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April 24, 2014 14:12
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Codewars perfect square ruby kata implemented in elixir
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| # The ruby kata was: | |
| # Given an array of numbers, which are perfect squares? | |
| # get_squares(1..16) # => [1, 4, 9, 16] | |
| # get_squares(1..100) # => [1, 4, 9, 16, 25, 36, 49, 64, 81, 100] | |
| # | |
| # This version accepts lists an ranges | |
| defmodule ElixirKatas do | |
| def get_squares(numbers) do | |
| cond do | |
| Range.range?(numbers) -> | |
| for n <- numbers, is_sqrt_natural?(n), do: n | |
| Kernel.is_list(numbers) -> | |
| for n <- numbers, is_sqrt_natural?(n), do: n | |
| true -> | |
| IO.puts "Arg must be a list or a range !" | |
| end | |
| end | |
| defp is_sqrt_natural?(n) when is_integer(n) do | |
| :math.sqrt(n) |> :erlang.trunc |> :math.pow(2) == n | |
| end | |
| defp is_sqrt_natural?(_n) do | |
| false | |
| end | |
| end |
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| iex(25)> ElixirKatas.get_squares [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16] | |
| [1, 4, 9, 16] | |
| iex(26)> ElixirKatas.get_squares 1..16 | |
| [1, 4, 9, 16] | |
| iex(27)> ElixirKatas.get_squares 1..1 | |
| [1] | |
| iex(28)> ElixirKatas.get_squares 1 | |
| Arg must be a list or a range ! | |
| :ok | |
| iex(29)> ElixirKatas.get_squares ["a", :ok] | |
| [] | |
| iex(30)> |
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