I am high school student interested in Olympiad of Informatics and want to be part of my IOI team . So for my preparation i use codeforces of course but also i try to focus on usaco guide since it has learning ressources sorted with problems like kind of roadmap but i was always wondering is it useful for me although i am not from USA and if yes what other ressources should i include too?? by the way i have been doing cp for 1month you might see me registered 11months ago but my first contest was 1month ago.Anyways i hope you answer my question.