README.md

🏆 Curated solutions to Leetcode problems in multiple languages to ace the Coding Interviews.

🔍 Press Ctrl+F or ⌘+F to search for a specific problem

#	Solution	Tag	Difficulty	Remark
0001	Two Sum	Array, Hash Table
0002	Add Two Numbers	Linked List, Math, Recursion
0004	Median of Two Sorted Arrays	Array, Binary Search, Divide & Conquer
0007	Reverse Integer	Math
0009	Palindrome Number	Math
0013	Roman to Integer	String, Math, Hash Table
0014	Longest Common Prefix	String
0020	Valid Parentheses	String, ST
0021	Merge Two Sorted Lists	LL, Recursion
0022	Generate Parentheses	String, DP, Backtracking
0024	Swap Nodes in Pairs	Linked List, Recursion
0026	Remove Duplicates	Array, Two Pointers
0027	Remove Element	Array, Two Pointers
0028	Find the Index of the First Occurrence in a String	2P, String, String Matching
0035	Search Insert Position	Array, BS
0037	Sudoku Solver	Array, Backtracking, Matrix
0041	First Missing Positive	Array, Hash Table
0042	Trapping Rain Water	Array, 2P, DP, ST, Monotonic Stack
0048	Rotate Image	Array, Math, Matrix
0051	N-Queens	Array, Backtracking
0053	Maximum Subarray	Array, DNC, DP
0055	Jump Game	Array, DP, Greedy
0058	Length of Last Word	String
0061	Rotate List	Linked List, Two Pointers
0066	Plus One	Array, Math
0067	Add Binary	Math, String, Bit Manip, Simulation
0069	Sqrt(x)	Math, BS
0070	Climbing Stairs	Math, DP, Memorization
0072	Edit Distance	String, DP
0074	Search a 2D Matrix	Array, BS, Matrix
0075	Sort Colors	Array, Two Pointers, Sorting
0078	Subsets	Array, Backtracking, Bit Manip
0083	Remove Duplicates from Sorted List	LL
0088	Merge Sorted Array	Array, 2P, Sorting
0094	Binary Tree Inorder Traversal	Tree, Stack, DFS, Binary Tree
0098	Validate BST	Tree, DFS, BST, Binary Tree
0100	Same Tree	Tree, DFS, BFS, Binary Tree
0101	Symmetric Tree	Tree, Depth-First Search, Breadth-First Search, Binary Tree
0103	Binary Tree Zigzag Level Order Traversal	Tree, BFS, Binary Tree
0104	Maximum Depth of Binary Tree	Tree, BFS, DFS, Binary Tree
0106	Construct Binary Tree from Inorder and Postorder Traversal	Array, Hash Table, DNC, Tree, Binary Tree
0108	Convert Sorted Array to Binary Search Tree	Array, DNC, Tree, BST, Binary Tree
0109	Convert Sorted List to Binary Search Tree	LL, DNC, Tree, BST, Binary Tree
0110	Balanced Binary Tree	Tree, DFS, Binary Tree
0111	Minimum Depth of Binary Tree	Tree, DFS, BFS, Binary Tree
0112	Path Sum	Tree, Depth-First Search, Breadth-First Search, Binary Tree
0118	Pascal's Triangle	Array, DP
0119	Pascal's Triangle II	Array, DP
0121	Best Time to Buy and Sell Stock	Array, DP
0122	Best Time to Buy and Sell Stock II	Array, DP, Greedy
0125	Valid Palindrome	2P, String
0129	Sum Root to Leaf Numbers	Tree, Depth-First Search, Binary Tree
0136	Single Number	Array, Bit Manip
0141	Linked List Cycle	Hash Table, LL, 2P
0142	Linked List Cycle II	Hash Table, LL, 2P
0144	Binary Tree Preorder Traversal	Stack, Tree, DFS, Binary Tree
0145	Binary Tree Postorder Traversal	Stack, Tree, DFS, Binary Tree
0160	Intersection of Two Linked Lists	Hash Table, LL, 2P
0169	Majority Element	Array, Hash Table, DNC, Sorting, Counting
0172	Factorial Trailing Zeroes	Math
0190	Reverse Bits	DNC, Bit Manip
0191	Number of 1 Bits	Divide & Conquer, Bit Manipulation
0193	Valid Phone Numbers	Shell
0195	Tenth Line	Shell
0199	Binary Tree Right Side View	Tree, DFS, BFS, Binary Tree
0200	Number of Islands	Array, Depth-First Search, Breadth-First Search, Union Find, Matrix
0202	Happy Number	Hash Table, Math, 2P
0203	Remove Linked List Elements	LL, Recursion
0205	Isomorphic Strings	Hash Table, String
0206	Reverse Linked List	Linked List, Recursion
0211	Design Add and Search Words Data Structure	String, Depth-First Search, Design, Trie
0217	Contains Duplicate	Array, Hash Table, Sorting
0219	Contains Duplicate II	Array, Hash Table, Sliding Window
0222	Count Complete Tree Nodes	Binary Search, Tree, DFS, Binary Tree
0225	Implement Stack using Queues	ST, Design, Q
0226	Invert Binary Tree	Tree, Depth-First Search, Breadth-First Search, Binary Tree
0228	Summary Ranges	Array
0230	Kth Smallest Element in a BST	Tree, DFS, BST, Binary Tree
0231	Power of Two	Math, Bit Manipulation, Recursion
0232	Implement Queue using Stacks	ST, Design, Q
0234	Palindrome Linked List	LL, 2P, ST, Recursion
0236	Lowest Common Ancestor of a Binary Tree	Tree, Depth-First Search, Binary Tree
0242	Valid Anagram	Hash Table, String, Sorting
0257	Binary Tree Paths	String, Backtracking, Tree, Depth-First Search, Binary Tree
0258	Add Digits	Math, Simulation, Number Theory
0263	Ugly Number	Math
0268	Missing Number	Array, Hash Table, Math, BS, Bit Manip, Sorting
0278	First Bad Version	Binary Search, Interactive
0279	Perfect Squares	Math, DP, Breadth-First Search
0283	Move Zeroes	Array, Two Pointers
0290	Word Pattern	Hash Table, String
0292	Nim Game	Math, Brainteaser, Game Theory
0300	Longest Increasing Subsequence	Array, Binary Search, DP
0322	Coin Change	Array, DP, BFS
0326	Power of Three	Math, Recursion
0337	House Robber III	DP, Tree, DFS, Binary Tree
0338	Counting Bits	DP, Bit Manip
0342	Power of Four	Math, Bit Manip, Recursion
0344	Reverse String	Two Pointers, String, Recursion
0345	Reverse Vowels of a String	2P, String
0349	Intersection of Two Arrays	Array, Hash Table, 2P, BS, Sorting
0350	Intersection of Two Arrays II	Array, Hash Table, 2P, BS, Sorting
0367	Valid Perfect Square	Math, Binary Search
0369	Plus One Linked List	Linked List, Math		🔒
0374	Guess Number Higher or Lower	BS, Interactive
0382	Linked List Random Node	LL, Math, Reservoir Sampling, Randomized
0383	Ransom Note	Hash Table, String, Counting
0387	First Unique Character in a String	Hash Table, String, Q, Counting
0389	Find the Difference	Hash Table, String, Bit Manipulation, Sorting
0392	Is Subsequence	2P, String, DP
0401	Binary Watch	Backtracking, Bit Manip
0404	Sum of Left Leaves	Tree, Depth-First Search, Breadth-First Search, Binary Tree
0412	Fizz Buzz	Math, String, Simulation
0414	Third Maximum Number	Array, Sorting
0434	Number of Segments in a String	String
0438	Find All Anagrams in a String	Hash Table, String, Sliding Window
0441	Arranging Coins	Math, BS
0442	Find All Duplicates	Array, Hash Table
0443	String Compression	2P, String
0445	Add Two Numbers II	Linked List, Math, Stack
0448	Find All Numbers Disappeared in an Array	Array, Hash Table
0461	Hamming Distance	Bit Manip
0463	Island Perimeter	Array, Depth-First Search, Breadth-First Search, Matrix
0476	Number Complement	Bit Manip
0482	License Key Formatting	String
0485	Max Consecutive Ones	Array
0492	Construct the Rectangle	Math
0498	Diagonal Traverse	Array, Matrix, Simulation
0502	IPO	Array, Greedy, Sorting, Heap (Priority Queue)
0504	Base 7	Math
0506	Relative Ranks	Array, Sorting, Heap
0507	Perfect Number	Math
0509	Fibonacci Number	Math, Recursion, DP, Memoization
0516	Longest Palindromic Subsequence	String, DP
0518	Coin Change 2	Array, DP
0530	Minimum Absolute Difference in BST	Tree, Depth-First Search, Breadth-First Search, BST, Binary Tree
0540	Single Element in a Sorted Array	Array, BS
0541	Reverse String II	Two Pointers, String
0543	Diameter of Binary Tree	Tree, DFS, Binary Tree
0605	Can Place Flowers	Array, Greedy
0652	Find Duplicate Subtrees	Hash Table, Tree, Depth-First Search, Binary Tree
0653	Two Sum IV - Input is a BST	Tree, DFS, BST, Binary Tree
0695	Max Area of Island	Array, Depth-First Search, Breadth-First Search, Union Find, Matrix
0704	Binary Search	Array, Binary Search
0739	Daily Temperatures	Array, Stack, Monotonic Stack
0771	Jewels and Stones	String, Hashtable
0799	Minimum Distance Between BST Nodes	Tree, Depth-First Search, Breadth-First Search, BST, Binary Tree
0875	Koko Eating Bananas	Array, BS
0876	Middle of the Linked List	Linked List, Two Pointers
0888	Fair Candy Swap	Array, Hash Table, Binary Search, Sorting
0912	Sort an Array	Array, DNC, Sorting, Heap (Priority Queue), Merge Sort, Bucket Sort, Radix Sort, Counting Sort
0944	Delete Columns to Make Sorted	Array, String
0958	Check Completeness of a Binary Tree	Tree, Breadth-First Search, Binary Tree
0997	Find the Town Judge	Array, Hash Table, Graph
1011	Capacity To Ship Packages Within D Days	Array, BS
1029	Two City Scheduling	Array, Greedy, Sorting
1047	Remove All Adjacent Duplicates In String	String, Stack
1092	Shortest Common Supersequence	String, DP
1108	Defanging an IP Address	String
1143	Longest Common Subsequence	String, DP
1232	Check If It Is a Straight Line	Array, Math, Geometry
1345	Jump Game IV	Array, Hash Table, Breadth-First Search
1431	Kids With the Greatest Number of Candies	Array
1461	Check If a String Contains All Binary Codes of Size K	String, Hash Table, Bit Manipulation
1472	Design Browser History	Array, LL, ST, Design, Doubly-Linked List, Data Stream
1480	Running Sum of 1d Array	Array, Prefix Sum
1491	Average Salary Excluding the Minimum and Maximum	Array, Sorting
1498	Number of Subsequences That Satisfy the Given Sum Condition	Array, Two Pointer, Binary Search, Sorting
1512	Number of Good Pairs	Array, Hash Table, Math, Counting
1537	Get the Maximum Score	Array, Two Pointer, DP, Greedy
1539	Kth Missing Positive Number	Array, BS
1580	Shuffle the Array	Array
1630	Count Odd Numbers in an Interval Range	Math
1672	Richest Customer Wealth	Array, Matrix
1689	Partitioning Into Minimum Number Of Deci-Binary Numbers	String, Greedy
1920	Build Array from Permutation	Array, Simulation
1929	Concatenation of Array	Array
1957	Delete Characters to Make Fancy String	String
2011	Final Value of Variable After Performing Operations	Array, String, Simulation
2114	Maximum Number of Words Found in Sentences	Array, String
2160	Minimum Sum of Four Digit Number After Splitting Digits	Math, Greedy, Sorting
2176	Count Equal and Divisible Pairs in an Array	Array
2187	Minimum Time to Complete Trips	Array, BS
2235	Add Two Integers	Math
2236	Root Equal to Sum of Children	Tree, Binary Tree
2348	Number of Zero-Filled Subarrays	Array, Math
2396	Strictly Palindromic Number	Math, 2P, Brainteaser
2413	Smallest Even Multiple	Math, Number Theory
2427	Number of Common Factors	Math, Enumeration, Number Theory
2444	Count Subarrays With Fixed Bounds	Array, Q, Sliding Window, Monotonic Queue
2469	Convert the Temperature	Math
2551	Put Marbles in Bags	Array, Greedy, Sorting, Heap (Priority Queue)
2574	Left and Right Sum Differences	Array, Prefix Sum