NeetCode 250

NeetCode 150 plus 100 more beginner-friendly problems. The most approachable list for people completely new to algorithms. Each topic has extra easy problems.

Title	Solution	Practice	Difficulty	Companies	Topics
649. Dota2 Senate	Solution	Solve	Medium	-	Greedy Queue+1
199. Binary Tree Right Side View	Solution	Solve	Medium	-	Binary Tree Breadth-First Search+2
200. Number of Islands	Solution	Solve	Medium	-	Array Breadth-First Search+3
201. Bitwise AND of Numbers Range	Solution	Solve	Medium	-	Bit Manipulation
202. Happy Number	Solution	Solve	Easy	-	Hash Table Math+1
207. Course Schedule	Solution	Solve	Medium	-	Breadth-First Search Depth-First Search+2
208. Implement Trie (Prefix Tree)	Solution	Solve	Medium	-	Design Hash Table+2
210. Course Schedule II	Solution	Solve	Medium	-	Breadth-First Search Depth-First Search+2
211. Design Add and Search Words Data Structure	Solution	Solve	Medium	-	Depth-First Search Design+2
212. Word Search II	Solution	Solve	Hard	-	Array Backtracking+3
213. House Robber II	Solution	Solve	Medium	-	Array Dynamic Programming
215. Kth Largest Element in an Array	Solution	Solve	Medium	-	Array Divide and Conquer+3
226. Invert Binary Tree	Solution	Solve	Easy	-	Binary Tree Breadth-First Search+2
230. Kth Smallest Element in a BST	Solution	Solve	Medium	-	Binary Search Tree Binary Tree+2
252. Meeting Rooms	Solution	Solve	Easy	-	Array Sorting
253. Meeting Rooms II	Solution	Solve	Medium	-	Array Greedy+4
261. Graph Valid Tree	Solution	Solve	Medium	-	Breadth-First Search Depth-First Search+2
268. Missing Number	Solution	Solve	Easy	-	Array Binary Search+4
269. Alien Dictionary	Solution	Solve	Hard	-	Array Breadth-First Search+4
279. Perfect Squares	Solution	Solve	Medium	-	Breadth-First Search Dynamic Programming+1
286. Walls and Gates	Solution	Solve	Medium	-	Array Breadth-First Search+1
295. Find Median from Data Stream	Solution	Solve	Hard	-	Data Stream Design+3
297. Serialize and Deserialize Binary Tree	Solution	Solve	Hard	-	Binary Tree Breadth-First Search+4
300. Longest Increasing Subsequence	Solution	Solve	Medium	-	Array Binary Search+1
309. Best Time to Buy and Sell Stock with Cooldown	Solution	Solve	Medium	-	Array Dynamic Programming
310. Minimum Height Trees	Solution	Solve	Medium	-	Breadth-First Search Depth-First Search+2
312. Burst Balloons	Solution	Solve	Hard	-	Array Dynamic Programming
322. Coin Change	Solution	Solve	Medium	-	Array Breadth-First Search+1
323. Number of Connected Components in an Undirected Graph	Solution	Solve	Medium	-	Breadth-First Search Depth-First Search+2
329. Longest Increasing Path in a Matrix	Solution	Solve	Hard	-	Array Breadth-First Search+6
332. Reconstruct Itinerary	Solution	Solve	Hard	-	Depth-First Search Eulerian Circuit+1
337. House Robber III	Solution	Solve	Medium	-	Binary Tree Depth-First Search+2
338. Counting Bits	Solution	Solve	Easy	-	Bit Manipulation Dynamic Programming
343. Integer Break	Solution	Solve	Medium	-	Dynamic Programming Math
355. Design Twitter	Solution	Solve	Medium	-	Design Hash Table+2
371. Sum of Two Integers	Solution	Solve	Medium	-	Bit Manipulation Math
377. Combination Sum IV	Solution	Solve	Medium	-	Array Dynamic Programming
399. Evaluate Division	Solution	Solve	Medium	-	Array Breadth-First Search+5
416. Partition Equal Subset Sum	Solution	Solve	Medium	-	Array Dynamic Programming
417. Pacific Atlantic Water Flow	Solution	Solve	Medium	-	Array Breadth-First Search+2
427. Construct Quad Tree	Solution	Solve	Medium	-	Array Divide and Conquer+2
435. Non-overlapping Intervals	Solution	Solve	Medium	-	Array Dynamic Programming+2
450. Delete Node in a BST	Solution	Solve	Medium	-	Binary Search Tree Binary Tree+1
463. Island Perimeter	Solution	Solve	Easy	-	Array Breadth-First Search+2
473. Matchsticks to Square	Solution	Solve	Medium	-	Array Backtracking+3
494. Target Sum	Solution	Solve	Medium	-	Array Backtracking+1
502. IPO	Solution	Solve	Hard	-	Array Greedy+2
518. Coin Change II	Solution	Solve	Medium	-	Array Dynamic Programming
543. Diameter of Binary Tree	Solution	Solve	Easy	-	Binary Tree Depth-First Search+1
572. Subtree of Another Tree	Solution	Solve	Easy	-	Binary Tree Depth-First Search+3
621. Task Scheduler	Solution	Solve	Medium	-	Array Counting+4
647. Palindromic Substrings	Solution	Solve	Medium	-	Dynamic Programming String+1
1046. Last Stone Weight	Solution	Solve	Easy	-	Array Heap (Priority Queue)
2807. Insert Greatest Common Divisors in Linked List	Solution	Solve	Medium	-	Linked List Math+1
2709. Greatest Common Divisor Traversal	Solution	Solve	Hard	-	Array Math+2
2707. Extra Characters in a String	Solution	Solve	Medium	-	Array Dynamic Programming+3
2402. Meeting Rooms III	Solution	Solve	Hard	-	Array Hash Table+3
2392. Build a Matrix With Conditions	Solution	Solve	Hard	-	Array Graph+2
2013. Detect Squares	Solution	Solve	Medium	-	Array Counting+2
1899. Merge Triplets to Form Target Triplet	Solution	Solve	Medium	-	Array Greedy
1871. Jump Game VII	Solution	Solve	Medium	-	Dynamic Programming Prefix Sum+2
1863. Sum of All Subset XOR Totals	Solution	Solve	Easy	-	Array Backtracking+4
1851. Minimum Interval to Include Each Query	Solution	Solve	Hard	-	Array Binary Search+3
1834. Single-Threaded CPU	Solution	Solve	Medium	-	Array Heap (Priority Queue)+1
1631. Path With Minimum Effort	Solution	Solve	Medium	-	Array Binary Search+5
1584. Min Cost to Connect All Points	Solution	Solve	Medium	-	Array Graph+2
1489. Find Critical and Pseudo-Critical Edges in Minimum Spanning Tree	Solution	Solve	Hard	-	Graph Minimum Spanning Tree+3
1462. Course Schedule IV	Solution	Solve	Medium	-	Breadth-First Search Depth-First Search+2
1448. Count Good Nodes in Binary Tree	Solution	Solve	Medium	-	Binary Tree Breadth-First Search+2
1406. Stone Game III	Solution	Solve	Hard	-	Array Dynamic Programming+2
1405. Longest Happy String	Solution	Solve	Medium	-	Greedy Heap (Priority Queue)+1
1325. Delete Leaves With a Given Value	Solution	Solve	Medium	-	Binary Tree Depth-First Search+1
1143. Longest Common Subsequence	Solution	Solve	Medium	-	Dynamic Programming String
1140. Stone Game II	Solution	Solve	Medium	-	Array Dynamic Programming+3
1137. N-th Tribonacci Number	Solution	Solve	Easy	-	Dynamic Programming Math+1
1094. Car Pooling	Solution	Solve	Medium	-	Array Heap (Priority Queue)+3
1071. Greatest Common Divisor of Strings	Solution	Solve	Easy	-	Math String
1049. Last Stone Weight II	Solution	Solve	Medium	-	Array Dynamic Programming
778. Swim in Rising Water	Solution	Solve	Hard	-	Array Binary Search+5
678. Valid Parenthesis String	Solution	Solve	Medium	-	Dynamic Programming Greedy+2
684. Redundant Connection	Solution	Solve	Medium	-	Breadth-First Search Depth-First Search+2
695. Max Area of Island	Solution	Solve	Medium	-	Array Breadth-First Search+3
698. Partition to K Equal Sum Subsets	Solution	Solve	Medium	-	Array Backtracking+4
701. Insert into a Binary Search Tree	Solution	Solve	Medium	-	Binary Search Tree Binary Tree+1
703. Kth Largest Element in a Stream	Solution	Solve	Easy	-	Binary Search Tree Binary Tree+4
721. Accounts Merge	Solution	Solve	Medium	-	Array Breadth-First Search+5
743. Network Delay Time	Solution	Solve	Medium	-	Breadth-First Search Depth-First Search+3
746. Min Cost Climbing Stairs	Solution	Solve	Easy	-	Array Dynamic Programming
752. Open the Lock	Solution	Solve	Medium	-	Array Breadth-First Search+2
763. Partition Labels	Solution	Solve	Medium	-	Greedy Hash Table+2
767. Reorganize String	Solution	Solve	Medium	-	Counting Greedy+4
918. Maximum Sum Circular Subarray	Solution	Solve	Medium	-	Array Divide and Conquer+3
997. Find the Town Judge	Solution	Solve	Easy	-	Array Graph+1
994. Rotting Oranges	Solution	Solve	Medium	-	Array Breadth-First Search+1
978. Longest Turbulent Subarray	Solution	Solve	Medium	-	Array Dynamic Programming+1
973. K Closest Points to Origin	Solution	Solve	Medium	-	Array Divide and Conquer+5
953. Verifying an Alien Dictionary	Solution	Solve	Easy	-	Array Hash Table+1
860. Lemonade Change	Solution	Solve	Easy	-	Array Greedy
787. Cheapest Flights Within K Stops	Solution	Solve	Medium	-	Breadth-First Search Depth-First Search+4
846. Hand of Straights	Solution	Solve	Medium	-	Array Greedy+2

NeetCode 250

Dota2 Senate

Binary Tree Right Side View

Number of Islands

Bitwise AND of Numbers Range

Happy Number

Course Schedule

Implement Trie (Prefix Tree)

Course Schedule II

Design Add and Search Words Data Structure

Word Search II

House Robber II

Kth Largest Element in an Array

Invert Binary Tree

Kth Smallest Element in a BST

Meeting Rooms

Meeting Rooms II

Graph Valid Tree

Missing Number

Alien Dictionary

Perfect Squares

Walls and Gates

Find Median from Data Stream

Serialize and Deserialize Binary Tree

Longest Increasing Subsequence

Best Time to Buy and Sell Stock with Cooldown

Minimum Height Trees

Burst Balloons

Coin Change

Number of Connected Components in an Undirected Graph

Longest Increasing Path in a Matrix

Reconstruct Itinerary

House Robber III

Counting Bits

Integer Break

Design Twitter

Sum of Two Integers

Combination Sum IV

Evaluate Division

Partition Equal Subset Sum

Pacific Atlantic Water Flow

Construct Quad Tree

Non-overlapping Intervals

Delete Node in a BST

Island Perimeter

Matchsticks to Square

Target Sum

IPO

Coin Change II

Diameter of Binary Tree

Subtree of Another Tree

Task Scheduler

Palindromic Substrings

Last Stone Weight

Insert Greatest Common Divisors in Linked List

Greatest Common Divisor Traversal

Extra Characters in a String

Meeting Rooms III

Build a Matrix With Conditions

Detect Squares

Merge Triplets to Form Target Triplet

Jump Game VII

Sum of All Subset XOR Totals

Minimum Interval to Include Each Query

Single-Threaded CPU

Path With Minimum Effort

Min Cost to Connect All Points

Find Critical and Pseudo-Critical Edges in Minimum Spanning Tree

Course Schedule IV

Count Good Nodes in Binary Tree

Stone Game III

Longest Happy String

Delete Leaves With a Given Value

Longest Common Subsequence

Stone Game II

N-th Tribonacci Number

Car Pooling

Greatest Common Divisor of Strings

Last Stone Weight II

Swim in Rising Water