题解 | 交换变量值

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int a = scanner.nextInt();
        int b = scanner.nextInt();

        a = b - a;
        b = b - a;
        a = a + b;
        

        System.out.println(a+" "+b);
    }
}

想不到思路的时候带入两个值，3 和1 .然后就根据加减自由组合下，能够看出来规律 的