I had two technical phone interviews. Both were strictly limited to 45 minutes.

On the first one, I was asked a few technical questions and one brainteaser. Afterward, I needed to write a small program and post it through Google Docs.

On the second interview, I was asked to dictate code, so that the interviewer would write it down and estimate. One of the questions was terribly difficult. I spent about 20 minutes trying to resolve it but could not.

Another question was much simpler and doable. The interviewer did not test my language, technology knowledge, or experience at all. He just wanted me to resolve difficult brainteasers, which hypothetically even a student without any experience could do.

One independent survey showed that 70% of people asked like coffee.

Another independent survey showed that 80% of people like tea.

What are the upper and lower bounds of people who like both coffee and tea?

Write a function Brackets(int n) that prints all combinations of well-formed brackets. For Brackets(3) the output would be:

((())) (()()) (())() ()(()) ()()()