Reorder List

Given a singly linked list L: L₀→L₁→…→L_n-1→L_n,
reorder it to: L₀→L_n→L₁→L_n-1→L₂→L_n-2→…

You must do this in-place without altering the nodes' values.

For example,
Given {1,2,3,4}, reorder it to {1,4,2,3}.

#include 

struct ListNode
{
	int val;
	ListNode* next;
	ListNode(int x) : val(x), next(0){}
};
ListNode* reverseList(ListNode* pList, ListNode* &head)
{
	if (0 == pList || 0 == pList->next)
	{
		head = pList;
		return pList;
	}

	ListNode* tmp = reverseList(pList->next, head);
	tmp->next = pList;
	pList->next = 0;
	return pList;

}
void reorderList(ListNode *head)
{
	if (0 == head || 0 == head->next) return;

	ListNode* slow = head;
	ListNode* fast = head;

	while(0 != fast->next && 0 != fast->next->next)
	{
		slow = slow->next;
		fast = fast->next->next;
	}

	ListNode* head2 = 0;
	ListNode* tail = reverseList(slow->next, head2);
	slow->next = 0;

	ListNode* dummy = (ListNode*)malloc(sizeof(ListNode));
	dummy->next = head;
	ListNode* dummybk = dummy;

	while(0 !=  head|| 0 != head2)
	{
		if (0 != head)
		{
			dummy->next = head;
			head = head->next;
			dummy = dummy->next;
		}
		if (0 != head2)
		{
			dummy->next = head2;
			head2 = head2->next;
			dummy = dummy->next;
		}
	}
	head = dummybk->next;
	delete dummybk;
}

int main(int argc, char* argv[])
{
	ListNode* head = (ListNode*)malloc(sizeof(ListNode));
	ListNode* tmp = head;
	head->val = 1;
	for (int i = 2; i < 8; i++)
	{
		ListNode* newNode = (ListNode*)malloc(sizeof(ListNode));
		newNode->val = i;
		newNode->next = 0;
		tmp->next = newNode;
		tmp = tmp->next;
	}
	
	reorderList(head);
	return 0;
}