leetcode解题—Longest Palindromic Substring

题目： 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.

解题：参考网上大神做法，解题如下：

class Solution:

    def get_palindromic(self, s, k, l):
        s_len = len(s)
        while k >= 0 and l < s_len and s[k] == s[l]:
            k -= 1
            l += 1
        return s[k+1:l]

    def longestPalindrome(self, s):
        L_palindromic = ''
        for i in range(len(s)):
            temp_palindromic1 = self.get_palindromic(s, i, i)
            if len(temp_palindromic1) > len(L_palindromic):
                L_palindromic = temp_palindromic1

            temp_palindromic2 = self.get_palindromic(s, i, i+1)
            if len(temp_palindromic2) > len(L_palindromic):
                L_palindromic = temp_palindromic2

        return L_palindromic