5. To find the new tasks for the active robots in group 2 it is only necessary to find, for each robot, the safe node that is closest to the current position of that robot. The adjacency matrices for each group 2 robot are obtained by selecting the appropriate rows and columns of the updated of adjacency matrices from stage 1. The group 2 safe nodes are the set of safe nodes of the original problem with, of course, any destroyed safe nodes removed. The problem is then solved by first using the shortest-path algorithm to find, for each robot, the minimum costs from its present position to all safe nodes and then selecting the closets safe node.