头像真扁
by sleepyNick @ 2018-10-02 14:04:19
```cpp
#include<bits/stdc++.h>
using namespace std;
int ans,sum;
struct node{
int p;
int a;
}s[5000];
bool cmp(node x , node y){
return x.p < y.p;
}
int main(){
int n,m;
scanf("%d%d",&n,&m);
sum = n;
for(int i = 0; i < m; i++) scanf("%d%d",&s[i].p,&s[i].a);
sort(s ,s + m, cmp);
for(int i = 0; i < m && sum > 0; i++){
if(sum >= s[i].a){
sum -= s[i].a;
ans += s[i].p * s[i].a;
}
else {
ans += sum * s[i].p;
break;
}
}
printf("%d",ans);
return 0;
}
```
by Frostmourne✡凛 @ 2018-10-02 14:26:08
你的sum赋值为n，在你输入n之前，因此sum!=n所以会错，至于RE的我卡了卡空间
by Frostmourne✡凛 @ 2018-10-02 14:30:20