题解 | #数字颠倒#

import java.util.Scanner;
public class Main{
    public static void main(String []args){
        Scanner in = new Scanner(System.in);
        int num = in.nextInt();
        if(0 <= num && num <= Integer.MAX_VALUE/4 - 1){
            StringBuilder strBui = new StringBuilder();
            if(num == 0){
                System.out.print(0);
            }
            while(num > 0){
                strBui.append(num % 10);
                num /= 10;
            }
            System.out.print(strBui);
        }       
    }
}