This is used for LeetCode Java practice
Date Started: May 29th 2017
May 29th 2017: Two Sum & Add Two Numbers Learned HashMap and linked list
May 31th 2017: Longest Substring without Repeating Characters: Use both HashSet and HashMap to approach.
Jun 2nd 2017: After couple days of coding, finished Longest Palindromic Substring! Jun 3rd 2017: Reverse Integer Jun 5rd 2017: Palindrome Number Jun 6th 2017: Finished ATOI
Algorithm info:http://www.cs.princeton.edu/~wayne/kleinberg-tardos/