public bool IsStronglyConnected(List <int>[] graph)
{
int v = graph.Length;
bool[] vs = new bool[v];
DFSUtil(graph, 0, vs);
if (vs.Any(s => !s))
{
return(false);
}
var tGraph = GraphListHelper.GetTransposeGraph(graph);
for (int i = 0; i < v; i++)
{
vs[i] = false;
}
DFSUtil(tGraph, 0, vs);
if (vs.Any(s => !s))
{
return(false);
}
return(true);
}
/// <summary>
/// Get strongly Connected Component, return array vetex number and componenet id
/// </summary>
/// <param name="graph"></param>
/// <returns></returns>
public static int[] GetSCC(List <int>[] graph)
{
var stack = new Stack <int>();
int v = graph.Length;
bool[] visited = new bool[v];
for (int i = 0; i < v; i++)
{
if (!visited[i])
{
DFS(i, visited, stack, graph);
}
}
var rGraph = GraphListHelper.GetTransposeGraph(graph);
int[] scc = new int[v];
for (int i = 0; i < v; i++)
{
scc[i] = -1;
}
int numCompoents = 0;
while (stack.Count > 0)
{
int i = stack.Pop();
if (scc[i] == -1)
{
DFSComponents(i, scc, rGraph, numCompoents);
}
numCompoents++;
}
return(scc);
}