Discrete mathematics is the study of mathematical structures that are discrete rather than continuous. It has many applications in computer science, as computers use discrete structures to represent and manipulate data. Some key topics in discrete mathematics include logic and proofs, number theory, counting, and graph theory. These topics help with problem solving, algorithms, data structures, cryptography, and the design of efficient computer systems and networks. Examples of problems solved with discrete mathematics include the fastest sorting algorithms, map coloring, efficient data transmission, electronic health records, and Google Maps routing.