（相似题目：）

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

Example 1:

Input: 1->1->2Output: 1->2

Example 2:

Input: 1->1->2->3->3Output: 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) {        //comepared with the 81-th problem,I think this is more simple..        ListNode* cur = head;        while(cur != NULL && cur->next != NULL){              if(cur->val == cur->next->val){                cur->next = cur->next->next;                    }               else cur = cur->next;        }        return head;    }};

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