單鏈表的合併，排序與翻轉

1.單鏈表的合併：

　　合併兩個有序（從小到大）鏈表，首先比較兩鏈表第一個結點值的大小，將小的放入新的鏈表（創建的臨時鏈表）；然後將小的那條鏈表向後移動一個位置，重複比較。當然，在進行這些處理之前，先處理空鏈表的情況。

２.單鏈表的排序：

　　這裏排序方式採用之前熟悉的冒泡排序。

３.單鏈表的翻轉：

　　對翻轉的要求：遍歷一次。這裏需要三個指針一個指向當前結點，一個指向下一個結點，一個保存翻轉後的鏈表。邏輯代碼裏有註釋。代碼如下

//鏈表的合併，Merge爲遞歸法，Merge2爲非遞歸法
pList Merge(pList l1, pList l2)
{
	pList list1 = l1;
	pList list2 = l2;
	pList newlist = NULL;
	if (list1 == NULL )
		return list2;
	if (list2 == NULL)
		return list1;
	if ((list1->data) < (list2->data))
	{
		newlist = list1;
		newlist->next = Merge(list1->next, list2);
	}
	if ((list1->data) > (list2->data))
	{
		newlist = list2;
		newlist->next = Merge(list1, list2->next);
	}
	return newlist;
}
void Merge2Logic(pList *newlist, pList *list, pList *tmpnode)
{
	if (newlist == NULL)
	{
		newlist = *list;
		*list = (*list)->next;
		*tmpnode = newlist;
	}
	else
	{
		(*tmpnode)->next = *list;
		*list = (*list)->next;
		*tmpnode = (*tmpnode)->next;
	}
}
pList Merge2(pList l1, pList l2)
{
	pList list1 = l1;
	pList list2 = l2;
	pNode tmpnode = NULL;
	pList newlist = NULL;
	if (list1 == NULL)
		return list2;
	if (list2 == NULL)
		return list1;
	while (list1 != NULL && list2 != NULL)
	{
		if (list1->data >= list2->data)
		{
			Merge2Logic(&newlist, &list2, &tmpnode);
		}
		else if (list1->data < list2->data)
		{
			Merge2Logic(&newlist, &list1, &tmpnode);
		}
	}
	if (list1 == NULL)
		tmpnode->next = list2;
	if (list2 == NULL)
		tmpnode->next = list1;
	return newlist;
}

排序代碼

void BubbleSort(pList *pplist)
{
	pNode tail = *pplist;
	pNode cur = NULL;
	int tmp = 0;
	if ((*pplist) == NULL || (*pplist)->next == NULL)
		return;
	while (tail->next != NULL)
	{
		cur = *pplist;
		while ((cur->data) > (cur->next->data))
		{
			tmp = cur->data;
			cur->data = cur->next->data;
			cur->next->data = tmp;
			cur = cur->next;
			if (cur->next == NULL)
			{
				break;
			}
		}
		tail = tail->next;
	}
}

翻轉代碼

void ReverseList(pList *pplist)
{
	assert(pplist);
	pNode cur = *pplist;
	pNode tmp = cur;
	pList newlist = NULL;
	if((*pplist) == NULL || (*pplist)->next == NULL)
		return;
	while(cur)
	{
		tmp = cur;
		cur = cur->next;
		tmp->next = newlist;
		newlist = tmp;
	}
	*pplist = newlist;
}