArrayBinary Search
198. House Robber	Medium	ArrayDynamic Programming
199. Binary Tree Right Side View	Medium	TreeDepth-First SearchBreadth-First Search+1 more
200. Number of Islands	Medium	ArrayDepth-First SearchBreadth-First Search+2 more
206. Reverse Linked List	Easy	Linked ListRecursion
207. Course Schedule	Medium	Depth-First SearchBreadth-First SearchGraph Theory+1 more
208. Implement Trie (Prefix Tree)	Medium	Hash TableStringDesign+1 more
213. House Robber II	Medium	ArrayDynamic Programming
217. Contains Duplicate	Easy	ArrayHash TableSorting
226. Invert Binary Tree	Easy	TreeDepth-First SearchBreadth-First Search+1 more
230. Kth Smallest Element in a BST	Medium	TreeDepth-First SearchBinary Search Tree+1 more
238. Product of Array Except Self	Medium	ArrayPrefix Sum