#include <bits/stdc++.h>
using namespace std;
const double eps = 1e-8;
const int INF = (1 << 30) - 1;
const int MAXN = 200010;
int n;
int A[MAXN];
double B[MAXN];
double sum[MAXN];
double Cal(double v) {
  for (int i = 1; i <= n; ++i) {
    B[i] = 1.0 * A[i] - v;
  }
  long long MAX_LL = 1LL << 60;
  double sum_max = 0, sum_min = 0;
  double ans_max = 0, ans_min = MAX_LL;
  for (int i = 1; i <= n; ++i) {
    if (sum_min > 0) sum_min = 0;
    if (sum_max < 0) sum_max = 0;
    sum_max += B[i];
    sum_min += B[i];
    ans_max = max(ans_max, sum_max);
    ans_min = min(ans_min, sum_min);
  }
  if (ans_max < 0) ans_max = -ans_max;
  if (ans_min < 0) ans_min = -ans_min;
  return max(ans_max, ans_min);
}
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; ++i) {
    scanf("%d", &A[i]);
  }
  double l = -10000.0, r = 10000.0;
  int cnt = 100;
  while (cnt--) {
    double mid = ((l) + ((r) - (l)) / 2);
    double MID = ((mid) + ((r) - (mid)) / 2);
    double A1 = Cal(mid);
    double A2 = Cal(MID);
    if (A1 < A2)
      r = MID;
    else
      l = mid;
  }
  printf("%.12f\n", Cal(l));
  return 0;
}
