Java 最优题解| #最长回文子串#

import java.util.Scanner;

public class Main {
    public static void main(String args[]) {
        Scanner input = new Scanner(System.in);
        String s = input.nextLine();
        int max = 0;

        for (int i = 0; i < s.length(); i++) 
            for (int j = s.length() - 1; j - i > max; j--) 
                if (isPalindromeString(s, i, j)) max = Math.max(max, j - i + 1);

        System.out.print(max);
    }
    
    static boolean isPalindromeString(String s, int head, int tail) {
        while (head < tail) if (s.charAt(head++) != s.charAt(tail--)) return false;
        return true;
    }
}

双重for剪枝 + 无复制判断