#include <bits/stdc++.h>
using namespace std;
int n, a[200005], sp[200005];
double val(double x) {
  double mx = sp[0], mn = sp[0];
  for (int i = 1; i <= n; i++) {
    mx = (((mx) > (sp[i] - i * x)) ? (mx) : (sp[i] - i * x));
    mn = (((mn) < (sp[i] - i * x)) ? (mn) : (sp[i] - i * x));
  }
  return mx - mn;
}
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) {
    scanf("%d", &a[i]);
    sp[i] = sp[i - 1] + a[i];
  }
  double l = -10002, r = 10002, mid1, mid2;
  for (int iter = 1; iter <= 200; iter++) {
    double x = (r - l) / 3;
    mid1 = l + x;
    mid2 = r - x;
    double xx = val(mid1), yy = val(mid2);
    if (fabs(xx - yy) < 1e-9) break;
    if (xx < yy)
      r = mid2;
    else
      l = mid1;
  }
  printf("%.10f\n", val((l + r) / 2));
  return 0;
}
