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

import java.util.Scanner;

public class E {
    static int n;
    static double[] a;

    public static void main(String[] args) {
        Scanner cin = new Scanner(System.in);

        n = cin.nextInt();
        a = new double[n];
        for (int i=0;i<n;i++) {
            a[i]=cin.nextDouble();
        }

        double left, right;
        left = -1e5;
        right = 1e5;
        for (int i = 0; i < 100; i++) {
            double x = (left + right) / 2;
            if (f(x) > f((x + right) / 2)) {
                left = x;
            } else {
                right = (x + right) / 2;
            }
        }

        System.out.println(f(right));

        cin.close();
    }

    private static double f(double x) {
        double ans = 0;
        double sum = 0;
        for (int i = 0; i < n; i++) {
            sum += a[i] - x;
            if (sum > ans) ans = sum;
            if (sum < 0) sum = 0;
        }

        sum = 0;
        for (int i = 0; i < n; i++) {
            sum -= a[i] - x;
            if (sum > ans) ans = sum;
            if (sum < 0) sum = 0;
        }
        return ans;
    }
}
