A Two-Phase Heuristic Algorithm for the Common Frequency Routing Problem with Vehicle Type Choice in the Milk Run

Algorithm 2

Set the total number of iterations performed by the TS (NI). Set tabulist = . Set the initial solution to , , which is generated in

the first phase. Let the optimal solution be , and the current solution , .

Let (record the number of current iterations). Set the number of candidate solutions () in the TS.

Do while   < NI

 Employ the four neighborhood methods to generate h candidate solutions satisfying the time

 constraint in (9) with values greater than . Calculate the objective function values of these solutions

 .

 Obtain (, ), whose objective function value is optimal.

 If  min

   Update the tabulist.

 Else

   Do while (, ) is in the tabulist

    Select the suboptimal solution from the candidate solutions and record it as (, ).

   End  do

   ()

   Update the tabulist

 End if

End do