单链表的反转

　　public ListNode reverse(ListNode head)
	{
		if(head == null || head.next == null)
		{
			return head;
		}
		ListNode pPre = head;
		ListNode pCurr = head.next;
		ListNode pNext = null;
		head.next = null;
		while(pCurr != null)
		{
			pNext = pCurr.next;
			pCurr.next = pPre;
			pPre = pCurr;
			pCurr = pNext;
		}
		return pPre;
	}