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leetcode - Remove Duplicates from Sorted List II

2013-11-27 08:38  张汉生  阅读(166)  评论(0)    收藏  举报

 

 1 class Solution {
 2 public:
 3     ListNode *deleteDuplicates(ListNode *head) {
 4         // IMPORTANT: Please reset any member data you declared, as
 5         // the same Solution instance will be reused for each test case.
 6         if (head==NULL)
 7         return head;
 8     ListNode * curHead = head, *curTail = head, *lastTail=NULL;
 9     ListNode * itr = head->next;
10     while (itr!=NULL){
11         ListNode * nextNode = itr->next;
12         if (itr->val == curTail->val)
13         curTail = curTail->next;
14         else{
15         if (curHead!=curTail){
16             if (curHead==head){
17             head = itr;
18             }
19             else lastTail->next = itr;
20         }
21         else lastTail = curTail;
22         curHead = curTail = itr;
23         }
24         itr = nextNode;
25     }
26     if (curHead != curTail){
27         if (curHead == head)
28         return NULL;
29         else lastTail->next = NULL;
30     }
31     return head;
32     }
33 };