Research and application of strongly connected directed digraph with period

The model of strongly connected directed diagraph under certain conditions is optimized by making the digraph stage. And, is the period of the strongly connected directed digraph. Based on this model, the algorithm of calculating the optimization route of two arbitrary nodes is designed. Besides, an algorithm of calculating the shortest length of directed H circleis presented. In the end, an example is given to show the feasibility of the two algorithms. This research can be the theoretical base for the logistic optimization of city with lane.