The CPP programme is used to solve Chinese Postman Problems in undirected and directed and mixed networks. In this problem beginning from a starting node every (directed or undirected) arc must be reached at least one time and then it should be returned to the starting node. The arc-oriented round trip to be found shall minimize the whole distance (or costs, etc.).
The Chinese Postman Problem can be in fact applied for the determination
of routes for postmen but also for the planning of street cleaning and
winter maintenance by a vehicle in a specified network of streets or for
the efficient organization of garbage disposal. A postman has to serve
all streets in a delivery area. Therewith, under certain circumstances
it can be necessary to serve certain streets after the delivery again
in order to reach another street within the delivery area. Passing a
street with no delivery symbolises an unproductive leg. It is obvious
that it is in the interest of the postman to minimize the unproductive
legs and therewith the whole distance of the delivery tour from the
starting point via all streets back to the start.