LeetCode Solutions

You can find the answer to LeetCode's questions that are group by difficulty, company, and topic in this repo.

All codes are written by c#. Please don't hesitate to create an issue, if you see a mistake, wrong solution/information.

As you can see below lists, there are a lot of questions. You can choose one of them and contribute it :)

Questions

Arrays and Strings

• Two Sum
• Longest Substring Without Repeating Characters
• String to Integer (atoi)
• Container With Most Water
• Integer to Roman
• Roman to Integer
• 3Sum
• 3Sum Closest
• Implement strStr()
• Rotate Image
• Group Anagrams
• Minimum Window Substring
• Compare Version Numbers
• Product of Array Except Self
• Missing Number
• Integer to English Words
• First Unique Character in a String
• Valid Parentheses
• Most Common Word
• Reorder Log Files
• Remove Duplicates from Sorted Array
• Best Time to Buy and Sell Stock II
• Rotate Array
• Contains Duplicate
• Single Number
• Intersection of Two Arrays II
• Plus One
• Move Zeroes
• Two Sum
• Valid Sudoku
• Rotate Image
• 3Sum
• Set Matrix Zeroes
• Increasing Triplet Subsequence
• Missing Ranges
• Spiral Matrix
• 4Sum II
• Game of Life
• First Missing Positive
• Longest Consecutive Sequence
• Find the Duplicate Number
• Longest Substring with At Most K Distinct Characters
• Basic Calculator II
• Sliding Window Maximum

Backtracking

• Permutations
• Subsets
• Palindrome Partitioning
• Remove Invalid Parentheses
• Wildcard Matching
• Regular Expression Matching

Design

• LRU Cache
• Min Stack
• Find Median from Data Stream
• Serialize and Deserialize Binary Tree
• Design Tic-Tac-Toe
• Design Search Autocomplete System
• Maximum Frequency Stack
• Shuffle an Array
• Min Stack
• Flatten 2D Vector
• Insert Delete GetRandom O(1)
• Implement Trie (Prefix Tree)
• Flatten Nested List Iterator
• Range Sum Query 2D - Mutable

Dynamic Programming

• Longest Palindromic Substring
• Maximum Subarray
• Best Time to Buy and Sell Stock
• Word Break
• Coin Change
• Climbing Stairs
• Best Time to Buy and Sell Stock
• Maximum Subarray
• House Robber
• Jump Game
• Unique Paths
• Longest Increasing Subsequence
• Maximum Product Subarray
• Decode Ways
• Best Time to Buy and Sell Stock with Cooldown
• Perfect Squares
• Word Break II
• Burst Balloons

Linked Lists

• Add Two Numbers
• Merge Two Sorted Lists
• Reverse Nodes in k-Group
• Copy List with Random Pointer
• Reverse Linked List
• Merge k Sorted Lists
• Delete Node in a Linked List
• Remove Nth Node From End of List
• Reverse Linked List
• Merge Two Sorted Lists
• Palindrome Linked List
• Linked List Cycle
• Odd Even Linked List
• Intersection of Two Linked Lists
• Sort List

Math

• Fizz Buzz
• Count Primes
• Power of Three
• Roman to Integer
• Happy Number
• Factorial Trailing Zeroes
• Excel Sheet Column Number
• Pow(x, n)
• Sqrt(x)
• Divide Two Integers
• Fraction to Recurring Decimal
• Largest Number
• Max Points on a Line

Others

• Reverse Integer
• Second Highest Salary
• Partition Labels
• Prison Cells After N Days
• Number of 1 Bits
• Hamming Distance
• Reverse Bits
• Pascal's Triangle
• Valid Parentheses
• Missing Number
• Sum of Two Integers
• Evaluate Reverse Polish Notation
• Majority Element
• Find the Celebrity
• Task Scheduler
• Queue Reconstruction by Height
• The Skyline Problem
• Largest Rectangle in Histogram

Recursion

• Letter Combinations of a Phone Number
• Generate Parentheses
• Word Search
• Word Search II

Sorting and Searching

• Median of Two Sorted Arrays
• Search in Rotated Sorted Array
• Merge Intervals
• Two Sum II - Input array is sorted
• Kth Largest Element in an Array
• Meeting Rooms II
• Top K Frequent Elements
• K Closest Points to Origin
• Merge Sorted Array
• First Bad Version
• Sort Colors
• Find Peak Element
• Search for a Range
• Search a 2D Matrix II
• Wiggle Sort II
• Kth Smallest Element in a Sorted Matrix

Strings

• Reverse String
• Reverse Integer
• First Unique Character in a String
• Valid Anagram
• Valid Palindrome
• String to Integer (atoi)
• Implement strStr()
• Count and Say
• Longest Common Prefix

Trees

• Maximum Depth of Binary Tree
• Validate Binary Search Tree
• Symmetric Tree
• Binary Tree Level Order Traversal
• Convert Sorted Array to Binary Search Tree

Trees and Graphs

• Validate Binary Search Tree
• Symmetric Tree
• Binary Tree Level Order Traversal
• Binary Tree Zigzag Level Order Traversal
• Binary Tree Maximum Path Sum
• Word Ladder II
• Word Ladder
• Number of Islands
• Course Schedule
• Lowest Common Ancestor of a Binary Tree
• Diameter of Binary Tree
• Cut Off Trees for Golf Event
• Flood Fill
• Binary Tree Inorder Traversal
• Binary Tree Zigzag Level Order Traversal
• Construct Binary Tree from Preorder and Inorder Traversal
• Populating Next Right Pointers in Each Node
• Kth Smallest Element in a BST
• Inorder Successor in BST
• Surrounded Regions
• Friend Circles
• Course Schedule II
• Longest Increasing Path in a Matrix
• Alien Dictionary
• Count of Smaller Numbers After Self