#include <bits/stdc++.h>
#define double long double
#define int long long
using namespace std;
struct avg
{
pair<int, int> p;
int l, r;
bool operator < (const avg &c) const {
return p.first * c.p.second < p.second * c.p.first;
}
};
int arr[2005];
int s[2005];
pair<int, int> dp[2005][2005];
double diff(multiset<avg> &st)
{
pair<int, int> high = (*--st.end()).p;
double h = (double)high.first / high.second;
pair<int, int> low = (*st.begin()).p;
double l = (double)low.first / low.second;
return h - l;
}
signed main()
{
ios::sync_with_stdio(false); cin.tie(0);
int n; cin >> n;
for (int i = 1; i <= n; i++) {
cin >> arr[i];
s[i] = s[i-1] + arr[i];
}
multiset<avg> st;
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= n - i + 1; j++) {
//(j, j + i - 1) 범위
dp[i][j] = make_pair(s[j+i-1] - s[j-1], i);
}
}
for (int i = 1; i <= n; i++) {
avg av = {dp[i][1], i, 1};
st.insert(av);
}
double ans = 1e9;
while (1) {
ans = min(ans, diff(st));
auto it = st.begin();
if ((*it).l + (*it).r == n + 1) {
break;
}
avg av = *it; st.erase(it);
int newi = av.l;
int newj = av.r + 1;
av = {dp[newi][newj], newi, newj};
st.insert(av);
}
cout.precision(10);
cout << fixed;
cout << ans << '\n';
}
