10
-405 -230 252 -393 -390 -259 97 163 81 -129
 3
10000 -10000 10000
 1
-10000
 20
-16 -23 29 44 -40 -50 -41 34 -38 30 -12 28 -44 -49 15 50 -28 38 -2 0

702.333333333333712
 10000.000000000016371
 0.000000000000000
 113.875000000000043

#include <bits/stdc++.h>
using namespace std;
double a[212345], x[212345], a0, a1;
int n;
void gao(double &res) {
  double sum = 0;
  for (int i = 0; i < int(n); ++i) {
    sum += x[i];
    if (sum < 0) sum = 0;
    res = max(res, sum);
  }
}
int main() {
  scanf("%d", &n);
  double L, R;
  for (int i = 0; i < int(n); ++i) scanf("%lf", a + i);
  L = -1e4, R = 0;
  for (int tt = 0; tt < int(50); ++tt) {
    double M = L + (R - L) / 2.0;
    for (int i = 0; i < int(n); ++i) x[i] = a[i] + M;
    a0 = a1 = 0;
    gao(a0);
    for (int i = 0; i < int(n); ++i) x[i] = -x[i];
    gao(a1);
    if (a0 > a1)
      R = M;
    else
      L = M;
  }
  double ans = max(a0, a1);
  printf("%.10lf\n", ans);
}
