During high school, I participated in the International Mathematical Olympiad (IMO) and the International Olympiad in Informatics (IOI). Later I competed in ACM-ICPC World Finals 2017 and 2019. I have authored several problems for IOI-style competitions. Below is a list of some of my personal favourites.
While not thinking about math, I often enjoy playing table tennis and I've recently taken up bouldering. On the weekends, I like going hiking or skiing depending on the season.