Agreed. The recursion has to be killing their time. My code is about 35% faster than theirs. I don't understand bitwise operators yet. My code and yours run neck and neck.

It seems like you should be able to shave some time off of yours by changing your for loop to somehow account for the actual bit size of 'n' instead of using 32 bits regardless of 'n'. A little above my grasp thus far in my coding journey.