public static IWeightedEndpointPair <TVertex, TEdge> ToEndpointPair <TVertex, TEdge>(
this IWeightedEndpoint <TVertex, TEdge> endpoint,
TVertex origin
)
{
return(new WeightedEndpointPair <TVertex, TEdge>(origin, endpoint.Vertex, endpoint.Edge));
}
private IEnumerable <IWeightedEndpoint <TVertex, TEdge> > CreatePath(
IWeightedEndpoint <TVertex, TEdge> origin,
TVertex destination
)
{
if (origin == null)
{
throw new ArgumentNullException(nameof(origin));
}
if (destination == null)
{
throw new ArgumentNullException(nameof(destination));
}
return(CreatePath(origin, destination, new HashSet <TVertex>()));
}
private IEnumerable <IWeightedEndpoint <TVertex, TEdge> > CreatePath(
IWeightedEndpoint <TVertex, TEdge> origin,
TVertex destination,
ICollection <TVertex> visited
)
{
if (origin == null)
{
throw new ArgumentNullException(nameof(origin));
}
if (destination == null)
{
throw new ArgumentNullException(nameof(destination));
}
if (visited == null)
{
throw new ArgumentNullException(nameof(visited));
}
var random = new Random();
visited.Add(origin.Vertex);
var stack = new Stack <Tuple <IWeightedEndpoint <TVertex, TEdge>, IList <IWeightedEndpoint <TVertex, TEdge> > > >();
stack.Push(new Tuple <IWeightedEndpoint <TVertex, TEdge>, IList <IWeightedEndpoint <TVertex, TEdge> > >(
origin,
Graph.SuccessorEndpoints(origin.Vertex).ToList()
));
while (stack.Count > 0)
{
var(endpoint, successorEndpoints) = stack.Peek();
if (Equals(endpoint.Vertex, destination))
{
return(stack.Select(tuple => tuple.Item1).Reverse());
}
if (successorEndpoints.Count == 0)
{
stack.Pop();
}
else
{
var index = random.Next(successorEndpoints.Count);
var successorEndpoint = successorEndpoints[index];
visited.Add(successorEndpoint.Vertex);
bool Predicate(IWeightedEndpoint <TVertex, TEdge> grandchildEndpoint)
{
return(!visited.Contains(grandchildEndpoint.Vertex));
}
stack.Push(new Tuple <IWeightedEndpoint <TVertex, TEdge>, IList <IWeightedEndpoint <TVertex, TEdge> > >(
successorEndpoint,
Graph.SuccessorEndpoints(successorEndpoint.Vertex).Where(Predicate).ToList()
));
successorEndpoints.RemoveAt(index);
}
}
return(null);
}
