array_shuffle.rb

class Integer
  def to_binary_array(size)
    result = to_s(2).split(//).map{ |i| 1 if i == '1' }
    result = [nil] + result while result.size < size
    result
  end
end

class Array
  def map_with_other(other)
    result = []
    each_with_index do |item, index|
      result[index] = yield(item, other[index])
    end
    result
  end

  def shuffle(min_size = 1, max_size = nil)
    (1..(2**size - 1)).map { |s| s.to_binary_array(size) }.map do |bin_ary|
      map_with_other(bin_ary) do |item, bin|
        bin && item
      end.compact
    end.select do |row|
      row.size >= min_size && (!max_size || row.size <= max_size)
    end
  end
end

puts [1, 2, 3].shuffle(1, 2).inspect