78 lines
1.5 KiB
Elixir
78 lines
1.5 KiB
Elixir
input = IO.gets("input?")
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|> String.trim
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|> String.split(" ")
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defmodule Solver do
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def to_list(string) do
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case string do
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"" -> []
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_ ->
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string
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|> String.split("")
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|> Enum.filter(fn char ->
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char != ""
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end)
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end
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end
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# get the common string between the box ids
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def get_common(box_id, box_id_2) do
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# convert to list
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box_id_l = to_list(box_id)
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box_id_2_l = to_list(box_id_2)
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# zip them
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list_chars = Enum.zip(box_id_l, box_id_2_l)
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# if theyre equal, we add to the accumulator
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common_str = Enum.reduce(list_chars, "", fn tup, acc ->
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{c1, c2} = tup
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if c1 == c2 do
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acc <> c1
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else
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acc
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end
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end)
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# for common_str to be valid it has to be
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# L(common_str) = L(box_id) - 1
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# since correct box ids have just *ONE*
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# character difference between them
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if String.length(common_str) == (String.length(box_id) - 1) do
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{:ok, common_str}
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else
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:not_found
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end
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end
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def solve(input) do
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# find all the common strings
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# and filter shit
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commons = Enum.map(input, fn box_id ->
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Enum.map(input, fn box_id_2 ->
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common = get_common(box_id, box_id_2)
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case common do
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:not_found -> nil
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{:ok, str} -> str
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end
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end)
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|> Enum.filter(fn combo ->
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combo != nil
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end)
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end)
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|> Enum.filter(fn combo ->
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combo != []
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end)
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end
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end
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res = Solver.solve(input)
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IO.puts "result: #{inspect res}"
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