Thank to your answer and sorry for my ambiguous question.
I was make my room generation like the Binding of Isaac.(if player entered the door, add child nextroom and remove child currentroom)
I want to know as arrange rock, or another objects regularly to their rooms. (specific rule?)
use array get the vaule of room position? and In array, whether there is or not objects (empty => 0, object1 => 1 etc.)
I think there is only that. Is there any other good way? If you create an array, the x and y indexes exceed 20, so it doesn't seem like a good way. (By default, there are more than 10 rooms.)
I explained by painting.