#include <stdio.h>
#include <stdlib.h>

typedef  struct node
{
	struct node * Llink;
	int data;
	struct node * Rlink;

} DLinklist;

void * Getnode()
{
	DLinklist * tmp;
	tmp = (DLinklist*)malloc(sizeof(DLinklist));
	tmp->Llink = NULL;
	tmp->Rlink = NULL;
	return tmp;
}

void Insert(DLinklist**head, int data)
{
	if (!*head)
	{
		*head = Getnode();
		(*head)->data = data;
		return;
	}
	Insert(&(*head)->Rlink, data);
	(*head)->Rlink->Llink = *head;
}

void Output(DLinklist**head)
{
	if (*head)
	{
		printf("%d ", (*head)->data);
		Output(&(*head)->Rlink);
	}
}

void Add(DLinklist**head, int data1, int data2)
{
	DLinklist * tmp=NULL;
	if ((*head)->data == data1)
	{
		Insert(&tmp, data2);
		tmp->Llink = *head;
		tmp->Rlink = (*head)->Rlink;
		(*head)->Rlink->Llink = tmp;
		(*head)->Rlink = tmp;

		return;
	}
	else
	Add(&(*head)->Rlink, data1, data2);
}

void Delete(DLinklist **head, int data)
{
	DLinklist *tmp = NULL;
	if ((*head)->data == data)
	{
		tmp = *head;
		if ((*head)->Rlink == NULL)	// 마지막 노드
			*head = NULL;
		else
		{
			*head = (*head)->Rlink;
			(*head)->Llink = (*head)->Llink->Llink;
		}
		free(tmp);
	}
	else
		Delete(&(*head)->Rlink, data);

}


int main()
{
	DLinklist * head = NULL;

	Insert(&head, 10);
	Insert(&head, 20);
	Insert(&head, 30);

	//Add(&head, 10, 15);
	Output(&head);
	Delete(&head, 20);


}