24 lines
762 B
Plaintext
24 lines
762 B
Plaintext
defmodule Superpermutation do
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def minimisation(1), do: [1]
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def minimisation(n) do
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Enum.chunk(minimisation(n-1), n-1, 1)
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|> Enum.reduce({[],nil}, fn sub,{acc,last} ->
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if Enum.uniq(sub) == sub do
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i = if acc==[], do: 0, else: Enum.find_index(sub, &(&1==last)) + 1
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{acc ++ (Enum.drop(sub,i) ++ [n] ++ sub), List.last(sub)}
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else
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{acc, last}
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end
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end)
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|> elem(0)
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end
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end
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to_s = fn list -> Enum.map_join(list, &Integer.to_string(&1,16)) end
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Enum.each(1..8, fn n ->
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result = Superpermutation.minimisation(n)
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:io.format "~3w: len =~8w : ", [n, length(result)]
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IO.puts if n<5, do: Enum.join(result),
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else: to_s.(Enum.take(result,20)) <> "...." <> to_s.(Enum.slice(result,-20..-1))
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end)
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