#include <bits/stdc++.h>
using namespace std;
double a[200005];
int n;
double maxi(double x) {
  double min1 = 0, ans = -1000000007;
  a[1] -= x;
  ans = a[1];
  min1 = min(min1, ans);
  for (int i = 2; i <= n; i++) {
    a[i] -= i * x;
    ans = max(ans, a[i] - min1);
    if (a[i] < min1) min1 = a[i];
  }
  return ans;
}
double mini(double x) {
  double max1 = 0, ans = 1000000007;
  ans = a[1];
  max1 = max(max1, ans);
  a[1] += x;
  for (int i = 2; i <= n; i++) {
    ans = min(ans, a[i] - max1);
    if (a[i] > max1) max1 = a[i];
    a[i] += i * x;
  }
  return ans;
}
int main() {
  int i, j, k, t;
  double l, r, m, tol = 0.0000001, x = 1, y = 100;
  scanf("%d", &n);
  for (i = 1; i <= n; i++) {
    scanf("%lf", &a[i]);
    a[i] += a[i - 1];
  }
  l = -10000, r = 10000;
  t = 100;
  while (t--) {
    m = (l + r) / 2;
    y = maxi(m);
    x = mini(m);
    if (x > 0)
      l = m + tol;
    else if (y < 0)
      r = m - tol;
    else if (abs(x) == abs(y)) {
      printf("%lf\n", abs(x));
      return 0;
    } else if (abs(x) > abs(y))
      r = m - tol;
    else
      l = m + tol;
  }
  printf("%lf\n", abs(y));
  return 0;
}
