template <int Dim>
double KDTree<Dim>::dist(const Point<Dim>& a, const Point<Dim>& b) const
{
    /**
     * @todo Implement this function!
     */
     double pa = 0;
     for(int i = 0; i < Dim; i++){
       pa+=((a[i] - b[i])*(a[i] - b[i]));
     }
     return pa;
}