/**
* @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;
}
/**
* @return Digraph
*/
public function reverse() : Digraph
{
$graph = new Digraph($this->vertices);
foreach ($this->adj as $index => $bag) {
foreach ($bag as $item) {
$graph->addEdge($item, $index);
}
}
return $graph;
}
<?php
use Graph\Digraph;
use Graph\DirectDepthFirstSearch;
use Graph\DirectedCircle;
spl_autoload_register(function ($class) {
$file = str_replace('\\', '/', $class);
require "../{$file}.php";
});
$edges = [[0, 5], [4, 3], [0, 1], [9, 12], [6, 4], [5, 4], [0, 2], [11, 12], [9, 10], [0, 6], [7, 8], [9, 11], [5, 3], [3, 0]];
$graph = new Digraph(count($edges));
foreach ($edges as $edge) {
$graph->addEdge($edge[0], $edge[1]);
}
echo "edges: {$graph->edges()}\n";
echo "vertexes: {$graph->vertices()}\n";
echo "graph:\n{$graph}";
$dfs = new DirectDepthFirstSearch($graph, 0);
echo "0 -> 7 ? {$dfs->marked(7)}\n";
echo "0 -> 6 ? {$dfs->marked(6)}\n";
$directCircle = new DirectedCircle($graph);
echo "has circle: {$directCircle->hasCircle()}\n";
foreach ($directCircle->circle() as $item) {
echo "{$item}\n";
}