public static IList <string> Answer(IList <string> inputs)
{
var chars = new[] { ' ' };
var line0 = inputs[0].Split(chars);
var verticeCount = int.Parse(line0[0]);
var edgeCount = int.Parse(line0[1]);
var xs = Enumerable.Range(1, edgeCount)
.Select(i =>
{
var items = inputs[i].Trim().Split(chars, StringSplitOptions.RemoveEmptyEntries);
return(new
{
Left = GetIndex(items[0]),
Right = GetIndex(items[1])
});
});
var graph = new AdjacencyListGraph(verticeCount);
foreach (var x in xs)
{
graph.AddDirectedEdge(x.Left, x.Right);
}
//Console.WriteLine(graph);
var s = new TopologicalSort(graph);
s.Search();
var answer = string.Join(" ", s.Order.Select(GetSource));
return(new[] { answer });
}
private static bool IsCyclic(AdjacencyListGraph <long> g)
{
try
{
new DepthFirstSearchWithCycleDetection(g).Search();
return(false);
}
catch (GraphCycleException)
{
return(true);
}
}
public static IEnumerable <int> StronglyConnectedComponents(AdjacencyListGraph <long> graph, AdjacencyListGraph <long> reverse)
{
//run dfs of reverse graph
var srg = new TopologicalSort(reverse);
srg.Search();
//look for v in graph in reverse post order
var sg = new DepthFirstSearchWithComponents(graph);
var order = srg.Order;
foreach (var v in order)
{
//if not visited => explore and mark visted vertices as new component
sg.Explore(v);
}
return(sg.Components);
}
public static IList <string> Answer(IList <string> inputs)
{
var chars = new[] { ' ' };
var line0 = inputs[0].Split(chars);
var verticeCount = int.Parse(line0[0]);
var edgeCount = int.Parse(line0[1]);
var xs = Enumerable.Range(1, edgeCount)
.Select(i =>
{
var items = inputs[i].Trim().Split(chars, StringSplitOptions.RemoveEmptyEntries);
return(new
{
Left = GetIndex(items[0]),
Right = GetIndex(items[1])
});
});
var g = new AdjacencyListGraph(verticeCount);
var rg = new AdjacencyListGraph(verticeCount);
foreach (var x in xs)
{
g.AddDirectedEdge(x.Left, x.Right);
rg.AddDirectedEdge(x.Right, x.Left);
}
//Console.WriteLine(g);
//Console.WriteLine(rg);
var s = StronglyConnectedComponents(g, rg);
var answer = s.Count();
return(new[] { answer.ToString() });
}
