private SearchAlgorithmResult SearchShortestPaths(Graph graph, Guid origin, Guid destination, Guid nodeToNotInclude)
{
SearchAlgorithmResult result = null;
var visitedNodes = new List <Guid>();
var unvisitedNodes = new List <Guid>();
var searchVertices = new List <SearchVertex>();
graph.Vertices.ForEach(id =>
{
if (!unvisitedNodes.Contains(id) && id != nodeToNotInclude)
{
var distance = int.MaxValue;
if (id == origin)
{
distance = 0;
}
unvisitedNodes.Add(id);
searchVertices.Add(new SearchVertex(id, distance));
}
});
DepthFirstSearch(graph, visitedNodes, unvisitedNodes, searchVertices);
// Search from back to front ir order to build de path
var lastVertex = searchVertices.FirstOrDefault(vertex => vertex.VertexId == destination);
if (lastVertex != null && lastVertex.PreviousVertexId != Guid.Empty)
{
// The destination node is reachable from the origin
var stack = new Stack <SearchVertex>();
stack.Push(lastVertex);
while (lastVertex != null && lastVertex.VertexId != origin && lastVertex.PreviousVertexId != Guid.Empty)
{
var previousVertexId = lastVertex.PreviousVertexId;
lastVertex = searchVertices.FirstOrDefault(vertex => vertex.VertexId == previousVertexId);
if (lastVertex != null)
{
stack.Push(lastVertex);
}
}
result = new SearchAlgorithmResult();
foreach (var searchVertex in stack)
{
result.RouteVertex.Add(new Vertex(searchVertex.VertexId, searchVertex.DistanceToOrigin));
result.TotalDistance += searchVertex.DistanceToOrigin;
}
}
return(result);
}
/// <inheritdoc />
/// <summary>
/// Search the optimal path according to the parameters
/// </summary>
/// <param name="graph">The route graph to search</param>
/// <param name="origin">The origin point to search</param>
/// <param name="destination">The destination point</param>
/// <param name="searchOptionsPath">
/// Defines if the search can be direct or needs at least one hop between origin and
/// destination
/// </param>
public SearchAlgorithmResult Search(Graph graph, Guid origin, Guid destination,
SearchOptions.SearchOptionPath searchOptionsPath)
{
if (graph?.Vertices == null || origin == Guid.Empty || destination == Guid.Empty || origin == destination)
{
return(null);
}
SearchAlgorithmResult result = null;
if (searchOptionsPath == SearchOptions.SearchOptionPath.Direct)
{
result = SearchShortestPaths(graph, origin, destination);
}
else
{
var neighbors = graph.Neighbors(origin);
if (neighbors != null && neighbors.Any())
{
foreach (var neighbor in neighbors)
{
if (neighbor.NodeId != destination)
{
var neighborResult = SearchShortestPaths(graph, neighbor.NodeId, destination, origin);
if (neighborResult == null)
{
continue;
}
neighborResult.RouteVertex.Insert(0, new Vertex(origin, 0));
neighborResult.TotalDistance += neighbor.DistanceToNode;
if (result == null || result.TotalDistance > neighborResult.TotalDistance)
{
result = neighborResult;
}
}
}
}
}
return(result);
}