public static bool DFS(this Graph g, VisitVertexFunction preVisit, VisitVertexFunction postVisit, VisitEdgeFunction visitEdge,
int startingIndex, out bool[] visited)
{
if (startingIndex < 0 || startingIndex >= g.VerticesCount)
{
throw new IndexOutOfRangeException("startingIndex must be between (inclusive) 0 and VerticesCount-1");
}
bool[] visitedTab = new bool[g.VerticesCount];
visited = visitedTab;
return(RecursiveDFS(g, preVisit, postVisit, visitEdge, startingIndex, visitedTab));
}
public static bool BFS(this Graph g, VisitVertexFunction preVisit, VisitVertexFunction postVisit, VisitEdgeFunction visitEdge,
int startingIndex, out bool[] visited)
{
if (startingIndex < 0 || startingIndex >= g.VerticesCount)
{
throw new IndexOutOfRangeException("startingIndex must be between (inclusive) 0 and VerticesCount-1");
}
bool[] visitedTab = new bool[g.VerticesCount];
visited = visitedTab;
List <Edge> edges = new List <Edge>();
Edge e = null;
do
{
e = null;
if (!visitedTab[startingIndex])
{
visitedTab[startingIndex] = true;
if (null != preVisit)
{
if (!preVisit(startingIndex))
{
return(false);
}
}
edges.AddRange(g.GetEdgesFrom(startingIndex));
if (null != postVisit)
{
if (!postVisit(startingIndex))
{
return(false);
}
}
}
if (edges.Count > 0)
{
e = edges[0];
edges.RemoveAt(0);
if (null != visitEdge)
{
if (!visitEdge(e))
{
return(false);
}
}
startingIndex = e.To;
}
}while (null != e);
return(true);
}
private static bool RecursiveDFS(this Graph g, VisitVertexFunction preVisit, VisitVertexFunction postVisit, VisitEdgeFunction visitEdge,
int startingIndex, bool[] visited)
{
if (visited[startingIndex])
{
return(true);
}
visited[startingIndex] = true;
if (null != preVisit)
{
bool preVisitResult = preVisit(startingIndex);
if (false == preVisitResult)
{
return(false);
}
}
foreach (Edge e in g.GetEdgesFrom(startingIndex))
{
if (null != visitEdge)
{
bool visitEdgeResult = visitEdge(e);
if (false == visitEdgeResult)
{
continue;
}
}
if (false == g.RecursiveDFS(preVisit, postVisit, visitEdge, e.To, visited))
{
return(false);
}
}
if (null != postVisit)
{
bool postVisitResult = postVisit(startingIndex);
if (false == postVisitResult)
{
return(false);
}
}
return(true);
}
public static bool GeneralSearch <T>(this Graph g, VisitVertexFunction preVisit, VisitVertexFunction postVisit, VisitEdgeFunction visitEdge,
int startingIndex, out bool[] visited)
where T : IEdgeCollection, new()
{
if (startingIndex < 0 || startingIndex >= g.VerticesCount)
{
throw new IndexOutOfRangeException("startingIndex must be between (inclusive) 0 and VerticesCount-1");
}
bool[] visitedTab = new bool[g.VerticesCount];
int[] post = new int[g.VerticesCount];
visited = visitedTab;
T collection = new T();
foreach (var e in g.GetEdgesFrom(startingIndex))
{
collection.Push(e);
}
post[startingIndex] = g.GetOutDegree(startingIndex);
visitedTab[startingIndex] = true;
if (null != preVisit)
{
if (!preVisit(startingIndex))
{
return(false);
}
}
post[startingIndex] = g.GetOutDegree(startingIndex);
while (!collection.IsEmpty())
{
Edge e = collection.Pop();
post[e.From]--;
if (null != visitEdge)
{
if (!visitEdge(e))
{
return(false);
}
}
if (!visitedTab[e.To])
{
visitedTab[e.To] = true;
if (null != preVisit)
{
if (!preVisit(startingIndex))
{
return(false);
}
}
foreach (var f in g.GetEdgesFrom(e.To))
{
collection.Push(f);
}
post[e.To] = g.GetOutDegree(e.To);
}
if (0 == post[e.From])
{
if (null != postVisit)
{
if (!postVisit(e.From))
{
return(false);
}
}
}
}
return(true);
}
