You know that walls are an area not a volume. So when room is not a perfect cube you need to know dimensions of the walls.

Thank you. That was a headscratcher for me. I am really thankful for your help.

Thank you for your answer! Turns out the tests are wrong. In the directions for that exercise we have: (...) The array is either entirely comprised of odd integers or entirely comprised of even integers except for a single integer N.(...)
but in the textFixed log I get that input is: 2,6,8,10,32,6,8,200,700,1,84,10,417,6,8,10,6,12,24,36 in which there are two odd integers. Moreover I get a message saying: expected:<17> but was:<6> and there isn't a 17 in that input! The rest of the input is even so how come the answer is 6? I would be glad for helping me further with this issue. Or maybe changing the exercise if it is ineed with some errors.

So you are saying that 20th century took 99 years while 21 century will last for almost a 1000 years?