#include <bits/stdc++.h>
using namespace std;
struct __s {
  __s() {
    if (1) {
      ios_base::Init i;
      cin.sync_with_stdio(0);
      cin.tie(0);
    }
  }
  ~__s() {
    if (!1)
      fprintf(stderr, "Execution time: %.3lf s.\n",
              (double)clock() / CLOCKS_PER_SEC);
    long long n;
    cin >> n;
  }
} __S;
long long n;
double a[211111];
double mx() {
  double ans = a[0];
  double sum = 0;
  double min_sum = 0;
  for (long long r = 0; r < (long long)(n); r++) {
    sum += a[r];
    ans = max(ans, sum - min_sum);
    min_sum = min(min_sum, sum);
  }
  return ans;
}
int main(void) {
  cin >> n;
  for (long long i = 0; i < (long long)(n); i++) {
    long long x;
    cin >> x;
    a[i] = x;
  }
  double l = 2e4;
  double r = -2e4;
  for (long long _ = 0; _ < (long long)(60); _++) {
    double x = (l + r) / 2.0;
    for (long long i = 0; i < (long long)(n); i++) {
      a[i] += x;
    }
    double mx1 = mx();
    for (long long i = 0; i < (long long)(n); i++) {
      a[i] *= -1;
    }
    double mx2 = mx();
    for (long long i = 0; i < (long long)(n); i++) {
      a[i] *= -1;
      a[i] -= x;
    }
    if (mx1 >= mx2) {
      l = x;
    } else {
      r = x;
    }
  }
  double x = l;
  for (long long i = 0; i < (long long)(n); i++) {
    a[i] += x;
  }
  double mx1 = mx();
  for (long long i = 0; i < (long long)(n); i++) {
    a[i] *= -1;
  }
  double mx2 = mx();
  cout << fixed << setprecision(10) << max(mx1, mx2) << '\n';
  return 0;
}
