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.

思路：这就是个链表遍历的问题。 so easy

注意p何时移动到下一位。

/**
 * 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 && p->next){
            if(p->val == (p->next)->val)
                p->next=p->next->next;
            else p=p->next;
        }
        return head;
    }
};