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).




 
class
    APPLICATION
 
create
    make
 
feature
 
    make
            -- Max Licences used.
        local
            count: INTEGER
            max_count: INTEGER
            date: STRING
        do
            read_list
            create date.make_empty
            across
                data as d
            loop
                if d.item.has_substring ("OUT") then
                    count := count + 1
                    if count > max_count then
                        max_count := count
                        date := d.item
                    end
                elseif d.item.has_substring ("IN") then
                    count := count - 1
                end
            end
            io.put_string ("Max Licences OUT: " + max_count.out)
            io.new_line
            io.put_string ("Date: " + date.substring (15, 33))
        end
 
    original_list: STRING = "mlijobs.txt"
 
feature {NONE}
 
    read_list
            -- Data read into 'data.
        local
            l_file: PLAIN_TEXT_FILE
        do
            create l_file.make_open_read_write (original_list)
            l_file.read_stream (l_file.count)
            data := l_file.last_string.split ('%N')
            l_file.close
        end
 
    data: LIST [STRING]
 
end
 