//Use this to add an edge to the graph. The method will ensure that the
//edge passed as a parameter is valid before adding it to the graph. If the
//graph is a digraph then a similar edge connecting the nodes in the opposite
//direction will be automatically added.
public void AddEdge(GraphEdge edge)
{
//first make sure the from and to nodes exist within the graph
Assert.IsTrue((edge.From() < m_iNextNodeIndex) && (edge.To() < m_iNextNodeIndex),
"<SparseGraph::AddEdge>: invalid node index" + " edge:" + edge.From() + "->" + edge.To() + " NextNode : " + m_iNextNodeIndex);
//make sure both nodes are active before adding the edge
if ((m_Nodes[edge.To()].Index() != GraphNode.INVALID_NODE_INDEX) &&
(m_Nodes[edge.From()].Index() != GraphNode.INVALID_NODE_INDEX))
{
//add the edge, first making sure it is unique
if (UniqueEdge(edge.From(), edge.To()))
{
m_Edges[edge.From()].AddLast(edge);
}
//if the graph is undirected we must add another connection in the opposite
//direction
if (!m_bDigraph)
{
//check to make sure the edge is unique before adding
if (UniqueEdge(edge.To(), edge.From()))
{
GraphEdge NewEdge = edge.Clone() as GraphEdge;
NewEdge.SetTo(edge.From());
NewEdge.SetFrom(edge.To());
m_Edges[edge.To()].AddLast(NewEdge);
}
}
}
}
//this method performs the DFS search
private bool Search()
{
//create a std stack of edges
Stack <GraphEdge> stack = new Stack <GraphEdge>();
//create a dummy edge and put on the stack
GraphEdge Dummy = new GraphEdge(m_iSource, m_iSource, 0);
stack.Push(Dummy);
//while there are edges in the stack keep searching
while (0 != stack.Count)
{
//grab the next edge
GraphEdge Next = stack.Peek();
//Debug.Log(Next); //chamto test
//remove the edge from the stack
stack.Pop();
//make a note of the parent of the node this edge points to
m_Route[Next.To()] = Next.From();
//put it on the tree. (making sure the dummy edge is not placed on the tree)
if (Next != Dummy)
{
m_SpanningTree.Add(Next);
}
//and mark it visited
m_Visited[Next.To()] = (int)Aid.visited;
//if the target has been found the method can return success
if (Next.To() == m_iTarget)
{
return(true);
}
//push the edges leading from the node this edge points to onto
//the stack (provided the edge does not point to a previously
//visited node)
foreach (GraphEdge pE in m_Graph.GetEdges(Next.To()))
{
if (m_Visited[pE.To()] == (int)Aid.unvisited)
{
stack.Push(pE);
}
}
}
//no path to target
return(false);
}
