Text processing/Max licenses in use

Text processing/Max licenses in use
You are encouraged to solve this task according to the task description, using any language you may know.

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 softwares file faithfully records a checkout event when a copy of the software starts and a checkin event when the software finishes. 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

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.

APL

Works with: APL2

Translation of: J

      ⍝  Copy/paste file's contents into TXT (easiest), or TXT ← ⎕NREAD
      I  ←  TXT[;8+⎕IO]
      D  ←  TXT[;⎕IO+14+⍳19]
      lu ←  +\ ¯1 * 'OI' ⍳ I
      mx ←  (⎕IO+⍳⍴lu)/⍨lu= max ← ⌈/ lu
      ⎕  ←  'Maximum simultaneous license use is ' , ' at the following times:' ,⍨ ⍕max ⋄ ⎕←D[mx;]
Maximum simultaneous license use is 99 at the following times:
2008/10/03_08:39:34
2008/10/03_08:40:40

Fortran

Works with: Fortran version 90 and later

PROGRAM MAX_LICENSES
  IMPLICIT NONE

  INTEGER :: out=0, maxout=0, maxcount=0, err
  CHARACTER(50) :: line
  CHARACTER(19) :: maxtime(100)

  OPEN (UNIT=5, FILE="Licenses.txt", STATUS="OLD", IOSTAT=err)
  IF (err > 0) THEN
    WRITE(*,*) "Error opening file Licenses.txt"
    STOP
  END IF

  DO 
    READ(5, "(A)", IOSTAT=err) line
    IF (err == -1) EXIT          ! EOF detected
    IF (line(9:9) == "O") THEN
      out = out + 1
    ELSE IF (line(9:9) == "I") THEN
      out = out - 1
    END IF
    IF (out > maxout ) THEN
      maxout = maxout + 1
      maxcount = 1
      maxtime(maxcount) = line(15:33)
    ELSE IF (out == maxout) THEN
      maxcount = maxcount + 1
      maxtime(maxcount) = line(15:33)
    END IF
  END DO
 
  CLOSE(5)
 
  WRITE(*,"(A,I4,A)") "Maximum simultaneous license use is", maxout, " at the following times:"
  WRITE(*,"(A)") maxtime(1:maxcount)
 
END PROGRAM MAX_LICENSES

Output

Maximum simultaneous license use is  99 at the following times:
2008/10/03_08:39:34                                           
2008/10/03_08:40:40

J

   NB.  Parse data, select columns
   'I D' =: (8 ; 14+i.19) { ::]"1 L:0 ];._2 ] 1!:1 ::(''"_) <'licenses.txt'
   
   NB.  Calculate number of licenses used at any given time
   lu    =:  +/\ _1 ^ 'OI' i. I
   
   NB.  Find the maxima
   mx    =:  (I.@:= >./) lu
  
   NB.  Output results
   (mx { D) ,~ 'Maximum simultaneous license use is ' , ' at the following times:' ,~ ": {. ,mx { lu
Maximum simultaneous license use is 99 at the following times:
2008/10/03_08:39:34                                           
2008/10/03_08:40:40

OCaml

<ocaml>let () =

 let out = ref 0 in
 let max_out = ref(-1) in
 let max_times = ref [] in

 let ic = open_in "mlijobs.txt" in
 try while true do
   let line = input_line ic in
   let io, date, n =
     Scanf.sscanf line
       "License %3[IN OUT] %_c %19[0-9/:_] for job %d"
       (fun io date n -> (io, date, n))
   in
   if io = "OUT" then incr out else decr out;
   if !out > !max_out then
   ( max_out := !out;
     max_times := date :: []; )
   else if !out = !max_out then
     max_times := date :: !max_times;
 done
 with End_of_file ->
   close_in ic;
   Printf.printf
     "Maximum simultaneous license use is %d \
      at the following times:\n" !max_out;
   List.iter print_endline !max_times;

</ocaml>

Python

<python> out = 0 max_out = -1 max_times = []

for job in open('mlijobs.txt'):

   if "OUT" in job:
       out += 1
   else:
       out -= 1
   if out > max_out:
       max_out = out
       max_times = []
   if out == max_out:
       max_times.append(job.split()[3])

print "Maximum simultaneous license use is", max_out, "at the following times:" for time in max_times:

   print " ", time</python>

Example output:

Maximum simultaneous license use is 99 at the following times:
  2008/10/03_08:39:34
  2008/10/03_08:40:40