简易写法：

#include<bits/stdc++.h>
using namespace std;
int n;
struct Node{
	int idx;
	int time;
}arr[1010];
bool cmp(Node a,Node b){
	if(a.time<b.time) return 1;
	else if(a.time==b.time&&a.idx<b.idx) return 1;
	else return 0;
}
int main(){
	cin>>n;
	for(int i=1;i<=n;i++){
		cin>>arr[i].time;
		arr[i].idx=i;
	}
	sort(arr+1,arr+n+1,cmp);
	double cnt=0;
	for(int i=1;i<=n;i++){
		cnt=cnt+(n-i)*arr[i].time;
		cout<<arr[i].idx<<' ';
	}
	cout<<endl<<fixed<<setprecision(2)<<cnt/n;
	return 0;
}