Right after this round, Scott Wu and Andrew He streamed a post-contest discussion on twitch (CF post). Unfortunately the recording is no longer available, but the concept is exciting and I've enjoyed listening to a part of it.
The round had a few mathy problems, but I'd like to highlight problem E which had a more algorithmic flavor: you are given a prime modulo p up to 109 and two numbers u and v between 0 and p-1. In one step, you can either add one modulo p, subtract one modulo p, or take inverse modulo p. You need to obtain v from u in at most 200 steps (the solution doesn't need to be the shortest). Do you see a way?
Thanks for reading, and check back for more!