2023 Day 2

This commit is contained in:
Adam Millerchip 2023-12-02 15:00:28 +09:00
parent 3d68fa4048
commit 17e72ebf4c
2 changed files with 81 additions and 1 deletions

79
2023/day2.exs Executable file
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@ -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()

3
dayN.exs Normal file → Executable file
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@ -1,3 +1,4 @@
#!/usr/bin/env elixir
defmodule DayREPLACE_ME do defmodule DayREPLACE_ME do
def part1(input) do def part1(input) do
input input
@ -35,7 +36,7 @@ defmodule DayREPLACE_ME do
defp run_with_timer(part, fun) do defp run_with_timer(part, fun) do
{time, result} = :timer.tc(fun) {time, result} = :timer.tc(fun)
IO.puts("Part #{part} (completed in #{format_time(time)}):\n") IO.puts("Part #{part} (completed in #{format_time(time)}):\n")
IO.puts("#{result}\n") IO.puts("#{inspect result}\n")
end end
defp format_time(μsec) when μsec < 1_000, do: "#{μsec}μs" defp format_time(μsec) when μsec < 1_000, do: "#{μsec}μs"