consecutive.rb

class Consecutive
  
  attr_reader :string, :totals

  def initialize(string)
    @string          = string
    @totals          = count_characters
  end
  
  def max_consecutive_characters
    matches
  end
  
  private

  # Produce an array of tuples containing the consecutive characters in
  # a string and its character, removing duplicates.  Assume @string to 
  # be aaffffddddaa in this example:
  #   
  #  consecutive_characters
  #    => [ ["aa", "a"], ["dddd", "d"], ["ffff", "f"] ]
  def consecutive_characters
     string.scan(/((.)\2+)/).uniq
  end

  # Mangle the array of tuples from consecutive_characters to include a
  # total.  Using the previous example:
  #
  #  count_characters
  #    => [ ["a", 2], ["d", 4], ["f", 4]
  def count_characters
    consecutive_characters.map { |tuple| [tuple.last, tuple.first.chars.count] }
  end

  # Do the real work.  Grab all the counts and find the highest value, then
  # produce an array of all characters matching that count.
  def matches
    highest_count = totals.map(&:last).max
    totals.each.map { |character, count| character if count == highest_count }.compact.sort
  end
  
end

Not as pretty as I'd like. I'd like to clean things up enough so that it's a little more intention revealing. I also don't like the looks of lines 10-12