PHP:如何以递归方式在树状JSON结构中搜索ID，并返回包含所有先前ID的路径

function searchIdInJson($json, $id, $path = []) {
    foreach ($json as $key => $value) {
        if ($key === 'id' && $value === $id) {
            $path[] = $id;
            return $path;
        }
        if (is_array($value)) {
            $result = searchIdInJson($value, $id, $path);
            if ($result !== null) {
                $path[] = $key;
                return $result;
            }
        }
    }
    return null;
}

// 示例用法
$json = [
    'id' => 'root',
    'children' => [
        [
            'id' => '1',
            'children' => [
                [
                    'id' => '2',
                    'children' => [
                        [
                            'id' => '3',
                            'children' => []
                        ]
                    ]
                ]
            ]
        ],
        [
            'id' => '4',
            'children' => []
        ]
    ]
];

$id = '3';
$path = searchIdInJson($json, $id);
if ($path !== null) {
    echo implode(' -> ', $path);
} else {
    echo 'ID not found';
}