#include <bits/stdc++.h>
using namespace std;
using ll = long long; using pii = pair<ll,ll>; using ld = long double;
using pld = pair<ld,ld>;
ll N; const ll Nm = 2e5+5; const ld INF = 1e18; const ld DEL = 1e-10;
ld avg;
ld psa[Nm+1];
ld ans = INF;
int main() {
ios_base::sync_with_stdio(false); cin.tie(0);
cin >> N;
psa[0]=0.0L;
for (ll i=0;i<N;i++) {
ll a1; cin >> a1;
psa[i+1]=psa[i]+a1;
}
avg = psa[N]/N;
//cout << "avg="<<avg<<"\n";
ld maxv = avg;
set<pld> s0;
ld imin = avg;
s0.insert({avg,avg});
for (ll L=1;L<N;L++) {
ll xmin = 0;
ll xmax = N-L;
while (xmin != xmax) {
ll xt = (xmin+xmax+1)/2;
ld avt = (psa[xt+L]-psa[xt])/L;
if (avt >= (avg+DEL)) {
xmax = xt-1;
} else {
xmin = xt;
}
}
s0.insert({(psa[xmin+L]-psa[xmin])/L,(psa[xmin+1+L]-psa[xmin+1])/L});
//cout << "pair: "<<(psa[xmin+L]-psa[xmin])/L<<","<<(psa[xmin+1+L]-psa[xmin+1])/L<<"\n";
imin = min(imin,(psa[xmin+L]-psa[xmin])/L);
}
ans = min(ans,avg-imin);
while (s0.size()>=2) {
auto A0 = s0.begin(); pld p0 = *A0;
s0.erase(A0);
maxv = max(maxv,p0.second);
ld cmin = (*(s0.begin())).first;
//cout << "maxv,cmin="<<maxv<<","<<cmin<<"\n";
ans = min(ans,maxv-cmin);
}
cout << setprecision(20);
cout << ans << "\n";
}
