1037 Magic Coupon （25 分）

The magic shop in Mars is offering some magic coupons. Each coupon has an integer N printed on it, meaning that when you use this coupon with a product, you may get N times the value of that product back! What is more, the shop also offers some bonus product for free. However, if you apply a coupon with a positive N to this bonus product, you will have to pay the shop N times the value of the bonus product... but hey, magically, they have some coupons with negative N's!

For example, given a set of coupons { 1 2 4 −1 }, and a set of product values { 7 6 −2 −3 } (in Mars dollars M$) where a negative value corresponds to a bonus product. You can apply coupon 3 (with N being 4) to product 1 (with value M$7) to get M$28 back; coupon 2 to product 2 to get M$12 back; and coupon 4 to product 4 to get M$3 back. On the other hand, if you apply coupon 3 to product 4, you will have to pay M$12 to the shop.

Each coupon and each product may be selected at most once. Your task is to get as much money back as possible.

Input Specification:

Each input file contains one test case. For each case, the first line contains the number of coupons N​C​​, followed by a line with N​C​​ coupon integers. Then the next line contains the number of products N​P​​, followed by a line with N​P​​ product values. Here 1≤N​C​​,N​P​​≤10​5​​, and it is guaranteed that all the numbers will not exceed 2​30​​.

Output Specification:

For each test case, simply print in a line the maximum amount of money you can get back.

Sample Input:

4
1 2 4 -1
4
7 6 -2 -3

Sample Output:

43

代码如下：

#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
bool compare(int a,int b)
{
	return a > b;
}
int main()
{
	int M, N;
	cin >> M;
	vector<int> coupon, product;
	for (int i = 0; i < M; i++)
	{
		int temp;
		cin >> temp;
		coupon.push_back(temp);
	}
	cin >> N;
	for (int i = 0; i < N; i++)
	{
		int temp;
		cin >> temp;
		product.push_back(temp);
	}
	sort(coupon.begin(), coupon.end(), compare);
	sort(product.begin(), product.end(), compare);
	int positiveCouponCount = 0, positiveProductCount = 0;;
	for (int i = 0; i < M; i++)
	{
		if (coupon[i] > 0)
		{
			positiveCouponCount++;  //正数券数量
		}
		else
		{
			break;
		}

	}
	for (int i = 0; i < N; i++)
	{
		if (product[i] > 0)
		{
			positiveProductCount++;  //正数产品数量
		}
		else
		{
			break;
		}
	}
	int size;
	int index;
	if (M > N)
	{
		size = N;
		index = positiveProductCount;
	}
	else if (M < N)
	{
		size = M;
		index = positiveCouponCount;
	}
	else if (M == N)
	{
		size = M;
		index = positiveCouponCount;
	}
	int count = 0;
	for (int i = 0; i < index; i++)
	{
		if (coupon[i] * product[i] > 0)
		{
			count += coupon[i] * product[i];
		}
	}
	for (int i =0; i<size-index; i++)
	{
		if (coupon[M - i - 1] * product[N - i - 1] > 0)
		{
			count += coupon[M - i - 1] * product[N-i-1];
		}
	}
	cout<<count;
	system("pause");
	return 0;
}