题解 | #数字颠倒#

方法1

import java.util.*;

public class Main{
    public static int[] s1 = new int[128];
    public static void main(String[] args){
        Scanner in =  new Scanner(System.in);
        Long a = in.nextLong();
        Long temp = 0L;
        if(a == 0){
            System.out.println(a);
        }
        else{
            while(a != 0){
                temp = a%10;
                a = a/10;
                System.out.print(temp);
            }
        }    
    }
}

方法2

import java.util.*;

public class Main{
    public static void main(String[] args){
        Scanner in =  new Scanner(System.in);
        Long a = in.nextLong();
        String str = "" + a;
        
        for(int i = str.length()-1; i >= 0; i--){
            System.out.print(str.charAt(i)); 
        }
         
    }
}