As for self-study, data structure is the most difficult. The textbook I use in class is published in Tsinghua University. Discrete mathematics is relatively simple, and self-study is no problem!
The theoretical knowledge of management principles is the mainstay, so it is very simple to establish a mind map when reviewing. Don't recite. For exams, different schools have different ways to set questions. The simple point is to ask knowledge points directly, and the difficult point is case analysis, which should be analyzed theoretically in connection with actual cases.
Microeconomics, I like it very much, and it is easy to map theory to life. There are many ways to set questions in the exam, such as noun explanation, theoretical discussion, connecting with actual cases and calculating questions! I haven't studied macroeconomics, so I have nothing to say. The content is macroeconomics and policies!
To sum up, I think data organization is the most difficult, followed by western classics, and management is similar to discrete mathematics. It should be a piece of cake for you with a mathematical mind!