#include <bits/stdc++.h>
using namespace std;
#define int long long
#define F first
#define S second
#define pb push_back
#define all(x) x.begin() , x.end()
#define debug while(1) cout << "Test\n"
#pragma GCC optimize ("O3,unroll-loops")
#pragma GCC target ("avx2")
const int N = 2e5 + 10;
const int mod = 1e9 + 7;
const int INF = 1e15 + 10;
int pref[N];
int a[N];
int n;
long double f(int l , int r) {
return (long double) (pref[r] - pref[l-1]) / (r - l + 1);
}
void solve() {
cin >> n;
for(int i = 1 ; i <= n ; i++)
cin >> a[i] , pref[i] = pref[i-1] + a[i];
int l = 1;
int r = n;
long double mn , ans , w = f(l , r); mn = ans = w;
for(int i = n-1 ; i ; i--) {
long double x = f(l + 1 , r);
if(x <= w) {l++ , ans = x; continue;}
ans = f(l , --r);
mn = min(mn , ans);
}
long double mx; mx = ans = w;
l = 1;
r = n;
for(int i = n-1 ; i ; i--) {
long double x = f(l , r - 1);
if(x >= w) {r-- , ans = x; continue;}
ans = f(++l , r);
mx = max(mx , ans);
}
cout << fixed << setprecision(20) << min(w - mn , mx - w) << "\n";
}
signed main() {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
solve();
}
