FizzBuzz Problem Solution
That's a classic FizzBuzz solution.  I wouldn't try to do any clever optimization — it won't make any difference to performance.  One hundred iterations of anything is trivial for a computer.  Furthermore, most of the time will be dominated by the output routines, which you can't do much about.

The code formatting, on the other hand, could be improved.  The most glaring issue is the omission of the braces for the final else.  Why make your code ugly to save a couple of bytes?

Also note a de facto formatting convention: Put a space after if and for, and before any opening { brace.