#include <iostream>
using namespace std;
int main()
{
    int n;
    double head,tail;
    cin>>n>>head>>tail;
    double * c =new double[n];
    int i=0;
    while(i!=n)
    {
        cin>>c[i];
        i++;
    }
    double csum=0;
    for(int j=0;j<n;j++)
    csum+=(n-j)*c[j];

    double a1;
    a1=(head+n*tail-2*csum)/(n+1);
    printf("%2.2f",a1);
    return 0;
}

my mistake,head and tail should be swapped!



Edited by author 09.10.2008 23:14