LeetCode 83 Remove Duplicates from Sorted List

Problem:

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

For example,
Given 1->1->2, return 1->2.
Given 1->1->2->3->3, return 1->2->3.

Summary:

删除链表中的重复元素。

Analysis:

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