private static int?getIndexByIdDestino(int Id)
{
if (Id == -1)
{
return(null);
}
var _db = new travelEntities();
var destinos = _db.Destinos.OrderBy(d => d.Id).ToList();
var n = destinos.Count;
for (int i = 0; i < n; i++)
{
if (destinos[i].Id == Id)
{
return(i);
}
}
return(0);
}
public static Arista[,] getMatrizAdyacencia()
{
var _db = new travelEntities();
var nodos = _db.Destinos.ToList();
var n = nodos.Count;
Arista[,] matriz = new Arista[n, n];
for (var i = 0; i < n; i++)
{
for (var j = 0; j < n; j++)
{
var IdDestinoInicial = nodos[i].Id;
var IdDestinoFinal = nodos[j].Id;
var arista = _db.Aristas.SingleOrDefault(a => a.IdDestinoInicial == IdDestinoInicial && a.IdDestinoFinal == IdDestinoFinal);
matriz[i, j] = arista;
}
}
return(matriz);
}
public static List <Destino> DijkstraAlgorithm(Arista[,] graph, int IdDestinoInicial, int IdDestinoFinal)
{
var _db = new travelEntities();
var destinos = _db.Destinos.OrderBy(d => d.Id).ToList();
var n = graph.GetLength(0);
var distance = new Decimal[n];
for (int i = 0; i < n; i++)
{
distance[i] = Decimal.MaxValue;
}
distance[getIndexByIdDestino(IdDestinoInicial).Value] = 0;
var used = new bool[n];
var previous = new int?[n];
while (true)
{
var minDistance = Decimal.MaxValue;
var minNode = 0;
for (int i = 0; i < n; i++)
{
if (!used[i] && minDistance > distance[i])
{
minDistance = distance[i];
minNode = i;
}
}
if (minDistance == Decimal.MaxValue)
{
break;
}
used[minNode] = true;
for (int i = 0; i < n; i++)
{
if (graph[minNode, i] != null && graph[minNode, i].Distancia > 0)
{
var shortestToMinNode = distance[minNode];
var distanceToNextNode = graph[minNode, i].Distancia;
var totalDistance = shortestToMinNode + distanceToNextNode;
if (totalDistance < distance[i])
{
distance[i] = totalDistance;
previous[i] = minNode;
}
}
}
}
if (distance[getIndexByIdDestino(IdDestinoFinal).Value] == Decimal.MaxValue)
{
return(null);
}
var path = new LinkedList <Destino>();
int?currentNode = getIndexByIdDestino(IdDestinoFinal);
while (currentNode != null)
{
path.AddFirst(destinos[currentNode.Value]);
currentNode = previous[currentNode.Value];
}
return(path.ToList());
}
