Dynamic programming to solve Single-item UDLSP

This code is to find an optimal solution for the single-item uncapacitated dynamic lot-sizing problem with time-varying costs (UDLSP)

Dynamic programming based on network flow approach is applied to find an optimal solution for the single-item uncapacitated dynamic lot-sizing problem. This code is used for calculating in article , W.Boonphakdee and P. Charnsethikul "Column generation approach for solving uncapacitated dynamic lot-sizing problems with time-varying costs" International Journal of Mathematics in Operational Research vol.23 no.1 pp.55-75. 2022.