28 lines
1.0 KiB
Plaintext
28 lines
1.0 KiB
Plaintext
defmodule Dinesman do
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def problem do
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names = ~w( Baker Cooper Fletcher Miller Smith )a
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predicates = [fn(c)-> :Baker != List.last(c) end,
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fn(c)-> :Cooper != List.first(c) end,
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fn(c)-> :Fletcher != List.first(c) && :Fletcher != List.last(c) end,
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fn(c)-> floor(c, :Miller) > floor(c, :Cooper) end,
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fn(c)-> abs(floor(c, :Smith) - floor(c, :Fletcher)) != 1 end,
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fn(c)-> abs(floor(c, :Cooper) - floor(c, :Fletcher)) != 1 end]
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permutation(names)
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|> Enum.filter(fn candidate ->
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Enum.all?(predicates, fn predicate -> predicate.(candidate) end)
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end)
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|> Enum.each(fn name_list ->
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Enum.with_index(name_list)
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|> Enum.each(fn {name,i} -> IO.puts "#{name} lives on #{i+1}" end)
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end)
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end
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defp floor(c, name), do: Enum.find_index(c, fn x -> x == name end)
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defp permutation([]), do: [[]]
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defp permutation(list), do: (for x <- list, y <- permutation(list -- [x]), do: [x|y])
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end
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Dinesman.problem
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