private static void ValidateSourceNode(ListGraphNode <TNode> source)
{
if (source is null)
{
throw new NullReferenceException("The source is not exist in the graph!");
}
}
private bool HasPath(
ListGraphNode <TNode> source
, ListGraphNode <TNode> destination
, HashSet <TNode> visited)
{
ValidateSourceNode(source);
var alreadyVisited = visited.Contains(source.Value);
if (alreadyVisited)
{
return(false);
}
MarkSourceVisited(source, visited);
var destinationFinded = source == destination;
if (destinationFinded)
{
return(true);
}
return(LookingUpAtNeighbors(source, destination, visited));
}
private bool LookingUpAtNeighbors(
ListGraphNode <TNode> source,
ListGraphNode <TNode> destination,
HashSet <TNode> visited)
{
foreach (var child in source.Neighbors)
{
if (HasPath(child, destination, visited))
{
return(true);
}
}
return(false);
}
private void MarkSourceVisited(ListGraphNode <TNode> source, HashSet <TNode> visited) => _ = visited.Add(source.Value);
