Walk Through Combinatorics, A: An Introduction To Enumeration And Graph TheoryThis is a textbook for an introductory combinatorics course that can take up one or two semesters. An extensive list of exercises, ranging in difficulty from routine to worthy of independent publication, is included. In each section, there are also exercises that contain material not explicitly discussed in the text before, so as to provide instructors with extra choices if they want to shift the emphasis of their course. It goes without saying that