Coding Challenge #2

question-marks.rb

def question_marks(str)
  # Get any number + chars + number pattern...
  regex = /(\d)[a-zA-Z\?]*(\d)/

  # Iterate over each occurrence and return the MatchData object
  matches = str.to_enum(:scan, regex).map { Regexp.last_match }

  # Iterate over each match and return a boolean meeting the following conditions...
  bools = matches.collect do |match|

    # Do the numbers at the beginning and end of the string add up to 10?
    if match[1].to_i + match[2].to_i == 10
      # Are there exactly 3 question marks within the string?
      match.to_s.scan(/\?/).count == 3
    end

  end.compact # .compact removes any nil entries

  # Evaluate if all items in our array are true and return the result
  !bools.empty? && bools.all?
end


# ---------------------------------------- //

str = "arrb6???4xxbl5???eee5"
puts "#{str}: #{question_marks(str)}" # true

str = "aa6?9"
puts "#{str}: #{question_marks(str)}" # false

str = "acc?7??sss?3rr1??????5"
puts "#{str}: #{question_marks(str)}" # true

str = "dk7???3j??hk8???2jd?k?sj?hfkj"
puts "#{str}: #{question_marks(str)}" # true

str = "dk7??3j??hk8???2jd?k?sj?hfkj"
puts "#{str}: #{question_marks(str)}" # false