I joined Google at the age of 50. Just send a resume. They are not trying to surprise you and want you to do your best. Consequently, not only do they tell you what to expect from the interview process, the recruiter will send you a PDF that talks through what to expect along with a reading list you can use to prepare. (For example: cracking the coding interview and CLRS are on it.)
That said, I just went in cold. If you've been coding and are current in one of the 3 big interview languages (C++/Java/Python), and if you still understand your undergraduate level algorithms course and the corresponding vocabulary, then you know what you need to know.
Side note: A thing that no one told me but that I had to figure out on my own is that your technical writing skills are one of the most important skills to doing well at google. It was unironically said to me that the highest reward/effort one can do at Google is to write documents. The person who said it was correct about that IMO.
That said, I just went in cold. If you've been coding and are current in one of the 3 big interview languages (C++/Java/Python), and if you still understand your undergraduate level algorithms course and the corresponding vocabulary, then you know what you need to know.
Side note: A thing that no one told me but that I had to figure out on my own is that your technical writing skills are one of the most important skills to doing well at google. It was unironically said to me that the highest reward/effort one can do at Google is to write documents. The person who said it was correct about that IMO.