Google Software Development Engineer interview questions

The interview process at Google is very smooth and organized. The recruiter kept me updated at every step of the interview process. Initial round consisted of phone screen interview of 45 mins. Questions were based on Data structure & algortihms and then coding them. I got the interview result within a day and they asked me to come for an onsite interview which I scheduled for after 3 weeks. The onsite interview lasted for 4 hours (4 technical rounds and 1 lunch interview). All the interviewers were very good and the questions were based on Data structures, Algorithms, OS/Kernel, Networking and then coding in C(or your language of preference). Out of 4 rounds I did pretty good in 3 but I screwed up badly in 1. And that's why the rejection. Had it been any other company I would have got the offer but google looks for best answers not just an answer.