#!/usr/bin/env elixir defmodule Day6 do def part1(input) do input |> Enum.map(fn {race, record} -> scores = for n <- 1..div(race, 2), do: n * (race - n) [_middle | rev_no_middle] = reversed = Enum.reverse(scores) scores = scores ++ if rem(race, 2) == 1, do: reversed, else: rev_no_middle Enum.count(scores, fn score -> score > record end) end) |> Enum.product() end def part2(_input) do :ok end def input do with [input_filename] <- System.argv(), {:ok, input} <- File.read(input_filename) do input |> String.split("\n", trim: true) |> Enum.map(fn line -> line |> String.split() |> Enum.drop(1) |> Enum.map(&String.to_integer/1) end) |> Enum.zip() else _ -> :error 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 day6.exs input_filename") end end # Day6.run()