PHP를 사용하여 그래프에 대한 깊이 우선 검색 알고리즘을 작성하는 방법

class Node {
   public $value;
   public $visited;
   public $neighbors;

   public function __construct($value) {
      $this->value = $value;
      $this->visited = false;
      $this->neighbors = array();
   }

   public function addNeighbor($neighbor) {
      array_push($this->neighbors, $neighbor);
   }
}

class Graph {
   public $nodes;

   public function __construct() {
      $this->nodes = array();
   }

   public function addNode($value) {
      $node = new Node($value);
      array_push($this->nodes, $node);
   }

   public function getNode($value) {
      foreach ($this->nodes as $node) {
         if ($node->value == $value) {
            return $node;
         }
      }
      return null;
   }

   public function addEdge($value1, $value2) {
      $node1 = $this->getNode($value1);
      $node2 = $this->getNode($value2);
      $node1->addNeighbor($node2);
      $node2->addNeighbor($node1);
   }

   public function depthFirstSearch($startNode) {
      $stack = new SplStack();
      $stack->push($startNode);
      $startNode->visited = true;

      while (!$stack->isEmpty()) {
         $currentNode = $stack->pop();
         echo $currentNode->value . " ";

         foreach ($currentNode->neighbors as $neighbor) {
            if (!$neighbor->visited) {
               $stack->push($neighbor);
               $neighbor->visited = true;
            }
         }
      }
   }
}

$graph = new Graph();
$graph->addNode("A");
$graph->addNode("B");
$graph->addNode("C");
$graph->addNode("D");
$graph->addNode("E");

$graph->addEdge("A", "B");
$graph->addEdge("A", "C");
$graph->addEdge("B", "D");
$graph->addEdge("C", "E");

echo "Depth First Search: ";
$graph->depthFirstSearch($graph->getNode("A"));