Remove Duplicates from Sorted List

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

For example,
Given 1->1->2, return 1->2.

Given 1->1->2->3->3, return 1->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) {                ListNode *p = head;        while(p != NULL && p->next != NULL)        {            if(p->val == p->next->val)            {                ListNode *del = p->next;                p->next = p->next->next;                delete del;            }            else                p = p->next;        }                return head;    }};