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).




my %licenses;
 
%licenses<count max> = 0,0;
 
for $*IN.lines -> $line {
    my ( $license, $date_time );
    ( *, $license, *, $date_time ) = split /\s+/, $line;
    if $license eq 'OUT' {
        %licenses<count>++;
        if %licenses<count> > %licenses<max> {
            %licenses<max>   = %licenses<count>;
            %licenses<times> = [$date_time];
        }
        elsif %licenses<count> == %licenses<max> {
            %licenses<times>.push($date_time);
        }
    }
    elsif $license eq 'IN' {
        if %licenses<count> == %licenses<max> {
            %licenses<times>[*-1] ~= " through " ~ $date_time;
        }
        %licenses<count>--;
    }
    else {
        # Not a licence OUT or IN event, do nothing
    }
};
 
my $plural = %licenses<times>.elems == 1 ?? '' !! 's';
 
say "Maximum concurrent licenses in use: {%licenses<max>}, in the time period{$plural}:";
say join ",\n", %licenses<times>.list;