#include <bits/stdc++.h>
using namespace std;
long long a[222222];
long long n;
double f(double x) {
  double s = 0, mx = 0, mn = 0;
  for (int i = 1; i <= n; i++) {
    s += a[i] - x;
    if (s < 0) s = 0;
    if (s > mx) mx = s;
  }
  s = 0;
  for (int i = 1; i <= n; i++) {
    s += a[i] - x;
    if (s > 0) s = 0;
    if (s < mn) mn = s;
  }
  mn = -mn;
  return mx > mn ? mx : mn;
}
int main() {
  scanf("%lld", &n);
  for (int i = 1; i <= n; i++) scanf("%lld", a + i);
  long double l = -20000, r = 20000, eps = 1e-9;
  int t = 300;
  while (t--) {
    long double m1 = (l + l + r) / 3;
    long double m2 = (r + r + l) / 3;
    long double f1 = f(m1);
    long double f2 = f(m2);
    if (f1 >= f2)
      l = m1;
    else
      r = m2;
  }
  printf("%.10f", f(l));
}
