First consider the situation that the number of elective courses you want is small:

Set these nine courses x 1~x9.

Where xi can only be 0 or 1.

Then the objective function is min x 1+x2+...+x9.

You must have taken at least two math courses, three operational research courses and two computer courses when you graduated.

So the constraint is

x 1+x2+x3+x4+X5 & gt； =2

x3+X5+X6+x8+x9 & gt； =3

x4+X6+x7+x9 & gt； =2

In addition, X3 must learn x 1x2, and x3.

Write constraints in the same way as others.

This is 0- 1 linear programming, and lingo should be enough.

After calculating the results, linear programming is made with the goal of multi-credits.

That is, the objective function is max 5x 1+4x2+...3x9.

In fact, you can find a book on mathematical modeling. I wrote it by impression. It may not be clear, but I remember the same example in the book.