#include <bits/stdc++.h>
using namespace std;
const long long N = 2e5 + 5;
const long long mod = 1e9 + 7;
long long n;
long double l, r, ans = 1e18, arr[N], sum[N];
long double func(long double val) {
  long double mn = 0, mx = 0, fin = -1e12;
  for (long long i = 1; i <= n; i++) {
    sum[i] = sum[i - 1] + arr[i] - val;
    fin = max(fin, max(sum[i] - mn, mx - sum[i]));
    mx = max(mx, sum[i]);
    mn = min(mn, sum[i]);
  }
  return fin;
}
int main() {
  cin >> n;
  for (long long i = 1; i <= n; i++) cin >> arr[i];
  r = 1e6, l = -1e6;
  ans = func(0);
  for (long long i = 1; i <= 200; i++) {
    long double mid1 = l + (r - l) / 3;
    long double mid2 = r - (r - l) / 3;
    long double x = func(mid1), y = func(mid2);
    ans = min(ans, min(x, y));
    if (x < y)
      r = mid2;
    else
      l = mid1;
  }
  cout << fixed << setprecision(18) << ans;
}
