leetcode5. 最长回文子串

class Solution {
    public String longestPalindrome(String s) {
        int n = s.length();
        boolean[][] f = new boolean[n][n];
        int left = 0,right = 0;
        for(int i = n-1;i >= 0;i--){
            for(int j = i;j < n;j++){
                if(s.charAt(i) == s.charAt(j)){
                    if(j-i <= 1)
                        f[i][j] = true;
                    else
                        f[i][j] = f[i+1][j-1];
                }

                if(f[i][j] && right-left < j-i){
                    left = i;
                    right = j;
                }
            }
        }

        return s.substring(left,right+1);
    }
}