#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 9;
int a[N], n;
double ans(double x) {
  double arr[N];
  for (int i = 0; i < n; i++) arr[i] = a[i] - x;
  double neg = 0;
  double pos = 0;
  double ans = 0;
  for (int i = 0; i < n; i++) {
    if (neg > 0) neg = 0;
    if (pos < 0) pos = 0;
    neg += arr[i];
    pos += arr[i];
    ans = max(ans, max(-neg, pos));
  }
  return ans;
}
int main() {
  cin >> n;
  for (int i = 0; i < n; i++) cin >> a[i];
  double l = -1e5 - 9, r = 1e5 + 9;
  for (int i = 0; i < 100; i++) {
    double m1 = l + (r - l) / 3, m2 = r - (r - l) / 3;
    if (ans(m1) > ans(m2))
      l = m1;
    else
      r = m2;
  }
  cout << setprecision(12) << fixed << ans(l) << endl;
  return 0;
}
