#include <bits/stdc++.h>   using namespace std;   double cal(int n, int *a, double x) {     double ret = 0, t1 = 0, t2 = 0;     for (int i = 0; i < n; i++) {       t1 += a[i] - x;       t2 += a[i] - x;       t1 = max(0., t1);       t2 = min(0., t2);       ret = max(ret, t1);       ret = max(ret, -t2);     }     return ret;   }   int main() {     int n;     scanf( %d , &n);     static int a[200000];     for (int i = 0; i < n; i++) {       scanf( %d , a + i);     }     double l = -10001, r = 10001, ans;     for (int t = 0; t < 100; t++) {       double d1 = (2 * l + r) / 3, d2 = (l + 2 * r) / 3;       double e1 = cal(n, a, d1), e2 = cal(n, a, d2);       if (e1 <= e2) {         r = d2;         ans = e1;       } else {         l = d1;         ans = e2;       }     }     printf( %.9lf n , ans);     return 0;   }   