LeetCode: Remove Duplicates from Sorted List II

忘了边界条件，少数次过

 1 /**

 2  * Definition for singly-linked list.

 3  * struct ListNode {

 4  *     int val;

 5  *     ListNode *next;

 6  *     ListNode(int x) : val(x), next(NULL) {}

 7  * };

 8  */

 9 class Solution {

10 public:

11     ListNode *deleteDuplicates(ListNode *head) {

12         // Start typing your C/C++ solution below

13         // DO NOT write int main() function

14         if (!head) return NULL;

15         ListNode *pre = new ListNode(head->val-1);

16         pre->next = head;

17         ListNode *cur = pre;

18         while (cur) {

19             ListNode *p = cur->next;

20             bool dup = false;

21             while (p && p->next && p->val == p->next->val) {

22                 dup = true;

23                 p->next = p->next->next;

24             }

25             if (dup) cur->next = p->next;

26             else cur = cur->next;

27         }

28         return pre->next;

29     }

30 };

 C#

 1 /**

 2  * Definition for singly-linked list.

 3  * public class ListNode {

 4  *     public int val;

 5  *     public ListNode next;

 6  *     public ListNode(int x) { val = x; }

 7  * }

 8  */

 9 public class Solution {

10     public ListNode DeleteDuplicates(ListNode head) {

11         if (head == null) return null;

12         ListNode pre = new ListNode(head.val-1);

13         pre.next = head;

14         ListNode cur = pre;

15         while (cur != null) {

16             ListNode p = cur.next;

17             bool dup = false;

18             while (p != null && p.next != null && p.val == p.next.val) {

19                 dup = true;

20                 p.next = p.next.next;

21             }

22             if (dup) cur.next = p.next;

23             else cur = cur.next;

24         }

25         return pre.next;

26     }

27 }

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