LeetCode解题报告--Longest Palindromic Substring

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.
题目来源：https://leetcode.com/problems/longest-palindromic-substring/

题意：给定某一字符串，找到最长的回文子串！（注意：最大回文子串是唯一，即一个字符串不能同时存在多个最长回文子串）

解法：从长度为len (len = s.length(), len = s.length() –)开始寻找该字符串的子串，一旦在某一len值找到符合要求子串str,则该str就是要找的最长回文子串，其他长度的回文子串则不需要考虑。

/** * 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. * @author ganyee * */public class LongestPalindromicSubstring {    public static void main(String[] args) {        // TODO Auto-generated method stub        System.out.println(longestPalindrome("abaaba "));    }     public static String longestPalindrome(String s) {            String maxStr = "";            for(int i = s.length();i >= 0;i --){                maxStr = isPalindrom(s, i);                if(maxStr.length() !=0)                    break;            }            return maxStr;        }     public static String isPalindrom(String s,int len){         int i = 0;         StringBuffer str = new StringBuffer(s);         String str1;         String str2;         String str3 = "";         while(i + len <= s.length()){             str1 = str.substring(i,i + len).toString();             StringBuffer str4 = new StringBuffer(str1);             str2 = str4.reverse().toString();             if(str1.equals(str2) && str3.length() < str1.length()){                 str3 = str1;                 break;             }             else{                 i ++;             }         }         return str3;     }}

另解：引自
1)http://articles.leetcode.com/2011/11/longest-palindromic-substring-part-i.html
2）http://articles.leetcode.com/2011/11/longest-palindromic-substring-part-i.html