public static void Dijkstra <T>(RGGraph <T> graph, 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);
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;
}
}
}
}
public static void BreadthFirstSearch <T>(RGGraph <T> graph, 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;
queue.Enqueue(neighbour);
}
}
vertex.Visited = true;
}
}
void TestDirectedGraph()
{
StringBuilder sb = new StringBuilder();
sb.Append("Begin Testing Directed Graph").AppendLine();
RGVertex <string> V1 = new RGVertex <string>("v1");
RGVertex <string> V2 = new RGVertex <string>("v2");
RGVertex <string> V3 = new RGVertex <string>("v3");
RGVertex <string> V4 = new RGVertex <string>("v4");
List <RGVertex <string> > Vertices = new List <RGVertex <string> > {
V1, V2, V3, V4
};
RGGraph <string> graph = new RGGraph <string>(Vertices);
graph.CreateDirectedEdge(V1, V2, 3);
graph.CreateDirectedEdge(V4, V1, 1);
graph.CreateDirectedEdge(V2, V3, 1);
graph.CreateDirectedEdge(V2, V4, -5);
sb.Append(graph.ToString()).AppendLine();
sb.Append("End of Testing Directed Graph").AppendLine();
debugClass.WriteStringToFile(DirectedGraphFile, sb.ToString());
}
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);
}
// DFS BEGINS
public static void DepthFirstSearch <T>(RGGraph <T> graph, RGVertex <T> sourceVertex, bool reverseNeighbours = false)
{
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;
stack.Push(neighbour);
}
}
vertex.Visited = true;
}
}
void TestBFS()
{
StringBuilder sb = new StringBuilder();
sb.Append("Begin BFS test").AppendLine();
RGVertex <string> V1 = new RGVertex <string>("V1");
RGVertex <string> V2 = new RGVertex <string>("V2");
RGVertex <string> V3 = new RGVertex <string>("V3");
RGVertex <string> V4 = new RGVertex <string>("V4");
RGVertex <string> V5 = new RGVertex <string>("V5");
RGVertex <string> V6 = new RGVertex <string>("V6");
RGVertex <string> V7 = new RGVertex <string>("V7");
List <RGVertex <string> > vertices = new List <RGVertex <string> >
{
V1, V2, V3, V4, V5, V6, V7
};
RGGraph <string> graph = new RGGraph <string>(vertices);
graph.CreateUnDirectedEdge(V4, V5);
graph.CreateUnDirectedEdge(V4, V2);
graph.CreateUnDirectedEdge(V4, V1);
graph.CreateUnDirectedEdge(V5, V6);
graph.CreateUnDirectedEdge(V2, V5);
graph.CreateUnDirectedEdge(V2, V7);
graph.CreateUnDirectedEdge(V2, V1);
graph.CreateUnDirectedEdge(V1, V3);
graph.CreateUnDirectedEdge(V1, V7);
graph.CreateUnDirectedEdge(V7, V6);
string graphData = graph.ToString();
sb.Append(graphData).AppendLine();
sb.Append("Running BFS from : ").Append(V4.ToString()).AppendLine();
RGSearchAlgorithms.BreadthFirstSearch <string>(graph, V4);
List <RGVertex <string> > fromV6 = RGSearchAlgorithms.GetPathToSource <string>(V6);
sb.Append("Start vertex : V6").AppendLine();
foreach (RGVertex <string> vertex in fromV6)
{
sb.Append(vertex.ToString());
}
sb.AppendLine();
List <RGVertex <string> > path = RGSearchAlgorithms.BreadthFirstSearchWithGoal <string>(graph, V6, V3);
sb.Append("Path from v3 to v6").AppendLine();
foreach (RGVertex <string> vertex in path)
{
sb.Append(vertex.ToString());
}
sb.AppendLine();
sb.Append("End BFS test").AppendLine();
debugClass.WriteStringToFile(BFSFile, sb.ToString());
}