Created
December 8, 2019 07:55
-
-
Save ragiragi/2d4edbd786ec2aa21035d5b077fdf3c9 to your computer and use it in GitHub Desktop.
Advent of Code 2019, Day3 Part 1
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| defmodule Day3 do | |
| @central_port {0, 0} | |
| def run() do | |
| p1 = read_path() | |
| p2 = read_path() | |
| intersection(p1, p2) | |
| |> Enum.reject(¢ral_port?/1) | |
| |> Enum.map(&manhattan_distance/1) | |
| |> Enum.min() | |
| |> IO.puts() | |
| end | |
| def read_path() do | |
| IO.read(:line) | |
| |> String.trim() | |
| |> path_of_line() | |
| end | |
| def path_of_line(line) do | |
| line | |
| |> String.split(",") | |
| |> Enum.reduce([@central_port], fn <<direction::utf8, distance::binary>>, path -> | |
| move(path, direction, String.to_integer(distance)) | |
| end) | |
| |> Enum.reverse() | |
| end | |
| defp move(path, _, 0), do: path | |
| defp move([{x, y} | _] = path, ?R, distance), do: move([{x + 1, y} | path], ?R, distance - 1) | |
| defp move([{x, y} | _] = path, ?L, distance), do: move([{x - 1, y} | path], ?L, distance - 1) | |
| defp move([{x, y} | _] = path, ?U, distance), do: move([{x, y + 1} | path], ?U, distance - 1) | |
| defp move([{x, y} | _] = path, ?D, distance), do: move([{x, y - 1} | path], ?D, distance - 1) | |
| def intersection(p1, p2) do | |
| MapSet.intersection(MapSet.new(p1), MapSet.new(p2)) | |
| |> MapSet.to_list() | |
| end | |
| defp central_port?(coord), do: @central_port == coord | |
| def manhattan_distance({x1, y1} \\ @central_port, {x2, y2}), do: abs(x2 - x1) + abs(y2 - y1) | |
| end |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment