#include <bits/stdc++.h>
const double f1 = (double)1 / 3, f2 = (double)2 / 3;
const double INF = 1e9;
int a[200005], n;
inline double max(double a, double b) { return a > b ? a : b; }
double poor(double x) {
  double m = 0, M = 0, sum = INF, suM = -INF;
  double ret;
  for (int i = 0; i < n; i++) {
    double num = a[i] - x;
    if (sum > 0)
      sum = num;
    else
      sum += num;
    if (suM < 0)
      suM = num;
    else
      suM += num;
    ret = max(ret, max(fabs(sum), fabs(suM)));
  }
  return ret;
}
double solve() {
  double r[2] = {-1e4 - 1, 1e4 + 1};
  for (int t = 0; t < 100 && r[0] < r[1]; t++) {
    double v[2], diff = r[1] - r[0];
    v[0] = poor(r[0] + f1 * diff);
    v[1] = poor(r[0] + f2 * diff);
    if (v[0] < v[1])
      r[1] = r[0] + f2 * diff;
    else
      r[0] = r[0] + f1 * diff;
  }
  return poor(r[0]);
}
int main() {
  scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    scanf("%d", &a[i]);
  }
  printf("%f\n", solve());
}
