算法（20）-merge不去重-链表-C++

merge单链表。

例如：head1:0->2->3->7
           list2:1->3->5->7->9
结果：0->1->2->3->3->5->7->7->9
 

class Node
{
public:
	int m_value;
	Node* next;
	Node(int value);

};
Node::Node(int value)
{
	m_value = value;
}


Node* mergetwoLists(Node* head1, Node* head2)
{
	if(head1==NULL||head2==NULL)
	{
		return head1 != NULL ? head1 : head2;//如果head1不为空，则返回head1,否则返回head2
	}
	Node* head=head1->m_value< head2->m_value?head1:head2;//head1 head2 谁小取谁
	//cur1是head 值  小的值
	Node* cur1= (head==head1?head1:head2);
	Node* cur2= (head == head1 ? head2: head1);
	Node* pre=NULL;//两个较小的那个
	Node* next = NULL;
	while (cur1 != NULL && cur2 != NULL)
	{
		if (cur1->m_value <= cur2->m_value)//链表1值小
		{
			pre = cur1;
			cur1 = cur1->next;
		}
		else//链表2值小
		{
			next = cur2->next;//保存一下2的下一个点
			pre->next = cur2; //2到1中
			cur2->next = cur1;
			pre = cur2;       //当前指针后移
			cur2 = next;     //2指针后移
		}
	}
	  pre->next = cur1 == NULL ? cur2 : cur1;//最后一个节点是cur2或者1
		return head;
}
void printLinkedList(Node* head)
{
	while (head != nullptr)
	{
		cout << "head.value= " << head->m_value << endl;
		head = head->next;
	}

}
 void main()
{

    Node* pnode11 = new Node(0);
	Node* pnode12 = new Node(2);
	Node* pnode13 = new Node(3);
	Node* pnode14 = new Node(7);
	pnode11->next = pnode12;
	pnode11->next->next = pnode13;
	pnode11->next->next->next = pnode14;

	Node* pnode21 = new Node(1);
	Node* pnode22 = new Node(3);
	Node* pnode23 = new Node(5);
	Node* pnode24 = new Node(7);
	Node* pnode25 = new Node(9);
	pnode21->next = pnode22;
	pnode21->next->next = pnode23;
	pnode21->next->next->next = pnode24;
	pnode21->next->next->next->next = pnode25;
	cout << "pnode1 *************" << endl;
	printLinkedList(pnode11);
	cout << "pnode1 *************" << endl;
	printLinkedList(pnode21);

	Node* rcptwo = mergetwoLists(pnode11, pnode21);
	cout << "merge *************" << endl;
	printLinkedList(rcptwo);

}