LeetCode-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.

Solution:

Code:

<span style="font-size:14px;">/** * 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 || head->next == NULL) return head;        ListNode *begin = head, *end = head;        head = head->next;        while (head != NULL) {            if (head->val != end->val) {                end->next = head;                end = head;            }            head = head->next;        }        end->next = NULL;        return begin;    }};</span>