CATERER PROBLEM

Caterer problem - A caterer has booked his services for the next T days. He requires r_t fresh napkins on the t-th day, t=1,...,T. He sends his soiled napkins to the laundry, which has 3 speeds of service: s=1, 2, or 3 days. The faster the service, the higher the cost, c_s, of laundering a napkin. He can also purchase new napkins at a cost, c_0. With an initial stock of N napkins, the caterer wishes to minimize his total cost. (This can be formulated as a transportation problem .)