like that:
defmodule War do
@doc """
The main module to the challenge.
This module exposes a deal/1 function to play the game.
"""
# prefers to use a weight as we don't
# need to represent the card suite
@ace_weight 14
def deal(deck) do
{p1, p2} =
deck
|> Enum.map(&apply_ace_weight/1)
|> deal_deck()
winner = play_game(p1, p2)
Enum.map(winner, &remove_ace_weight/1)
end
def deal_deck(deck) do
{Enum.take_every(deck, 2), Enum.drop_every(deck, 2)}
end
defp play_game(p1, p2, tied \\ [])
defp play_game([], p2, tied), do: p2 ++ tied
defp play_game(p1, [], tied), do: p1 ++ tied
# War, cards tied
defp play_game([c | xs], [c | ys], tied) do
cards = Enum.sort([c, c] ++ tied, :desc)
play_game(xs, ys, cards)
end
# Normal game turn
defp play_game([x | xs], [y | ys], tied) do
cards = Enum.sort([x, y] ++ tied, :desc)
if x > y do
play_game(xs ++ cards, ys)
else
play_game(xs, ys ++ cards)
end
end
defp apply_ace_weight(card) do
(card == 1 && @ace_weight) || card
end
defp remove_ace_weight(card) do
(card == @ace_weight && 1) || card
end
end
