LeetCode Problem and Solutions

This is a summary of my solutions to the problems on LeetCode. The solution approaches of each problem are usually at the beginning of the source file. Please feel free to share any of your thoughts!

#	Problems and Solutions
1	Two Sum [ python java cpp ]
7	Reverse Integer [ python java cpp ]
8	String to Integer (atoi) [ python java cpp ]
9	Palindrome Number [ python java cpp ]
10	Regular Expression Matching [ python java cpp ]
13	Roman to Integer [ python java cpp ]
14	Longest Common Prefix [ python java cpp ]
15	3Sum [ python java cpp ]
16	3Sum Closest [ python java cpp ]
18	4Sum [ python java cpp ]
19	Remove Nth Node From End of List [ python java cpp ]
20	Valid Parentheses [ python java cpp ]
21	Merge Two Sorted Lists [ python java cpp ]
22	Generate Parentheses [ python java cpp ]
26	Remove Duplicates from Sorted Array [ python java cpp ]
27	Remove Element [ python java cpp ]
28	Implement strStr() [ python java cpp ]
34	Search for a Range [ python java cpp ]
35	Search Insert Position [ python java cpp ]
36	Valid Sudoku [ python java cpp ]
38	Count and Say [ python java cpp ]
41	First Missing Positive [ python java cpp ]
49	Group Anagrams [ python java cpp ]
56	Merge Intervals [ python java cpp ]
58	Length of Last Word [ python java cpp ]
66	Plus One [ python java cpp ]
67	Add Binary [ python java cpp ]
69	Sqrt(x) [ python java cpp ]
70	Climbing Stairs [ python java cpp ]
71	Simplify Path [ python java cpp ]
74	Search a 2D Matrix [ python java cpp ]
79	Word Search [ python java cpp ]
83	Remove Duplicates from Sorted List [ python java cpp ]
84	Largest Rectangle in Histogram [ python java cpp ]
88	Merge Sorted Array [ python java cpp ]
91	Decode Ways [ python java cpp ]
94	Binary Tree Inorder Traversal [ python java cpp ]
98	Validate Binary Search Tree [ python java cpp ]
100	Same Tree [ python java cpp ]
101	Symmetric Tree [ python java cpp ]
102	Binary Tree Level Order Traversal [ python java cpp ]
104	Maximum Depth of Binary Tree [ python java cpp ]
106	Construct Binary Tree from Inorder and Postorder Traversal [ python java cpp ]
107	Binary Tree Level Order Traversal II [ python java cpp ]
110	Balanced Binary Tree [ python java cpp ]
111	Minimum Depth of Binary Tree [ python java cpp ]
112	Path Sum [ python java cpp ]
118	Pascal's Triangle [ python java cpp ]
119	Pascal's Triangle II [ python java cpp ]
121	Best Time to Buy and Sell Stock [ python java cpp ]
124	Binary Tree Maximum Path Sum [ python java cpp ]
125	Valid Palindrome [ python java cpp ]
133	Clone Graph [ python java cpp ]
136	Single Number [ python java cpp ]
139	Word Break [ python java cpp ]
140	Word Break II [ python java cpp ]
144	Binary Tree Preorder Traversal [ python java cpp ]
151	Reverse Words in a String [ python java cpp ]
152	Maximum Product Subarray [ python java cpp ]
155	Min Stack [ python java cpp ]
160	Intersection of Two Linked Lists [ python java cpp ]
165	Compare Version Numbers [ python java cpp ]
168	Excel Sheet Column Title [ python java cpp ]
169	Majority Element [ python java cpp ]
171	Excel Sheet Column Number [ python java cpp ]
172	Factorial Trailing Zeroes [ python java cpp ]
173	Binary Search Tree Iterator [ python java cpp ]
187	Repeated DNA Sequences [ python java cpp ]
189	Rotate Array [ python java cpp ]
190	Reverse Bits [ python java cpp ]
191	Number of 1 Bits [ python java cpp ]
198	House Robber [ python java cpp ]
199	Binary Tree Right Side View [ python java cpp ]
202	Happy Number [ python java cpp ]
204	Count Primes [ python java cpp ]
205	Isomorphic Strings [ python java cpp ]
206	Reverse Linked List [ python java cpp ]
212	Word Search II [ python java cpp ]
217	Contains Duplicate [ python java cpp ]
218	The Skyline Problem [ python java cpp ]
219	Contains Duplicate II [ python java cpp ]
220	Contains Duplicate III [ python java cpp ]
224	Basic Calculator [ python java cpp ]
225	Implement Stack using Queues [ python java cpp ]
226	Invert Binary Tree [ python java cpp ]
228	Summary Ranges [ python java cpp ]
231	Power of Two [ python java cpp ]
232	Implement Queue using Stacks [ python java cpp ]
234	Palindrome Linked List [ python java cpp ]
235	Lowest Common Ancestor of a Binary Search Tree [ python java cpp ]
237	Delete Node in a Linked List [ python java cpp ]
238	Product of Array Except Self [ python java cpp ]
240	Search a 2D Matrix II [ python java cpp ]
242	Valid Anagram [ python java cpp ]
257	Binary Tree Paths [ python java cpp ]
258	Add Digits [ python java cpp ]
263	Ugly Number [ python java cpp ]
278	First Bad Version [ python java cpp ]
283	Move Zeroes [ python java cpp ]
290	Word Pattern [ python java cpp ]
299	Bulls and Cows [ python java cpp ]
310	Minimum Height Trees [ python java cpp ]
334	Increasing Triplet Subsequence [ python java cpp ]
344	Reverse String [ python java cpp ]
349	Intersection of Two Arrays [ python java cpp ]
350	Intersection of Two Arrays II [ python java cpp ]
368	Largest Divisible Subset [ python java cpp ]
371	Sum of Two Integers [ python java cpp ]
378	Kth Smallest Element in a Sorted Matrix [ python java cpp ]
406	Queue Reconstruction by Height [ python java cpp ]
467	Unique Substrings in Wraparound String [ python java cpp ]
516	Longest Palindromic Subsequence [ python java cpp ]
530	Minimum Absolute Difference in BST [ python java cpp ]