Depth-first Search in PHP

<?php

class DFS {

   public static function dfsIterative($G, $startVert) {
       $visited = array();
       for($i = 0; $i < $G->size; $i++) {
           array_push($visited, false);
       }
       $s = SplStack();
       
       $s->push($startVert);

       while(!$s->isEmpty()) {
           $v = $s->pop();
           foreach($G->adj[$v] as $adjV) {
               if(!$visited[$adjV]) {
                   $visited[$adjV] = true;
                   $s->push($adjV);
               }
           }
       }
   }

   public static function dfsRecursive($G, $startVert) {
       $visited = array();
       for($i = 0; $i < $G->size; $i++) {
           array_push($visited, false);
       }
       DFS::dfsAux($G, $startVert, $visited);
   }

   public static function dfsAux($G, $v, $visited) {
       $visited[$v] = true;
       foreach($G->adj[$v] as $adjV) {
           if(!$visited[$adjV]) {
               DFS::dfsAux($G, $adjV, $visited);
           }
       }
   }
}

// Example class of what a graph might look like.

class Graph {
   public $adj;
   public $size;
}