#include <bits/stdc++.h>
using namespace std;
int N;
double a[200010], sum[200010];
double cal(double X) {
  double hsgs = 0.0, Mn = 0.0, Mx = 0.0;
  for (int i = 1; i <= N; i++) {
    sum[i] = sum[i - 1] + a[i] - X;
    hsgs = max(max(fabs(sum[i] - Mn), fabs(sum[i] - Mx)), hsgs);
    Mn = min(Mn, sum[i]);
    Mx = max(Mx, sum[i]);
  }
  return hsgs;
}
int main() {
  scanf("%d", &N);
  for (int i = 1; i <= N; i++) scanf("%lf", &a[i]);
  double l = -1e9, r = 1e9;
  for (int i = 1; i <= 500; i++)
    if (cal((2 * l + r) / 3) < cal((l + 2 * r) / 3))
      r = (l + 2 * r) / 3;
    else
      l = (2 * l + r) / 3;
  printf("%.15lf", cal(l));
}
