/// <summary>
/// Implementation of Dijkstra's between 2 nodes
/// </summary>
/// <param name="node1"></param>
/// <param name="node2"></param>
/// <returns>A tuple containing the degrees of seperation of the two nodes and a detailing the connections between the two nodes.
/// Returns an "empty" tuple (0, new List) if the connection wasn't found</returns>
private Tuple <int, List <Edge <T2, T1> >, List <MyNode <T1> > > MyDijkstras(MyNode <T1> node1, MyNode <T1> node2)
{
// TODO: Implement logic to handle disconnected graphs
// TODO: Implement logic to handle weighted connections
// TODO: Implement logic to handle directed connections
int degreeOfSep = 0;
List <MyNode <T1> > nodesOnPath = new List <MyNode <T1> >();
List <Edge <T2, T1> > edgesOnPath = new List <Edge <T2, T1> >();
Dictionary <MyNode <T1>, double> nodeDistances = new Dictionary <MyNode <T1>, double>();
HashSet <MyNode <T1> > toBeVisited = new HashSet <MyNode <T1> >();
foreach (MyNode <T1> node in nodesInGraph)
{
toBeVisited.Add(node);
nodeDistances.Add(node, Int32.MaxValue);
}
nodeDistances[node1] = 0; //setting starting node distance as 0
MyNode <T1> previous = node1;
while (toBeVisited.Count > 0)
{
MyNode <T1> nearestNode = NodeWithShortestDistance(nodeDistances);
toBeVisited.Remove(nearestNode); //progressing towards condition to exit while loop
//nodesOnPath.Add(nearestNode);
degreeOfSep++;
if (!nearestNode.Equals(node2)) //nearest node isn't the one we're looking for
{
nodesOnPath.Add(nearestNode); //add nearest node to path
foreach (Edge <T2, T1> edge in adjacencyListEdges[previous])
{
if (edge.Node2.Equals(nearestNode)) //found an edge from current node to nearestEdge, TODO: need to account for when there are mutliple edges between these two nodes
{
edgesOnPath.Add(edge);
}
}
}
if (nearestNode.Equals(node2)) //found the desired node
{
//add nearest node on the path, as the terminal node
nodesOnPath.Add(nearestNode);
foreach (Edge <T2, T1> edge in adjacencyListEdges[previous])
{
if (edge.Node2.Equals(nearestNode)) //found an edge from current node to nearestEdge which in this case is the terminal node, TODO: need to account for when there are mutliple edges between these two nodes
{
edgesOnPath.Add(edge); // TODO: choose edge with smallest weight etc.
}
return(Tuple.Create(degreeOfSep, edgesOnPath, nodesOnPath));
}
}
foreach (MyNode <T1> node in nearestNode.NEIGHBORS) //updating the distance for neighbors of found nearest node
{
double temp = nodeDistances[nearestNode] + DistanceBetweenNodes(nearestNode, node, false);
if (temp < nodeDistances[node])
{
nodeDistances[node] = temp;
}
}
previous = nearestNode; //now we will progress from the currently found nearest node
}
return(Tuple.Create(degreeOfSep, edgesOnPath, nodesOnPath)); // TODO: investigate what this statement can return
}