AddArc adds an Arc from |from| to |to|, having |capacity| and |priority|.

FindMaxFlow determines the maximum flow of the flow network rooted at |source|.

InitNodes returns a slice of Nodes having size |n|.

SortNodeArcs orders the Arcs of one or more Nodes by their respective priorities.

Arc defines an edge along which flow may occur in a flow network.

Node defines a vertex in a flow network, through which flow occurs.