longest_palindrome_substring.py

"""
Given a string S, find the longest palindromic substring in S. You may assume that the maximum length of S is 1000, and there exists one unique longest palindromic substring.

"""


class Solution(object):
    def longestPalindrome(self, s):
        """
        :type s: str
        :rtype: str
        """
        start = 0
        end = len(s)
        maxima = ""
        for i in range(len(s)):
            for j in reversed(range(len(s))):
                if s[i] == s[j]:    
                    start = i
                    end = j
                    length = end - start + 1
                    while(s[start] == s[end] and start != end and start < end):
                        start += 1
                        end -= 1

                    if start >= end:
                        maxima = max((maxima, s[i:j+1]), key = lambda k: len(k))
        return maxima