public UnweightedDirectedPath(
IUnweightedDirectedGraph <TVertex> graph,
TVertex origin
) : this(graph, origin, origin, new List <TVertex> {
origin
})
{
}
public UnweightedDirectedPathCollection(
IUnweightedDirectedGraph <TVertex> graph,
TVertex origin,
IDictionary <TVertex, TVertex> vertices
) : base(graph, origin)
{
Graph = graph;
Vertices = vertices;
}
public UnweightedDirectedPath(
IUnweightedDirectedGraph <TVertex> graph,
TVertex origin,
TVertex destination,
IEnumerable <TVertex> vertices
) : base(graph, origin, destination, vertices)
{
Graph = graph;
}
public DepthFirstSearchUnweightedDirectedPathEnumerator(
IUnweightedDirectedGraph <TVertex> graph,
TVertex origin
)
{
Graph = graph;
Origin = origin;
Stack = new Stack <TVertex>();
Visited = new Dictionary <TVertex, TVertex>();
Initialize();
}
public BreadthFirstSearchUnweightedDirectedPathEnumerator(
IUnweightedDirectedGraph <TVertex> graph,
TVertex origin
)
{
Graph = graph;
Origin = origin;
Queue = new Queue <TVertex>();
Visited = new Dictionary <TVertex, TVertex>();
Initialize();
}
public static IUnweightedDirectedGraph <TVertex> DepthFirstSearch <TVertex>(
this IUnweightedDirectedGraph <TVertex> graph,
TVertex origin
)
{
if (graph == null)
{
throw new ArgumentNullException(nameof(graph));
}
if (origin == null)
{
throw new ArgumentNullException(nameof(origin));
}
if (!graph.Vertices.Contains(origin))
{
throw new ArgumentException();
}
var visited = new HashSet <TVertex>();
var output = new UnweightedDirectedGraph <TVertex>();
var stack = new Stack <TVertex>();
visited.Add(origin);
stack.Push(origin);
while (stack.Count > 0)
{
var vertex = stack.Pop();
bool Predicate(TVertex successorVertex)
{
return(!visited.Contains(successorVertex));
}
foreach (var successorVertex in graph.SuccessorVertices(vertex).Where(Predicate))
{
output.AddEdge(vertex, successorVertex);
visited.Add(successorVertex);
stack.Push(successorVertex);
}
}
return(output);
}
public DepthFirstSearchUnweightedDirectedPathAlgorithm(IUnweightedDirectedGraph <TVertex> graph)
{
Graph = graph;
}
public static IEnumerable <IUnweightedDirectedPath <TVertex> > AllSimplePaths <TVertex>(
this IUnweightedDirectedGraph <TVertex> graph,
TVertex origin,
TVertex destination,
int maxDepth = int.MaxValue
)
{
if (graph == null)
{
throw new ArgumentNullException(nameof(graph));
}
if (origin == null)
{
throw new ArgumentNullException(nameof(origin));
}
if (destination == null)
{
throw new ArgumentNullException(nameof(destination));
}
if (!graph.Vertices.Contains(origin))
{
throw new ArgumentException();
}
if (!graph.Vertices.Contains(destination))
{
throw new ArgumentException();
}
var visited = new Stack <TVertex>();
var paths = new HashSet <IUnweightedDirectedPath <TVertex> >();
visited.Push(origin);
var stack = new Stack <Tuple <TVertex, Queue <IUnweightedEndpoint <TVertex> > > >();
stack.Push(new Tuple <TVertex, Queue <IUnweightedEndpoint <TVertex> > >(
origin,
graph.SuccessorEndpoints(origin).ToQueue()
));
while (stack.Count > 0)
{
var(vertex, successorEndpoints) = stack.Peek();
if (Equals(vertex, destination) || successorEndpoints.Count == 0 || stack.Count > maxDepth)
{
if (Equals(vertex, destination))
{
var unweightedDirectedPath = new UnweightedDirectedPath <TVertex>(
graph,
origin,
destination,
new Stack <TVertex>(visited)
);
paths.Add(unweightedDirectedPath);
}
visited.Pop();
stack.Pop();
}
else
{
var successorEndpoint = successorEndpoints.Dequeue();
visited.Push(successorEndpoint.Vertex);
bool Predicate(IUnweightedEndpoint <TVertex> grandchildEndpoint)
{
return(!visited.Contains(grandchildEndpoint.Vertex));
}
stack.Push(new Tuple <TVertex, Queue <IUnweightedEndpoint <TVertex> > >(
successorEndpoint.Vertex,
graph.SuccessorEndpoints(successorEndpoint.Vertex).Where(Predicate).ToQueue()
));
}
}
return(paths);
}
