PAT 1070. Mooncake (25)

按單價進行排序，依次選擇就行了

注意，每種月餅的數量是double，

代碼如下：

#include <iostream>
#include <algorithm>

using namespace std;

typedef struct Mcake
{
	double amounts;  //this must be double
	double money;
	double  price;
}Mcake;

Mcake a[1001];

int cmp(Mcake c,Mcake d)
{
	return c.price > d.price;
}

int main()
{
	int N,D;

	cin >> N >> D;
	
	int i;
	for(i = 0;i<N;i++)
		cin >> a[i].amounts;
	for(i = 0;i<N;i++)
	{
		cin >> a[i].money;
		a[i].price = a[i].money/a[i].amounts;
	}

	sort(a,a+N,cmp);
	int sum = 0;
	double profit = 0.0;
	i = 0;
	while(sum < D && i < N)
	{
		if(sum + a[i].amounts <= D){
			profit += a[i].money;
			sum += a[i].amounts;
		}
		else{
			profit += (D-sum)*a[i].price;
			sum = D;
			break;
		}
		i++;
	}

	printf("%.2lf\n",profit);
	return 0;

}