#include<bits/stdc++.h>
using namespace std;
#define int long long
using ld=long double;
const int MAX_VAL=200*1000+5,INFINI=1000*1000*1000+5;
int nbVal,deb,fin;
int val[MAX_VAL],cumu[MAX_VAL];
vector<pair<ld,ld>> segInter;
vector<pair<ld,ld>> segRep;
ld rep;
ld bary(int debInter,int finInter) {
return (ld) (cumu[finInter]-cumu[debInter-1])/(finInter-debInter+1);
}
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
cin>>nbVal;
for (int i=1;i<=nbVal;i++) {
cin>>val[i];
cumu[i]=cumu[i-1]+val[i];
}
segInter.push_back({-1,bary(1,nbVal)});
segInter.push_back({bary(1,nbVal),INFINI});
deb=1;
fin=nbVal;
while (deb!=fin) {
deb++;
if (bary(deb,fin)>bary(1,nbVal)) {
deb--;
fin--;
}
//cout<<deb<<" "<<fin<<endl;
segInter.push_back({bary(deb,fin),bary(deb+1,fin+1)});
}
sort(segInter.begin(),segInter.end());
reverse(segInter.begin(),segInter.end());
for (auto i:segInter) {
while (!segRep.empty() and segRep.back().second<i.second) {
segRep.pop_back();
}
segRep.push_back(i);
}
reverse(segRep.begin(),segRep.end());
rep=INFINI;
for (int i=0;i<(int)segRep.size()-1;i++) {
rep=min(rep,abs(segRep[i].second-segRep[i+1].first));
}
cout<<setprecision(10);
cout<<rep<<endl;
return 0;
}
