Given a string s, find the longest palindromic substring in s. You may assume that the maximum length of s is 1000.
Example 1:
Input: "babad"Output: "bab"Note: "aba" is also a valid answer.
Example 2:
Input: "cbbd"Output: "bb"
public static String longestPalindrome(String s) { int n = s.length(); if(n==0 || s==null) return s; String reString = null; boolean[][] dp = new boolean[n][n]; for(int i = n-1;i >= 0; i--) { for(int j = i; j < n; j++) { dp[i][j] = s.charAt(i)==s.charAt(j)&&(j-i<3 || dp[i+1][j-1]); //判断是否为回文串 if(dp[i][j] && (reString==null || reString.length() 使用boolean创建一个二维数组dp[][],dp[i][j]的值代表从第i个字符到第j个字符的字符串是否为回文串。
首先判定一个字符串是回文串有什么特点，如果dp[i][j]是回文串，那么dp[i+1][j-1]也是回文串，由此我们可以得出：
dp[i][j] = s.charAt(i)==s.charAt(j)&&(j-i<3 || dp[i+1][j-1])
