53 lines
1.4 KiB
Elixir
53 lines
1.4 KiB
Elixir
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defmodule Day1 do
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def part1(<<>>), do: 0
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def part1(<<?(, rest::binary>>), do: 1 + part1(rest)
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def part1(<<?), rest::binary>>), do: -1 + part1(rest)
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def part2(input), do: find_basement(input, _floor = 0, _pos = 1)
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def find_basement(<<?), _::binary>>, 0, pos), do: pos
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def find_basement(<<?), rest::binary>>, floor, pos), do: find_basement(rest, floor - 1, pos + 1)
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def find_basement(<<?(, rest::binary>>, floor, pos), do: find_basement(rest, floor + 1, pos + 1)
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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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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 day1.exs input_filename")
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end
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end
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Day1.run()
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