Recently, I've finished writing an article in which I explain how to solve problems from IOI 2018.
In my opinion the problems are really challenging and interesting, and are good learning material. However, the official webpage of the competition provides only sketchy explanations, and they miss implementations.
In the article I try to present detailed approach for each problem, going through subsequent subtasks. I've also prepared full C++ implementations (38 programs in total).
I hope you will find it useful!