// static method only
public static IList <V> GetShortestPath <V, E>(IGraph <V, E> graph, V node1, V node2, bool directionSensitive)
{
if (node1.Equals(node2))
{
return(Java.Util.Collections.SingletonList(node2));
}
ICollection <V> visited = Generics.NewHashSet();
IDictionary <V, V> previous = Generics.NewHashMap();
BinaryHeapPriorityQueue <V> unsettledNodes = new BinaryHeapPriorityQueue <V>();
unsettledNodes.Add(node1, 0);
while (unsettledNodes.Count > 0)
{
double distance = unsettledNodes.GetPriority();
V u = unsettledNodes.RemoveFirst();
visited.Add(u);
if (u.Equals(node2))
{
break;
}
unsettledNodes.Remove(u);
ICollection <V> candidates = ((directionSensitive) ? graph.GetChildren(u) : graph.GetNeighbors(u));
foreach (V candidate in candidates)
{
double alt = distance - 1;
// nodes not already present will have a priority of -inf
if (alt > unsettledNodes.GetPriority(candidate) && !visited.Contains(candidate))
{
unsettledNodes.RelaxPriority(candidate, alt);
previous[candidate] = u;
}
}
}
if (!previous.Contains(node2))
{
return(null);
}
List <V> path = new List <V>();
path.Add(node2);
V n = node2;
while (previous.Contains(n))
{
path.Add(previous[n]);
n = previous[n];
}
Java.Util.Collections.Reverse(path);
return(path);
}
public static /*<V, E>*/ List <V> GetShortestPath <V, E>(IGraph <V, E> graph, V node1, V node2, bool directionSensitive)
{
if (node1.Equals(node2))
{
//return Collections.singletonList(node2);
return(new List <V>()
{
node2
});
}
Set <V> visited = new Util.HashSet <V>();
var previous = new Dictionary <V, V>();
var unsettledNodes = new BinaryHeapPriorityQueue <V>();
unsettledNodes.Add(node1, 0);
while (unsettledNodes.Size() > 0)
{
var distance = unsettledNodes.GetPriority();
var u = unsettledNodes.RemoveFirst();
visited.Add(u);
if (u.Equals(node2))
{
break;
}
unsettledNodes.Remove(u);
var candidates = ((directionSensitive) ? graph.GetChildren(u) : new ReadOnlyCollection <V>(graph.GetNeighbors(u)));
foreach (var candidate in candidates)
{
var alt = distance - 1;
// nodes not already present will have a priority of -inf
if (alt > unsettledNodes.GetPriority(candidate) && !visited.Contains(candidate))
{
unsettledNodes.RelaxPriority(candidate, alt);
previous[candidate] = u;
}
}
}
if (!previous.ContainsKey(node2))
{
return(null);
}
var path = new List <V>
{
node2
};
var n = node2;
while (previous.ContainsKey(n))
{
path.Add(previous[n]);
n = previous[n];
}
path.Reverse();
return(path);
}