10
-405 -230 252 -393 -390 -259 97 163 81 -129
 3
10000 -10000 10000
 1
-10000
 20
-16 -23 29 44 -40 -50 -41 34 -38 30 -12 28 -44 -49 15 50 -28 38 -2 0

702.333333333333712
 10000.000000000016371
 0.000000000000000
 113.875000000000043

#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  scanf("%d", &n);
  int a[n];
  for (int i = 0; i < n; i++) scanf("%d", &a[i]);
  long double x = -10000, t1, t2, t, sum1, sum2;
  for (double b = 10000; b > 1e-9; b /= 2) {
    t1 = t2 = t = sum1 = sum2 = 0;
    for (int i = 0; i < n; i++) {
      sum1 = max(a[i] - x - b, sum1 + a[i] - x - b);
      t1 = max(sum1, t1);
      sum2 = min(a[i] - x - b, sum2 + a[i] - x - b);
      t2 = min(t2, sum2);
    }
    t1 = max(t1, -t2);
    t2 = t = sum1 = sum2 = 0;
    for (int i = 0; i < n; i++) {
      sum1 = max(a[i] - x - b - 1e-9, sum1 + a[i] - x - b - 1e-9);
      t = max(sum1, t);
      sum2 = min(a[i] - x - b - 1e-9, sum2 + a[i] - x - b - 1e-9);
      t2 = min(t2, sum2);
    }
    t2 = max(-t2, t);
    if (t1 > t2) x += b;
  }
  printf("%.15Lf\n", t1);
  return 0;
}
