LeetCode 83: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.

简单链表操作，代码例如以下：

/**
 * 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)
            return head;
        ListNode * p = head;
        while (p) {
            ListNode *q = p->next;
            if (q == NULL) {
                break;
            }
            if (p->val == q->val) {
                p->next = q->next;
            }else{
                p = p->next;
            }
        }
        return head;
    }
};