题解 | #23年OPPO-a的翻转#

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();
        StringBuilder s = new StringBuilder();
        int c = Integer.parseInt(s.append(a).reverse().toString());
        System.out.println(a+c);
    }
}

翻转这里就是 12 => 21, 1234 => 4321