Given a sorted linked list, delete all duplicates such that each element appear only once.

Example 1:

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

Example 2:

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

class Solution {
public:
    ListNode* deleteDuplicates(ListNode* head) {
        ListNode* p=head;
        while(p&&p->next){
            if(p->next->val==p->val)
                p->next=p->next->next;
            else
                p=p->next;            
        }
        return head;
    }
};
 

一開始自己寫的垃圾程式碼

class Solution {
public:
    ListNode* deleteDuplicates(ListNode* head) {
        ListNode* p=head;
        while(p!=NULL&&p->next!=NULL){
            if(p->next->val==p->val){
                ListNode* m=p;
                while(p->next!=NULL&&p!=NULL&&p->next->val==p->val){
                        p=p->next;
                }
                m->next=p->next;
                p=p->next;
            }   
            else
                p=p->next;
        }
        return head;
    }
};