Chinese judges/platforms/resources

Hi everyone, recently I have seen https://usaco.guide/general/olympiads?lang=cpp, where there are several online judges, but since chinese team is quite good and in addition they are kind of inactive in the most popular CP web-pages/platforms/online-judges, I would like to know if someone know something about “Which resources do they use?” or “Is there any famous online judge that they use?”
Thank you in advance

https://www.acwing.com/

the problems are actually pretty good lmao