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 n;
double a[200005];
double fabs(double x) { return x < 0 ? -x : x; }
double max(double x, double y) { return x > y ? x : y; }
double min(double x, double y) { return x < y ? x : y; }
inline double f(double x) {
  double sum = 0, k = 0, minn = 0, maxn = 0;
  for (register int i = 1; i <= n; i++) {
    sum += a[i] - x;
    k = max(k, fabs(sum - minn));
    k = max(k, fabs(sum - maxn));
    minn = min(minn, sum);
    maxn = max(maxn, sum);
  }
  return k;
}
int main() {
  int i;
  double l = 0, r;
  scanf("%d", &n);
  for (i = 1; i <= n; i++) {
    scanf("%lf", &a[i]);
    l = min(l, -fabs(a[i]));
  }
  r = -l;
  while ((r - l) * 10000000 >= 1) {
    double mid1 = l + (r - l) / 3, mid2 = r - (r - l) / 3;
    double x1 = f(mid1), x2 = f(mid2);
    if (x1 < x2)
      r = mid2;
    else
      l = mid1;
  }
  printf("%.6lf\n", f((l + r) / 2));
  return 0;
}
