17 lines
432 B
Elixir
17 lines
432 B
Elixir
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defmodule One do
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def part1(list, initial_freq \\ 0), do: initial_freq + Enum.sum(list)
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def part2(list, initial_freq \\ 0) do
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list
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|> Stream.cycle()
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|> Enum.reduce_while({initial_freq, MapSet.new([initial_freq])}, &part2_reducer/2)
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end
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def part2_reducer(i, {last, set}) do
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case (i + last) in set do
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true -> {:halt, i + last}
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_ -> {:cont, {i + last, MapSet.put(set, i + last)}}
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end
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end
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end
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