72 lines
2.1 KiB
Elixir
72 lines
2.1 KiB
Elixir
defmodule Mix.Tasks.Day5 do
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use Mix.Task
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def run(_) do
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IO.stream() |> parse() |> part1() |> IO.puts()
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end
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def split_int_list(s, sep) do
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s |> String.split(sep) |> Enum.map(fn n -> Integer.parse(n) |> elem(0) end)
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end
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def parse_line("seeds: " <> seeds) do
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{:seeds, seeds |> split_int_list(" ")}
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end
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def parse_line(line) when line != "" do
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make_range = fn line ->
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[dest_start, source_start, len] = line |> split_int_list(" ")
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{:range, {RangeUtil.from_start(dest_start, len), RangeUtil.from_start(source_start, len)}}
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end
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cap = Regex.run(~r/(\w+)-to-(\w+) map:/, line)
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case cap do
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[_, source, dest] -> {:map_key, { source |> String.to_atom(), dest |> String.to_atom() } }
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nil -> make_range.(line)
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end
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end
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def parse(input) do
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for line <- input,
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line = line |> String.trim(),
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line != "",
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reduce: %{} do
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acc ->
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{type, data} = parse_line(line)
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case type do
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:seeds -> acc |> Map.put(type, data)
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:map_key -> { source, dest } = data
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acc
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|> Map.update(:maps, %{source => {dest, []}}, fn maps -> maps |> Map.put(source, {dest, []}) end)
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|> Map.put(:last_map_key, source)
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:range -> %{last_map_key: last_map_key} = acc
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acc |> Map.update!(
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:maps,
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fn maps -> maps
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|> Map.update!(last_map_key, fn {dest, ranges} ->
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{dest, [data | ranges]}
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end)
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end)
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end
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end
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end
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def get_location(:location, n, _) do
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n
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end
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def get_location(source, n, maps) do
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{dest, ranges} = maps |> Map.get(source)
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transpose = case ranges |> Enum.find(fn {_, source} ->
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n in source
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end) do
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{dest_range, source_range} ->RangeUtil.transpose(n, source_range, dest_range)
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nil -> n
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end
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IO.puts({dest, transpose} |> inspect())
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get_location(dest, transpose, maps)
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end
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def part1(state) do
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for seed <- state.seeds do
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get_location(:seed, seed, state.maps)
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end |> Enum.min()
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end
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end
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