Solutions for Leetcode

Now all solutions are only based on Python. But, I will include some

Problems & Solutions

#	Title	Solution	Basic idea (One line)
1	Two Sum	Python	1. Hash O(n) and O(n) space. 2. Sort and search with two points O(n) and O(1) space.
2	Add Two Numbers	Python	Take care of the carry from lower digit.
3	Longest Substring Without Repeating Characters	Python	1. Check every possible substring O(n^2). 2. Remember the character index and current check pos, if character index >= current pos, then there is duplicate.

Attributions/Thanks

• This project borrowed some code from qiyuangong.