Leetcode: Remove Duplicates from Sorted List

问题：

Given a sorted linked list, delete all duplicates such that each element appear onlyonce.

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

解决方案：

因为是有序列表所以我们只需要以此比较相邻的两个节点就好了，定义两个指针，循环着遍历一遍原始列表。

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