insertion_sort.rb

# Insertion sort algorithm,
# uses N^2/4 compares and N^2/4 exchanges to sort a randomly ordered array,
# see test/insertion_sort_test.rb
module Insertion
  def self.sort(array)
    1.upto(array.size - 1) do |i|
      j = i
      while j > 0 && array[j] < array[j - 1]
        array[j], array[j - 1] = array[j - 1], array[j]
        j -= 1
      end
    end

    array
  end  
end