增加只显示有效TAG的功能

web/template/syzoj/category.php

@@ -26,6 +26,16 @@
             <div class="tag-cloud">
             <?php foreach ($tags as $tag): 
             $label_theme = "default";
+            // Check if this tag has any problems associated with it
+            $sql = "SELECT count(*) as cnt FROM `problem` WHERE defunct='N' AND (title LIKE ? OR source LIKE ?)";
+            $tag_search = "%" . $tag . "%";
+            $result = pdo_query($sql, $tag_search, $tag_search);
+            if (!$result || $result[0]['cnt'] <= 0) continue; // Skip tags with no active problems
+            
+            // Choose a random color theme for the tag
+            $hash_num = hexdec(substr(md5($tag), 0, 7));
+            $label_theme = $color_theme[$hash_num % count($color_theme)];
+            if ($label_theme == "") $label_theme = "default";
             ?>
             <a href="problemset.php?search=<?php echo urlencode($tag); ?>" class="ui <?php echo $label_theme; ?> label"><?php echo $tag; ?></a>
             <?php endforeach; ?>