反转链表

 1 struct  ListNode
 2 {
 3     int val;
 4     ListNode *next;
 5 };
 6 
 7 ListNode* ReverseList(ListNode *pHead)
 8 {
 9     ListNode *pReversedHead = NULL;
10     ListNode *pNode = pHead;
11     ListNode *pPrev=NULL;
12 
13     while(pNode!=NULL)
14     {
15         ListNode* pNext=pNode->next;
16 
17         if(pNext==NULL)
18             pReversedHead=pNode;
19 
20         pNode->next=pPrev;
21 
22         pPrev=pNode;
23         pNode=pNext;
24     }
25 
26     return pReversedHead;
27 }