同样
```cpp
#include<bits/stdc++.h>
using namespace std;
//#Forza0222#
//Code by Keth George
//NO copying except who has K.G.'s agreement
struct milk
{
int sg,am;
};
bool cmp(milk a,milk b)
{
return a.sg<b.sg;
}
milk l[10000];
int mil,num;
int tam;
long long pri;
int main()
{
cin>>mil>>num;
for(int i=0;i<num;i++)
{
cin>>l[i].sg>>l[i].am;
}
sort(l,l+num+1,cmp);
for(int i=0;i<num;i++)
{
if(tam+l[i].am<mil)
{
pri+=l[i].am*l[i].sg;
tam+=l[i].am;
continue;
}
if(tam+l[i].am==mil)
{
pri+=l[i].am*l[i].sg;
break;
}
if(tam+l[i].am>mil)
{
pri+=(mil-tam)*l[i].sg;
break;
}
}
cout<<pri;
}
```
by 邹榆冬 @ 2017-07-10 10:43:58