PTA 乙级 1020 月饼

代码实现：

#include
#include

typedef struct
{
	double stock, price;
}goods;

int main()
{
	int N, D;
	goods *cargo;

	scanf("%d %d", &N, &D);
	cargo = (goods*)malloc(sizeof(goods)*N);
	for (int i = 0; i < N; i++)scanf("%lf", &cargo[i].stock);
	for (int i = 0; i < N; i++)
	{
		scanf("%lf", &cargo[i].price); cargo[i].price /= cargo[i].stock;
	}
	for (int i = 0; i < N; i++)
	{
		int index = i;
		goods temp;

		for (int j = i; j < N; j++)if (cargo[index].price < cargo[j].price)index = j;
		temp = cargo[i]; cargo[i] = cargo[index]; cargo[index] = temp;
	}

	int cnt = 0; double get = 0;

	do
	{
		if (cargo[cnt].stock >= D)
		{
			get += D * cargo[cnt].price;
			D = 0;
		}
		else if (cargo[cnt].stock < D)
		{
			get += cargo[cnt].stock*cargo[cnt].price;
			D -= cargo[cnt].stock;
			cnt++;
		}
	} while (D != 0 && cnt != N);
	printf("%.2f", get);

	return 0;
}