A branch-and-price algorithm for the scheduling of customer visits in the context of multi-period service territory design

A problem that arises in the context of multi-period service territory design is the scheduling of customer visits. In this problem, customer visits must be assigned to the days of the planning horizon subject to customer-specific requirements. We consider a highly relevant planning scenario of this problem and present an exact branch-and-price algorithm. We propose specialized acceleration techniques, particularly a fast pricing heuristic and techniques to reduce the symmetry inherent to the problem. Experiments on real-world data sets show that instances with up to 55 customers and a planning horizon of four weeks with five days per week can be solved to optimality in reasonable running times.