Asteroids.java

import java.util.*;
public class Asteroids{
    public static void state(int arr[]){
        Stack<Integer> s = new Stack<>();
        for(int i=0;i<arr.length;i++){
            if (s.isEmpty()){
                s.push(arr[i]);
            }else if(s.peek()>0 && arr[i]>0){
                s.push(arr[i]);
            }else{
                boolean con=true;
                while(!s.isEmpty() && s.peek()>0 && arr[i]<0 ){
                    if (s.peek()==Math.abs(arr[i])){
                        s.pop();
                        con=false;
                        break;
                    }else if(s.peek()<Math.abs(arr[i])){
                        s.pop();
                    }else if(s.peek()>Math.abs(arr[i])){
                        con=false;
                        break;
                    }
                }
                if (con){
                    s.push(arr[i]);
                }
            }
        }
        int arr1[]=new int[s.size()];
        for(int i=s.size()-1;i>=0;i--){
            arr1[i]=s.peek();
            s.pop();
        }
        for(int i=0;i<arr1.length;i++){
            System.out.print(arr1[i]+" ");
        }System.out.println();
    }
    public static void main(String args[]){
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter size: ");
        int size = sc.nextInt();
        int arr[] = new int[size];
        System.out.println("Enter " + size + " elements:");
        for(int i = 0; i < size; i++){
        arr[i] = sc.nextInt();
        }
        state(arr);

    }
}