public static function routeExists(StatefulGraphNode $startNode, StatefulGraphNode $endNode)
{
if ($startNode === $endNode) {
return true;
}
$startNode->setState(StatefulGraphNode::VISITING);
$queue = [$startNode];
while (!empty($queue)) {
$node = array_shift($queue);
foreach ($node->getConnectedNodes() as $childNode) {
if ($childNode->getState() === StatefulGraphNode::UNVISITED) {
if ($childNode === $endNode) {
return true;
}
$childNode->setState(StatefulGraphNode::VISITING);
array_push($queue, $childNode);
}
}
$node->setState(StatefulGraphNode::VISITED);
}
return false;
}
public function testRouteExists()
{
$n1 = new StatefulGraphNode("one");
$n2 = new StatefulGraphNode("two");
$n3 = new StatefulGraphNode("three");
$n4 = new StatefulGraphNode("four");
$n5 = new StatefulGraphNode("five");
$n6 = new StatefulGraphNode("six");
$n7 = new StatefulGraphNode("seven");
$n8 = new StatefulGraphNode("eight");
$n9 = new StatefulGraphNode("nine");
$n10 = new StatefulGraphNode("ten");
$n11 = new StatefulGraphNode("eleven");
$n12 = new StatefulGraphNode("twelve");
$graph = [$n1, $n2, $n3, $n4, $n5, $n6, $n7, $n8, $n9, $n10, $n11, $n12];
// Graph A
$n1->addNode($n2);
$n1->addNode($n3);
$n1->addNode($n4);
$n3->addNode($n5);
$n3->addNode($n6);
// Graph B
$n7->addNode($n8);
$n7->addNode($n9);
$n7->addNode($n12);
$n8->addNode($n10);
$n9->addNode($n11);
$n9->addNode($n12);
// There are now 2 nodes connected to $n12
$this->assertTrue(RouteBetweenNodes::routeExists($n1, $n1));
self::resetNodes($graph);
$this->assertTrue(RouteBetweenNodes::routeExists($n1, $n2));
self::resetNodes($graph);
$this->assertTrue(RouteBetweenNodes::routeExists($n1, $n3));
self::resetNodes($graph);
$this->assertTrue(RouteBetweenNodes::routeExists($n1, $n4));
self::resetNodes($graph);
$this->assertTrue(RouteBetweenNodes::routeExists($n1, $n5));
self::resetNodes($graph);
$this->assertTrue(RouteBetweenNodes::routeExists($n1, $n6));
self::resetNodes($graph);
$this->assertFalse(RouteBetweenNodes::routeExists($n1, $n7));
self::resetNodes($graph);
$this->assertFalse(RouteBetweenNodes::routeExists($n1, $n8));
self::resetNodes($graph);
$this->assertFalse(RouteBetweenNodes::routeExists($n1, $n9));
self::resetNodes($graph);
$this->assertFalse(RouteBetweenNodes::routeExists($n1, $n10));
self::resetNodes($graph);
$this->assertFalse(RouteBetweenNodes::routeExists($n1, $n11));
self::resetNodes($graph);
$this->assertFalse(RouteBetweenNodes::routeExists($n1, $n12));
// connect Graph A and Graph B
$n6->addNode($n7);
self::resetNodes($graph);
$this->assertTrue(RouteBetweenNodes::routeExists($n1, $n7));
self::resetNodes($graph);
$this->assertTrue(RouteBetweenNodes::routeExists($n1, $n8));
self::resetNodes($graph);
$this->assertTrue(RouteBetweenNodes::routeExists($n1, $n9));
self::resetNodes($graph);
$this->assertTrue(RouteBetweenNodes::routeExists($n1, $n10));
self::resetNodes($graph);
$this->assertTrue(RouteBetweenNodes::routeExists($n1, $n11));
self::resetNodes($graph);
$this->assertTrue(RouteBetweenNodes::routeExists($n1, $n12));
// disconnect them again
$n6->setConnectedNodes([]);
self::resetNodes($graph);
$this->assertFalse(RouteBetweenNodes::routeExists($n1, $n7));
self::resetNodes($graph);
$this->assertFalse(RouteBetweenNodes::routeExists($n1, $n8));
self::resetNodes($graph);
$this->assertFalse(RouteBetweenNodes::routeExists($n1, $n9));
self::resetNodes($graph);
$this->assertFalse(RouteBetweenNodes::routeExists($n1, $n10));
self::resetNodes($graph);
$this->assertFalse(RouteBetweenNodes::routeExists($n1, $n11));
self::resetNodes($graph);
$this->assertFalse(RouteBetweenNodes::routeExists($n1, $n12));
}