#include <bits/stdc++.h>
using namespace std;
#define int long long
#define double long double
using tp = tuple<double, int, int>;
const int N = 2e5 + 5;
const long long INF = 1e18;
int n, a[N], pref[N];
double res = INF;
map<int, bool> mrk[N];
priority_queue<tp, vector<tp>, greater<>> pq;
multiset<double> s;
double MID(int l, int r){ return (double)(pref[r] - pref[l - 1]) / (r - l + 1); }
void init(){
for(int i = 1; i <= n; i++) pref[i] = pref[i - 1] + a[i];
for(int i = n; i >= 1; i--){
int l = 1, r = n - i + 1, pos1 = -1;
while(l <= r){
int mid = (l + r)/2;
if(MID(mid, mid + i - 1) <= MID(1, n)) l = (pos1 = mid) + 1;
else r = mid - 1;
}
int pos2 = pos1 + 1;
if(1 <= pos1 && pos1 <= n - i + 1){
mrk[pos1][pos1 + i - 1] = true;
pq.emplace(MID(pos1, pos1 + i - 1), pos1, pos1 + i - 1);
s.insert(MID(pos1, pos1 + i - 1));
}
if(1 <= pos2 && pos2 <= n - i + 1){
mrk[pos2][pos2 + i - 1] = true;
pq.emplace(MID(pos2, pos2 + i - 1), pos2, pos2 + i - 1);
}
}
}
void solve(){
init();
while(pq.size()){
auto [mn, l, r] = pq.top(); pq.pop();
res = min(res, *s.rbegin() - mn);
s.erase(s.find(mn));
if(mrk[l + 1].find(r + 1) == mrk[l + 1].end() || (l == 1 && r == n)) break;
s.insert(MID(l + 1, r + 1));
}
cout << setprecision(12) << fixed << res << "\n";
}
int32_t main(){
cin.tie(0)->sync_with_stdio(0);
cin >> n;
for(int i = 1; i <= n; i++) cin >> a[i];
solve();
return 0;
}
