Çàäà÷à . Ðåâåðñ ArrayList

import java.util.ArrayList;
import java.util.Collections;
import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        int n;
        Scanner in = new Scanner(System.in);
        n = in.nextInt();         

        for (Integer a: arr) {
                System.out.print(a+" ");
        }
    }
}