#include <bits/stdc++.h>
using namespace std;
int main() {
    int n; cin >> n;
    vector<long long> a(n+1), pf(n+1,0);
    for(int i=1;i<=n;i++) cin >> a[i], pf[i]=pf[i-1]+a[i];
    auto q=[&](int l,int r){return (double)(pf[r]-pf[l-1])/(r-l+1);};
    double A=q(1,n);
    vector<array<double,2>> c={{A,A}};
    for(int len=1;len<n;len++){
        int L=1,R=n-len+1,p=0;
        while(L<=R){
            int m=(L+R)/2;
            if(q(m,m+len-1)<A) p=m,L=m+1;
            else R=m-1;
        }
        c.push_back({q(p,p+len-1),q(p+1,p+len)});
    }
    sort(c.begin(),c.end());
    double r=1e9,mx=c.back()[0];
    for(auto [x,y]:c) r=min(r,mx-x), mx=max(mx,y);
    cout << fixed << setprecision(12) << r;
}

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