Output Wordpress Categories and Posts Removing Duplicates

<?php
$url = explode('/',$_SERVER['REQUEST_URI']);
$dir = $url[2] ? $url[2] : 'UX-Style-Guide';
$result = str_replace ("?", "", $dir);
$final = current(explode('=', $result));
$style = str_replace ("-", " ", $final);
$style = ucwords($style);
$post_id = $post->ID;
$class = '';
?>

<!-- THIS IS THE LEFTNAV -->
<nav id="verticalNav" class="ui-side-nav-drawer">
    <div class="cssmenu">
        <div id="entry-search">
            <input type="text" placeholder="Search Styleguide Entries" class="fuzzy-search" />
        </div>
        <ul class="list">
            <?php
            $nav_cat_args = array(
                'orderby' => 'name',
                'order' => 'ASC',
                'child_of' => 0,
                'exclude'=> 1
            );

            $nav_categories =   get_categories($nav_cat_args);
            $displayedPosts = array();

            foreach($nav_categories as $category) {
                echo "<li><span class='navAppTitle'>" . $category->name . "</span></li>\n";

                 $nav_post_args = array(
                      'numberposts' => -1,
                      'category' => $category->term_id,
                      'post_type' => $final,
                      'orderby' => 'name',
                      'order' => 'ASC',
                      'child_of' => 0
                 );

                $nav_posts = get_posts($nav_post_args);

                foreach($nav_posts as $post) {
                    if (in_array($post->ID, $displayedPosts)) {
                        continue; //Skip this post if it has already been displayed once.
                    }

                    $title = the_title();
                    $link = the_permalink();

                    $displayedPosts[] = $post->ID;
                    $class = '';

                    if ($post_id == $post->ID) {
                        $class = 'entry-title current';
                    } else {
                        $class = 'entry-title';
                    }

                    echo "<li class='$class'>";
                    echo "<a class='entry-link' href='{$link}'>{$title}</a>";
                    echo "</li>\n";
                }
            }
            ?>

            <?php wp_reset_query(); ?>
            <div id="job-listings"></div>
        </ul>
    </div>
</nav><!-- /END #verticalNav -->