23 lines
609 B
Plaintext
23 lines
609 B
Plaintext
defmodule Digital do
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def root(n, base\\10), do: root(n, base, 0)
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defp root(n, base, ap) when n < base, do: {n, ap}
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defp root(n, base, ap) do
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Integer.digits(n, base) |> Enum.sum |> root(base, ap+1)
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end
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end
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data = [627615, 39390, 588225, 393900588225]
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Enum.each(data, fn n ->
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{dr, ap} = Digital.root(n)
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IO.puts "#{n} has additive persistence #{ap} and digital root of #{dr}"
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end)
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base = 16
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IO.puts "\nBase = #{base}"
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fmt = "~.#{base}B(#{base}) has additive persistence ~w and digital root of ~w~n"
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Enum.each(data, fn n ->
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{dr, ap} = Digital.root(n, base)
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:io.format fmt, [n, ap, dr]
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end)
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