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.
思路：找出字符串s中最长的回文子串。我们可以这样考虑，从中间向两边扩展，尽可能找出最长的回文子串。在此注意要考虑奇偶位置的比较，这一点要考虑清楚。
class Solution { public: string Sub_Palindrome(string s,int left,int right) { int l=left,r=right; int n=s.length(); while(l>=0 && r<=n-1 && s[l]==s[r]) { l--; r++; } return s.substr(l+1,r-l-1); } string longestPalindrome(string s) { int n=s.length(); if(n==0) return ""; string longest=s.substr(0,1); for(int i=0;i<n-1;i++) { string sub_str1=Sub_Palindrome(s,i,i);//奇数 if(sub_str1.length()>longest.length()) longest=sub_str1; string sub_str2=Sub_Palindrome(s,i,i+1);//偶数 if(sub_str2.length()>longest.length()) longest=sub_str2; } return longest; } };
Longest Palindromic Substring,布布扣,bubuko.com
原文：http://www.cnblogs.com/awy-blog/p/3794068.html