72 lines
1.4 KiB
Elixir
72 lines
1.4 KiB
Elixir
|
defmodule Day8 do
|
||
|
|
def part1 do
|
||
|
|
File.read!("lib/day8/input.txt")
|
||
|
|
|> parse_input()
|
||
|
|
|> split_into_layers(25, 6)
|
||
|
|
|> min_zeros()
|
||
|
|
|> ones_times_twos()
|
||
|
|
|
||
|
|
# "123456789012"
|
||
|
|
# |> parse_input()
|
||
|
|
# |> split_into_layers(3, 2)
|
||
|
|
# |> min_zeros()
|
||
|
|
# |> ones_times_twos()
|
||
|
|
end
|
||
|
|
|
||
|
|
def part2 do
|
||
|
|
File.read!("lib/day8/input.txt")
|
||
|
|
|> parse_input()
|
||
|
|
|> split_into_layers(25, 6)
|
||
|
|
|> combine_layers()
|
||
|
|
|> Enum.map(fn
|
||
|
|
0 -> ?\s
|
||
|
|
1 -> ?X
|
||
|
|
end)
|
||
|
|
|> Enum.chunk_every(25)
|
||
|
|
|> Enum.each(&IO.puts/1)
|
||
|
|
|
||
|
|
# "0222112222120000"
|
||
|
|
# |> parse_input()
|
||
|
|
# |> split_into_layers(2, 2)
|
||
|
|
# |> combine_layers()
|
||
|
|
end
|
||
|
|
|
||
|
|
def parse_input(str) do
|
||
|
|
str
|
||
|
|
|> String.trim()
|
||
|
|
|> String.to_charlist()
|
||
|
|
|> Enum.map(fn digit -> digit - ?0 end)
|
||
|
|
end
|
||
|
|
|
||
|
|
def split_into_layers(input, layer_width, layer_height) do
|
||
|
|
Enum.chunk_every(input, layer_width * layer_height)
|
||
|
|
end
|
||
|
|
|
||
|
|
def min_zeros(layers) do
|
||
|
|
layers
|
||
|
|
|> Enum.min_by(fn layer ->
|
||
|
|
Enum.count(layer, &(&1 == 0))
|
||
|
|
end)
|
||
|
|
end
|
||
|
|
|
||
|
|
def ones_times_twos(layer) do
|
||
|
|
ones = Enum.count(layer, &(&1 == 1))
|
||
|
|
twos = Enum.count(layer, &(&1 == 2))
|
||
|
|
ones * twos
|
||
|
|
end
|
||
|
|
|
||
|
|
def combine_layers(layers) do
|
||
|
|
Enum.zip(layers)
|
||
|
|
|> Enum.map(&combine_pixel/1)
|
||
|
|
end
|
||
|
|
|
||
|
|
def combine_pixel(pixel) do
|
||
|
|
0..(tuple_size(pixel) - 1)
|
||
|
|
|> Enum.map(fn index -> elem(pixel, index) end)
|
||
|
|
|> Enum.reduce(2, fn
|
||
|
|
val, 2 -> val
|
||
|
|
_, it -> it
|
||
|
|
end)
|
||
|
|
end
|
||
|
|
end
|