Probability theory and mathematical statistics are particularly useful after the graduate school begins to do experiments, but they are not obvious at the undergraduate stage (as far as most universities are concerned);
Linear algebra is very practical and targeted in the computer field, especially in dealing with large-scale data, matrix problems, image processing and other issues in algorithm design.
Discrete mathematics is a specialized mathematics course of computer, and the content it tells plays an important role in algorithm design, so the importance of making software can be imagined!