brute force:最长回文子串

JavaCode

import java.util.*;

public class Solution {
    //helper function
    public boolean isPalindrome(String A, int n) {
        int k = n / 2;
        for (int i = 0; i < k; ++i) {
            if (A.charAt(i) != A.charAt(n - 1 - i)) {
                return false;
            }
        }
        return true;
    }
    public int getLongestPalindrome(String A, int n) {
        // write code here
        int maxlen  = 0;
        for (int i = 0; i < n; i++) {
            for (int j = i + 1; j <= n ; j++) {
                if (isPalindrome(A.substring(i, j), j - i)) {
                    if (j - i > maxlen) {
                        maxlen = j - i;
                    }
                }
            }
        }
        return maxlen;
    }