The EdgeWeightedDirectedCycle class represents a data type for determining whether an edge-weighted digraph has a directed cycle. The HasCycle operation determines whether the edge-weighted digraph has a directed cycle and, if so, the Cycle operation returns one.

This implementation uses depth-first search. The constructor takes time proportional to V + E (in the worst case), where V is the number of vertices and E is the number of edges. Afterwards, the HasCycle operation takes constant time; the Cycle operation takes time proportional to the length of the cycle.

See to compute a topological order if the edge-weighted digraph is acyclic.