Either a lie or you are unusually good at algorithms. People work > 50 hours on Leetcode, CTCI, etc. to try and get a job at Big 4. A couple of hours just reading Wikipedia articles isn't even close to the amount of effort people put into 'gaming' the system these days.
That was the only prep I did for the interview. I was a senior software engineer at EA at the time, with about a decade of professional software experience.
I don't have much of an academic background, but I had written and shipped quite a lot of code by that point in time.
The cramming did help—several of the algorithms I read about were either new to me or I hadn't seen in ages—and some of them did come up on the interview. (I've also used almost everyone of them at my work at Google since, strangely enough.)
My point was just, if you are already a good enough engineer to be successful at Google but don't "interview well" because of whiteboard experience or algorithms it's pretty easy to shore up those two things. You don't need to spend a decade at a monastery meditating on Knuth.
If you're a decent coder, you've already done way harder things. Breaking down a big messy problem into pieces you can code and test is hard. Shipping applications is hard. Breadth-first search is not hard.