diff --git a/2023/day2.exs b/2023/day2.exs new file mode 100755 index 0000000..d13b73b --- /dev/null +++ b/2023/day2.exs @@ -0,0 +1,79 @@ +#!/usr/bin/env elixir +defmodule Day2 do + def part1(input) do + input + |> Map.filter(fn {_id, cubes} -> + cubes["red"] <= 12 and cubes["green"] <= 13 and cubes["blue"] <= 14 + end) + |> Map.keys() + |> Enum.sum() + end + + def part2(input) do + input + |> Enum.map(fn {_id, cubes} -> cubes |> Map.values() |> Enum.product() end) + |> Enum.sum() + end + + def input do + with [input_filename] <- System.argv(), + {:ok, input} <- File.read(input_filename) do + input + |> String.split("\n", trim: true) + |> Map.new(fn line -> + ["Game " <> id | rounds] = String.split(line, [": ", "; "]) + + rounds = + rounds + |> Enum.map(&parse_round/1) + |> Enum.reduce( + %{"red" => 0, "green" => 0, "blue" => 0}, + &Map.merge(&1, &2, fn _colour, count1, count2 -> max(count1, count2) end) + ) + + {String.to_integer(id), rounds} + end) + else + _ -> :error + end + end + + def parse_round(round) do + round + |> String.split([", ", " "]) + |> Enum.chunk_every(2) + |> Map.new(fn [number, colour] -> {colour, String.to_integer(number)} end) + end + + ####################### + # HERE BE BOILERPLATE # + ####################### + + def run do + case input() do + :error -> print_usage() + input -> run_parts_with_timer(input) + end + end + + defp run_parts_with_timer(input) do + run_with_timer(1, fn -> part1(input) end) + run_with_timer(2, fn -> part2(input) end) + end + + defp run_with_timer(part, fun) do + {time, result} = :timer.tc(fun) + IO.puts("Part #{part} (completed in #{format_time(time)}):\n") + IO.puts("#{inspect(result)}\n") + end + + defp format_time(μsec) when μsec < 1_000, do: "#{μsec}μs" + defp format_time(μsec) when μsec < 1_000_000, do: "#{μsec / 1000}ms" + defp format_time(μsec), do: "#{μsec / 1_000_000}s" + + defp print_usage do + IO.puts("Usage: elixir day2.exs input_filename") + end +end + +Day2.run() diff --git a/dayN.exs b/dayN.exs old mode 100644 new mode 100755 index c266fcf..9398faf --- a/dayN.exs +++ b/dayN.exs @@ -1,3 +1,4 @@ +#!/usr/bin/env elixir defmodule DayREPLACE_ME do def part1(input) do input @@ -35,7 +36,7 @@ defmodule DayREPLACE_ME do defp run_with_timer(part, fun) do {time, result} = :timer.tc(fun) IO.puts("Part #{part} (completed in #{format_time(time)}):\n") - IO.puts("#{result}\n") + IO.puts("#{inspect result}\n") end defp format_time(μsec) when μsec < 1_000, do: "#{μsec}μs"