insertion_sort.rb

class Array
  def insertion_sort
    return self if size < 2
    1.upto(size - 1) do |i|
      # tmp = self[i]
      i.downto(1) do |j|
        if self[j - 1] > self[j]
          self[j - 1], self[j] = self[j], self[j - 1]
p self
        else
          break
        end
      end
    end
    self
  end
end

a = (1..10).to_a.shuffle
p a
p a.insertion_sort