递归实现合并两个有序链表成一个链表依然有序

Node * MergeRecursive(Node *head1 , Node *head2) {     if ( head1 == NULL )         return head2 ;     if ( head2 == NULL)         return head1 ;     Node *head = NULL ;     if ( head1->data < head2->data )    {        head = head1 ;        head->next = MergeRecursive(head1->next,head2);    }    else    {       head = head2 ;       head->next = MergeRecursive(head1,head2->next);    }    return head ; }