public static List <RGVertex <T> > DepthFirstSearchWithGoal <T>(RGGraph <T> graph, RGVertex <T> sourceVertex, RGVertex <T> goalVertex, bool reverseNeighbours = false)
{
if (sourceVertex.Equals(goalVertex))
{
return(new List <RGVertex <T> > {
sourceVertex
});
}
foreach (RGVertex <T> vertex in graph.Vertices)
{
vertex.Parent = null;
vertex.Distance = 0;
vertex.Visited = false;
}
Stack <RGVertex <T> > stack = new Stack <RGVertex <T> >();
stack.Push(sourceVertex);
while (stack.Count > 0)
{
RGVertex <T> vertex = stack.Pop();
List <RGVertex <T> > neighbours = graph.GetAdjacentVertices(vertex);
if (reverseNeighbours)
{
neighbours.Reverse();
}
foreach (RGVertex <T> neighbour in neighbours)
{
if (!neighbour.Visited)
{
neighbour.Parent = vertex;
neighbour.Distance = vertex.Distance + graph.GetEdgeWeight(vertex, neighbour);
neighbour.Visited = true;
if (neighbour.Equals(goalVertex))
{
return(GetPathToSource <T>(neighbour));
}
stack.Push(neighbour);
}
}
vertex.Visited = true;
}
// no path found
return(null);
}
public static List <RGVertex <T> > BreadthFirstSearchWithGoal <T>(RGGraph <T> graph, RGVertex <T> sourceVertex, RGVertex <T> goalVertex)
{
if (sourceVertex.Equals(goalVertex))
{
return(new List <RGVertex <T> > {
sourceVertex
});
}
foreach (RGVertex <T> vertex in graph.Vertices)
{
vertex.Parent = null;
vertex.Distance = 0;
vertex.Visited = false;
}
Queue <RGVertex <T> > queue = new Queue <RGVertex <T> >();
queue.Enqueue(sourceVertex);
while (queue.Count > 0)
{
RGVertex <T> vertex = queue.Dequeue();
foreach (RGVertex <T> neighbour in graph.GetAdjacentVertices(vertex))
{
if (!neighbour.Visited)
{
neighbour.Parent = vertex;
neighbour.Distance = vertex.Distance + graph.GetEdgeWeight(vertex, neighbour);
neighbour.Visited = true;
if (neighbour.Equals(goalVertex))
{
return(GetPathToSource <T>(neighbour));
}
queue.Enqueue(neighbour);
}
}
vertex.Visited = true;
}
// no path to goal vertex
return(null);
}
public static List <RGVertex <T> > DijkstraWithGoal <T>(RGGraph <T> graph, RGVertex <T> source, RGVertex <T> goal)
{
if (source.Equals(goal))
{
return(new List <RGVertex <T> > {
source
});
}
List <RGVertex <T> > unfinishedVertices = new List <RGVertex <T> >();
foreach (RGVertex <T> vertex in graph.Vertices)
{
vertex.Distance = int.MaxValue;
vertex.Parent = null;
unfinishedVertices.Add(vertex);
}
source.Distance = 0;
while (unfinishedVertices.Count > 0)
{
RGVertex <T> vertex = GetClosestVertex(unfinishedVertices);
unfinishedVertices.Remove(vertex);
if (vertex.Equals(goal))
{
return(GetPathToSource(vertex));
}
foreach (RGVertex <T> adjVertex in graph.GetAdjacentVertices(vertex))
{
if (adjVertex.Distance > vertex.Distance + graph.GetEdgeWeight(vertex, adjVertex))
{
adjVertex.Distance = vertex.Distance + graph.GetEdgeWeight(vertex, adjVertex);
adjVertex.Parent = vertex;
}
}
}
return(null);
}