#include <bits/stdc++.h>
using namespace std;
const int MOD = 1e9 + 7;
const int maxn = 300009;
const int maxm = 300009;
const double pi = acos(-1.0);
const double eps = 1e-15;
double data[maxn], sum, maxx, minx;
double tmp[maxn];
double f2(double x, int n) {
  for (int i = 1; i <= n; i++) tmp[i] = data[i] - x;
  double tmpp = tmp[1], tmpn = tmp[1];
  double ans = tmpp, ans2 = tmpn;
  for (int i = 2; i <= n; i++) {
    if (tmpp > 0)
      tmpp += tmp[i];
    else
      tmpp = tmp[i];
    ans = max(tmpp, ans);
    if (tmpn < 0)
      tmpn += tmp[i];
    else
      tmpn = tmp[i];
    ans2 = min(tmpn, ans2);
  }
  return max(abs(ans), abs(ans2));
}
double sanfen(int n) {
  double l = minx, r = maxx, mid = l + (r - l) / 3., midd = r - (r - l) / 3.;
  int cnt = 100;
  while (fabs(r - l) > eps && cnt--) {
    double fmid = f2(mid, n), fmidd = f2(midd, n);
    if (fmid < fmidd)
      r = midd;
    else
      l = mid;
    mid = l + (r - l) / 3., midd = r - (r - l) / 3.;
  }
  return f2((l + r) / 2., n);
}
int main() {
  int n;
  while (~scanf("%d", &n)) {
    maxx = -1000000.;
    minx = 1000000.;
    sum = 0.0;
    for (int i = 1; i <= n; i++) scanf("%lf", &data[i]), sum += data[i];
    if (n != 1)
      printf("%.15f\n", sanfen(n));
    else
      printf("%.15lf\n", 0.0);
  }
  return 0;
}
