#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define double long double
#define int ll
const int N = (int)1e6 + 10, MOD = (int)1e9 + 7, inf = (int)2e9;
int n, a[N], p[N];
double s[N];
double get(int l, int r) {
return (1.0 * (p[r] - p[l - 1])) / (1.0 * (r - l + 1)) ;
}
array<double, 2> c[N];
void test() {
cin >> n;
for(int i = 1; i <= n; i++) {
cin >> a[i];
p[i] = p[i - 1] + a[i];
}
double f = get(1, n);
for(int i = 1; i < n; i++) {
int l = 1, r = n - i + 1;
while(r - l > 1) {
int mid = (l + r) >> 1;
if(get(mid, mid + i - 1) > f) {
r = mid;
} else {
l = mid;
}
}
// cout << i << ' ' << l << ' ' << r << '\n';
c[i] = {get(r, r + i - 1), get(l, l + i - 1)};
}
sort(c + 1, c + n);
for(int i = 1; i < n; i++) swap(c[i][0], c[i][1]);
s[n] = inf;
for(int i = n - 1; i >= 1; i--) {
s[i] = min(s[i + 1], c[i][0]);
}
for(int i = 1; i < n; i++) {
// cout << c[i][0] << ' ' << c[i][1] << '\n';
}
double res = inf;
for(int i = 0; i < n; i++) {
double val = (i == n - 1 ? f : s[i + 1]);
res = min(res, max(f, c[i][1]) - val);
// cout << i << ' ' << max(f, c[i][1]) - val << ' ' << val << '\n';
}
cout << fixed << setprecision(10) << res << '\n';
}
int32_t main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
int t = 1;
// cin >> t;
while(t--) {
test();
}
}
