Pretty much what others are saying.

Avoid this company if you want to save time. I was asked an algorithm question and gave multiple solutions, taking into consideration tradeoffs and time/space complexities. The interviewer wanted an even faster solution (there was no faster way to solve the problem given the constraints that were provided), which I ended up "getting," in part due to help from the interviewer. But at the end of the interview, the interviewer realized the solution he/she helped me write didn't work and was thus invalid (what kinds of engineers are they hiring at Livongo?).

I got the exact same question from Google and passed their interview without any problems because people there can actually solve problems without overcomplicating things. Sometimes, the best solution you can hope for will not always be O(logn) time and O(1) space.

All in all, I was initially pretty intrigued by what they're doing but terribly turned off by the incapability of their engineering team. I have interviewed with many companies at this point and have been fortunate enough to receive offers from a lot, including "big N," unicorns, and prestigious startups, but for some reason failed this one because of an amateur engineer who wasn't able to solve his/her own question. Ridiculous.

I'm not sure I can divulge the question. I didn't sign any NDA (again, which speaks to poor company practices, lol), but out of decency, I will not disclose anything.