Leetcode-Remove Duplicates from Sorted List II（二级指针）

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

Given 

1->2->3->3->4->4->5

, return 

1->2->5

.

Given 

1->1->1->2->3

, return 

2->3

.

Seen this question in a real interview before?   

Yes
 

/**
* Definition for singly-linked list.
* struct ListNode {
* int val;
* ListNode *next;
* ListNode(int x) : val(x), next(NULL) {}
* };
*/
class Solution {
public:
ListNode *deleteDuplicates(ListNode *head) {
ListNode **runner = &head;

if(!head || !head->next)return head;

while(*runner)
{
if((*runner)->next && (*runner)->next->val == (*runner)->val)
{
ListNode *temp = *runner;
while(temp && (*runner)->val == temp->val)
temp = temp->next;

*runner = temp;
}
else
runner = &((*runner)->next);
}

return head;
}
};