#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 10;
int a[N], n;
double solve(double x) {
  double ma = -1, now = 0;
  for (int i = 0; i < n; i++) ma = max(ma, now = max(0.0, now + a[i] - x));
  now = 0;
  for (int i = 0; i < n; i++) ma = max(ma, now = max(0.0, now + x - a[i]));
  return ma;
}
int main() {
  scanf("%d", &n);
  for (int i = 0; i < n; i++) scanf("%d", a + i);
  double l = -1e4, r = 1e4;
  int T = 200;
  while (T--) {
    double m = (l + r) / 2, ml = (l + m) / 2, mr = (r + m) / 2;
    if (solve(ml) <= solve(mr))
      r = mr;
    else
      l = ml;
  }
  printf("%.15f\n", solve(l));
  return 0;
}
