删除链表中重复的结点

 1 class Solution {
 2 public:
 3     ListNode* deleteDuplication(ListNode* pHead)
 4     {
 5      if(pHead == NULL || pHead->next == NULL)
 6          return pHead;
 7      ListNode *head = NULL, *pb = pHead, *pe = pHead->next, *pre = head;
 8      while(pb && pe)
 9          {
10          while(pe && pb->val == pe->val)
11              {
12               pe = pe->next;
13               if(!pe)
14                   {
15                   if(pre)
16                   pre->next = NULL;
17                   return head;
18               }
19               else if(pb->val != pe->val)
20                   {
21                      pb = pe;
22                      pe = pe->next;
23                    //  if(!pe)
24                       //   return head;
25                   }
26              }
27            if(pre != NULL)
28                {
29                 pre->next = pb;
30                 pre = pb;
31                 pb = pe;
32                 if(pe)
33                 pe =pe->next;
34                }
35          else 
36          {
37              head = pb;
38              pre = head;
39              pb = pe;
40              if(pe)
41              pe = pe->next;
42              
43          }
44          
45          }
46         return head;
47     }
48 };