Personally, I think the key things in the data structure of discrete mathematics are trees (including binary trees), graphs, and infixes and suffixes of expressions (of course, if you just take the postgraduate entrance examination, this problem is not big, and many schools don't take the data structure exam). In fact, in addition to some discrete mathematics knowledge, the key points in data structure include algorithm idea, algorithm understanding and algorithm design, which are not available in discrete mathematics. And if I have a good programming foundation (including algorithm design), I really don't have too many requirements for discrete mathematics just for the joint exam. Of course, it would be better if I could understand the classical algorithms of trees and graphs (both discrete mathematics and data structures can be used) and code them.