双向链表的实现2

这里介绍冒泡排序在链表中的实现。

/*
*	bubble sort for bi-linked list;
*	flag > 0, oreder from little to large, < 0 from large to little;
*/

#if 1
int sort_lst(list *head, const int flag)
{
	if (head == NULL)
		return -1;
	
	list *p, *q;
	int value0, value1;

	printf("%s\n", __func__);

	struct timeval t1, t2;
	gettimeofday(&t1, NULL);

	for (p = head; p != NULL; p = p->next)
	{
		value0 = *((int *)(p->p_data));

		for (q = p->next; q != NULL; q = q->next)
		{
			value1 = *((int *)(q->p_data));

			if (flag >= 0)
			{
				if (value0 > value1)
				{
					value0 = value0 ^ value1;
					value1 = value1 ^ value0;
					value0 = value0 ^ value1;

					*((int *)(q->p_data)) = value1;
					*((int *)(p->p_data)) = value0;
				}
			}
			else
			{
				if (value0 < value1)
				{
					value0 = value0 ^ value1;
					value1 = value1 ^ value0;
					value0 = value0 ^ value1;

					*((int *)(q->p_data)) = value1;
					*((int *)(p->p_data)) = value0;
				}
			} 
		}
	}

	gettimeofday(&t2, NULL);	
	printf("spend: %ld us\n", 1000000*(t2.tv_sec - t1.tv_sec) + t2.tv_usec - t1.tv_usec);

	return 0;
}
#else
int sort_lst(list *head, const int flag)
{
	if (head == NULL)
		return -1;
	
	list *p, *q, *r = NULL;
	int value0, value1;
	int changed = 1;

	printf("%s\n", __func__);

	struct timeval t1, t2;
	gettimeofday(&t1, NULL);

	for (p = head; p != NULL && changed > 0; p = p->next)
	{
		changed = 0;
		value0 = *((int *)(p->p_data));

		for (q = p->next; q != NULL; q = q->next)
		{
			value1 = *((int *)(q->p_data));

			if (flag >= 0)
			{
				if (value0 > value1)
				{
					value0 = value0 ^ value1;
					value1 = value1 ^ value0;
					value0 = value0 ^ value1;

					*((int *)(q->p_data)) = value1;
					*((int *)(p->p_data)) = value0;
					
					r = q;
					changed = 1;
				}
			}
			else
			{
				if (value0 < value1)
				{
					value0 = value0 ^ value1;
					value1 = value1 ^ value0;
					value0 = value0 ^ value1;

					*((int *)(q->p_data)) = value1;
					*((int *)(p->p_data)) = value0;

					r = q;
					changed = 1;
				}
			} 
		}
	}

	gettimeofday(&t2, NULL);	
	printf("spend: %ld us\n", 1000000*(t2.tv_sec - t1.tv_sec) + t2.tv_usec - t1.tv_usec);

	return 0;
}
#endif 

这里第二种是优化的算法，经测试性能有所提升。

下一篇将进行链表的测试。