#include <bits/stdc++.h>
using namespace std;
long double v[200101];
const long double eps = 1e-8;
int n;
long double f(long double x) {
  long double maxx = -1e18;
  long double minx = 1e18;
  long double last_max = 0;
  long double last_min = 0;
  for (int i = 0; i < n; i++) {
    last_max += v[i] - x;
    last_min += v[i] - x;
    maxx = max(maxx, last_max);
    minx = min(minx, last_min);
    if (last_max + eps < 0.0) {
      last_max = 0;
    }
    if (last_min - eps > 0.0) {
      last_min = 0;
    }
  }
  return max(fabs(maxx), fabs(minx));
}
int main() {
  scanf("%d", &n);
  double sum = 0;
  double b1 = -1e18;
  double b2 = 1e18;
  for (int i = 0; i < n; i++) {
    cin >> v[i];
    sum += v[i];
    b1 = max(b1, sum / (i + 1));
    b2 = min(b2, sum / (i + 1));
  }
  long double l = -5e4, r = 5e4;
  while (l + eps < r) {
    long double m1 = l + (r - l) / 3.0;
    long double m2 = r - (r - l) / 3.0;
    long double f1 = f(m1);
    long double f2 = f(m2);
    if (f1 - eps > f2) {
      l = m1;
    } else {
      r = m2;
    }
  }
  printf("%.7lf", (double)min(f(l), min(f(b1), f(b2))));
  return 0;
}
