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leetcode第19题--Remove Nth Node From End of List

时间:2014-10-19 01:12:55      阅读:190      评论:0      收藏:0      [点我收藏+]

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Problem:

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

For 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.
Try to do this in one pass.

果然一次就通过了。先读到尾,知道长度后,再从头开始读到要去掉的前一位,然后把要去掉的next复制给要去掉的前一个的next就可以。

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:
ListNode *removeNthFromEnd(ListNode *head, int n)
{
    int len = 1;
    ListNode *tmp = head;
    while(tmp -> next != NULL)
    {
        len++;
        tmp = tmp -> next;
    }
    if (len == n)
        return head -> next;
    ListNode *p = head;
    for(int i = 1; i < len - n; i++)
    {
        p = p -> next;
    }
    p -> next = p -> next -> next;
    return head;
}
};

 

leetcode第19题--Remove Nth Node From End of List

标签:style   blog   color   io   for   strong   sp   div   on   

原文地址:http://www.cnblogs.com/higerzhang/p/4034061.html

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