#5 Longest Palindromic Substring

问题：

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"

思路：
动态规划
代码：

package solution;

public class Solution5 {
    public static String longestPalindrome(String s) {
        int n = s.length();
        String res = 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]);
                if(dp[i][j] && (res == null || j - i + 1 > res.length())){
                    res = s.substring(i,j+1);
                }
            }
        }
        return res;
    }
    public static void main(String[] args){
        System.out.println(longestPalindrome("cvbasdsabllj"));
    }
}