#include <stdio.h>

BOOL Insert_Last(List *ls, Data data)
{
	if (NULL == ls)
		return ERROR;
	
	Node *node = (Node *)malloc(sizeof(Node)/sizeof(char));
	if (NULL == node)
		return ERROR;
	
	node->data = data;
	node->next = NULL;
	
	Node *tmp = ls->head;         // 頭結點
	while (tmp->next)
	{
		tmp = tmp->next;
	}
	
	tmp->next = node;
	
	return TRUE;
}

void Display(List *ls)
{
	if (NULL == ls)
		return;
	
	Node *tmp = ls->head->next;   // 第一個結點
	while (tmp)
	{
		printf ("%-4d", tmp->data);
		tmp = tmp->next;
	}
	printf ("\n");	
}

List *CreateList()//建立連結串列
{
	List *ls = (List*)malloc(sizeof(List)/sizeof(char));
	if (NULL == ls)
		return NULL;
	
	// 建立頭結點
	ls->head = (Node*)malloc(sizeof(Node)/sizeof(char));
	if(NULL == ls->head)
	{
		free(ls);
		return NULL;
	}
	
	ls->head->next = NULL;   // 空連結串列
	
	return ls;
}

int OverLap(List *ls1 , List *ls2)//找兩個連結串列重合的點
{
	if(NULL == ls1 || NULL == ls2)
		return;
	
	Node *tmp1 = ls1->head;
	Node *tmp2 = ls2->head;
	Node *tmp = ls2->head;
	int pos1 = 1;
	int pos2 = 1;
	
	while(tmp1->next)
	{
		
		tmp1 = tmp1->next;  //第一遍指向ls1的第一個結點
		//printf("tmp1 = %d\n",tmp1->data);	
		
		while(tmp2->next)
		{
			if(tmp1->data == tmp2->next->data)
				return pos1;
			pos2++;
			tmp2 = tmp2->next;
			//printf("pos2 = %d\n",pos2);	
		}
		tmp2 = tmp;
		pos2 = 1;
		pos1++;
		
	}
	
	
	return pos1;
}

int Find_K(List *ls , int k)//找一個不知長度的連結串列的倒數第K個點
{
	if(NULL == ls)
		return;
	
	int i , count = 0;
	Node *tmp1 = ls->head;
	Node *tmp2 = ls->head;
	
	for(i = 0; i < k; i++)
	{
		tmp1 = tmp1->next;
	}
	
	while(tmp1->next)
	{
		tmp1 = tmp1->next;
		tmp2 = tmp2->next;
		count++;
	}
	
	return count;	
}

int main()
{
	List *ls1 = CreateList();
	List *ls2 = CreateList();
	if (NULL == ls1 || NULL == ls2)
	{
		printf ("建立失敗\n");
	}
	printf ("建立成功\n");
	
	int i;
	for (i = 0; i < 10; i++)
	{

		Insert_Last(ls1, i);
	}
	Display(ls1);
	printf("----------------\n");
	
	Insert_Last(ls2, 3);
	Insert_Last(ls2, 4);
	Insert_Last(ls2, 7);
	Insert_Last(ls2, 11);
	Insert_Last(ls2, 12);
	Display(ls2);
	printf("----------------\n");
	
	int a;
	a = OverLap(ls1 , ls2);
	printf("在連結串列ls1的第 %d 個位置重合\n", a);
	
	a = Find_K(ls1 , 2);
	printf("倒數第K個數是 %d \n", a);
	
	return 0;
}