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;
double a[200010], sum[200010];
int n;
double f(double x) {
  for (int i = 0; i < n; i++) sum[i] = a[i] - x;
  int temp1 = 0, ans1 = 0;
  for (int i = 0; i < n; i++) {
    temp1 += sum[i];
    if (temp1 > ans1) ans1 = temp1;
    if (temp1 < 0) temp1 = 0;
  }
  for (int i = 0; i < n; i++) sum[i] = -sum[i];
  int temp2 = 0, ans2 = 0;
  for (int i = 0; i < n; i++) {
    temp2 += sum[i];
    if (temp2 > ans2) ans2 = temp2;
    if (temp2 < 0) temp2 = 0;
  }
  return max(ans1, ans2);
}
double sanfen() {
  double l = -1e9, r = 1e9;
  while (l + 1e-11 < r) {
    double mid1 = l + (r - l) / 3;
    double mid2 = r - (r - l) / 3;
    if (f(mid1) >= f(mid2))
      l = mid1;
    else
      r = mid2;
  }
  return f((l + r) / 2);
}
int main() {
  scanf("%d", &n);
  for (int i = 0; i < n; i++) scanf("%lf", &a[i]);
  printf("%.12lf", sanfen());
  return 0;
}
