In this paper, we introduce a constraint programming-based approach for optimization of routing and reconfiguration overhead for a class of reconfigurable processor array architectures called weakly programmable. For a given set of different algorithms the execution of which is supposed to be switched upon request at run-time, we provide static solutions for optimal routing of data between processors as well as for minimization of the routing area and the reconfiguration overhead when switching between the execution of these algorithms. In fact, applying the switching can be accomplished in just a few clock cycles. Our experiments confirm that our method can minimize routing overhead and reduce reconfiguration time significantly.