Leetcode5：Longest Palindromic [email protected]

Given a string s, find the longest palindromic substring in s. You may assume that the maximum length of s is 1000.

Example:

Input: "babad"

Output: "bab"

Note: "aba" is also a valid answer.

Example:

Input: "cbbd"

Output: "bb"

动态规划法：以"ababae"为例：

 1 class Solution(object):
 2     def longestPalindrome(self, s):
 3         """
 4         :type s: str
 5         :rtype: str
 6         """
 7         sLength=len(s)
 8         begin=0
 9         length=0
10         table=[]
11         for i in range(sLength):
12             tem=[]
13             for j in range(sLength):
14                 tem.append(0)
15             table.append(tem)
16
17         for i in range(sLength):
18             table[i][i]=1
19
20         for i in range(sLength-1):
21             if s[i]==s[i+1]:
22                 table[i][i+1]=1
23                 begin=i
24                 length=1
25
26         for tem in range(1,sLength):
27             for i in range(sLength-tem):
28                 j=i+tem
29                 if (s[i]==s[j] and table[i+1][j-1])==1:
30                     table[i][j]=1
31                     length=tem
32                     begin=i
33
34         return s[begin:begin+length+1]