题解 | #密码截取#

import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String str = in.nextLine();
        char[] strchar = str.toCharArray();
        int max = 1;
        for (int i = 0; i < strchar.length; i++) {
            int num = 0;
            for (int j = strchar.length - 1; j > i; j--) {
                if (strchar[i] == strchar[j]) {
                    StringBuilder  string = new StringBuilder(str.substring(i, j + 1));
                    StringBuilder  string_rel = new StringBuilder(str.substring(i,
                            j + 1)).reverse();
                    if (String.valueOf(string).equals(String.valueOf(string_rel))) {
                        num = string.length();
                        if (num > max) {
                            max = num;
                        }
                        break;
                    }
                }
            }
        }
        System.out.print(max);
    }
}