New initiates a new Graph.

NewLabeledGraph initializes a LabeledGraph with specified vertices and set the status of each vertex to unvisited.

TopologicalOrder determines whether the directed graph is acyclic, and if so then finds a topological-order, or a linear order, of the vertices.

Edge represents one edge of a directed graph.

Graph represents a directed graph.

LabeledGraph extends a generic Graph by associating a label (or status) with each vertex.

TopologicalSorter ranks vertices using Kahn's algorithm: https://en.wikipedia.org/wiki/Topological_sorting#Kahn's_algorithm However, if two vertices can be scheduled in parallel then the same rank is returned.