From: Christian Neukirchen <chneukirchen@...>
Date: 2008-09-23T02:44:35+09:00
Subject: Re: [QUIZ] One-Liners Mashup (#177 again)

class Array
  # the classic
  def repeat(n)
    r = []; each { |e| n.times { r << e } }; r
  end

  # the nice
  def repeat(n)
    inject([]) { |a,e| a.concat [e]*n }
  end

  # the probably most efficient
  def repeat(n)
    Array.new(size*n) { |i| self[i/n] }
  end
end

# next challenge: return the power set of an Array's elements
# (my solution: https://gist.github.com/e05c3be86abf74b44853)