LeetCode Remove Duplicates from Sorted List

// 84ms
 1 /**
 * 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) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        ListNode *p,*q;
        p=head;
        while(p)
        {
            while((p->next)&&(p->val==p->next->val))
            {
                p->next=p->next->next;
            }
            p=p->next;
        }
        return head;
    }
};