| Constructive_Heuristic( ) |
| find customers’ geometric centre |
| divide customers into 4 quadrants with their geometric centre as a reference |
| sort each quadrant list of customers in increasing order of time window opening |
| //Travel quadrants in anti-clockwise sequence starting from the upper right quadrant// |
| for each quadrant customer list do |
| for every customer with a list of authorised vehicles do |
| find the smallest insertion cost position among authorised vehicle workdays |
| if a position was found then |
| insert the customer and remove it from the quadrant list |
| sort the list of vehicles in decreasing order of cargo capacity |
| sort the list of vehicles in increasing order of cost with a stable sorting algorithm |
| for each vehicle in the sorted list of vehicles do |
| //Travel quadrants in an anti-clockwise sequence// |
| for each quadrant customer list do |
| for each customer do |
| find smallest insertion cost position in the current vehicle workday |
| if a position was found then |
| insert the customer and remove it from quadrant list |
| //Check if the current solution is infeasible// |
| if there are unserved customers then |
| if tabu search was never called then |
| //“Make room” for future insertions by cost reduction// |
| call tabu search of few iterations to improve the current solution |
| go to line 5 to insert unserved customers |
| else |
| call a commercial software to find a feasible solution |
