kitcheck-homework.rb

class Indexer
  attr :dictionary

  LETTER_TO_NUMBER = {
                      2 => ['a','b','c'],
                      3 => ['d','f','e'],
                      4 => ['g','h','i'],
                      5 => ['j','k','l'],
                      6 => ['m','n','o'],
                      7 => ['p','q','r','s'],
                      8 => ['t','u','v'],
                      9 => ['w','x','y','z'],
                     }


  def initialize(dictionary)
    dictionary = dictionary.map{|s| s.strip}.compact.uniq
    @dictionary =  encode_dictionary(dictionary)
  end

  # {1233 => ['aa','dd'], 322 => ['e']}
  def encode_dictionary(dictionary)
    encoded_dictionary = {}
    dictionary.each do |string|
      code = encode(string)
      unless encoded_dictionary[code]
        encoded_dictionary[code] = [string]
      else
        encoded_dictionary[code] << string
      end
    end
    encoded_dictionary
  end

  # string => 123
  def encode(string)
    encoded_string = []
    #encode each character
    string.chars.each do |char|
      code = LETTER_TO_NUMBER.detect{|k,v| v.include?(char)}[0]
      encoded_string << code
    end
    encoded_string.join()
  end


  #222 => abc,aaa,...
  def decode(encoded_string)
    @dictionary[encoded_string.gsub(/\D+/, '').strip]
  end
end


path = ARGV[0]
code = ARGV[1]

dictionary = File.readlines('words')
p = Indexer.new(dictionary)
p p.dictionary
p p.decode(code)