public override bool RemoveVertex(DVertex <T> vertex)
{
if (!Vertices.Contains(vertex))
{
return(false);
}
for (int i = 0; i < Edges.Count; i++)
{
if (Edges[i].StartingPoint == vertex)
{
Edges.RemoveAt(i);
i--;
}
else if (Edges[i].EndingPoint == vertex)
{
Edges[i].StartingPoint.Neighbors.RemoveAt(Edges[i].StartingPoint.Neighbors.FindIndex((a) => { return(a.EndingPoint == vertex); }));
Edges.RemoveAt(i);
i--;
}
}
Vertices.Remove(vertex);
return(true);
}
public void BreadthFirstTraversal(DVertex <T> start)
{
breadthFirstTraversal(start, new Queue <DVertex <T> >(new DVertex <T>[] { start }));
for (int i = 0; i < Count; i++)
{
this[i].IsVisited = false;
}
void breadthFirstTraversal(DVertex <T> current, Queue <DVertex <T> > queue)
{
current.IsVisited = true;
foreach (var neighbor in current.Neighbors)
{
if (!neighbor.EndingPoint.IsVisited && !queue.Contains(neighbor.EndingPoint))
{
queue.Enqueue(neighbor.EndingPoint);
}
}
queue.Dequeue();
if (queue.Count == 0)
{
return;
}
Console.WriteLine($"\t{current.Value}->{queue.Peek().Value}");
breadthFirstTraversal(queue.Peek(), queue);
}
}
public void DepthFirstSearch(DVertex <T> start)
{
depthFirstSearch(start);
for (int i = 0; i < Count; i++)
{
this[i].IsVisited = false;
}
void depthFirstSearch(DVertex <T> current)
{
current.IsVisited = true;
foreach (var neighbor in current.Neighbors)
{
if (!neighbor.EndingPoint.IsVisited)
{
Console.WriteLine($"\t{current.Value}->{neighbor.EndingPoint.Value}");
depthFirstSearch(neighbor.EndingPoint);
}
}
return;
}
}
public override void AddVertex(DVertex <T> vertex)
{
if (Vertices.Contains(vertex))
{
throw new Exception("Vertex already exists");
}
Vertices.Add(vertex);
}
public override bool AddEdge(DVertex <T> a, DVertex <T> b, int distance)
{
if (GetEdge(a, b) != null)
{
return(false);
}
a.Neighbors.Add(new Edge <T>(a, b, distance));
Edges.Add(a.Neighbors[a.Count - 1]);
return(true);
}
public override bool RemoveEdge(DVertex <T> a, DVertex <T> b)
{
Edge <T> temp = GetEdge(a, b);
if (temp == null)
{
return(false);
}
a.Neighbors.Remove(temp);
Edges.Remove(temp);
return(true);
}
public Edge <T> GetEdge(DVertex <T> a, DVertex <T> b)
{
if (!(Vertices.Contains(a) && Vertices.Contains(b)))
{
return(null);
}
for (int i = 0; i < Edges.Count; i++)
{
if (Edges[i].StartingPoint == a && Edges[i].EndingPoint == b)
{
return(Edges[i]);
}
}
return(null);
}
public Edge(DVertex <T> startingPoint, DVertex <T> endingPoint, int distance)
{
StartingPoint = startingPoint;
EndingPoint = endingPoint;
Distance = distance;
}
public bool CombineVerticies(DVertex <T> a, DVertex <T> b)
{
throw new NotImplementedException();
}
public IEnumerable <DVertex <T> > Dijkstra(DVertex <T> start, DVertex <T> end)
{
if (!Vertices.Contains(start) && !Vertices.Contains(end))
{
return(null);
}
var info = new Dictionary <DVertex <T>, (DVertex <T> founder, int distance)>();
var queue = new PriorityQueue <DVertex <T> >(Comparer <DVertex <T> > .Create((a, b) => info[a].distance.CompareTo(info[b].distance)));
for (int i = 0; i < Count; i++)
{
this[i].IsVisited = false;
info.Add(this[i], (null, int.MaxValue));
}
info[start] = (null, 0);
queue.Enqueue(start);
while (!queue.IsEmpty())
{
var vertex = queue.Dequeue();
vertex.IsVisited = true;
//if infinite graph, break if you just popped the end
//find tentative distances
foreach (var edge in vertex.Neighbors)
{
var neighbor = edge.EndingPoint;
int tentative = edge.Distance + info[vertex].distance;
if (tentative < info[neighbor].distance)
{
info[neighbor] = (vertex, tentative);
neighbor.IsVisited = false;
}
//if they are not in the queue AND have not been visited, add them to the queue
if (!queue.Contains(neighbor) && !neighbor.IsVisited)
{
queue.Enqueue(neighbor);
}
}
}
//start at end and build stack of founders back to beginning
Stack <DVertex <T> > stack = new Stack <DVertex <T> >();
var current = info.ElementAt(info.Count - 1);
while (true)
{
stack.Push(current.Key);
if (current.Value.founder == null)
{
break;
}
current = new KeyValuePair <DVertex <T>, (DVertex <T> founder, int distance)>(current.Value.founder, info[current.Value.founder]);
}
return(stack);
}
