leetcode 083 Remove Duplicates from Sorted List

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.

Subscribe to see which companies asked this question

/** * 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;ListNode *pre=head, *cur=NULL, *ret=NULL, *retCur=NULL;for(cur=head->next; cur!=NULL; cur=cur->next) {if(cur->val != pre->val){if(ret==NULL) {ret = pre;} else {retCur->next = pre;}retCur = pre;retCur->next=NULL;}pre=cur;}if(ret==NULL) {ret = pre;} else {retCur->next = pre;}retCur = pre;retCur->next=NULL;return ret;    }};