#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
using pdi = pair<double, int>;
#define pb push_back
#define ff first
#define ss second
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n; cin>>n;
vector<int> a(n + 1);
vector<ll> p(n + 1);
for (int i = 1; i <= n; i++){
cin>>a[i];
p[i] = p[i - 1] + a[i];
}
auto get = [&](int l, int r){
return 1.0 * (p[r] - p[l - 1]) / (r - l + 1);
};
double A = get(1, n);
vector<pii> all = {{1, n}};
int l = 1, r = n, dx = 1, dy = 0;
while (l < r){
l += dx; r -= dy;
if (get(l, r) > A){
swap(dx, dy);
}
all.pb({l, r});
}
l = 1; r = n; dx = 0; dy = 1;
while (l < r){
l += dx; r -= dy;
if (get(l, r) > A){
swap(dx, dy);
}
all.pb({l, r});
}
auto cmp = [&](pii x, pii y){
return get(x.ff, x.ss) < get(y.ff, y.ss);
};
sort(all.begin(), all.end(), cmp);
auto d = [&](int i){
return get(all[i].ff, all[i].ss);
};
vector<int> f(n);
int j = 0, cnt = 0;
double out = 1e9 + 1;
for (int i = 0; i < all.size(); i++){
while (cnt < n && j < all.size()){
int k = all[j].ss - all[j].ff;
if (!f[k]) cnt++;
f[k]++;
j++;
}
if (cnt == n) out = min(out, d(j - 1) - d(i));
int k = all[i].ss - all[i].ff;
f[k]--;
if (!f[k]) cnt--;
}
cout<<fixed<<setprecision(12)<<out<<"\n";
}
