#include <memory>
#include <iostream>
#include <chrono>
#include <thread>
using namespace std;

struct ListNode{
	int val;
	shared_ptr<ListNode> next;
};

bool InsertNode(shared_ptr<ListNode>& insertPos,int val)
{
	shared_ptr<ListNode> node(new ListNode);
	if (!node)
		return false;
	node->val = val;
	node->next = NULL;
	insertPos->next = node;
	insertPos = node;

	return true;
}

bool  InitLinkList(shared_ptr<ListNode>& head)
{
	if ( (!head) || NULL != head->next )
		return false;

	head->val = 1;
	shared_ptr<ListNode> tail = head;

	InsertNode(tail, 1);
	InsertNode(tail, 2);
	InsertNode(tail, 3);
	InsertNode(tail, 3);


	return true;
}

void CoutLinkList(const shared_ptr<ListNode>& head)
{
	for (shared_ptr<ListNode> node = head;
		node; node = node->next)
	{
		cout << node->val << " ";
	}
	cout << endl;
}

shared_ptr<ListNode>  removeDuplicates(shared_ptr<ListNode>& head)
{
	if (head == NULL)
	{
		return NULL;
	}

	shared_ptr<ListNode> node = head;
	while(node->next != NULL){
		if(node->val == node->next->val){
			shared_ptr<ListNode> tmp = node->next;
			node->next = node->next->next;
		}else
		{
			node = node->next;
		}
	}
	return head;
}




int main()
{
	shared_ptr<ListNode> head(new ListNode);
	InitLinkList(head);

	CoutLinkList(head);

	head = removeDuplicates(head);

	CoutLinkList(head);

    return 0;
}