#include<bits/stdc++.h>
#define fi first
#define se second
#define eb emplace_back
#define mp make_pair
using namespace std;
typedef long double ld;
typedef long long ll;
typedef unsigned long long ull;
typedef __int128 i128;
template<typename T,typename U>
T ceil(T x, U y) {return (x>0?(x+y-1)/y:x/y);}
template<typename T,typename U>
T floor(T x, U y) {return (x>0?x/y:(x-y+1)/y);}
template<class T,class S>
bool chmax(T &a,const S b) {return (a<b?a=b,1:0);}
template<class T,class S>
bool chmin(T &a,const S b) {return (a>b?a=b,1:0);}
int popcnt(int x) {return __builtin_popcount(x);}
int popcnt(ll x)  {return __builtin_popcountll(x);}
int topbit(int x) {return (x==0?-1:31-__builtin_clz(x));}
int topbit(ll x)  {return (x==0?-1:63-__builtin_clzll(x));}
int lowbit(int x) {return (x==0?-1:__builtin_ctz(x));}
int lowbit(ll x)  {return (x==0?-1:__builtin_ctzll(x));}

#define int long long
#define rep(i,a,b) for(int i=(a);i<=(b);i++)
#define per(i,a,b) for(int i=(a);i>=(b);i--)
typedef pair<int,int> pii; 
typedef vector<int> vi;
typedef vector<pii> vp;
typedef tuple<int,int,int> tiii;
int read() {
  int x=0,w=1; char c=getchar(); 
  while(!isdigit(c)) {if(c=='-') w=-1; c=getchar();}
  while(isdigit(c)) {x=x*10+(c-'0'); c=getchar();}
  return x*w;
}

const int N=2e5+5;
const ld inf=1e9,eps=1e-9;
int n,a[N],s[N],f[105][105];
ld ans=inf,b[N];

ld avg(int l,int r) {
  return 1.*(s[r]-s[l-1])/(r-l+1);
}
bool work(ld L,ld R,int l,int r) {
  if(l==r) return 1;
  if(f[l][r]!=-1) return f[l][r];
  ld pl=avg(l,r-1), pr=avg(l+1,r);
  bool res=0;
  if(L<=pl&&pl<=R) res|=work(L,R,l,r-1);
  if(L<=pr&&pr<=R) res|=work(L,R,l+1,r);
  return f[l][r]=res;
}

signed main() {
  n=read();
  rep(i,1,n) a[i]=read(), s[i]=s[i-1]+a[i];
  rep(i,1,n) b[i]=a[i]; b[n+1]=avg(1,n);
  rep(i,1,n+1) if(b[i]-eps<avg(1,n)) {
    ld L=b[i];
    ld x=0, y=inf, res=inf;
    x=max(x,avg(1,n)-L);
    while(y-x>eps) {
      ld p=(x+y)/2;
      rep(l,1,n) rep(r,l+1,n) f[l][r]=-1;
      if(work(L,L+p,1,n)) res=p, y=p;
      else x=p;
    }
    chmin(ans,res);
  }
  rep(i,1,n+1) if(b[i]+eps>avg(1,n)) {
    ld L=b[i];
    ld x=0, y=inf, res=inf;
    x=max(x,L-avg(1,n));
    while(y-x>eps) {
      ld p=(x+y)/2;
      rep(l,1,n) rep(r,l+1,n) f[l][r]=-1;
      if(work(L-p,L,1,n)) res=p, y=p;
      else x=p;
    }
    chmin(ans,res);
  }
  printf("%.8Lf\n",ans);
  return 0;
}