Asteroid Collision

import java.util.Scanner;

public class AsteroidColision {
    public static  void collision(Stack<Integer> stack){
        ArrayStack<Integer> pom=new ArrayStack<>(100);
        while(!stack.isEmpty()){
            int num1=stack.pop();
            if(stack.isEmpty()) {
                stack.push(num1);
                break;
            }
            int num2=stack.pop();

            if((num1>0 && num2<0) || (num1<0 && num2>0)){
                if(Math.abs(num1) > Math.abs(num2)){
                    stack.push(num1);
                }
                else if(Math.abs(num1) < Math.abs(num2)){
                    stack.push(num2);
                }
            }
            else{
                stack.push(num2);
                pom.push(num1);
            }

        }

        while (!stack.isEmpty()){
           pom.push(stack.pop());
        }
        if (pom.isEmpty())
            System.out.println("none");
        while (!pom.isEmpty()){
            System.out.println(pom.pop());
        }
    }
    public static void main(String[] args) {
        Scanner in=new Scanner(System.in);
        int n=in.nextInt();

        ArrayStack<Integer> stack=new ArrayStack<>(100);
        for(int i=0;i<n;i++){
            stack.push(in.nextInt());
        }

        collision(stack);
    }
}