Sequencing jobs that require common resources on a single machine: A solvable case of the TSP

In this paper a one-machine scheduling model is analysed where n diierent jobs are classiied into K groups depending on which additional resource they require. The changeover time from one job to another consists of the removal or the setup time of the two jobs and is sequence-dependent in the sense that the changeover time is determined by whether or not the two jobs belong to the same group. The objective is to minimize the makespan. The problem can also be modeled as an asymmetric Traveling Salesman Problem with a special structure on the distance matrix. For this problem we give an exact solution algorithm that requires O(n 2) elementary operations.