leetcode-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.

For example,

Given 

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

, return 

1->2->5

.

Given 

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

, return 

2->3

.

/**
* 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) {
if(head == NULL)return NULL;
if(head->next == NULL)return head;
ListNode *temp = head;
bool del = false;
while(temp->val == temp->next->val)
{
while(temp->val == temp->next->val)
{
temp = temp->next;
if(temp->next == NULL)break;
}
temp = temp->next;
if((temp == NULL)||(temp->next == NULL))break;
}
head = temp;
ListNode *temp1;
while((temp)&&(temp->next))
{
if(temp->val != temp->next->val)temp1 = temp;
while(temp->val == temp->next->val)
{
temp = temp->next;
if(temp->next == NULL)break;
}
temp = temp->next;
temp1->next = temp;
}
return head;
}
};