10
-405 -230 252 -393 -390 -259 97 163 81 -129
 3
10000 -10000 10000
 1
-10000
 20
-16 -23 29 44 -40 -50 -41 34 -38 30 -12 28 -44 -49 15 50 -28 38 -2 0

702.333333333333712
 10000.000000000016371
 0.000000000000000
 113.875000000000043

#include <bits/stdc++.h>
using namespace std;
const int maxn = 200003;
int a[maxn];
long double b[maxn];
long double eps = 1e-10;
int main() {
  ios_base::sync_with_stdio(false);
  int n;
  cin >> n;
  for (int i = 1; i <= n; i++) cin >> a[i];
  long double l = -10001, r = 10001;
  long double ans = 0;
  while (r - l > eps) {
    long double c = (l + r) / 2;
    for (int i = 1; i <= n; i++) b[i] = a[i] - c;
    long double x = 0;
    long double cursum = 0;
    for (int i = 1; i <= n; i++) {
      cursum += b[i];
      if (cursum < 0) cursum = 0;
      x = max(x, cursum);
    }
    long double y = 0;
    cursum = 0;
    for (int i = 1; i <= n; i++) {
      cursum += b[i];
      if (cursum > 0) cursum = 0;
      y = max(y, -cursum);
    }
    ans = y;
    if (x > y)
      l = c;
    else
      r = c;
  }
  cout.precision(8);
  cout << fixed << ans << "\n";
  return 0;
}
