题解 | 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 sc = new Scanner(System.in);
        while (sc.hasNextInt()) {
            int a = sc.nextInt();
            String str1 = Integer.toString(a);
            if (a == 1) {
                System.out.println(2);
            } else {
                int c = 0;
                for (int i = 1;  i <= a ; i++) {
                    double b = Math.pow(i, 2);
                    String str = Integer.toString((int)b);
                    String str4 = Integer.toString(i);
                    String str2 = new StringBuilder(str).reverse().toString();
                    String str3 = new StringBuilder(str4).reverse().toString();

                    if (str3.equals(str2.substring(0, str4.length()))) {
                        c++;
                        //      System.out.println(str4+" "+str2);
                    }
                }
                System.out.println(c + 1);

            }
        }
    }
}