/**
* struct ListNode {
* int val;
* struct ListNode *next;
* ListNode(int x): val(x), next(nullptr) {};
* };
*/
class Solution {
public:
/**
*
* @param head ListNode类
* @return ListNode类
*/
ListNode* deleteDuplicates(ListNode* head) {
// write code here
ListNode* slow = head;
ListNode* fast = head;
while(fast != nullptr){
while(fast != nullptr && fast->val == slow->val){
fast = fast->next;
}
slow->next = fast;
slow = fast;
}
return head;
}
};