neetcode-150.md

Neetcode 150

Arrays & Hashing

Status	Problem	Difficulty	Source
✅	Contains Duplicate	💚 Easy	🔗
✅	Valid Anagram	💚 Easy	🔗
✅	Two Sum	💚 Easy	🔗
✅	Group Anagrams	💛 Medium	🔗
✅	Top K Frequent Elements	💛 Medium	🔗
✅	Encode and Decode Strings	💛 Medium	🔗
✅	Product of Array Except Self	💛 Medium	🔗
✅	Valid Sudoku	💛 Medium	🔗
✅	Longest Consecutive Sequence	💛 Medium	🔗

Two Pointers

Status	Problem	Difficulty	Source
✅	Valid Palindrome	💚 Easy	🔗
✅	Two Sum II - Input Array Is Sorted	💛 Medium	🔗
✅	3Sum	💛 Medium	🔗
✅	Container With Most Water	💛 Medium	🔗
✅	Trapping Rain Water	❤️ Hard	🔗

Sliding Window

Status	Problem	Difficulty	Source
✅	Best Time to Buy and Sell Stock	💚 Easy	🔗
✅	Longest Substring Without Repeating Characters	💛 Medium	🔗
✅	Longest Repeating Character Replacement	💛 Medium	🔗
✅	Permutation in String	💛 Medium	🔗
✅	Minimum Window Substring	❤️ Hard	🔗
✅	Sliding Window Maximum	❤️ Hard	🔗

Stack

Status	Problem	Difficulty	Source
✅	Valid Parentheses	💚 Easy	🔗
✅	Min Stack	💛 Medium	🔗
✅	Evaluate Reverse Polish Notation	💛 Medium	🔗
✅	Daily Temperatures	💛 Medium	🔗
✅	Car Fleet	💛 Medium	🔗

Binary Search

Status	Problem	Difficulty	Source
✅	Binary Search	💚 Easy	🔗
✅	Search a 2D Matrix	💛 Medium	🔗
✅	Koko Eating Bananas	💛 Medium	🔗
✅	Find Minimum in Rotated Sorted Array	💛 Medium	🔗
✅	Search in Rotated Sorted Array	💛 Medium	🔗
✅	Median of Two Sorted Arrays	❤️ Hard	🔗

Linked list

Status	Problem	Difficulty	Source
✅	Reverse Linked List	💚 Easy	🔗
✅	Merge Two Sorted Lists	💚 Easy	🔗
✅	Linked List Cycle	💚 Easy	🔗
✅	Reorder List	💛 Medium	🔗
✅	Remove Nth Node From End of List	💛 Medium	🔗
✅	Copy List with Random Pointer	💛 Medium	🔗
✅	Add Two Numbers	💛 Medium	🔗
✅	Find the Duplicate Number	💛 Medium	🔗
✅	LRU Cache	💛 Medium	🔗
✅	Merge k Sorted Lists	❤️ Hard	🔗
✅	Reverse Nodes in k-Group	❤️ Hard	🔗

Trees

Status	Problem	Difficulty	Source
✅	Invert Binary Tree	💚 Easy	🔗
✅	Maximum Depth of Binary Tree	💚 Easy	🔗
✅	Diameter of Binary Tree	💚 Easy	🔗
✅	Balanced Binary Tree	💚 Easy	🔗
✅	Same Tree	💚 Easy	🔗
✅	Subtree of Another Tree	💚 Easy	🔗
✅	Lowest Common Ancestor of a Binary Search Tree	💛 Medium	🔗
✅	Binary Tree Level Order Traversal	💛 Medium	🔗
✅	Binary Tree Right Side View	💛 Medium	🔗
✅	Count Good Nodes in Binary Tree	💛 Medium	🔗
✅	Validate Binary Search Tree	💛 Medium	🔗
✅	Kth Smallest Element in a BST	💛 Medium	🔗

Heap / Priority Queue

Status	Problem	Difficulty	Source
✅	Kth Largest Element in a Stream	💚 Easy	🔗
✅	Last Stone Weight	💚 Easy	🔗
✅	K Closest Points to Origin	💛 Medium	🔗
✅	Kth Largest Element in an Array	💛 Medium	🔗
✅	Task Scheduler	💛 Medium	🔗
✅	Design Twitter	💛 Medium	🔗
✅	Find Median from Data Stream	❤️ Hard	🔗

Backtracking

Status	Problem	Difficulty	Source
✅	Subsets	💛 Medium	🔗
✅	Combination Sum	💛 Medium	🔗
✅	Combination Sum II	💛 Medium	🔗
✅	Permutations	💛 Medium	🔗
✅	Subsets II	💛 Medium	🔗
✅	Word Search	💛 Medium	🔗
✅	Letter Combinations of a Phone Number	💛 Medium	🔗

Tries

Status	Problem	Difficulty	Source
✅	Implement Trie (Prefix Tree)	💛 Medium	🔗

Graphs

Status	Problem	Difficulty	Source
✅	Number of Islands	💛 Medium	🔗
✅	Max Area of Island	💛 Medium	🔗
✅	Clone Graph	💛 Medium	🔗
✅	Walls and Gates	💛 Medium	🔗
✅	Rotting Oranges	💛 Medium	🔗
✅	Pacific Atlantic Water Flow	💛 Medium	🔗
✅	Surrounded Regions	💛 Medium	🔗
✅	Course Schedule	💛 Medium	🔗
✅	Course Schedule II	💛 Medium	🔗

1-D Dynamic Programming

Status	Problem	Difficulty	Source
✅	Climbing Stairs	💚 Easy	🔗
✅	Min Cost Climbing Stairs	💚 Easy	🔗
✅	House Robber	💛 Medium	🔗
✅	House Robber II	💛 Medium	🔗
🚧	Longest Palindromic Substring	💛 Medium	🔗
✅	Longest Increasing Subsequence	💛 Medium	🔗

2-D Dynamic Programming

Status	Problem	Difficulty	Source
🚧	Regular Expression Matching	❤️ Hard	🔗

Greedy

Status	Problem	Difficulty	Source
✅	Maximum Subarray	💛 Medium	🔗
✅	Jump Game	💛 Medium	🔗

Intervals

Status	Problem	Difficulty	Source
✅	Insert Interval	💛 Medium	🔗
✅	Merge Intervals	💛 Medium	🔗
✅	Meeting Rooms	💛 Medium	🔗

Math & Geometry

Status	Problem	Difficulty	Source
✅	Set Matrix Zeroes	💛 Medium	🔗
✅	Happy Number	💚 Easy	🔗
✅	Plus One	💚 Easy	🔗
✅	Pow(x, n)	💛 Medium	🔗

Bit Manipulation

Status	Problem	Difficulty	Source
✅	Single Number	💚 Easy	🔗
✅	Number of 1 Bits	💚 Easy	🔗
✅	Counting Bits	💚 Easy	🔗
✅	Reverse Bits	💚 Easy	🔗
✅	Missing Number	💚 Easy	🔗
✅	Reverse Integer	💛 Medium	🔗