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);
        // 注意 hasNext 和 hasNextLine 的区别
        // while (in.hasNextInt()) { // 注意 while 处理多个 case
        //     int a = in.nextInt();
        //     int b = in.nextInt();
        //     System.out.println(a + b);
        // }
        int max = 1;
        String line = in.nextLine();
        int len = line.length();
        for (int i = 1; i < len; i++) {
            char c = line.charAt(i);
            int n = 1;
            int count = 1;
            for (int j = i + 1; j < len; j++) {

                if (line.charAt(j) == c) {
                    count++;
                } else if (i - n >= 0 && line.charAt(j) == line.charAt(i - n)) {
                    count += 2;
                    n++;
                    c = '0';
                } else {
                    break;
                }
            }
            max = Math.max(max, count);
        }
        System.out.print(max);
    }
}