29 lines
1.2 KiB
Elixir
29 lines
1.2 KiB
Elixir
|
defmodule Day12Part1 do
|
||
|
|
def run do
|
||
|
|
File.read!("input")
|
||
|
|
|> String.split("\n", trim: true)
|
||
|
|
|> Enum.map(fn <<action::binary-1>> <> value -> {action, String.to_integer(value)} end)
|
||
|
|
|> Enum.reduce({0, 0, {1, 0}}, &process/2)
|
||
|
|
|> manhattan_distance()
|
||
|
|
|> IO.puts()
|
||
|
|
end
|
||
|
|
|
||
|
|
def process({"N", value}, {x, y, direction}), do: {x, y + value, direction}
|
||
|
|
def process({"S", value}, {x, y, direction}), do: {x, y - value, direction}
|
||
|
|
def process({"E", value}, {x, y, direction}), do: {x + value, y, direction}
|
||
|
|
def process({"W", value}, {x, y, direction}), do: {x - value, y, direction}
|
||
|
|
def process({"L", value}, {x, y, direction}), do: {x, y, turn_left(direction, value)}
|
||
|
|
def process({"R", value}, {x, y, direction}), do: {x, y, turn_right(direction, value)}
|
||
|
|
def process({"F", value}, {x, y, {vx, vy}}), do: {x + vx * value, y + vy * value, {vx, vy}}
|
||
|
|
|
||
|
|
def turn_left(direction, 0), do: direction
|
||
|
|
def turn_left({vx, vy}, degrees), do: turn_left({-vy, vx}, degrees - 90)
|
||
|
|
|
||
|
|
def turn_right(direction, 0), do: direction
|
||
|
|
def turn_right({vx, vy}, degrees), do: turn_right({vy, -vx}, degrees - 90)
|
||
|
|
|
||
|
|
def manhattan_distance({x, y, _}), do: abs(x) + abs(y)
|
||
|
|
end
|
||
|
|
|
||
|
|
Day12Part1.run()
|