#include <bits/stdc++.h>
using namespace std;
long long gcd(long long a, long long b) { return b ? gcd(b, a % b) : a; }
long long lcm(long long a, long long b) { return a / gcd(a, b) * b; }
long long powmod(long long a, long long b, long long MOD) {
  if (a == 0ll) {
    return 0ll;
  }
  a %= MOD;
  long long ans = 1;
  while (b) {
    if (b & 1) {
      ans = ans * a % MOD;
    }
    a = a * a % MOD;
    b >>= 1;
  }
  return ans;
}
long long poww(long long a, long long b) {
  if (a == 0ll) {
    return 0ll;
  }
  long long ans = 1;
  while (b) {
    if (b & 1) {
      ans = ans * a;
    }
    a = a * a;
    b >>= 1;
  }
  return ans;
}
void Pv(const vector<int> &V) {
  int Len = int(V.size());
  for (int i = 0; i < Len; ++i) {
    printf("%d", V[i]);
    if (i != Len - 1) {
      printf(" ");
    } else {
      printf("\n");
    }
  }
}
void Pvl(const vector<long long> &V) {
  int Len = int(V.size());
  for (int i = 0; i < Len; ++i) {
    printf("%lld", V[i]);
    if (i != Len - 1) {
      printf(" ");
    } else {
      printf("\n");
    }
  }
}
inline long long readll() {
  long long tmp = 0, fh = 1;
  char c = getchar();
  while (c < '0' || c > '9') {
    if (c == '-') fh = -1;
    c = getchar();
  }
  while (c >= '0' && c <= '9') tmp = tmp * 10 + c - 48, c = getchar();
  return tmp * fh;
}
inline int readint() {
  int tmp = 0, fh = 1;
  char c = getchar();
  while (c < '0' || c > '9') {
    if (c == '-') fh = -1;
    c = getchar();
  }
  while (c >= '0' && c <= '9') tmp = tmp * 10 + c - 48, c = getchar();
  return tmp * fh;
}
const int maxn = 1000010;
const int inf = 0x3f3f3f3f;
int n;
int a[maxn];
double b[maxn];
double getv(double x) {
  for (int i = 1; i <= n; i++) {
    b[i] = a[i] - x;
  }
  double res = 0;
  double sum = 0;
  for (int i = 1; i <= n; i++) {
    sum += b[i];
    res = max(res, sum);
    if (sum < 0) sum = 0;
  }
  sum = 0;
  for (int i = 1; i <= n; i++) {
    b[i] *= -1;
  }
  for (int i = 1; i <= n; i++) {
    sum += b[i];
    res = max(res, sum);
    if (sum < 0) sum = 0;
  }
  return res;
}
int main() {
  n = readint();
  for (int i = 1; i <= n; i++) {
    a[i] = readint();
  }
  double low = *min_element(a + 1, a + 1 + n);
  double high = *max_element(a + 1, a + 1 + n);
  for (int rp = 1; rp <= 80; rp++) {
    double lmid = (low + low + high) / 3.000000;
    double rmid = (low + high + high) / 3.000000;
    double mv = getv(lmid);
    double mmv = getv(rmid);
    if (mv > mmv) {
      low = lmid;
    } else {
      high = rmid;
    }
  }
  printf("%.6f\n", min(getv(low), getv(high)));
  return 0;
}
