*（leetcode） 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： 两个节点p,q 如果p q的val相同，则删掉q节点，然后p指向q->next， q节点仍指向p后面的节点，continue判断。 如果不相等，两节点都后移。

/**
 * 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,*q;
        if(head == NULL||head->next==NULL) return head;
        p = head;
        q = head->next;
        while(p!=NULL&&q!=NULL){
            if(p->val == q->val){
                p->next = q->next;
                q = p->next;
                continue;
            }
            else{
                p = q;
                q = q->next;
            }
        }
        return head;
    }
};