function bfs(Gr_Node $node){
    $queue = array($node);
    while (count($queue)){
        $v = array_shift($queue);
        if (!$v->marca){ 
            print $v->name . " ";
            $v->marca = 1;
            foreach ($v->linked as $child){
                if (!$child->marca){
                $queue[] = $child;
                }
            }
        }
    }
}