Hello! APIO 2018 is near the end, and IOI 2018 is in this September. I hope you are preparing it well!
I'm here to present my OI problem checklist :
I used this to train myself in IOI 2015~2016, and to train Korean IOI 2017 Team (probably 2018 too). For long it was in the "beta" phase, but I think it's now good enough to share!
This problemset contains about 300 ~ 400 hard and interesting problems, with appropriate judge links given. (If there is problem in judging, maybe ojuz can help that..)
I hope this can help anyone preparing for future OIs, and a complete answer to the question "How to excel at IOI-style contests" :D
(Note : Inspired by this article, I was also making an ICPC version of this spreadsheet. However, sorting out ICPC sets are far harder than OIs, and the process itself is very tedious. :/ I don't expect it to be completed soon, but I will share as soon as I'm done :) )