/**
* @param Digraph $graph
* @param int $vertex
*/
private function depthSearch(Digraph $graph, int $vertex)
{
$this->onStack[$vertex] = true;
$this->marked[$vertex] = true;
foreach ($graph->adjacent($vertex) as $item) {
if ($this->hasCircle()) {
return;
} else {
if (!isset($this->marked[$item])) {
$this->edgeTo[$item] = $vertex;
$this->depthSearch($graph, $item);
} else {
if ($this->onStack[$item]) {
$this->circle = new Stack();
for ($x = $vertex; $x !== $item; $x = $this->edgeTo[$x]) {
$this->circle->add($x);
}
$this->circle->add($vertex);
$this->circle->add($item);
}
}
}
}
$this->onStack[$vertex] = false;
}
