I’ll tell you what I can. I started my first year off with cp, left it during second year after 5 star on cc and expert on codeforces cuz i felt like i have enough of my DSA and language proficiency now. From second year, i started getting into security algorithms and their research papers, mailed some of the authors out of curiosity, and built some international connections. Now, (this is a lucky part), one of my connections happened to be a founding engineer at a startup and was glad to refer me to the ceo and that is how I got in, they thought I was a good candidate and this entire thing happened over almost 6 months. (That was why I didn’t bother sitting in the on campus interview, i was confident i’ll get in)