As far as the overall level of computer science and technology of these two universities is concerned, Nanjing University is better. Nanjing University has an absolute advantage in software theory, especially in software engineering. A++ level, Nanjing University pays attention to theory, Southeast University pays attention to application, Nanjing University has a higher admission score than Southeast University, and Southeast University ranks better in engineering than Nanjing University. You should analyze which one is more suitable for you. You'd better go to the Postgraduate Entrance Examination Forum, as well as their school's website and BBS to learn more about it, and then make a decision based on your actual situation! Wish you success!