#include <bits/stdc++.h>
using namespace std;
const int maxn = 2e5 + 10;
int a[maxn];
double b[maxn];
int n;
double maxsum(double a[maxn]) {
  double mx = 0, now = 0;
  for (int i = 1; i <= n; ++i) {
    now += a[i];
    if (now > mx) mx = now;
    if (now < 0) {
      now = 0;
    }
  }
  return mx;
}
double f(double x) {
  for (int i = 1; i <= n; ++i) {
    b[i] = a[i] - x;
  }
  double psum = maxsum(b);
  for (int i = 1; i <= n; ++i) {
    b[i] *= -1;
  }
  double nsum = maxsum(b);
  return max(psum, nsum);
}
double ts(double l, double r) {
  for (int i = 1; i <= 300; ++i) {
    double m1 = l + (r - l) / 3;
    double m2 = r - (r - l) / 3;
    double f1 = f(m1);
    double f2 = f(m2);
    if (f1 > f2) {
      l = m1;
    } else {
      r = m2;
    }
  }
  return f(l);
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  cin >> n;
  for (int i = 1; i <= n; ++i) {
    cin >> a[i];
  }
  double l = *min_element(a + 1, a + n + 1);
  double r = *max_element(a + 1, a + n + 1);
  cout << fixed << setprecision(12) << ts(l, r) << "\n";
  return 0;
}
