public static bool IsRoutePresentBFS(DirectedGaph grph, int source, int destination)
{
if (source == destination)
{
return(true);
}
grph.visited[source] = true;
Queue <int> verticesQueue = new Queue <int>();
verticesQueue.Enqueue(source);
while (verticesQueue.Count > 0)
{
int vertice = verticesQueue.Dequeue();
foreach (int adjVertice in grph.edges[vertice])
{
if (adjVertice == destination)
{
return(true);
}
if (!grph.visited[adjVertice])
{
grph.visited[adjVertice] = true;
verticesQueue.Enqueue(adjVertice);
}
}
}
return(false);
}
public static void BuildOrderMain()
{
DirectedGaph graph = new DirectedGaph(6);
graph.AddEdge(0, 3);
graph.AddEdge(5, 1);
graph.AddEdge(5, 0);
graph.AddEdge(1, 3);
graph.AddEdge(3, 2);
//graph.AddEdge(3, 0);
GetBuildOrder(graph);
}
public static Stack <int> GetBuildOrder(DirectedGaph graph)
{
HashSet <int> addedToBuild = new HashSet <int>(); // Store which are added to build order
Stack <int> buildOrder = new Stack <int>(); // Store what is the build order
for (int i = 0; i < graph.edges.Length; i++)
{ //GO DFS for all edges
if (!addedToBuild.Contains(i)) // If not already added to build then DFS
{
DFS(graph, i, buildOrder, addedToBuild, new HashSet <int>());
}
}
return(buildOrder);
}
public static void RouteBetweenTwoNodesMain()
{
DirectedGaph grph = new DirectedGaph(7);
grph.AddEdge(0, 1);
grph.AddEdge(1, 2);
grph.AddEdge(2, 0);
grph.AddEdge(2, 3);
grph.AddEdge(3, 2);
grph.AddEdge(4, 6);
grph.AddEdge(5, 4);
grph.AddEdge(6, 5);
//bool isRoute = IsRoutePresentDFS(grph, 0, 3);
bool isRoute = IsRoutePresentBFS(grph, 0, 5);
}
public static bool IsRoutePresentDFS(DirectedGaph grph, int source, int destination)
{
grph.visited[source] = true;
if (source == destination) // Reached Destination node
{
return(true);
}
foreach (int vertice in grph.edges[source])
{
if (!grph.visited[vertice])
{
return(IsRoutePresentDFS(grph, vertice, destination));
}
}
return(false);
}
public static void DFS(DirectedGaph graph, int position, Stack <int> buildOrder, HashSet <int> addedToBuild, HashSet <int> visiting)
{
if (visiting.Contains(position))
{//If visited in this cycle then its Cyclic
throw new Exception("Cyclic Dependency");
}
else
{//Add to check for cycles
visiting.Add(position);
}
foreach (int dependent in graph.edges[position])
{//GO DFS for all dependents
if (!addedToBuild.Contains(dependent))
{
DFS(graph, dependent, buildOrder, addedToBuild, visiting);
}
}
buildOrder.Push(position);
addedToBuild.Add(position);
}