Remove Nth Node From End of List

	/**
	 * 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.
	 * 
	 * */