"Vehicle Routing Problem with Time Windows"

Given a depot with homogeneous fleet and a set of customers to be served.

Find a set of closed routes (start from depot, end at depot) to serve all customers with no exceeding vehicle's capacity and customers' due time.

Use as less number of vehicle and shorter total travel distance as possible.

• [Solomon's problem sets] (http://w.cba.neu.edu/~msolomon/problems.htm) (25, 50, and 100 customers)
• [Gehring & Homberger's extended benchmark] (http://www.sintef.no/Projectweb/TOP/VRPTW/Homberger-benchmark/) (200, 400, 600, 800, and 1000 customers)

• [VRPTW best solutions for Solomon's benchmarks] (http://sun.aei.polsl.pl/~zjc/best-solutions-solomon.html) (from Zbigniew J. Czech, 100 customers only)
• [VRPTW best solutions for Gehring and Homberger's benchmarks] (http://sun.aei.polsl.pl/~zjc/BestSolutionsGH.html) (from Zbigniew J. Czech)

vehicle_capacity
number_of_customers

Remaining lines are each customer's information:

id  x_pos  y_pos  demand  ready_time  due_time  unloading_time