Often the followup question to what is the O notation of X is why? So if you are just going to memorize the cheat sheet then it won't get you very far.
It is good to know what you should know about though.
It is good to know what you should know about though.
... obviously they wanted 2, but O() doesn't work that way - changing base is a constant factor. Sometimes there's a tension between figuring out someone's understanding of the algorithm and someone's understanding of the notation (and math behind it). Of course, I gave them both answers...
Only if the base is constant. For example B-trees have O(log_B n)-time operations, and you can't ignore the B because it is a parameter (hence non-constant).