After two technical phone interviews, I received a decision. I have interviewed with almost all the top companies, and Facebook's process is a thousand times better than all the others. I need to pick between the offers I have, so I have not yet decided where I will go. This is a neutral opinion, and Facebook is far ahead of others in their hiring process. They are extremely fast. If I had to rate them, it would be:

Facebook > Microsoft > Google > Amazon.

The interviewers at Facebook were awesome and spent a lot of time answering all my questions. The technical questions for both Google and Facebook were medium to hard, but Google's were a bit more difficult. Many people told me to do all the frequent Facebook and Google questions on LeetCode, but none of the questions were directly from LeetCode or CTCI. However, doing those questions helped a lot. In short, just prepare hard and practice, and that will help. Remembering a few questions is not the answer.