#include <bits/stdc++.h>
using namespace std;
template <class c>
struct rge {
  c b, e;
};
template <class c>
rge<c> range(c i, c j) {
  return rge<c>{i, j};
}
template <class c>
auto dud(c* x) -> decltype(cerr << *x, 0);
template <class c>
char dud(...);
struct debug {
  template <class c>
  debug& operator<<(const c&) {
    return *this;
  }
};
long double check(long double val, vector<long double>& a) {
  int n = a.size();
  for (int i = 0; i < n; i++) {
    a[i] -= val;
  }
  long double mx = -1e9;
  long double curr = -1e9;
  long double mn = 1e9;
  for (int i = 0; i < n; i++) {
    curr = max(curr + a[i], a[i]);
    mx = max(curr, mx);
  }
  curr = 1e9;
  for (int i = 0; i < n; i++) {
    curr = min(curr + a[i], a[i]);
    mn = min(curr, mn);
  }
  for (int i = 0; i < n; i++) {
    a[i] += val;
  }
  return max(abs(mn), abs(mx));
}
int32_t main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n;
  cin >> n;
  vector<long double> a(n);
  for (int i = 0; i < n; i++) {
    int chi;
    cin >> chi;
    a[i] = (long double)chi;
  }
  long double l = -100005.00, r = 100005.00;
  for (int i = 0; i < 350; i++) {
    long double m1 = l + (r - l) / 3.0;
    long double m2 = r - (r - l) / 3.0;
    long double f1 = check(m1, a);
    long double f2 = check(m2, a);
    if (f1 > f2) {
      l = m1;
    } else
      r = m2;
  }
  cout << fixed << setprecision(9) << check(r, a) << endl;
}
