leetcode刷题【简单】删除排序链表中的重复元素 c++

给定一个排序链表，删除所有重复的元素，使得每个元素只出现一次。

/** 
* 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 && head->next != NULL)        
        {            
            ListNode* p = head;            
            while(p != NULL && p->next != NULL)            
            {                                
                while(p->next != NULL && p->val == p->next->val)                
                {                    
                    ListNode* r;                    
                    r = p->next;                    
                    p->next = r->next;                    
                    delete r;                
                }                
                p = p->next;            
            }        
        }        
        return head;    
    }
};

---------ViVi 2020-4-3