19.2.21 [LeetCode 82] Remove Duplicates from Sorted List II

Given a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list.

Example 1:

Input: 1->2->3->3->4->4->5
Output: 1->2->5

Example 2:

Input: 1->1->1->2->3
Output: 2->3

题意

如果链表中有一个数重复了，去掉所有这个数

题解

 1 class Solution {
 2 public:
 3     ListNode* deleteDuplicates(ListNode* head) {
 4         ListNode*last = head, *p = head, *ans = new ListNode(0), *now = ans;
 5         if (!p||p->next==NULL)return head;
 6         p = p->next;
 7         bool flag = false;
 8         while (p) {
 9             if (last->val != p->val) {
10                 if (flag == false) {
11                     now->next = last; now = now->next;
12                     last = p, p = p->next;
13                 }
14                 else
15                     last = last->next, p = p->next;
16                 flag = false;
17             }
18             else {
19                 flag = true;
20                 last = last->next, p = p->next;
21             }
22         }
23         if(flag)
24             now->next = NULL;
25         else now->next = last;
26         return ans->next;
27     }
28 };
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posted @ 2019-02-21 19:58  TobicYAL  阅读(162)  评论(0)  编辑  收藏  举报