/**
* @param Graph $g
* @param mixed $vertex
* @param callable $callback A function to be called on each vertex
* If the function returns false, the graph is not traversed further
* @return \GraPHPy\Vertex[]
*/
public static function dfs(Graph $g, $vertex, $callback = null)
{
$stack = [[$g->getVertex($vertex)]];
$callbackIsCallable = is_callable($callback);
$discovered = [];
$recursionStack = [];
while (!empty($stack)) {
$vertices = array_pop($stack);
if (empty($vertices)) {
array_pop($recursionStack);
} else {
$currentVertex = array_pop($vertices);
array_push($stack, $vertices);
if (in_array($currentVertex, $discovered)) {
continue;
}
$discovered[] = $currentVertex;
if ($callbackIsCallable) {
if (!$callback($currentVertex, $discovered, $recursionStack)) {
break;
}
}
array_push($recursionStack, $currentVertex);
array_push($stack, $currentVertex->getAdjacentVertices());
}
}
return $discovered;
}
