public void EmptyTest()
{
var scc0 = new StronglyConnectedComponent(0);
Assert.That(scc0.GetGraph().Count, Is.Zero);
var scc1 = new StronglyConnectedComponent(0);
Assert.That(scc1.GetGraph().Count, Is.Zero);
}
public void SimpleGraphTest()
{
var scc = new StronglyConnectedComponent(2);
scc.AddEdge(0, 1);
scc.AddEdge(1, 0);
var graph = scc.GetGraph();
Assert.That(graph.Count, Is.EqualTo(1));
}
public static void Solve()
{
var NM = Console.ReadLine().Split(" ").Select(int.Parse).ToArray();
var(N, M) = (NM[0], NM[1]);
var G = new StronglyConnectedComponent(N);
for (var i = 0; i < M; i++)
{
var UV = Console.ReadLine().Split(" ").Select(int.Parse).ToArray();
var(u, v) = (UV[0], UV[1]);
G.AddEdge(u, v);
}
var scc = G.GetGraph();
Console.WriteLine(scc.Count());
foreach (var v in scc)
{
Console.WriteLine($"{v.Count()} {string.Join(" ", v)}");
}
}
public static void Solve()
{
var(N, M) = Scanner.Scan <int, int>();
var scc = new StronglyConnectedComponent(N);
for (var i = 0; i < M; i++)
{
var(a, b) = Scanner.Scan <int, int>();
a--; b--;
scc.AddEdge(a, b);
}
var answer = 0L;
foreach (var group in scc.GetGraph())
{
var c = (long)group.Count();
answer += c * (c - 1) / 2;
}
Console.WriteLine(answer);
}