题解 | #密码截取#

import java.util.*;

// 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 pwd = in.nextLine();
        int res = 0;
        for (int i = 0; i < pwd.length(); i++) {
            int len1 = longst(pwd, i, i);
            int len2 = longst(pwd, i, i + 1);
            res = Math.max(res, len1 > len2 ? len1 : len2);
        }
        System.out.print(res);

    }

    private static int longst(String pwd, int l, int r) {
        while (l >= 0 && r < pwd.length() && pwd.charAt(l) == pwd.charAt(r)) {

            l--;
            r++;
        }
        return r - l - 1;

    }
}