Increases the flow on the edge in the direction to the given vertex. If vertex is the tail vertex, this increases the flow on the edge by delta; if vertex is the head vertex, this decreases the flow on the edge by delta.

Demo test the FlowEdge data type.

Returns the endpoint of the edge that is different from the given vertex (unless the edge represents a self-loop in which case it returns the same vertex).

Returns the residual capacity of the edge in the direction to the given vertex.

Returns a string representation of the edge.