[Leetcode] Remove duplicates from sorted list 从已排序的链表中删除重复元素

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

For example,
Given1->1->2, return1->2.
Given1->1->2->3->3, return1->2->3.

思路：遍历链表。比较相邻的结点，若是有相等的情况，则cur不动，而将其后继从其next变为next->next；没有，则正常遍历就行。

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