First off, you must know that the recruitment organization at Google is run by complete and utter morons. Recruiters get hired and fired all the time, and almost all of them are completely useless. Trust me, I have interacted with a great many of them. They may not be bad (or dumb) people, but the environment in which they work makes it impossible for them to do a good job.

It is completely normal that they forget to call you, forget your interview halfway through, reassign you to random people, or to positions for which you are clearly not qualified. Almost every single person working at Google has a story regarding recruiter incompetence which affected them or one of their friends.

Now that that’s out of the way:

You either apply for a job (usually via our website), or a recruiter contacts you, usually because they found you on LinkedIn (or similar) or because someone referred you.

Then a recruiter looks at your CV (more on your CV later) to weed out the people who have obviously no business working in IT. If you have a suitable degree (e.g., BS in CS, EE, Math, or Physics), or a few years of experience, or are a contributor to some well-known open-source project, then the game can begin.

Given a linked list, swap the kth element from the end with the kth element from the beginning.