A Three-Stage Saving-Based Heuristic for Vehicle Routing Problem with Time Windows and Stochastic Travel Times

Algorithm 2

The procedure to construct an initial solution.

(1) Set savingList = , Solution = ;

(2) While at least one of customers has not been included in Solution, do:

(3)  Calculate the savings for all pairs of customers that can be directly connected, insert

     all the savings into savingList;

(4)  Fetch a saving, denoted as Sav, from savingList according to the roll-up evaluation

     strategy which is detailed in Section 3.3;

(5)  Connect the two routes that are corresponding to the two customers in Sav, so that a

     new route can be obtained;

(6)  Insert the new combined route into Solution and delete the route that is

     corresponding to the two customers in Sav from Solution if it has been included in Solution;

(7) Clear savingList;

(8) Endwhile;

(9) Return Solution.