#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 7;
int a[N], n;
double f(double x) {
  double sum = 0, mn = 0, mx = 0, ans = 0;
  for (int i = 0; i < n; i++) {
    mn = min(mn, sum);
    mx = max(mx, sum);
    sum += a[i] - x;
    ans = max(ans, abs(sum - mn));
    ans = max(ans, abs(sum - mx));
  }
  return ans;
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> n;
  for (int i = 0; i < n; i++) cin >> a[i];
  double l = -1e4 - 7, r = 1e4 + 7;
  int t = 230;
  while (t--) {
    double mid1 = (2 * r + l) / 3;
    double mid2 = (2 * l + r) / 3;
    if (f(mid1) < f(mid2))
      l = mid2;
    else
      r = mid1;
  }
  cout << setprecision(9) << fixed << f(l) << endl;
  return 0;
}
