[leetcode][list] Remove Duplicates from Sorted List

题目:

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){
ListNode *q = p->next;
while (q != NULL && q->val == p->val){
ListNode *tmp = q;
q = q->next;
delete tmp;
}
p->next = q;
p = p->next;
}
return head;
}
};