public static List <T> AEstrela <T>(this Grafo <T, double> grafo, T inicio, T fim, Func <T, double> heuristicCostEstimate = null, Action <List <T>, double> onChangePathCallback = null) where T : class
{
HashSet <T> closedSet = new HashSet <T>(), openSet = new HashSet <T> {
inicio
};
var cameFrom = new Dictionary <T, T>();
var gScore = new Dictionary <T, double>();
foreach (var vertex in grafo.PegarVertices())
{
gScore[vertex] = double.PositiveInfinity;
}
gScore[inicio] = 0;
var fScore = new Dictionary <T, double>();
foreach (var vertex in grafo.PegarVertices())
{
fScore[vertex] = double.PositiveInfinity;
}
if (heuristicCostEstimate == null)
{
heuristicCostEstimate = t => 0.0;
}
fScore[inicio] = gScore[inicio] + heuristicCostEstimate(inicio);
while (openSet.Count > 0)
{
var current = openSet.Aggregate((a, b) => fScore[a] < fScore[b] ? a : b);
if (current == fim)
{
var finalPath = CaminhoDeReconstrução(cameFrom, fim);
if (onChangePathCallback != null)
{
onChangePathCallback(finalPath, gScore[fim]);
}
return(finalPath);
}
openSet.Remove(current);
closedSet.Add(current);
foreach (var neighbor in grafo.VerticesAdjacentes(current))
{
if (closedSet.Contains(neighbor))
{
continue;
}
var tentativeGScore = gScore[current] + grafo.PegarAresta(current, neighbor);
if (!openSet.Contains(neighbor) || tentativeGScore < gScore[neighbor])
{
cameFrom[neighbor] = current;
gScore[neighbor] = tentativeGScore;
fScore[neighbor] = gScore[neighbor] + heuristicCostEstimate(neighbor);
if (!openSet.Contains(neighbor))
{
openSet.Add(neighbor);
}
if (onChangePathCallback != null)
{
onChangePathCallback(CaminhoDeReconstrução(cameFrom, neighbor), gScore[neighbor]);
}
}
}
}
throw new Exception();
}
