Remove Nth Node From End of List

Q:

Given a linked list, remove the n^th 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.

Solution:

/** * 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 null;        ListNode fakeHead = new ListNode(0);        fakeHead.next = head;        ListNode p = head;        ListNode q = head;        ListNode prev = fakeHead;        for (int i = 0; i < n; i++)            q = q.next;        while (q != null) {            q = q.next;            p = p.next;            prev = prev.next;        }        prev.next = p.next;        return fakeHead.next;    }}