[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;
     }
 };