【Leetcode】之Remove Duplicates from Sorted List

一.问题描述

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

.

二.我的解题思路

本题跟上一题解法一样，本题还更为简单。测试通过的程序如下：

/**
* 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;
ListNode* first=NULL; ListNode* last=NULL;
ListNode* curr=head; ListNode* next=curr->next;
while(curr && next){
while(next!=NULL && curr->val!=next->val){
curr=curr->next;
next=curr->next;
}
if(next==NULL) return head;
first=curr;
while(next!=NULL && curr->val==next->val){
curr=curr->next;
next=next->next;
}
if(next==NULL) {first->next=NULL;return head;}
last=next; first->next=last;
curr=last;next=curr->next;
}
return head;
}
};