#include <bits/stdc++.h>
using namespace std;
class fraction_t {
public:
int64_t x, y;
// x / y, normalized to y > 0 if x != 0 and y = 1 if x = 0
void fix() {
int64_t d = __gcd(abs(x), y);
x /= d;
y /= d;
}
fraction_t(const int64_t& x = 0, const int64_t& y = 1) : x(x), y(y) { fix(); }
friend bool operator<(const fraction_t& e, const fraction_t& f) { return (long double)e.x / e.y < (long double)f.x / f.y; }
friend bool operator<=(const fraction_t& e, const fraction_t& f) { return (long double)e.x / e.y <= (long double)f.x / f.y; }
friend bool operator==(const fraction_t& e, const fraction_t& f) { return e.x == f.x && e.y == f.y; }
friend bool operator!=(const fraction_t& e, const fraction_t& f) { return e.x * f.y != e.y * f.x; }
friend bool operator>(const fraction_t& e, const fraction_t& f) { return e.x * f.y > e.y * f.x; }
friend bool operator>=(const fraction_t& e, const fraction_t& f) { return e.x * f.y >= e.y * f.x; }
friend ostream& operator<<(ostream& out, const fraction_t& f) {
out << setprecision(11) << fixed << ((double)f.x) / f.y;
return out;
}
};
int32_t main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
int n;
cin >> n;
vector<int> a(n);
for (int i = 0; i < n; i++) cin >> a[i];
vector<int64_t> pref(n + 1, 0);
for (int i = 0; i < n; i++) pref[i + 1] = pref[i] + a[i];
fraction_t c(pref[n] - pref[0], n);
set<pair<fraction_t, int>> s;
vector<int> nxt(n, -1);
for (int i = n - 1; i > 0; i--) {
int l = 0, r = n - i, fl;
while (l <= r) {
int mid = l + r >> 1;
if (fraction_t(pref[mid + i] - pref[mid], i) <= c) {
fl = mid;
l = mid + 1;
} else {
r = mid - 1;
}
}
fraction_t f(pref[fl + i] - pref[fl], i);
if (f != c) {
nxt[i] = fl + 1;
}
s.emplace(f, i);
}
s.emplace(c, 0);
long double res = 1e18;
while (true) {
auto [f, i] = *s.begin();
auto a = s.rbegin()->first;
auto b = s.begin()->first;
long double aa = (long double)a.x / a.y;
long double bb = (long double)b.x / b.y;
res = min(res, aa - bb);
s.erase(s.begin());
if (nxt[i] == -1) break;
s.emplace(fraction_t(pref[nxt[i] + i] - pref[nxt[i]], i), i);
nxt[i] = -1;
}
cout << fixed << setprecision(11) << res;
}
