Helper Func

original_gfe.ex

def gfe(head], _, []), do: {head, []}
def gfe([], {:empty, :empty}, new_queue), do: {nil, new_queue}
def gfe([], front, new_queue), do: {front, new_queue}
def gfe([{head_item, head_prio} = head | []], front, new_queue) do 
	{front_item, front_prio}         = front
  if head_prio > front_prio do
  	{head, new_queue ++ [front]}
  else
    {front, new_queue ++ [head]}
 	end
end

def gfe([{head_item, head_prio} = head | tail], front, new_queue) do
	{front_item, front_prio}         = front
  {t_head_item, t_head_prio} = List.first tail
  if front_prio >= head_prio && front_prio != :empty do 
		gfe tail, front, new_queue ++ [head]
  else
  	if head_prio >= t_head_prio do 
      gfe tail -- [{t_head_item, t_head_prio}], head, 
        new_queue ++ [{t_head_item, t_head_prio}]
    else
      gfe tail -- [{t_head_item, t_head_prio}], {t_head_item, t_head_prio}, 
        new_queue ++ [head]
    end
  end
end