#include <bits/stdc++.h>
using namespace std;
int a1[200000];
int main() {
  int n;
  double l = -10000, r = 10000, md, a, b, c, d;
  scanf("%d", &n);
  for (int i = 0; i < n; ++i) scanf("%d", a1 + i);
  while (r - l > 1e-12) {
    md = (l + r) / 2;
    a = -10001;
    b = 10001;
    c = d = 0;
    for (int i = 0; i < n; ++i) {
      c += a1[i] - md;
      if (c < 0) c = 0;
      if (c > a) a = c;
      d += a1[i] - md;
      if (d > 0) d = 0;
      if (d < b) b = d;
    }
    if (a + b > 0)
      l = md;
    else
      r = md;
  }
  printf("%.9f\n", a);
}
