#include <bits/stdc++.h>   using namespace std;   const int N = 2e5 + 7;   int a[N], n;   double f(double x) {     double sum = 0, mn = 0, mx = 0, ans = 0;     for (int i = 0; i < n; i++) {       mn = min(mn, sum);       mx = max(mx, sum);       sum += a[i] - x;       ans = max(ans, abs(sum - mn));       ans = max(ans, abs(sum - mx));     }     return ans;   }   int main() {     ios::sync_with_stdio(0);     cin.tie(0);     cout.tie(0);     cin >> n;     for (int i = 0; i < n; i++) cin >> a[i];     double l = -1e4 - 7, r = 1e4 + 7;     int t = 230;     while (t--) {       double mid1 = (2 * r + l) / 3;       double mid2 = (2 * l + r) / 3;       if (f(mid1) < f(mid2))         l = mid2;       else         r = mid1;     }     cout << setprecision(9) << fixed << f(l) << endl;     return 0;   }   