#include <bits/stdc++.h>   using namespace std;   int n, a[200001];   const double esl = 1e-11;   double cal(double x) {     double t = 0;     double ans = 0;     for (int i = 1; i <= n; i++) {       if (t + a[i] - x < 0) {         ans = max(ans, t);         t = 0;       } else {         t += ((double)a[i] - x);         ans = max(ans, t);       }     }     ans = max(ans, t);     double t1 = 0;     for (int i = 1; i <= n; i++) {       if (t1 + a[i] - x > 0) {         ans = max(ans, -t1);         t1 = 0;       } else {         t1 += ((double)a[i] - x);         ans = max(ans, -t1);       }     }     ans = max(ans, -t1);     return ans;   }   int main() {     scanf( %d , &n);     for (int i = 1; i <= n; i++) {       scanf( %d , &a[i]);     }     double l = -(1e5);     double r = 1e5;     for (int i = 1; i <= 500; i++) {       double d = (2.0 * l + r) / 3;       double c = (2.0 * r + l) / 3;       if (cal(d) > cal(c)) {         l = d;       } else         r = c;     }     printf( %.10f , cal(l));     return 0;   }   