#include <bits/stdc++.h>
using namespace std;
template <typename T>
inline void mn(T& x, const T& y) {
  if (y < x) x = y;
}
template <typename T>
inline void mx(T& x, const T& y) {
  if (x < y) x = y;
}
template <typename T>
inline int sz(const T& x) {
  return x.size();
}
const int N = 200000;
int a[N];
double p[N + 1];
double f(const int n, const double x) {
  p[0] = 0;
  for (int i = 0; i < (n); ++i) {
    p[i + 1] = p[i] + (a[i] - x);
  }
  double min_prev = 0;
  double max_prev = 0;
  double min_total = numeric_limits<double>::max();
  double max_total = numeric_limits<double>::min();
  for (int i = 1; i <= n; ++i) {
    mn(min_total, p[i] - max_prev);
    mx(max_total, p[i] - min_prev);
    mn(min_prev, p[i]);
    mx(max_prev, p[i]);
  }
  return max(abs(min_total), abs(max_total));
}
int main() {
  int n;
  scanf("%d", &n);
  for (int i = 0; i < (n); ++i) {
    scanf("%d", &a[i]);
  }
  double l = -1e9;
  double r = +1e9;
  for (int iter = 0; iter < (200); ++iter) {
    double ll = l + (r - l) / 3;
    double rr = r - (r - l) / 3;
    if (f(n, ll) < f(n, rr)) {
      r = rr;
    } else {
      l = ll;
    }
  }
  printf("%.12lf\n", f(n, l));
  return 0;
}
