Also use this post for discussing the exams once its over. :)
Edit:
Sorry to hear about the bad experiences everyone had at the exam centers. On the positive side, everyone gets to compete in INOI! ( read more here Good News for ZCO 2017 Participants )
Also, here are the discussions for the ZCO, ZIO 2017 problems:
And lastly, in-case you want to start early on the INOI problems, here is the link: Intermediate concepts and problems