How can one optimize the code provided in the forum thread to improve performance?

The issue with the code provided in the forum thread is that it is using a nested loop to iterate over two arrays, resulting in a time complexity of O(n^2). To optimize the code and improve performance, we can use PHP's array_intersect function to find the common elements between the two arrays in a more efficient way.

// Original code
$common_elements = [];
foreach ($array1 as $element1) {
    foreach ($array2 as $element2) {
        if ($element1 == $element2) {
            $common_elements[] = $element1;
        }
    }
}

// Optimized code
$common_elements = array_intersect($array1, $array2);