PAT | A1037 Magic Coupon

#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

vector<int> coupons;
vector<int> products;

int main(){
	int n;
	scanf("%d",&n);
	for(int i = 0;i < n;i++){
		int temp;
		scanf("%d",&temp);
		coupons.push_back(temp);
	}
	int m;
	scanf("%d",&m);
	for(int i = 0;i < m;i++){
		int temp;
		scanf("%d",&temp);
		products.push_back(temp);
	}
	sort(coupons.begin(),coupons.end());
	sort(products.begin(),products.end());
	int ans = 0;
	int i = 0,j = 0;
	while(i < n && j < m && coupons[i] < 0 && products [j] < 0){
		ans += coupons[i] * products[j];
		i++;
		j++;
	}
	i = n - 1;
	j = m - 1;
	while(i >= 0 && j >= 0 && coupons[i] > 0 && products[j] > 0){
		ans += coupons[i] * products[j];
		i--;
		j--;
	}
	printf("%d",ans);
	system("pause");
	return 0;
}