bump_duplicates.rb

class Array
  def bump_duplicates!
    current = max.succ
    each_with_index do |element, i|
      if slice(0...i).include? element
        self[i] = current
        current = current.succ
      end
    end
  end
  
  def bump_duplicates
    dup.bump_duplicates!
  end
end
 
# a = [1,3,3,2,5]
# => [1, 3, 3, 2, 5] 
# a.increment_duplicates
# => [1, 3, 6, 2, 5] 
# a
# => [1, 3, 3, 2, 5] 
# a.increment_duplicates!
# => [1, 3, 6, 2, 5] 
# a
# => [1, 3, 6, 2, 5]
# %w(a b c c d e e f g h h h i j k).bump_duplicates
# => ["a", "b", "c", "l", "d", "e", "m", "f", "g", "h", "n", "o", "i", "j", "k"]