在数组数组中搜索数组

Question

I've found a few questions about searching arrays but none seem to satisfy my needs.

Basically I'm importing a large set of data from a CSV. I have:

$categories = array(
  [4] => array([1] => root_category, [2] => child_category, [3] => another_child, [4] => last_category),
  [8] => array([5] => root_category, [6] => child_category, [7] => another_child, [8] => last_category),
  [12] => array([9] => root_category, [10] => child_category, [11] => another_child, [12] => last_category),
);

// Category to insert:

$insert_category = array([1] => root_category, [2] => child_category, [3] => another_child, [4] => last_category);

I need to see if $insert_category already exists in $categories and then I need to return the key (which is the end ID of the category hierarchy) of the $categories array that matches.

In the $categories I have around 7500 rows of categories, a foreach loop over the $categories foreach $insert_category is hitting the max execution time so I was wondering if there is a more efficient way of doing this?

I'm currently using something like this:

  if(count($categories) > 0)
  {
    foreach($categories as $key => $category)
    {
      if(count(array_diff($insert_category, $category)) === 0)
      {
        return $key;
      }
    }
  }

Which is giving me "Maximum execution time of 300 seconds exceeded".

Some of the functions I'm using:

function get_category_parents($category_id, &$categories = array())
    {
        $db = new Database();

        $category_id = $db->prepareDBValue($category_id);

        $category = $this->get_category($category_id);

        // Append the category to the list
        $categories[] = $category;

        if($category->parentid !== '0')
        {
            // find its parent
            $SQL = "SELECT ID FROM categories WHERE ID = '$category->parentid'";

            $parentid = $db->getValue($SQL);

            if(is_numeric($parentid))
            {
                $this->get_category_parents($parentid, $categories);
            }
        }

        // No more parents, return the array
        return array_reverse($categories);
    }

function category_options($categories) 
    {
        $categoryObj = new Productcategories();

        $category_options = $categoryObj->array_flatten($categories);

        foreach($category_options as $key => $category)
        {
            if(!array_key_exists('children', (array)$category))
            {
                $parents = $categoryObj->get_category_parents($category->id);

                $chain = array();

                foreach($parents as $k => $parent)
                {
                    $chain[$parent->id] = $parent->slug;
                }

                $this->options[end($parents)->id] = $chain;
            }
        }

        return true;
    }

</div>