Write a function to find the longest palindrome from a string.

Write a function to find the longest palindrome from a string.

Suppose the string is str, you reverse the str get strr, make a suffix tree for these two strings. If palindrome is like “cabbad”, for every i find LCA of suffix i of str and suffix m-i+1of strr
If palindrome is like “dacab”, for every i find LCA of suffix i of str and suffix m-i of strr
Find maximal LCA, this O(n)
or
Use dynamic programming, find longest common substring with str and strr, O(n^2)
This is not right
forward T: ABCXYYZCBA
reverse T: ABCZYYXCBA
The longest common substring is ABC, but the longest palindromic substring is just YY.