69 lines
1.7 KiB
Elixir
69 lines
1.7 KiB
Elixir
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defmodule Day4 do
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def part1(input) do
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input
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|> Enum.map(fn {_id, winning, have} ->
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case MapSet.intersection(winning, have) |> MapSet.size() do
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0 -> 0
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num_winners -> 2 ** (num_winners - 1)
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end
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end)
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|> Enum.sum()
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end
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def part2(_input) do
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:ok
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end
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def input do
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with [input_filename] <- System.argv(),
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{:ok, input} <- File.read(input_filename) do
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input
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|> String.split("\n", trim: true)
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|> Enum.map(fn line ->
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[card_id, winning, have] = String.split(line, [": ", " | "])
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["Card", id] = String.split(card_id, " ", trim: true)
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[winning, have] =
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for cards <- [winning, have],
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do: cards |> String.split(" ", trim: true) |> MapSet.new(&String.to_integer/1)
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{String.to_integer(id), winning, have}
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end)
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else
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_ -> :error
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end
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end
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#######################
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# HERE BE BOILERPLATE #
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#######################
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def run do
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case input() do
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:error -> print_usage()
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input -> run_parts_with_timer(input)
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end
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end
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defp run_parts_with_timer(input) do
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run_with_timer(1, fn -> part1(input) end)
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run_with_timer(2, fn -> part2(input) end)
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end
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defp run_with_timer(part, fun) do
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{time, result} = :timer.tc(fun)
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IO.puts("Part #{part} (completed in #{format_time(time)}):\n")
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IO.puts("#{inspect(result)}\n")
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end
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defp format_time(μsec) when μsec < 1_000, do: "#{μsec}μs"
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defp format_time(μsec) when μsec < 1_000_000, do: "#{μsec / 1000}ms"
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defp format_time(μsec), do: "#{μsec / 1_000_000}s"
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defp print_usage do
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IO.puts("Usage: elixir day4.exs input_filename")
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end
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end
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# Day4.run()
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