Course supermarkets are emerging in many schools in China. Therefore, choosing the right courses has become a practical problem for many students. One of the primary concerns of students is to earn enough credits in a particular time limit. In this paper, we study the problem of credits maximization and evaluate the accuracy and efficiency of three different algorithms: greedy method, search method, and dynamic programming. Finally, we propose a practical implementation of the course selection algorithm that would provide new ideas for students to choose courses and suggestions for schools to set up online curriculums and course selection models.