#include <bits/stdc++.h>
using namespace std;
int p, q, r, n, a[200005];
double eps = 5e-7;
double mid(double a, double b) {
  if (a > b) swap(a, b);
  return a + (b - a) * 0.618;
}
double fun(double x) {
  double MAX, MIN, sum;
  int i;
  MAX = MIN = sum = 0;
  for (i = 0; i < n; i++) {
    sum += a[i] - x;
    MAX = max(MAX, sum);
    MIN = min(MIN, sum);
  }
  return MAX - MIN;
}
double dis(double a, double b) { return fabs(a - b); }
double find() {
  double m1, m2, l, r;
  double cl, cr, cm1, cm2;
  r = 100000;
  l = -100000;
  cl = fun(l);
  cr = fun(r);
  m2 = mid(r, l);
  cm2 = fun(m2);
  m1 = mid(l, m2);
  cm1 = fun(m1);
  while (fabs(l - r) + fabs(cl - cr) > eps) {
    if (cm1 < cm2) {
      r = m2;
      cr = cm2;
      m2 = m1;
      cm2 = cm1;
      m1 = mid(l, m2);
      cm1 = fun(m1);
    } else {
      l = m1;
      cl = cm1;
      m1 = m2;
      cm1 = cm2;
      m2 = mid(r, l);
      cm2 = fun(m2);
    }
  }
  return (cm1 + cm2) / 2;
}
int main() {
  int t, i;
  scanf("%d", &n);
  for (i = 0; i < n; i++) scanf("%d", &a[i]);
  printf("%.10f\n", find());
  return 0;
}
