#include <bits/stdc++.h>
using namespace std;
double cal(int n, int *a, double x) {
  double ret = 0, t1 = 0, t2 = 0;
  for (int i = 0; i < n; i++) {
    t1 += a[i] - x;
    t2 += a[i] - x;
    t1 = max(0., t1);
    t2 = min(0., t2);
    ret = max(ret, t1);
    ret = max(ret, -t2);
  }
  return ret;
}
int main() {
  int n;
  scanf("%d", &n);
  static int a[200000];
  for (int i = 0; i < n; i++) {
    scanf("%d", a + i);
  }
  double l = -10001, r = 10001, ans;
  for (int t = 0; t < 100; t++) {
    double d1 = (2 * l + r) / 3, d2 = (l + 2 * r) / 3;
    double e1 = cal(n, a, d1), e2 = cal(n, a, d2);
    if (e1 <= e2) {
      r = d2;
      ans = e1;
    } else {
      l = d1;
      ans = e2;
    }
  }
  printf("%.9lf\n", ans);
  return 0;
}
