#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include "debug.h"
#else
#define debug(...) 42
#endif
const int N = 2e5 + 5;
int n;
int a[N];
long long pf[N];
double qry(int l, int r) {
return (double) (pf[r] - pf[l - 1]) / (r - l + 1);
}
int main() {
ios::sync_with_stdio(false); cin.tie(nullptr);
cin >> n;
for (int i = 1; i <= n; ++i) {
cin >> a[i];
pf[i] = pf[i - 1] + a[i];
}
double A = qry(1, n);
vector<array<double, 2>> cands = {{A, A}};
for (int l = 1; l < n; ++l) {
int L = 1, R = n - l + 1, p = 0;
while (L <= R) {
int md = (L + R) / 2;
if (qry(md, md + l - 1) < A) {
p = md;
L = md + 1;
} else {
R = md - 1;
}
}
cands.push_back({qry(p, p + l - 1), qry(p + 1, p + l)});
}
sort(cands.begin(), cands.end());
double res = 1e9, mx = cands.back()[0];
for (auto [x, y] : cands) {
res = min(res, mx - x);
mx = max(mx, y);
}
cout << fixed << setprecision(12) << res;
return 0;
}
