A model for timetabling problems with period spread constraints

The generalized robust colouring problem (GRCP) deals with a robust colouring for a given graph with a fixed number of colours, not necessarily the chromatic number and considers the distance between colours as the penalization of complementary edges. This problem provides a way to solve timetabling problems that consider ‘event spread constraints’ such as ‘there must be at least d days between two events’. Because this problem is NP-hard, a heuristic approach is necessary to produce good solutions in a reasonable amount of time for large instances. In this work a greedy randomized adaptive search procedure (GRASP) is proposed to solve GRCP, which was used in instances to schedule course lectures requiring from 30 to 120h per week in total, in which the bound of the optimal solution is reached in almost every instance.