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).




$handle = fopen ("mlijobs.txt", "rb");
$maxcount = 0;
$count = 0;
$times = array();
while (!feof($handle)) {
    $buffer = fgets($handle);
    $op = trim(substr($buffer,8,3));
    switch ($op){
        case 'IN':
            $count--;
        break;
        case 'OUT':
            $count++;
            preg_match('/([\d|\/|_|:]+)/',$buffer,$time);
            if($count>$maxcount){
                $maxcount = $count;
                $times = Array($time[0]);
            }elseif($count == $maxcount){
                $times[] = $time[0];
            }
        break;
    }   
}
fclose ($handle);
 
echo $maxcount . '<br>';
for($i=0;$i<count($times);$i++){
    echo $times[$i] . '<br>';
}