Remove Nth Node From End of List (Java)

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.

	/**
	* Definition for singly-linked list.
	* public class ListNode {
	* int val;
	* ListNode next;
	* ListNode(int x) {
	* val = x;
	* next = null;
	* }
	* }
	*/
	public class Solution {
	public ListNode removeNthFromEnd(ListNode head, int n) {
	if (head==null){
	return head;
	}
	ListNode remove=head;
	ListNode last=head;
	ListNode preHead=new ListNode (-1);
	preHead.next=head;
	ListNode pre=preHead;
	while (n>1){
	if (last.next==null){
	return head;
	}
	last=last.next;
	n--;
	}
	while (last.next!=null){
	last=last.next;
	pre=pre.next;
	remove=remove.next;
	}
	pre.next=remove.next;
	return preHead.next;
	}
	}

view raw RemoveNthNodeFromEndOfList .java hosted with ❤ by GitHub