Sample Solutions for problems in leetcode.com
author: Yong Tao (sztaoyong@gmail.com)

I have selected a subset of problems from Online Judge(OJ) of leetcode.com. All 
codes are written in Jave. Note that although I have tried my best to double
-check the codes, provide clear comments and have tested with OJ, there is no 
warranty for the code.

I have grouped the sample problems and questions to mutliple folders based on 
their underlying data structures and algorithms. The name of folders and their
explanations are listed as follows:

Data Structures:
AS: array and string
LL: linked list
SQ: stack and queue
TG: tree and graph

Algorithms:
BT: back tracking
DP: dynamic programming and recursion
MA: math and statistics
SS: search and sorting

To find the problem index, please refer to leetcode problem difficulty 
level and frequency table (google 'leetcode frequency').