74 lines
1.5 KiB
Elixir
74 lines
1.5 KiB
Elixir
|
import AOC
|
||
|
|
|
||
|
|
aoc 2021, 13 do
|
||
|
|
def input(input_string \\ input_string()) do
|
||
|
|
[dots_string, folds_string] =
|
||
|
|
input_string
|
||
|
|
|> String.split("\n\n", trim: true)
|
||
|
|
|
||
|
|
dots =
|
||
|
|
dots_string
|
||
|
|
|> String.split("\n", trim: true)
|
||
|
|
|> Enum.map(fn line ->
|
||
|
|
[x, y] =
|
||
|
|
String.split(line, ",")
|
||
|
|
|> Enum.map(&String.to_integer/1)
|
||
|
|
|
||
|
|
{x, y}
|
||
|
|
end)
|
||
|
|
|> MapSet.new()
|
||
|
|
|
||
|
|
folds =
|
||
|
|
folds_string
|
||
|
|
|> String.split("\n", trim: true)
|
||
|
|
|> Enum.map(fn
|
||
|
|
"fold along y=" <> y -> {:y, String.to_integer(y)}
|
||
|
|
"fold along x=" <> x -> {:x, String.to_integer(x)}
|
||
|
|
end)
|
||
|
|
|
||
|
|
{dots, folds}
|
||
|
|
end
|
||
|
|
|
||
|
|
def do_fold({:y, line}, dots) do
|
||
|
|
for {x, y} <- dots, into: MapSet.new() do
|
||
|
|
if y > line do
|
||
|
|
{x, line - (y - line)}
|
||
|
|
else
|
||
|
|
{x, y}
|
||
|
|
end
|
||
|
|
end
|
||
|
|
end
|
||
|
|
|
||
|
|
def do_fold({:x, line}, dots) do
|
||
|
|
for {x, y} <- dots, into: MapSet.new() do
|
||
|
|
if x > line do
|
||
|
|
{line - (x - line), y}
|
||
|
|
else
|
||
|
|
{x, y}
|
||
|
|
end
|
||
|
|
end
|
||
|
|
end
|
||
|
|
|
||
|
|
def p1 do
|
||
|
|
{dots, [fold | _folds]} = input()
|
||
|
|
|
||
|
|
do_fold(fold, dots) |> MapSet.size()
|
||
|
|
end
|
||
|
|
|
||
|
|
def p2 do
|
||
|
|
{dots, folds} = input()
|
||
|
|
|
||
|
|
final_dots = Enum.reduce(folds, dots, &do_fold/2)
|
||
|
|
|
||
|
|
max_x = final_dots |> Enum.map(&elem(&1, 0)) |> Enum.max()
|
||
|
|
max_y = final_dots |> Enum.map(&elem(&1, 1)) |> Enum.max()
|
||
|
|
|
||
|
|
for x <- 0..max_x, into: "" do
|
||
|
|
for y <- 0..max_y, into: "" do
|
||
|
|
if MapSet.member?(final_dots, {x, y}), do: "#", else: "."
|
||
|
|
end <> "\n"
|
||
|
|
end
|
||
|
|
|> IO.puts()
|
||
|
|
end
|
||
|
|
end
|