Note that also an MPHF, as a static function, does not store the keys. A static function assigning a different output (e.g., rank) to every key will always use more space than a MPHF because you can choose the order.
Note that also an MPHF, as a static function, does not store the keys. A static function assigning a different output (e.g., rank) to every key will always use more space than a MPHF because you can choose the order.