【LeetCode从零单刷】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.

解答：

很简单的模拟，因为是 sorted，所以找到不重复的下一个元素即可。

/**
 * 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 head;

        if(head->next == NULL)
            return head;

        ListNode* tmp = head;
        ListNode* dup = NULL;
        while(tmp != NULL)
        {
            if(tmp->next != NULL && tmp->val == tmp->next->val){
                dup = tmp;
                while(dup->next != NULL && dup->next->val == dup->val)  dup = dup->next;
                dup = dup->next;

                tmp->next = dup;
            }
            tmp = tmp->next;
        }
        return head;
    }
};