In the last contest, which I couldn't take part, two users cheated. .eray and Lutfu submitted almost exactly the same code for problem B. I put the photos and links.

submission of .eray: https://mirror.codeforces.com/contest/1354/submission/80463880

submission of Lutfu: https://mirror.codeforces.com/contest/1354/submission/80509151

This things shouldn't happen.