/// <summary>
/// Constructs a new <see cref="DirectedGraph{T}"/>.
/// </summary>
public DirectedGraph()
{
_outgoing = new Dictionary <T, List <Edge <T> > >();
_incoming = new Dictionary <T, List <Edge <T> > >();
_arcs = new EdgeCollection();
}
/// <summary>
/// Constructs a new <see cref="Graph{T}"/>.
/// </summary>
public Graph()
{
_outgoing = new Dictionary <T, List <Edge <T> > >();
_edges = new EdgeCollection();
}
