#include <bits/stdc++.h>
using namespace std;
double find_max(int *a, int n, double x) {
  double min_p = a[0] - x;
  double max_p = a[0] - x;
  double maxv = abs(a[0] - x);
  for (int i = 1; i < n; ++i) {
    min_p = min(min_p + a[i] - x, a[i] - x);
    max_p = max(max_p + a[i] - x, a[i] - x);
    maxv = max(abs(min_p), maxv);
    maxv = max(abs(max_p), maxv);
  }
  return maxv;
}
int main() {
  ios_base::sync_with_stdio(false);
  int a[200000];
  int n;
  cin >> n;
  for (int i = 0; i < n; ++i) cin >> a[i];
  double L = -1e9;
  double R = 1e9 + 1e-2;
  while (abs(L - R) > 1e-11) {
    double x1 = L + (R - L) * 1 / 3;
    double x2 = L + (R - L) * 2 / 3;
    double vl = find_max(a, n, x1);
    double vr = find_max(a, n, x2);
    if (vl + 1e-9 < vr) {
      R = x2;
    } else {
      L = x1;
    }
  }
  std::cout.precision(8);
  cout << fixed << find_max(a, n, L) << endl;
  return 0;
}
