Sort By Reversing Digits - JAVA

// Author : Saurav Kalsoor
// Sort By Reversing Digits - JAVA

import java.util.*;

public class Test {

    static Scanner sc = new Scanner(System.in);
    public static void main(String[] args) {
        int n = sc.nextInt();
        ArrayList<Integer> arr = new ArrayList<>();

        for(int i=0; i < n; i++) {
            int input = sc.nextInt();
            arr.add(input);
        }

        ArrayList<Integer> result = sortByDigits(arr);

        for(int i=0; i < n; i++)
            System.out.print(result.get(i) + " ");

        System.out.println();
    }

    public static ArrayList<Integer> sortByDigits(ArrayList<Integer> arr){
        Collections.sort(arr, new SortByReversingDigits());
        return arr;
    }
}

class SortByReversingDigits implements Comparator<Integer> {

    public int compare(Integer a, Integer b){

        int revA = reverseDigits(a), revB = reverseDigits(b);
        if(revA == revB){
            return a - b;
        }
        else{
            return revA - revB;
        }
    }

    public int reverseDigits(int n){
        int rev = 0;
        while(n > 0){
            rev = rev * 10;
            rev = rev + n%10;
            n = n/10;
        }
        return rev;
    }
}