连接两个排序的单链表

牛客中的代码是这样的：

struct ListNode {
	int val;
	struct ListNode *next;
	ListNode(int x) :
		val(x), next(NULL) {
	}
};

	ListNode* Merge(ListNode* pHead1, ListNode* pHead2)
	{
		if (pHead1 == NULL && pHead2 == NULL)
		{
			return NULL;
		}
		if (pHead1 == NULL || pHead2 == NULL)
		{
			return pHead1 == NULL ? pHead2 : pHead1;
		}

		ListNode* ppHead1 = pHead1;
		ListNode* ppHead2 = pHead2;

		ListNode* newHead = new ListNode(0);
		ListNode* cur = newHead;


		while (ppHead1 && ppHead2)
		{
			if (ppHead1->val < ppHead2->val)
			{
				cur->next = ppHead1;
				ppHead1 = ppHead1->next;
			}
			else
			{
				cur->next = ppHead2;
				ppHead2 = ppHead2->next;
			}
			cur = cur->next;
		}

		if (ppHead1 == NULL)
		{
			cur->next = ppHead2;
		}

		if (ppHead2 == NULL)
		{
			cur->next = ppHead1;
		}
		return newHead->next;
	}

vs中的代码是这样的：

#pragma once
#include<assert.h>
#include<iostream>
using namespace std;

typedef int DataType;

//结构体 链表
typedef struct ListNode
{
	DataType data;
	struct ListNode *next;
}ListNode;

//初始化链表
void InitList(ListNode** pHead)
{
	*pHead = NULL;
}

//插入节点//尾插法
void Insert(ListNode*& pHead, DataType x)
{
	if (pHead == NULL)
	{
		pHead = new ListNode[sizeof(ListNode)];
		pHead->data = x;
		pHead->next = NULL;
	}
	else
	{
		ListNode* tial = pHead;
		ListNode* pos = new ListNode[sizeof(ListNode)];

		while (tial->next != NULL)
		{
			tial = tial->next;
		}
		pos->data = x;
		tial->next = pos;
		pos->next = NULL;
	}
}

//遍历单链表
void PrintList(ListNode* pHead)
{
	ListNode* cur = pHead;
	assert(pHead);
	while (cur)
	{
		cout << cur->data << "->";
		cur = cur->next;
	}
	cout << "NULL" << endl;
}

//翻转单链表
ListNode* Revers(ListNode* pHead)
{
	ListNode* newhead = NULL;
	ListNode* cur = pHead;
	while (cur)
	{

		ListNode* tmp = cur;
		cur = cur->next;
		tmp->next = newhead;
		newhead = tmp;
	}
	return newhead;
}

//合并两个单链表
ListNode* Merge(ListNode*& pHead1, ListNode*& pHead2)
{
	if (pHead1 == NULL && pHead2 == NULL)
	{
		return NULL;
	}
	if (pHead1 == NULL || pHead2 == NULL)
	{
		return pHead1 == NULL ? pHead2 : pHead1;
	}

	ListNode* ppHead1 = pHead1;
	ListNode* ppHead2 = pHead2;

	ListNode* newHead = new ListNode[sizeof(ListNode)];
	ListNode* cur = newHead;


	while (ppHead1 && ppHead2)
	{
		if (ppHead1->data < ppHead2->data)
		{
			cur->next = ppHead1;
			ppHead1 = ppHead1->next;
		}
		else
		{
			cur->next = ppHead2;
			ppHead2 = ppHead2->next;
		}
		cur = cur->next;
	}

	if (ppHead1 == NULL)
	{
		cur->next = ppHead2;
	}

	if (ppHead2 == NULL)
	{
		cur->next = ppHead1;
	}
	return newHead->next;
}

两个唯一的不同是在那个新链表的表头，重新申请的空间，牛客中的初始化一定要看结构体中是如何说的，很明显，按牛客给出的结构体中，对于节点的初始化时需要显式调用构造函数，而vS中的是人为初始化，这就是，用这种方法，牛客编译不通过的唯一原因