Elixir Queue: Fixing `queue.pop/1` Error in `halve_array` Function

The error message 'queue.pop/1 is undefined or private' indicates that the queue.pop/1 function is not available in the Elixir :queue module. Instead of pop/1, you should use the :queue.out/1 function to remove the first element from the queue.

Here's the corrected code:

defmodule Solution do
  @spec halve_array(nums :: [integer]) :: integer
  def halve_array(nums) do
    pq = :queue.new()
    Enum.each(nums, fn num -> :queue.in(num, pq) end)
    res = 0
    sum = Enum.reduce(nums, 0.0, &(&1 + &2))
    sum2 = 0.0
    halve_array_recursive(pq, sum, sum2, res)
  end

  defp halve_array_recursive(pq, sum, sum2, res) do
    case sum2 < sum / 2 do
      true ->
        {x, pq} = :queue.out(pq)
        sum2 = sum2 + x / 2
        pq = :queue.in(x / 2, pq)
        res = res + 1
        halve_array_recursive(pq, sum, sum2, res)
      false ->
        res
    end
  end
end

By replacing queue.pop(pq) with :queue.out(pq), you can correctly remove and retrieve the first element of the queue, ensuring the function operates as intended. This corrected code will resolve the error and enable your halve_array function to work properly.