39 lines
1.0 KiB
Plaintext
39 lines
1.0 KiB
Plaintext
defmodule RC do
|
|
def queen(n, display \\ true) do
|
|
solve(n, [], [], [], display)
|
|
end
|
|
|
|
defp solve(n, row, _, _, display) when n==length(row) do
|
|
if display, do: print(n,row)
|
|
1
|
|
end
|
|
defp solve(n, row, add_list, sub_list, display) do
|
|
Enum.map(Enum.to_list(0..n-1) -- row, fn x ->
|
|
add = x + length(row) # \ diagonal check
|
|
sub = x - length(row) # / diagonal check
|
|
if (add in add_list) or (sub in sub_list) do
|
|
0
|
|
else
|
|
solve(n, [x|row], [add | add_list], [sub | sub_list], display)
|
|
end
|
|
end) |> Enum.sum # total of the solution
|
|
end
|
|
|
|
defp print(n, row) do
|
|
IO.puts frame = "+" <> String.duplicate("-", 2*n+1) <> "+"
|
|
Enum.each(row, fn x ->
|
|
line = Enum.map_join(0..n-1, fn i -> if x==i, do: "Q ", else: ". " end)
|
|
IO.puts "| #{line}|"
|
|
end)
|
|
IO.puts frame
|
|
end
|
|
end
|
|
|
|
Enum.each(1..6, fn n ->
|
|
IO.puts " #{n} Queen : #{RC.queen(n)}"
|
|
end)
|
|
|
|
Enum.each(7..12, fn n ->
|
|
IO.puts " #{n} Queen : #{RC.queen(n, false)}" # no display
|
|
end)
|