#include <bits/stdc++.h>
using namespace std;
template <typename T>
int len(const T& a) {
  return a.size();
}
using ll = long long;
constexpr long double EPS = 1e-7;
long double MaxSubarray(const vector<long double>& a) {
  long double best = -1e8;
  long double cur = 0.0;
  for (auto& i : a) {
    cur = max((long double)0, cur + i);
    best = max(best, cur);
  }
  return best;
}
long double MinSubarray(const vector<long double>& a) {
  long double best = 1e8;
  long double cur = 0.0;
  for (auto& i : a) {
    cur = min((long double)0, cur + i);
    best = min(best, cur);
  }
  return best;
}
long double Check(const vector<long double>& a, long double x) {
  vector<long double> new_a(a.size());
  for (int i = 0; i < len(a); ++i) {
    new_a[i] = (long double)a[i] - x;
  }
  return max(abs(MaxSubarray(new_a)), abs(MinSubarray(new_a)));
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  cout << fixed << setprecision(6);
  int n;
  cin >> n;
  vector<long double> a(n);
  for (auto& i : a) cin >> i;
  long double l = -1e4 - 10, r = 1e4 + 10;
  for (int step = 0; step < 200; ++step) {
    long double m1 = l + (r - l) / 3.0;
    long double m2 = r - (r - l) / 3.0;
    if (Check(a, m1) - Check(a, m2) > EPS) {
      l = m1;
    } else {
      r = m2;
    }
  }
  cout << Check(a, l);
  return 0;
}
