That is correct. This solution functions correctly only because of the constraints specified. If the initial value is 10 then no matter what I do, my opponent can force me to lose the game, so I know that I will never recieve 10 as an input.

@SnickersTheCat, you are right, but the description specifies but you have a friend in judging who has excluded all hopeless initial l values for you, so a losing value will not be tested.

does this return 0 as a value which would be out of range?

when I pass 10 as length it is retuurning 0 which I would think would be outside of the allowed test values