10
-405 -230 252 -393 -390 -259 97 163 81 -129
 3
10000 -10000 10000
 1
-10000
 20
-16 -23 29 44 -40 -50 -41 34 -38 30 -12 28 -44 -49 15 50 -28 38 -2 0

702.333333333333712
 10000.000000000016371
 0.000000000000000
 113.875000000000043

#include <bits/stdc++.h>
using namespace std;
double maxi, mini, inf = 1e10, ma[200010], mi[200010], L, R, mid, eps = 1e-7,
                   now, las;
int n, a[200010], f = 0;
double work(double val) {
  maxi = -inf, mini = inf;
  for (int i = 1; i <= n; i++) {
    ma[i] = max(ma[i - 1], 0.0) + a[i] + val,
    mi[i] = min(mi[i - 1], 0.0) + a[i] + val;
    maxi = max(ma[i], maxi), mini = min(mi[i], mini);
  }
  if (abs(maxi) > abs(mini))
    return maxi;
  else
    return mini;
}
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) scanf("%d", &a[i]);
  L = -1e5, R = 1e5;
  while (1) {
    mid = (L + R) / 2;
    now = work(mid);
    if (f && abs(now - las) < eps) break;
    f = 1;
    las = now;
    if (now > 0)
      R = mid;
    else
      L = mid;
  }
  printf("%.6lf", abs(work(L)));
  return 0;
}
