<?php
// Database connection using mysqli
$mysqli = new mysqli("127.0.0.1","root","root", "Database");
if ($mysqli->connect_errno) {
    die("Failed to connect to MySQL: " . $mysqli->connect_error);
}

 // Prepare statement
    $sql = "SELECT * FROM tree_lr";
    $stmt = $mysqli->prepare($sql);
    $stmt->execute();
    $result = $stmt->get_result();
    
    // Fetch results into an array
    $array = array();
    while ($row = $result->fetch_assoc()) {
        $array[] = $row;
    }
    
    // Optimize the lefttree() function
    function lefttree($array){
        $tree = array();
        $categorylist = "";
        foreach ($array as $v) {
            $list = @$tree[$v['pid']] ?: array();
            $list[] = $v;
            $tree[$v['pid']] = $list;
        }
        if (is_array($tree[0])) {
            $categorylist = "<ul>\n";
            $categorylist .= sonTree($tree[0], $tree);
            $categorylist .= "</ul>\n";
        }
        return $categorylist;
    }
    
    function sonTree($arr, $tree, $level = 1) {
        $categorylist = "";
        foreach ($arr as $k => $v) {
            if ($tree[$v['id']]) {
                $categorylist .= "<li><a href=\"#\" style='color: ";
                $categorylist .= ($v['sex'] == '女') ? '#ff1493' : 'black';
                $categorylist .= ";'>{$v['name']}</a>\n";
                $categorylist .= "<ul>\n";
                $categorylist .= sonTree($tree[$v['id']], $tree, $level + 1);
                $categorylist .= "</ul>\n";
                $categorylist .= "</li>\n";
            } else {
                if ($v['is_link'] == 0) {
                    $categorylist .= "<li><a href=\"#\" style='color: ";
                    $categorylist .= ($v['sex'] == '女') ? '#ff1493' : 'black';
                    $categorylist .= ";'>{$v['name']}</a></li>\n";
                }
            }
        }
        return $categorylist;
    }
    
    // Generate the menu
    $menu = lefttree($array);
   if ($link && mysqli_ping($link)) {
    mysqli_close($link);
}
?>