Colorful Numbers Solution: https://algorithms.tutorialhorizon.com/colorful-numbers/

colorful-numbers.php

<?php
function isColorful($number)
{
    $number_as_string = strval($number);
    $hash = array();
    $number_as_array = str_split($number);
    
    foreach ($number_as_array as $int)
    {
        if (isset($hash[strval($int)])) return false;
        $hash[strval($int)] = 1;
    }

    $subsets = array();
    for ($i = 0; $i < count($number_as_array); $i++)
    {
        for ($j = $i+1; $j < count($number_as_array); $j++)
        {
            $subset = substr($number_as_string, $i, ($j-$i+1));
            if ($subset == $number_as_string) continue;
            if (isset($subsets[$subset])) return 0;

            $subsets[$subset] = 1;
            $product = array_product(str_split($subset));

            if (isset($hash[strval($product)])) return 0;
            $hash[strval($product)] = 1;
        }
    }
    return 1;
}
echo isColorful(326);
?>