parse_whackness.rb

require 'date'

def parse_whackness(date_string)
  year = parse_year(date_string)

  month, day = guess_day_month(date_string[0..-5])

  Date.new(year.to_i, month.to_i, day.to_i)
end

def guess_day_month(date_string)
  case date_string.length
  when 4
    return date_string[0..1], date_string[2..3]
  when 3
    if (10..12).include?(date_string[0..1].to_i) &&
       (1..9).include?(date_string[2].to_i)
      return date_string[0..1], date_string[2]
    else
      return date_string[0], date_string[1..2]
    end
  when 2
    return date_string[0], date_string[1]
  end
end

def parse_year(date_string)
  date_string[-4..-1]
end

parse_whackness('3242013')