Google's “Director of Engineering” Hiring Test

"There's an array of 10,000 16-bit values, how do you count the bits most efficiently?"

multiply 10,000 by 16. There are 160,000 bits

My sarcastic reply is to your very reasonable answer is:

On the x86 architecture, integer multiplies take more cycles than a comparable solution that uses bit twiddling so you're just WRONG!

You are the weakest link, GOODBYE!