letterpress.rb

class Letterpress
  def self.run(board)
    all_words = File.open('/usr/share/dict/words').readlines.map! { |line| line.strip.chomp }
    valid_words = all_words.select { |w| w =~ /[^#{board.join}]/ }

    valid_words = valid_words.select do |w|
      bool = true
      bool = false if w.size <= 2

      split_word = w.downcase.split('')

      split_word.each do |let|
        bool = false unless split_word.count(let) <= board.count(let)
      end if bool

      bool
    end

    p valid_words.sort {|x,y| y.length <=> x.length}
  end
end

Letterpress.run ARGV