A headhunter at Google found me on LinkedIn and contacted me.

He scheduled a non-technical call with me first, asking about what kind of job I wanted to work on.

Then, he quickly contacted another technical recruiter to schedule a 45-minute phone interview one week later.

The questions were classical and could be found on Glassdoor.

However, I was informed of my rejection after another week.

1. Count the number of positive integers less than N that do not contain the digit 4.

2. Design a data structure that can do the followings in O(1) time: (1) insert (2) remove (3) getRandom