Google

First, there is a telephonic round that explains the process, followed by a screening round. If you clear this, there are further rounds: three coding rounds, one "googliness" round, and one system design round.

Hard DSA questions: trees, graphs. Basically, you need optimistic ways to approach a solution. I am able to solve 2 out of 4 questions based on arrays, binary search trees, and one linked list question.

Interview preparation can take weeks or months. The HR department was very helpful, giving me three weeks to prepare. They provided interview preparation materials, videos, and useful links that aided my preparation.