A company currently pays a fixed sum for the use of a particular licensed software package.   In determining if it has a good deal it decides to calculate its maximum use of the software from its license management log file.

Assume the software's licensing daemon faithfully records a checkout event when a copy of the software starts and a checkin event when the software finishes to its log file.

An example of checkout and checkin events are:

 License OUT @ 2008/10/03_23:51:05 for job 4974
 ...
 License IN  @ 2008/10/04_00:18:22 for job 4974



Task

Save the 10,000 line log file from    here   into a local file, then write a program to scan the file extracting both the maximum licenses that were out at any time, and the time(s) at which this occurs.

Mirror of log file available as a zip here (offsite mirror).




out = 0
max_out = -1
max_times = []
 
File.foreach('mlijobs.txt') do |line|
  out += line.include?("OUT") ? 1 : -1
  if out > max_out
    max_out = out
    max_times = []
  end
  max_times << line.split[3]  if out == max_out
end
 
puts "Maximum simultaneous license use is #{max_out} at the following times:"
max_times.each {|time| puts "  #{time}"}