@[hegongda307](/space/show?uid=241456)
AC代码：
```cpp
#include<string>
#include<bits/stdc++.h>
using namespace std;
struct student {
int score ,level;
};
bool cmp(student a,student b){
return a.score<b.score;
}
int main(){
int n;
cin>>n;
student stu[n];
double ans=0;
for(int i=0;i<n;i++){
cin>>stu[i].score;
stu[i].level=i+1;
}
sort(stu,stu+n,cmp);
for(int i=0;i<n;i++){
ans = ans+stu[i].score*(n-i-1);
}
for(int i=0;i<n;i++){
cout<<stu[i].level<<" ";
}
cout<<endl;
cout<<fixed<<setprecision(2)<<ans*1.0/n<<endl;
}
```
by AK_黄铮_IMO @ 2019-08-29 08:18:33
@[hegongda307](/space/show?uid=241456)
c要开double
~~别问我为什么，我就是这么错的~~
https://www.luogu.org/record/25864328
https://www.luogu.org/record/25864368
by _StarBird_ @ 2019-10-28 14:22:38