#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MAX_N=2e5+10;
int val[MAX_N];
ll pre[MAX_N];
map<tuple<int,int,double,double>,double >dp;
double seesaw(int l,int r,double mi,double  ma){
  if(l==r) return max(ma,(double)val[r])-min(mi,(double)val[l]);
  auto sta=make_tuple(l,r,mi,ma);
  if(dp.find(sta)!=dp.end()) return dp[sta];
  double ans;
  double m=(r-l)+1;
  ll sum=pre[r]-pre[l-1];
  double ba=sum/m;
  ans=min(seesaw(l+1,r,min(mi,ba),max(ma,ba)),seesaw(l,r-1,min(mi,ba),max(ma,ba)));
  return dp[sta]=ans;
}
int main(){
  int n; scanf("%d",&n);
  for(int i=1;i<=n;i++){
    scanf("%d",&val[i]);
  }
  for(int i=1;i<=n;i++) pre[i]=pre[i-1]+val[i];
  printf("%.12f\n",seesaw(1,n,1e9+1,-1));
}