public void AddUndirectedEdge_ShouldThrowKeyNotFoundException_WhenNotExistingKeySpecified(UndirectedGraph <int> graph, int source, int destination)
{
Assert.Throws <KeyNotFoundException>(() =>
{
graph.AddUndirectedEdge(source, destination);
});
}
public void AddUndirectedEdge_ShouldThrowInvalidOperationException_WhenEdgeCreatesLoopOrMultipleEdge(UndirectedGraph <int> graph, int source, int destination)
{
Assert.Throws <InvalidOperationException>(() =>
{
graph.AddUndirectedEdge(source, destination);
});
}
public IEnumerable <TVertex> Execute(TGraph graph)
{
if (graph == null)
{
throw new ArgumentNullException(nameof(graph));
}
if (_connectedComponentsCounter.Execute(graph) > 1)
{
throw new InvalidOperationException("Target graph should be highly connected for searching articulation points in it");
}
var foundArticulationPoints = new List <TVertex>();
// Cloning graph to save the original one
var graphClone = new UndirectedGraph <TVertex>(graph.Vertices, graph.ReducedEdges) as TGraph;
var graphVertices = graphClone.Vertices.ToList();
foreach (var vertex in graphVertices)
{
var sourceEdges = graphClone.Edges.Where(e => e.Source.CompareTo(vertex) == 0);
var destinationEdges = graphClone.Edges.Where(e => e.Destination.CompareTo(vertex) == 0);
graphClone.RemoveVertex(vertex);
if (_connectedComponentsCounter.Execute(graphClone) > 1)
{
foundArticulationPoints.Add(vertex);
}
graphClone.AddVertex(vertex);
foreach (var edge in sourceEdges)
{
graphClone.AddUndirectedEdge(edge.Source, edge.Destination);
}
}
return(foundArticulationPoints);
}
