题解 | #按照格式输入并交换输出#

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        String[] s = sc.nextLine().split(",");
        // 将满足条件的字符串 1 换成 2， 2 换成 1
        for (int i = 0; i < s.length; i++) {
            if (s[i].indexOf("1") > 0) {
                s[i] = s[i].replace("1", "2");
            } else {
                s[i] = s[i].replace("2", "1");
            }
        }
        // 将数组转换成字符串
        String result = String.join(",", s);
        System.out.println(result);

    }
}