C++ :

#include<iostream>
#include<algorithm>
#include<cstdio>
using namespace std;
const int N = 10005;
struct per{
	int id,t;
};
per a[N];

bool comp(per x,per y){
	if (x.t!=y.t) return x.t<y.t;
	return x.id<y.id;
}

int main(){
	int n;
	cin>>n;
	for (int i=1; i<=n; i++){
		a[i].id=i;
		cin>>a[i].t;
	}
	sort(a+1,a+n+1,comp);
	for (int i=1; i<n; i++) cout<<a[i].id<<" ";
	cout<<a[n].id<<endl;
	double sum=0;
	for (int i=1,k=0; i<=n; i++){
		k+=a[i].t;
		sum+=k;
	}
	printf("%.2lf\n",sum/n);
	return 0;
}