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).




import java.io.{BufferedReader, InputStreamReader}
import java.net.URL
 
object License0 extends App {
  val url = new URL("https://raw.githubusercontent.com/def-/nim-unsorted/master/mlijobs.txt")
  val in = new BufferedReader(new InputStreamReader(url.openStream()))
 
  val dates = new collection.mutable.ListBuffer[String]
  var (count: Int, max: Int) = (0, Int.MinValue)
  var line: String = _
 
  while ( {line = in.readLine; line} != null) {
    if (line.startsWith("License OUT ")) count += 1
    if (line.startsWith("License IN ")) count -= 1 // Redundant test when "OUT" 
    if (count > max) { // Fruitless execution when "License IN " 
      max = count
      val date = line.split(" ")(3)
      dates.clear()
      dates += date
    } else if (count == max) {
      val date = line.split(" ")(3)
      dates += date
    }
  }
 
  println("Max licenses out: " + max)
  println("At time(s): " + dates.mkString(", "))
 
}