public void ComputeStronglyConnectedComponents_SimpleGraph_SecondRunReturnsNoComponents()
{
var g = CreateGraph(5, false, (0, 1), (1, 2), (2, 3), (3, 4), (0, 4));
var a = new TarjanStronglyConnectedComponentsAlgorithm <DirectedGraph <Empty, Empty>, VertexIdx, EdgeIdx>(g);
a.ComputeStronglyConnectedComponents(new VertexIdx(0));
var components = a.ComputeStronglyConnectedComponents(new VertexIdx(0));
Assert.That(components.Length, Is.Zero);
}
public void ComputeStronglyConnectedComponents_WikipediaExample_IsCorrect()
{
var g = CreateGraph(8, false, (0, 4), (1, 0), (2, 1), (2, 3), (3, 2), (4, 1), (5, 1), (5, 4), (5, 6),
(6, 2), (6, 5), (7, 3), (7, 6), (7, 7));
var a = new TarjanStronglyConnectedComponentsAlgorithm <DirectedGraph <Empty, Empty>, VertexIdx, EdgeIdx>(g);
var components = a.ComputeStronglyConnectedComponents(new VertexIdx(7));
Assert.That(components.Length, Is.EqualTo(4));
Assert.That(components[0].ToArray(), Is.EquivalentTo(Vertices(0, 1, 4)));
Assert.That(components[1].ToArray(), Is.EquivalentTo(Vertices(2, 3)));
Assert.That(components[2].ToArray(), Is.EquivalentTo(Vertices(5, 6)));
Assert.That(components[3].ToArray(), Is.EquivalentTo(Vertices(7)));
}
public void ComputeStronglyConnectedComponents_SimpleGraph_IsCorrect()
{
var g = CreateGraph(5, false, (0, 1), (1, 2), (2, 3), (3, 4), (0, 4));
var a = new TarjanStronglyConnectedComponentsAlgorithm <DirectedGraph <Empty, Empty>, VertexIdx, EdgeIdx>(g);
var components = a.ComputeStronglyConnectedComponents(new VertexIdx(0));
Assert.That(components.Length, Is.EqualTo(5));
Assert.That(components[0].ToArray(), Is.EqualTo(new[] { new VertexIdx(4) }));
Assert.That(components[1].ToArray(), Is.EqualTo(new[] { new VertexIdx(3) }));
Assert.That(components[2].ToArray(), Is.EqualTo(new[] { new VertexIdx(2) }));
Assert.That(components[3].ToArray(), Is.EqualTo(new[] { new VertexIdx(1) }));
Assert.That(components[4].ToArray(), Is.EqualTo(new[] { new VertexIdx(0) }));
}
public void ComputeStronglyConnectedComponents_SimpleGraph_CanRunPartially()
{
var g = CreateGraph(5, false, (0, 1), (1, 2), (2, 3), (3, 4), (0, 4));
var a = new TarjanStronglyConnectedComponentsAlgorithm <DirectedGraph <Empty, Empty>, VertexIdx, EdgeIdx>(g);
var components = a.ComputeStronglyConnectedComponents(new VertexIdx(2));
Assert.That(components.Length, Is.EqualTo(3));
Assert.That(components[0].ToArray(), Is.EqualTo(Vertices(4)));
Assert.That(components[1].ToArray(), Is.EqualTo(Vertices(3)));
Assert.That(components[2].ToArray(), Is.EqualTo(Vertices(2)));
components = a.ComputeStronglyConnectedComponents(new VertexIdx(0));
Assert.That(components.Length, Is.EqualTo(2));
Assert.That(components[0].ToArray(), Is.EqualTo(Vertices(1)));
Assert.That(components[1].ToArray(), Is.EqualTo(Vertices(0)));
}
public void ComputeStronglyConnectedComponents_DeepGraph_IsCorrect(int size)
{
var g = new DirectedGraph <Empty, Empty>();
var v0 = g.AddVertex(Empty.Default);
var v1 = v0;
for (var i = 0; i < size; i++)
{
var v2 = g.AddVertex(Empty.Default);
g.AddEdge(v1, v2, Empty.Default);
v1 = v2;
}
var a = new TarjanStronglyConnectedComponentsAlgorithm <DirectedGraph <Empty, Empty>, VertexIdx, EdgeIdx>(g);
var components = a.ComputeStronglyConnectedComponents(v0);
Assert.That(components.Length, Is.EqualTo(size + 1));
}
