public void Run()
{
using (var reader = new StreamReader("SCC.txt"))
using (var writer = new StreamWriter("output.txt"))
{
var graph = new DirectedGraph<int>();
while (true)
{
string row = reader.ReadLine();
if (row == null)
{
break;
}
var parts = row.Split(new[] { ' ', '\t' }, StringSplitOptions.RemoveEmptyEntries);
var numbers = parts.Select(x => int.Parse(x, CultureInfo.InvariantCulture) - 1).ToArray();
var from = numbers[0];
var to = numbers[1];
if (from != to)
{
graph.AddEdge(from, to);
}
}
var calculator = new StronglyConnectedComponentsCalculator<int>(graph);
var components = calculator.GetStronglyConnectedComponents().ToArray();
var top5Components = components.OrderByDescending(x => x.Length).Take(5).ToArray();
var result = string.Join(",", top5Components.Select(x => x.Length));
writer.WriteLine(result);
}
}
public static bool IsSatisfiable(IReadOnlyCollection<Clause> clauses)
{
var graph = new DirectedGraph<int>();
foreach (var clause in clauses)
{
var literal1 = clause.Literal1;
var literal2 = clause.Literal2;
var from1 = GetNodeIndex(literal1.Negate());
var to1 = GetNodeIndex(literal2);
graph.AddEdge(from1, to1);
var from2 = GetNodeIndex(literal2.Negate());
var to2 = GetNodeIndex(literal1);
graph.AddEdge(from2, to2);
}
var calculator = new StronglyConnectedComponentsCalculator<int>(graph);
var components = calculator.GetStronglyConnectedComponents().ToArray();
foreach (var component in components)
{
var positiveLiteralNodes = component.Where(node => node >= 0).ToArray();
var negativeLiteralNodes = new HashSet<int>(component.Where(node => node < 0));
if (positiveLiteralNodes.Any(node => negativeLiteralNodes.Contains(GetNegativeLiteralNodeIndex(node))))
{
return false;
}
}
return true;
}
public void GetStronglyConnectedComponentsTest()
{
var graph = GetTestGraph();
var calculator = new StronglyConnectedComponentsCalculator<int>(graph);
var components = calculator.GetStronglyConnectedComponents().ToArray();
components.Should().HaveCount(3);
components[0].Should().BeEquivalentTo(new[] { 0, 6, 3 });
components[1].Should().BeEquivalentTo(new[] { 8, 5, 2 });
components[2].Should().BeEquivalentTo(new[] { 7, 1, 4 });
}
public void DepthFirstSearchLoopTest()
{
var graph = GetTestGraph();
var calculator1 = new StronglyConnectedComponentsCalculator<int>(graph);
var result1 = calculator1.DepthFirstSearchLoop(graph.Keys, true).ToArray();
result1.Length.Should().BeLessOrEqualTo(3);
var calculator2 = new StronglyConnectedComponentsCalculator<int>(graph);
var result2 = calculator2.DepthFirstSearchLoop(graph.Keys.Reverse(), true).ToArray();
result2.Length.Should().BeLessOrEqualTo(3);
}
public void GetStronglyConnectedComponentsTest2()
{
var graph = new DirectedGraph<int>();
graph.AddEdge(1, 3);
graph.AddEdge(3, 5);
graph.AddEdge(3, 9);
graph.AddEdge(5, 7);
graph.AddEdge(7, 1);
var calculator = new StronglyConnectedComponentsCalculator<int>(graph);
var components = calculator.GetStronglyConnectedComponents().ToArray();
components.Should().HaveCount(2);
components[0].Should().BeEquivalentTo(new[] { 9 });
components[1].Should().BeEquivalentTo(new[] { 1, 3, 5, 7 });
}
public void DepthFirstSearchTest()
{
var graph1 = GetTestGraph();
var calculator1 = new StronglyConnectedComponentsCalculator<int>(graph1);
IEnumerable<int> vertices1 = calculator1.DepthFirstSearch(0, true);
vertices1.Should().HaveCount(9);
var calculator2 = new StronglyConnectedComponentsCalculator<int>(graph1);
IEnumerable<int> vertices2 = calculator2.DepthFirstSearch(1, true);
vertices2.Should().HaveCount(3);
var graph2 = new DirectedGraph<int>();
graph2.AddEdge(0, 1);
graph2.AddEdge(0, 2);
graph2.AddEdge(2, 1);
var calculator3 = new StronglyConnectedComponentsCalculator<int>(graph2);
IEnumerable<int> vertices3 = calculator3.DepthFirstSearch(0, false);
vertices3.Should().HaveCount(3);
}
