I have no idea what log * is
Well, look it up. Unfortunately, Google doesn't search for symbols too well, but Googling log star
turns up the iterated logarithm immediately, and SymbolHound, a search engine that doesn't ignore symbols, turns up a StackOverflow post explaining it. It's also probably in your book or course notes somewhere.
The iterated logarithm, denoted log*(n)
, is the number of times you need to take the logarithm of n
before you get a value less than or equal to 1.
To solve the problem, consider the following. If you need to take the logarithm of n
log*(n)
times before you get a value <= 1, how many times do you need to take the logarithm of log(n)
to do the same thing?