Related problems of university course selection system

A negative value indicates that the number of participants in the course exceeds the planned number. Finally, lots will be drawn and the excess will be brushed off. As far as my experience is concerned, such a lottery is generally drawn by all students who choose courses together, and the planned number will be randomly generated. It depends on personality. I don't know if the automatic screening you mentioned requires students to draw lots, even if it is generated by the system, it should be random.