Branch and Price and Cut for the Split-Delivery Vehicle Routing Problem with Time Windows and Linear Weight-Related Cost

This paper addresses a new vehicle routing problem that simultaneously involves time windows, split delivery, and linear weight-related cost. This problem is a generalization of the split delivery vehicle routing problem with time windows (SDVRPTW), which consists of determining a set of least-cost vehicle routes to serve all customers while respecting the restrictions of vehicle capacity and time windows. The travel cost per unit distance is a linear function of the vehicle weight and the customer demand can be fulfilled by multiple vehicles. To solve this problem, we propose an exact branch-and-price-and-cut algorithm, where the pricing subproblem is a variant of the resource-constrained elementary shortest path problem. We first prove that at least one optimal solution to the pricing subproblem is associated with an extreme delivery pattern, and then we design a tailored and novel label-setting algorithm to solve the pricing subproblem. Computational results show that our proposed algorithm can handle both the SDVRPTW and our new problem effectively.