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LeetCode-19-Remove Nth Node From End of List

时间:2019-01-25 13:42:02      阅读:169      评论:0      收藏:0      [点我收藏+]

标签:css   list   ptr   second   could   思路   you   算法   dup   

算法描述:

Given a linked list, remove the n-th node from the end of list and return its head.

Example:

Given linked list: 1->2->3->4->5, and n = 2.

After removing the second node from the end, the linked list becomes 1->2->3->5.

Note:

Given n will always be valid.

Follow up:

Could you do this in one pass?

 

解题思路:

这个题考查数据结构。设置两个指针,快指针先走n步,然后快指针和慢指针一起走,快指针停的时候,慢指针的下一个元素为待删除元素。

    ListNode* removeNthFromEnd(ListNode* head, int n) {
        ListNode* dup = new ListNode(-1);
        dup->next = head;
        ListNode* fast = dup;
        while(n>0){
            fast=fast->next;
            n--;
        }
        ListNode* slow = dup;
        while(fast!=nullptr && fast->next!=nullptr){
            fast=fast->next;
            slow=slow->next;
        }
        slow->next = slow->next->next;
        return dup->next;
    }

 

LeetCode-19-Remove Nth Node From End of List

标签:css   list   ptr   second   could   思路   you   算法   dup   

原文地址:https://www.cnblogs.com/nobodywang/p/10315115.html

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