题解HJ99 | #自守数#

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);
        int x = Integer.valueOf(in.nextLine());

        int count = 0;

        for (int i = 0; i <= x; i++) {
            if (check(i))
                count++;
        }

        System.out.println(count);
    }

    public static boolean check(int x) {
        String s = String.valueOf((int) Math.pow(Double.valueOf(x), 2));
        String target = String.valueOf(x);

        boolean flag = true;

        for (int i = 0; i < target.length(); i++) {
            if (s.charAt(s.length() - i - 1) != target.charAt(target.length() - i - 1))
                flag = false;
        }

        return flag;
    }
}