Hello, last night I checked the final standings of the contest Codeforces Global Round 31 (Div. 1 + Div. 2) and found something unusual. This guy (aka toberu) had really suspicious behaviour on that contest.

He reached GM with rank 69, that's totally legit, right?

Okay I was just kidding.

Firstly, in this contest he used only Java. It is really normal until I checked every other recent contests but he never used Java in any other contest. Do you see something unnatural? Why does he change the language on this contest? Is there anything suspicious behind this?

Secondly, this is the first submission of toberu at this contest (354179748).

Do you see this? Why does he comment in this code? Something like "__builtin_clzll(d) is equivalent to Long.numberOfLeadingZeros(d)". If you don't know, __builtin_clzll() is a C++ function, and with this comment, I have a doubt that this guy has used AI to convert C++ code to Java.

And this is the comparision between 354179748 (1st submission) and 354180518 (2nd submission)

Why does he even try to remove comments at the 2nd submission? It makes sense that he was trying to not be reported. But the first submission is enough to prove that he was cheating.

This leads to only one thing: He cheated by some reason using C++, the he used AI to convert every code to Java to avoid MOSS. I think he should be aborted on this contest.