wordpress automatic advertising code, please help to add category control

The following is a code that can automatically insert ads anywhere in wordpress articles, it is provided by jjarolim, thank him very much for his efforts, but there is an in-depth problem, my website has many categories, I do not want all the articles in the categories to appear the same ads, how should I control the categories? Please help me to improve this code, so that it can control the articles by category to show ads. Thank you very much!

add_filter('the_content', 'prefix_insert_post_ads');

/**
 * Content Filter 
 */
function prefix_insert_post_ads($content) {
    $insertion = 'Your AD Code';

    if (is_single()  ! is_admin()) {
        return prefix_insert_after_paragraphs($content, $insertion, array(4,20));
    }

    return $content;
}

// Function that makes the magic happen correctly
function prefix_insert_after_paragraphs($content, $insertion, $paragraph_indexes) {
    // find all paragraph ending offsets
    preg_match_all('#/p#i', $content, $matches, PREG_SET_ORDER+PREG_OFFSET_CAPTURE);

    // reduce matches to offset positions
    $matches = array_map(function($match) {
        return $match[0][1] + 4; // return string offset + length of /p Tag
    }, $matches);

    // reverse sort indexes: plain text insertion just works nicely in reverse order
    rsort($paragraph_indexes); 

    // cycle through and insert on demand
    foreach ($paragraph_indexes as $paragraph_index) {
        if ($paragraph_index = count($matches)) {
            $offset_position = $matches[$paragraph_index-1];
            $content = substr($content, 0, $offset_position) . $insertion . substr($content, $offset_position);
        }
    }

    return $content;
}