LeetCode 题解之Remove Duplicates from Sorted List II

1、题目描述

2、题目分析

链表的题，主要注意指针即可。

3、代码

 1  ListNode* deleteDuplicates(ListNode* head) {
 2         if (head == NULL || head->next == NULL)
 3             return head;
 4         
 5         ListNode *dummy = new ListNode(0);
 6         dummy->next = head;
 7         ListNode *p = head;
 8         ListNode *pre = dummy;
 9         
10         while (p != NULL) {
11             ListNode *tmp = p->next;
12             if (tmp == NULL)
13                 break;
14             while (tmp->val == p->val) {
15                 tmp = tmp->next;
16                 if (tmp == NULL) {
17                     pre->next = NULL;
18                     break;
19                 }
20             }
21                 
22             if (p->next == tmp) {
23                 pre = p;
24             }else {
25                 pre->next = tmp;
26             }
27             p = tmp;
28                 
29         }
30         return dummy->next;
31         
32     }