public void GeneratePath(List <Vertex> graphVertexes, Vertex destinationVertex)
{
DijkstraElement pathDijkstraElement;
Edge pathEdge;
GetShortestPathsWithDijkstra(graphVertexes, destinationVertex);
pathDijkstraElement = DijkstraElements.Find(DijkstraElement => DijkstraElement.IDVertex.Equals(destinationVertex));
do
{
pathEdge = pathDijkstraElement.PreviousDijkstraElement.IDVertex.EdgeList.Find(Edge => Edge.Destination.Equals(pathDijkstraElement.IDVertex));
if (pathEdge != null)
{
Path.Enqueue(pathEdge);
pathDijkstraElement = pathDijkstraElement.PreviousDijkstraElement;
}
}while (!pathDijkstraElement.IDVertex.Equals(OriginVertex));
Path = new Queue <Edge>(Path.Reverse());
CurrentEdge = Path.Dequeue();
}
// (N - 1)(N + log(N)) = (N^2 + Nlog(N) - N - log(N)) = O(N^2)
private void UpdateDijkstraElements(DijkstraElement definitiveDijkstraElement)
{
int destinationIndex;
foreach (Edge currentVertexEdge in definitiveDijkstraElement.IDVertex.EdgeList)
{
destinationIndex = DijkstraElements.FindIndex(DijkstraElement => DijkstraElement.IDVertex == currentVertexEdge.Destination);
if (currentVertexEdge.Weight + definitiveDijkstraElement.AccumulatedDistance < DijkstraElements[destinationIndex].AccumulatedDistance)
{
DijkstraElements[destinationIndex].AccumulatedDistance = currentVertexEdge.Weight + definitiveDijkstraElement.AccumulatedDistance;
DijkstraElements[destinationIndex].PreviousDijkstraElement = definitiveDijkstraElement;
RelocateDijkstraElement(destinationIndex);
}
}
}
// log(N)
private void RelocateDijkstraElement(int index)
{
DijkstraElement temporalDijkstraElement = DijkstraElements[index];
int newIndex;
DijkstraElements.RemoveAt(index);
newIndex = DijkstraElements.BinarySearch(temporalDijkstraElement, new CompareDijkstraElementsByAccumulatedDistance());
if (newIndex < 0)
{
DijkstraElements.Insert(~newIndex, temporalDijkstraElement);
}
else
{
DijkstraElements.Insert(newIndex, temporalDijkstraElement);
}
}
// N + log(N) + N(N^2) = N + log(N) + N^3 = O(N^3)
private void GetShortestPathsWithDijkstra(List <Vertex> graphVertexes, Vertex destinationVertex)
{
int definitiveDijkstraElements = 0, originVertexIndex = OriginVertex.VertexCircle.ID - 1;
foreach (Vertex currentVertex in graphVertexes)
{
DijkstraElements.Add(new DijkstraElement(currentVertex));
}
DijkstraElements[originVertexIndex].AccumulatedDistance = 0;
DijkstraElements[originVertexIndex].PreviousDijkstraElement = DijkstraElements[originVertexIndex];
RelocateDijkstraElement(originVertexIndex);
while (definitiveDijkstraElements != DijkstraElements.Count)
{
if (DijkstraElements[definitiveDijkstraElements].AccumulatedDistance == double.PositiveInfinity || DijkstraElements[definitiveDijkstraElements].IDVertex == destinationVertex)
{
break;
}
UpdateDijkstraElements(DijkstraElements[definitiveDijkstraElements++]);
}
}
