HDU 1009 FatMouse' Trade

题目地址：点击打开链接

思路：贪心

AC代码：

#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
struct Mouse
{
double a;
double b;
double c;
};
bool comp(const Mouse &d1,const Mouse &d2)
{
return d1.c>d2.c;
}
int main()
{
int m,n,i;
double sum;
vector<Mouse> v;
Mouse mouse;
while(cin>>m>>n)
{
v.clear();
if(m==-1&&n==-1)
break;
sum=0;
for(i=0;i<n;i++)
{
cin>>mouse.a>>mouse.b;
mouse.c=mouse.a/mouse.b;
v.push_back(mouse);
}
sort(v.begin(),v.end(),comp);
for(i=0;i<v.size();i++)
{
if(m>=v[i].b)
{
sum+=v[i].a;
m-=v[i].b;
}
else
{
sum+=m*v[i].c;
break;
}
}
printf("%.3lf\n",sum);
}
return 0;
}