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Contents
defmodule Queens do
@type t :: %Queens{ white: {integer, integer}, black: {integer, integer} }
defstruct white: {0, 3}, black: {7, 3}
@doc """
Creates a new set of Queens
"""
@spec new() :: Queens.t()
@spec new({integer, integer}, {integer, integer}) :: Queens.t()
def new(same, same), do: raise ArgumentError
def new(white, black) do
%Queens{white: white, black: black}
end
def new, do: %Queens{}
@doc """
Gives a string reprentation of the board with
white and black queen locations shown
"""
@spec to_string(Queens.t()) :: String.t()
def to_string(%Queens{ white: white, black: black }) do
generate_board
|> insert_queen(white, "W")
|> insert_queen(black, "B")
|> Enum.map(&Enum.join(&1, " "))
|> Enum.join("\n")
end
@doc """
Checks if the queens can attack each other
"""
@spec can_attack?(Queens.t()) :: boolean
def can_attack?(%Queens{ white: white, black: black }) do
{white_x, white_y} = white
{black_x, black_y} = black
white_x == black_x || white_y == black_y || diagonal?(white, black)
end
defp diagonal?({x1, y1}, {x2, y2}) do
abs(x1 - x2) == abs(y1 - y2)
end
defp insert_queen(board, {x, y}, letter) do
List.update_at board, x, fn(row) ->
List.replace_at row, y, letter
end
end
defp generate_board do
"_"
|> List.duplicate(8)
|> List.duplicate(8)
end
end
Version data entries
67 entries across 67 versions & 1 rubygems