#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
// const double oo = 1e18; // +∞
#define _all(i, a, b) for (int i = (a); i <= (int)(b); ++i)
struct Seg {
int l, r;
bool operator<(const Seg& s) const {
if (l != s.l) return l < s.l;
return r < s.r;
}
};
using VD = vector<double>;
VD S;
double ave(int l, int r) { return (S[r] - S[l - 1]) / (r - l + 1); }
bool inRange(double x, double l, double r) { return l <= x && x <= r; }
bool check(int n, double cl, double cr) {
queue<Seg> Q;
Seg s{1, n};
vector<vector<bool>> Vis(n + 1, vector<bool>(n + 1));
if (inRange(ave(s.l, s.r), cl, cr)) Q.push({s.l, s.r}), Vis[s.l][s.r] = true;
while (!Q.empty()) {
Seg s = Q.front();
Q.pop();
if (s.l == s.r) return true;
vector<Seg> vs{{s.l + 1, s.r}, {s.l, s.r - 1}};
for (Seg ns : vs)
if (inRange(ave(ns.l, ns.r), cl, cr) && !Vis[ns.l][ns.r])
Q.push(ns), Vis[ns.l][ns.r] = true;
}
return false;
}
int main() {
ios::sync_with_stdio(false), cin.tie(0);
int n;
cin >> n, S.resize(n + 1);
for (int i = 1, a; i <= n; i++) cin >> a, S[i] = S[i - 1] + a;
set<double> s0; // 所有子区间的重心
_all(i, 1, n) _all(j, i, n) s0.insert(ave(i, j));
VD C(begin(s0), end(s0)); // 所有可能的左右边界一定都是某个重心
int CL = C.size();
double w = 1e18;
_all(L, 0, CL - 1) _all(R, L, CL - 1) {
// printf("%.2lf-%.2lf: %.2lf\n", C[L], C[R], C[R] - C[L]);
if (check(n, C[L], C[R])) w = min(w, C[R] - C[L]);
}
printf("%.10lf\n", w);
}
