##### Question Given two N-ary trees (old and new versions) where each node has a key (string), value (int), and list of children, compute how many nodes are considered "changed" in the new tree. A node counts as changed if it is: deleted (present in old, absent in new), added (absent in old, present in new), has a different value for the same key, or has the same key/value but a different parent compared with the old tree. Design an efficient algorithm and explain its time- and space-complexity.