//A* is the exact same impleamentation as dijkstra below except queue.Dequeue() and queue.Enqueue takes into account the extra
//hueristic data A* star graphs have which is edge weight and an overall distance.
public static HashSet <WeightedVertex> DijkstraShortestPath(WeightedGraph graph, int startVertex, int endVertex)
{
var visited = new HashSet <WeightedVertex>();
WeightedVertex start = new WeightedVertex(startVertex, 0); //make start vertex with weight 0.
if (!graph.AdjacencyList.ContainsKey(start.Vertex))
{
return(visited);
}
var heap = new MinHeap();
heap.Add(start);
while (heap.Count > 0)
{
WeightedVertex current = heap.PopMin();
//if vistited.Contains(weightedVertex)
if (visited.Any(x => x.Vertex == current.Vertex))
{
continue;
}
visited.Add(current);
if (current.Vertex == endVertex)
{
break;
}
foreach (var neighbor in graph.AdjacencyList[current.Vertex])
{
if (!visited.Any(x => x.Vertex == neighbor.Vertex))
{
heap.Add(neighbor);
}
}
}
return(visited);
}
/// <summary>
/// Performs Heapify insert sorting by weight in ascending order.
/// </summary>
/// <param name="item"></param>
public void Add(WeightedVertex item)
{
this.innerList.Add(item);
this.innerList = this.innerList.OrderBy(x => x.Weight).ToList();
}
