Google Software Engineering interview questions

Got a 90 minute coding challenge 1 week after I applied online. About a week after I did it, I got email regarding scheduling 2 technical phone interviews and candidate profile questionnaire. I scheduled the interviews 5 weeks from the time I got the email because it was around new years back then and a lot of interviews were already scheduled. I got scheduled 2 back to back interviews. About 21 days after the interview, they emailed me to inform me that I passed the interview and will move to the host matching stage. I had 3 host matching interviews, and about 1-2 weeks after that, I was told that the team I liked most wants to move forward. Then google recruiter called me to give me the offer.

The interview was done over google call. Two interviews did a back to back two 45 minute interview sessions. There was a break of 15 minutes in between. They where very helpful with guiding toward the write direction of the solution. They asked the Big O complexity of a lot. And how to optimize it to make of lower complexity. They were nice and patient.