So I've filtered all the hacked submissions in the round, and I've noticed something strange: https://codeforces.com/contest/1772/submission/185895220 https://codeforces.com/contest/1772/submission/185894048 https://codeforces.com/contest/1772/submission/185892176 https://codeforces.com/contest/1772/submission/185890581 https://codeforces.com/contest/1772/submission/185890587 https://codeforces.com/contest/1772/submission/185888246 https://codeforces.com/contest/1772/submission/185888258 https://codeforces.com/contest/1772/submission/185887838 https://codeforces.com/contest/1772/submission/185868906
All these submissions have something in similar: if t == 1 or t == 2, it will automatically exit, causing it to be hacked
The codes look identical, it seems like they've been cheating and copying their code from somewhere. And it seems that someone shared deliberately incorrect code.