题解 | 变幻莫测

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 a = in.nextInt();
        int b = in .nextInt();
        if (a == b) {
            System.out.println(0);
            return;
        }
        if (a == 0) {
            System.out.println(2);
            return;
        }
        if (b == 0) {
            System.out.println(1);
            return;
        }
        if (Math.abs(a - b) % 2 == 0) {
            int count = 0;
            while (true) {
                if (b == 0) {
                    break;
                }
                if (a == 0) {
                    int temp = a;
                    a = b;
                    b = temp;
                    count++;
                    break;
                }
                count++;
                int temp1 = a + b;
                int temp2 = a - b;
                a = temp1;
                b = temp2;
                // System.out.println(a + " " + b);
            }
            System.out.println(count + 1);
        } else {
            System.out.println("-1");
        }
    }
}