#include <bits/stdc++.h>
using namespace std;
template <class T>
inline void Max(T &a, T b) {
  if (a < b) a = b;
}
template <class T>
inline void Min(T &a, T b) {
  if (a > b) a = b;
}
int a[200005];
double cal(double first, int n) {
  double s = 0, mi = 0, mx = 0;
  for (int i = 1; i <= n; i++) {
    s += a[i] - first;
    Min(mi, s);
    Max(mx, s);
  }
  return abs(mx - mi);
}
int main() {
  int T, i, j, k, m, n;
  scanf("%d", &n);
  double l = -1e9, r = 1e9;
  for (i = 1; i <= n; i++) {
    scanf("%d", &a[i]);
  }
  for (int it = 0; it < 100; it++) {
    double x1 = (11 * l + 10 * r) / 21;
    double x2 = (10 * l + 11 * r) / 21;
    double y1 = cal(x1, n), y2 = cal(x2, n);
    if (y1 >= y2)
      l = x1;
    else
      r = x2;
  }
  printf("%.9lf\n", cal(l, n));
  return 0;
}
