gistfile1.rb

# Adds minutes to the time string
# @param time [String] of format "[H]H:MM {AM|PM}"
# @param minutes [Integer] the number of minutes to add to the time
def add_minutes(time, minutes)
  hours, min, am_pm = time.match(/(\d+):(\d+)\s(\w\w)/).captures
  hours = hours.to_i
  min = min.to_i + minutes

  if hours == 11 && min > 59
    am_pm = am_pm == "PM" ? "AM" : "PM"
  end

  while min > 59
    min = min - 60
    hours = hours + 1
  end

  if hours > 12
    hours = hours - 12
  end

  min = "%02d" % min  # zero pad minutes
  "#{hours}:#{min} #{am_pm}"
end