Lot scheduling on a single machine to minimize the (weighted) number of tardy orders

We consider a single machine lot scheduling problem. A number of customer orders of different sizes may be processed in the same lot. We consider first the setting that splitting orders between consecutive lots is allowed. We focus on minimizing the number of tardy orders. A polynomial time solution algorithm is introduced for this problem. We then study the extension to minimizing the weighted number of tardy orders. This problem is NP-hard, and a pseudo-polynomial dynamic programming is provided and tested. We also study the setting of no-split. The problem of minimizing the number of tardy orders in this context is proved to be strongly NP-hard, and an efficient heuristic is introduced.