#include <bits/stdc++.h>
using namespace std;
const int maxn = 2e5 + 5;
int a[maxn];
int p[maxn];
int n;
long double f(long double x) {
  long double minx = 0;
  long double maxx = 0;
  for (int i = 0; i <= n; i++)
    minx = min(minx, (long double)p[i] + (long double)i * x),
    maxx = max(maxx, (long double)p[i] + (long double)i * x);
  return maxx - minx;
}
int main() {
  scanf("%d", &n);
  p[0] = 0;
  for (int i = 0; i < n; i++) {
    scanf("%d", &a[i]);
    p[i + 1] = p[i] + a[i];
  }
  long double l = -3e9;
  long double r = 3e9;
  for (int it = 0; it < 150; it++) {
    long double m1 = l + (r - l) / 3.;
    long double m2 = r - (r - l) / 3.;
    if (f(m1) < f(m2))
      r = m2;
    else
      l = m1;
  }
  printf("%.30f", (double)(f(l)));
  return 0;
}
