35 lines
631 B
Elixir
35 lines
631 B
Elixir
|
defmodule Day3Part2 do
|
||
|
|
def run do
|
||
|
|
answer =
|
||
|
|
slope(1, 1) *
|
||
|
|
slope(3, 1) *
|
||
|
|
slope(5, 1) *
|
||
|
|
slope(7, 1) *
|
||
|
|
slope(1, 2)
|
||
|
|
|
||
|
|
IO.puts(answer)
|
||
|
|
end
|
||
|
|
|
||
|
|
def slope(v_x, v_y) do
|
||
|
|
{_, trees} =
|
||
|
|
File.read!("input")
|
||
|
|
|> String.trim()
|
||
|
|
|> String.split("\n")
|
||
|
|
|> Enum.take_every(v_y)
|
||
|
|
|> Enum.map(&String.to_charlist/1)
|
||
|
|
|> Enum.reduce({0, 0}, fn row, {x, trees} ->
|
||
|
|
trees =
|
||
|
|
case Stream.cycle(row) |> Enum.at(x) do
|
||
|
|
?# -> trees + 1
|
||
|
|
?. -> trees
|
||
|
|
end
|
||
|
|
|
||
|
|
{x + v_x, trees}
|
||
|
|
end)
|
||
|
|
|
||
|
|
trees
|
||
|
|
end
|
||
|
|
end
|
||
|
|
|
||
|
|
Day3Part2.run()
|