PAT 1020 月饼

题目链接：PAT 1020 月饼

#include<iostream>
#include<algorithm>
#include<string>
#include<cstdio>
#include<cstring>
#include<cmath>

using namespace std;
struct mooncake
{
	double store;	//库存量 
	double sell;	//总售价 
	double price;	//单价 
}cake[10010];

bool cmp(mooncake a, mooncake b)
{
	return a.price > b.price ;
}

int main()
{
	int n;
	double d;
	scanf("%d%lf",&n,&d);
	
	for(int i=0;i<n;i++)
		scanf("%lf",&cake[i].store);
	for(int i=0;i<n;i++)
	{
		scanf("%lf",&cake[i].sell);
		cake[i].price = cake[i].sell / cake[i].store;
	}
	
	sort(cake,cake+n,cmp);	//按单价从高到低排序 
	
	double ans = 0;
	
	for(int i=0;i<n;i++)
	{
		if(cake[i].store<=d)	//如果需求量高于月饼库存量 
		{
			d -= cake[i].store; //第i种月饼全部卖出 
			ans += cake[i].sell;
		}
		else	//如果月饼库存量高于需求量 
		{
			ans += cake[i].price*d;	//只卖剩余需求量的月饼 
			break;
		}
	}
	printf("%.2f",ans);
	return 0;
}