Yo So apparently I found out this marshadow_ninja guy and he gain my suspicion through his code.
Problem A: "Okey normal dude coding yeah yeah"
https://mirror.codeforces.com/contest/2118/submission/324059526
Problem B: Instant change of coding style, using T instead of tt as his previous A submission, variable name starts to get longer. Also this style is very VERY similar to ChatGPT
https://mirror.codeforces.com/contest/2118/submission/324084308
Problem C: "onesAbove" array, interesting name tbh. Also the logic and style is the similar to ChatGPT
https://mirror.codeforces.com/contest/2118/submission/324094098
Problem D1: He did this BEFORE C, how good is he? Same style as ChatGPT, as usual
https://mirror.codeforces.com/contest/2118/submission/324091690
(using THIS
auto state_id = [&](int i, int dir, int r){return (i*2 + dir) * k + r;};
is what ChatGPT would do, yes i know there ARE people use this, but ChatGPT usually use this too, I'm just bringing up the issue.)
Problem E: Hmmm looks much more legit than the others, but his sorting method is just strange, usually people will create a bool function. Anyway still look ChatGPT.
https://mirror.codeforces.com/contest/2118/submission/324103638
Can't forget to tell you about his massive leap in rating. Bro just INSTANTLY jump to specialist after 4 contest. Almost every problem look sus and not hand-written, As you can see in his submissions (He only submit for contest only so its easy to tell)
https://mirror.codeforces.com/submissions/marshadow_ninja
Just look at it and tell me your opinion
EDIT: His submissions have a lot of strange and long and "meaningful" variable name.




