problem:
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
.
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题意:将一个已经排好序的单链表 中的重复元素删除,只留一个
thinking:
(1)这道题是上一题的简化版,上一题是把重复的元素一个不留的删除:http://blog.csdn.net/hustyangju/article/details/45028247
(2)双指针遍历,时间复杂度O(N),一次提交AC
code:
/** * 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 *p=head;//左指针 ListNode *q=p; //右指针 while(p!=NULL) { q=p->next; //右指针初始化 if(q==NULL) return head; if(p->val!=q->val) //不相等,同时前进 { p=p->next; q=q->next; } else //相等 ,右指针前进 { while(q!=NULL && q->val==p->val) { q=q->next; } p->next=q; //删除重复元素 p=q; //更新左指针 } } return head; } };
时间: 2024-11-29 07:13:15