LeetCode Solutions

I gathered all my solutions to the problems listed in LeetCode.com. If you think you have a better solution to offer or improvement suggestions, please issue a pull request. Implementations in other programming languages are welcome too!!

Problems sorted by their difficulties

• Easy
• Medium
• Hard

Problem List

Easy

Title	Solution	Notes
Delete Node in a Linked List	Python
Linked List Cycle	Python C++	Fast/Slow runner approach
Majority Element	Python
Move Zeros	Python C++	Using two pointers
Sum two integers	Python C++
Two Sum	Python
Valid Anagram	Python
Merge two sorted linked lists	Python
Lowest Common Ancestor of a BST	Python
Ugly Number	Python
Climbing Stairs	Python	Dynamic programming example
Best Time to Buy and Sell Stock	Python C++
Implement Queue using Stacks	Python
Remove Duplicates from Sorted Array	Python
Palindrome Number	Python C++
Valid Sudoku	Python
Path Sum	Python
Add Digits	Python
Maximum depth of binary tree	Python
Minimum depth of binary tree	Python	Level order search is used
Invert binary tree	Python	Iterative
Intersection of Two Arrays	Python
Intersection of Two Arrays 2	Python
Excel Sheet Column Number	Python
Contains Duplicate	Python
Roman to Integer	Python
Reverse linked list	Python
Power of two	Python
Power of three	Python
Power of four	Python
Happy Number	Python
Number of 1 bits	Python
Remove Duplicates from Sorted List	Python
Reverse Vowels of a String	C++
Swap nodes in pairs	Python
House robber	Python
Binary tree level order traversal	Python
Binary tree level order traversal II	Python
Remove Element	Python
Plus One	Python
Symmetric Tree	Python
Balanced Binary Tree	Python	Iterative approach
Pascal’s Triangle	Python
Pascal’s Triangle II	Python C++
Factorial Trailing Zeros	Python C++
Reverse Bits	Python
Reverse Integer	Python
String to Integer (atoi)	Python
Guess number Higher or Lower	Python
Binary Tree Path	Python
Isomorphic Strings	Python
Rectangle Area	Python
Stack using Queues	Python
Remove Nth Node From End of List	Python
First Unique Character in a String	Python
Word Pattern	Python
Implement strStr()	Python
Min Stack	Python
Merge sorted array	Python
Intersection of Two Linked Lists	Python
Add Binary	Python
Longest Common Prefix	Python
Range sum query	Python

Medium

Title	Solution	Notes
Counting Bits	Python	O(n) solution
Shuffle an array	Python
Maximum Subarray	Python
Bitwise AND of Numbers Range	Python
Simplify Path	Python

Hard

Title	Solution	Notes
Valid Number	Python	FA implementation
LRU Cache	Python	Double linked list solution