DoubleLinkedList<GraphNode *> Dijkstra(GraphNode *Start, GraphNode * End)
{
Map<GraphNode *, DijkstraHelperNode *> NodeHelperMap;
DoubleLinkedList<DijkstraHelperNode *> Visited;
MinHeap<DijkstraHelperNode *> OpenHeap;
DijkstraHelperNode *NewHelper = new DijkstraHelperNode();
NewHelper->m_Node = Start;
NewHelper->m_Cost = 0;
NodeHelperMap.Insert(Start, NewHelper);
OpenHeap.Insert(NewHelper);
while(!OpenHeap.IsEmpty())
{
DijkstraHelperNode *CurrentHelperNode = OpenHeap.PopTop();
assert(CurrentHelperNode != NULL);
GraphNode *CurrentGraphNode = CurrentHelperNode->m_Node;
assert(CurrentGraphNode != NULL);
DoubleLinkedList<GraphEdge *> *CurrendEdges = CurrentGraphNode->GetEdges();
DoubleListNode<GraphEdge *> *CurrentEdge = CurrentEdges.GetHead();
while(CurrentEdge != NULL)
{
GraphNode *OtherNode = CurrentEdge->m_End;
if(OtherNode == CurrentGraphNode)
{
OtherNode = CurrentEdge->m_Start;
}
assert(OtherNode != CurrentGraphNode);
DijkstraHelperNode *NodeHelper = NodeHelperMap.GetValue(OtherNode);
if(NodeHelper == NULL)
{
NodeHelper = new DijkstraHelperNode();
NodeHelper->m_Node = OtherNode;
NodeHelperMap.Insert(OtherNode, NodeHelper);
OpenHeap.Insert(NodeHelper);
}
int CostToNode = CurrentHelperNode->m_Cost + CurrentEdge->m_Cost;
if(CostToNode < NodeHelper->m_Cost)
{
NodeHelper->m_Cost = CostToNode;
NodeHelper->m_Previous = CurrentGraphNode;
OpenHeap.Update(NodeHelper);
}
if(OtherNode == End)
{
break;
}
}
}
DoubleLinkedList<GraphNode *> Path;
DijkstraHelperNode *EndHelper = NodeHelperMap.GetValue(End);
if(EndHelper != NULL)
{
DijkstraHelperNode *CurrentHelper = EndHelper;
while(CurrentHelper != NULL)
{
Path.AddFront(CurrentHelper->m_Node);
CurrentHelper = CurrentHelper->m_Previous;
}
}
}
