LeetCode——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：

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