execute_cm_ordering Subroutine

    subroutine execute_cm_ordering(start_node, node_adj, degree, visited, Q, R, R_count)
        implicit none
        integer(int32), intent(in) :: start_node
        class(type_node_adjacency), intent(in) :: node_adj
        integer(int32), intent(in) :: degree(:)
        logical, intent(inout) :: visited(:)
        integer(int32), intent(inout) :: Q(:), R(:), R_count
        integer(int32) :: q_head, q_tail, current_node

        q_head = 1
        q_tail = 1
        Q(1) = start_node
        visited(start_node) = .true.
        do while (q_head <= q_tail)
            current_node = Q(q_head)
            q_head = q_head + 1
            R_count = R_count + 1
            R(R_count) = current_node
            call sort_and_enqueue_neighbors(current_node, node_adj, degree, visited, Q, q_tail)
        end do
    end subroutine execute_cm_ordering