Level of usaco.guide needed to do well at ICPC Regionals?

Hello,

I not a high school student (so I'm not aiming to do well in USACO). I'm a college student who is going to participate in ICPC. I've taken an introductory data structures and algorithms class, but I've forgotten some of the particulars. I've got about 4 months to prepare and I'd like to become as useful of a team member as possible.

What level would you say is needed to get to a point where I can contribute to solving most of the questions?

Here's some problems for reference:

- https://icpcarchive.github.io/Mid-Atlantic_USA_Regional_Contest.html

- https://open.kattis.com/problem-sources/2025%20ICPC%20South%20Central%2C%20South%20East%20and%20Mid%20Atlantic%20Regional%20%28November%208%2C%202025%29

I also wanted to ask any ICPC participants in this subreddit: What platform would you say is most helpful (outside of Kattis) to improving the skills I need for ICPC? Codeforces? AtCoder? USACO?