P4086 30分

#include <iostream>
#include <cmath>
#define ll long long 
using namespace std;

const int n_=1e5+5;

int a[n_],minn[n_],s[n_];
double avg[n_];

int main()
{
    ll n;
    cin >> n;
    minn[n+1]=1e9;
    
    for (int i=1;i<=n;i++)
    {
        cin >> a[i];
        s[i]=s[i-1]+a[i];
    }
    
    for (int i=n;i>=1;i--)
    {
        minn[i]=min(minn[i+1],a[i]);
    }
    
    
    for (int i=1;i<=n-2;i++)
    {
        avg[i]=1.0*(s[n]-s[i]-minn[i])/(n-i-1);
    }
    
    int res=0,maxn=-1;
    
    for (int i=1;i<=n;i++)
    {
        if (avg[i]>=maxn)
        {
            maxn=avg[i];
            res=i;
        }
    }
    
    cout << res;
    return 0;
}