Cheaters have been a part of Codeforces for a long time now, but most of them haven't been banned. Some of them are pretty hidden about it, others don't even bother hiding their cheating. Whether it's AI, or those Youtube channels that post solutions, they should not be appreciated. In Codeforces Round 1050 (Div. 4) there is a cheater who used AI to assist him in problem D. He is an27102012

The cheating

Here is his score:

You see, he isn't that kind of guy who cheats on easy problems that basically anyone can solve, but rather the problems he's stuck on. The problem we are looking deeper today is problem D.

Problem D

First, let's look at his submission list for problem D

Let's get the AC code: submission 338476298.

At first glance, this may seem like a normal code, but I want you to note these things down:

1. Variables are declared locally

2. 'T' is in uppercase

3. if(!cin >> T) return 0;

4. ios::sync_with_stdio(false);

5. using ll = long long;

6. There are blank lines (for spacing)

Most of the properties mentioned about the AC code matches with the AI coding patterns, which might be implying that he has used AI to help him in problem D. But we need further proof!!

Now let's look at his other AC submissions (I know he AC A to E, but I'll only include B and C):

B (submission: 338388761):

C (submission: 338402129):

In these 2 submissions, we can see that:

1. Variables are declared globally

2. 't' is in lowercase

3. There is no if(!cin >> t) return 0;

4. There isn't ios::sync_with_stdio(false), instead it is ios_base::sync_with_stdio(false);

5. There is no using ll = long long; and he uses long long normally

6. There are no blank lines (for spacing)

This means that the AC code in D does not match his coding style, meaning that he had indeed used AI for problem D in the contest.

Conclusion

In conclusion, we can clearly see that an27102012 did use AI for problem D in the contest. If you guys can prove me wrong or add further proof, please leave a comment for this blog. Thanks