用O(1)的时间复杂度删除单链表中的某个节点

 1 /* Delete a node in a list with O(1)
 2  * input:    pListHead - the head of list
 3  *            pToBeDeleted - the node to be deleted
 4  */
 5 
 6 struct  ListNode  
 7 {
 8     int            m_nKey;
 9     ListNode*    m_pNext;
10 };
11 
12 void DeleteNode(ListNode *pListHead, ListNode *pToBeDeleted)
13 {
14     if (!pListHead || !pToBeDeleted)
15         return;
16     
17     if (pToBeDeleted->m_pNext != NULL) { 
18         ListNode *pNext = pToBeDeleted->m_pNext;
19         pToBeDeleted->m_pNext = pNext->m_pNext;
20         pToBeDeleted->m_nKey = pNext->m_nKey;
21 
22         delete pNext;
23         pNext = NULL;
24     }
25     else { //待删除节点为尾节点
26         ListNode *pTemp = pListHead;
27         while(pTemp->m_pNext != pToBeDeleted) 
28             pTemp = pTemp->m_pNext;
29         pTemp->m_pNext = NULL;
30 
31         delete pToBeDeleted;
32         pToBeDeleted = NULL;
33     }
34 }