The purpose of this paper is to propose a heuristic algorithm of constructing a school timetable under consideration of subjects, teachers, classes, teaching hours, rooms, and activity types. The algorithm gives an acceptable timetable which satisfies all indispensable requirements and as many other desirable requirements as possible. Different acceptable timetables also are obtained by changing parameters in the algorithm which determine the order of assignments. The algorithm can construct acceptable timetables in almost all types of schools and universities. With a little modification a computer with small memory size can carry out the algorithm.

This paper proposes a heuristic algorithm for constructing a new school timetable by revising partially the school timetable already constructed for the previous year. This algorithm is considered as an extension of the algorithm proposed in the author's previous paper which aims at constructing a new school timetable. It is noted that the assignments in the present algorithm begin with an almost filled school timetable, while the assignments in the previous algorithm begin with an almost empty school timetable. Numerical examples show that the computation time of the present algorithm is considerably shorter than that of the previous algorithm when a timetable for the previous year is available.