<?php
use Fhaculty\Graph\Graph;
use Fhaculty\Graph\Vertex;
use Graphp\Algorithms\Tarjan;

// Create a simple directed 3 node loop
$graph = new Graph();
$a = $graph->createVertex('a');
$b = $graph->createVertex('b');
$c = $graph->createVertex('c');
$a->createEdgeTo($b); $b->createEdgeTo($c); $c->createEdgeTo($a);

// Run the algorithm
$algorithm = new Tarjan();
$ret = $algorithm->getStronglyConnectedVerticesFromDirectedGraph($graph);
var_dump($ret[0]->getIds());

// display following: (there is obviously only one strongly connected component)
array(3) {
  [0]=>
  string(1) "c"
  [1]=>
  string(1) "b"
  [2]=>
  string(1) "a"
}