合并两个有序的链表

      记得以前写过一个合并两个有序数组的问题，也就是相互比较并放入合适的位置，今天的这个算法和数组的问题其实是一样的，这里不多做介绍了，直接贴出代码：

链表的定义：

typedef struct _Node
{
	int data;
	struct _Node *next;
}Node, *List;

首先给出非递归版本的：

合并代码：

List merge_two_list(List list1, List list2)
{
	List new_list = NULL;
	Node *temp = NULL;
	
	if (list1 == NULL)
		return list2;
	if (list2 == NULL)
		return list1;
	if (list1 -> data <= list2 -> data)
	{
		new_list = list1;
		list1 = list1 -> next;
	}
	else
	{
		new_list = list2;
		list2 = list2 -> next;
	}
	temp = new_list;
	while (list1 != NULL && list2 != NULL)
	{
		if (list1 -> data <= list2 -> data)
		{
			temp -> next = list1;
			temp = list1;
			list1 = list1 -> next;
		}
		else
		{
			temp -> next = list2;
			temp = list2;
			list2 = list2 -> next;
		}
	}
	if (list1 != NULL)
		temp -> next = list1;
	if (list2 != NULL)
		temp -> next = list2;
	return new_list;
}	

递归版本的代码：

List merge_two_list_2(List list1, List list2)
{
	List new_list = NULL;
	if (list1 == NULL)
		return list2;
	if (list2 == NULL)
		return list1;
	if (list1 -> data <= list2 -> data)
	{
		new_list = list1;
		new_list -> next = merge_two_list_2(list1 -> next, list2);
	}
	else
	{
		new_list = list2;
		new_list -> next = merge_two_list_2(list1, list2 -> next);
	}
	return new_list;
}

打印链表节点：

void print(List list_head)
{
	Node *temp = NULL;
	if (list_head == NULL)
		return;
	temp = list_head;
	while (temp != NULL)
	{
		printf("%d  ", temp -> data);
		temp = temp -> next;
	}
}