leetcode：Remove Nth Node From End of List 【Java】

一、问题描述

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.

二、问题分析

使用两个指针，使其中一个指针比另一个多走n步。

三、算法代码

/** * Definition for singly-linked list. * public class ListNode { *     int val; *     ListNode next; *     ListNode(int x) { val = x; } * } */public class Solution {    public ListNode removeNthFromEnd(ListNode head, int n) {        ListNode cur = head;        for(int i = 0; i < n; i++){            cur = cur.next;        }                if(cur == null){            head = head.next;            return head;        }                ListNode pre = head;        while(cur.next != null){            cur = cur.next;            pre = pre.next;        }        ListNode target = pre.next;        pre.next = target.next;        return head;    }}