66 lines
1.4 KiB
Elixir
66 lines
1.4 KiB
Elixir
defmodule Day2 do
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def part1(input) do
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input
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|> Enum.map(fn [x, y, z] ->
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a = x * y
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b = x * z
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c = y * z
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min = Enum.min([a, b, c])
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2 * (a + b + c) + min
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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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input
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|> Enum.map(fn box ->
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[x, y, z] = Enum.sort(box)
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2 * (x + y) + x * y * z
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end)
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|> Enum.sum()
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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", "x"], trim: true)
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|> Enum.map(&String.to_integer/1)
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|> Enum.chunk_every(3)
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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("#{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 day2.exs input_filename")
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end
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end
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Day2.run()
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