plagues

I think plagues should record himself participating in a Codeforces Div. 1 or Div. 1 + 2 round and upload the video publicly. That would explain everything much better. Otherwise, words alone aren't very convincing.

I suggest you better make a detailed analysis on his submission of 2129D.

I think it's too funny to be a human-made code.

• strange c++98-styled template class clarification: (notice the space between >>)

vector<vector<unordered_map<uint32_t, int> > > d(n + 2, vector<unordered_map<uint32_t, int> >(n + 2));

• Err... I don't want to say any word.

In main

while (t--) {
        int n;
        cin >> n;
        vector<int> v(n);
        for (int &x: v)cin >> x;
        cout << s(v) << '\n';
    }

In s(v) which is just called once:(vector v didn't appear in other places)

int s(vector<int> &v) {
    int n = v.size();
    vector<int> t(n + 2, -1);
    for (int i = 1; i <= n; i++)t[i] = v[i - 1];
    auto C = b(n);
    vector<vector<unordered_map<uint32_t, int> > > d(n + 2, vector<unordered_map<uint32_t, int> >(n + 2));

And there's a function b(n) also just called once:

vector<vector<int> > b(int n) {
    vector<vector<int> > c(n + 1, vector<int>(n + 1));
    for (int i = 0; i <= n; i++) {
        c[i][0] = c[i][i] = 1;
        for (int j = 1; j < i; j++)c[i][j] = a(c[i - 1][j - 1], c[i - 1][j]);
    }
    return c;
}

Btw, I think Skeleton difference could be explained if he wants to deny. As for the transfer, I myself sometimes mix those types, and I even mixed initializations like int x = 0 and int x(0);. The space after loop can be explained as the malfunctioning of formatter, while > > can't.

After reading this post, my initial reaction was that publicly accusing someone without sufficiently strong evidence was wrong. However, after examining two of plagues submissions myself, I found it increasingly difficult to believe that no generative AI was involved.

First, consider this submission:

The function $$$b(n)$$$ constructs the entire Pascal triangle in $$$O(n^2)$$$, yet it is called inside $$$s(v)$$$, which is executed separately for every test case. Therefore, the submission repeatedly performs the same quadratic combination-number preprocessing, for a total complexity of

$$$O\left(\sum_i n_i^2\right),$$$ or $$$O(Tn^2)$$$ in the worst case.

This is not a subtle optimization issue. Any experienced contestant—let alone an IGM—would know to precompute the table once up to the maximum required $$$n$$$, rather than rebuilding it for every test case. Repeating a complete quadratic preprocessing in this way is simply not the kind of elementary mistake I would expect an IGM to make.

There is also this submission:

The highlighted loop appears to search for the best value of $$$x$$$ from $$$1$$$ to $$$10$$$ by maximizing the size of $$$ws2$$$. Whether an element is inserted into $$$ws2$$$ is determined by $$$s+x \gt w$$$.

As $$$x$$$ increases, this condition only becomes easier to satisfy. Therefore, the set of input elements that qualify for $$$ws2$$$ can only grow, meaning that the size of $$$ws2$$$ is monotonically non-decreasing with respect to $$$x$$$. Its maximum over the range from $$$1$$$ to $$$10$$$ must consequently be attained at $$$x=10$$$.

It is deliberate code camouflage: a predetermined constant assignment has been wrapped inside a meaningless pseudo-search to make it look like genuine algorithmic reasoning. Its purpose is to disguise the code and evade AI-detection checks.

These are not merely unconventional stylistic choices. One submission repeats an obviously unnecessary $$$O(n^2)$$$ preprocessing for every test case, while another deliberately conceals a predetermined constant behind a ten-iteration pseudo-search. Together with the extremely unnatural naming, control flow, and data structures, this looks much more like generative-AI output that has been intentionally disguised than code genuinely written by an IGM.

At this point, I honestly cannot convince myself that no generative AI was used. I can hardly believe what I am seeing.

How the turns have tabled...

Hi!

I’ll gladly explain this.

First of all, if you want, you can do a more detailed analysis of my submissions over all these years.

My coding style has changed a lot at different times.

For some time, I used a lot of templates like

#define vector<vector<vector<long long>>> vvvll

and special template functions like sort(a), where a is a vector. Starting from C++23, something similar appeared in ranges.

There were even pictures and funny comments in my code, but later I stopped doing that.

My code used to contain a lot of indentation and extra lines, but later I realized that I don’t want things that are obvious from context, for example input, to take more than one line. Moreover, I often even write DFS in one line.

For example, you can definitely find something like this in my code:

for (int v, u, i = 0; i < n && cin >> u >> v; ++i) g[v].push_back(u), g[u].push_back(v);

Moreover, I used to always write using namespace std, but over time I got inspired by jiangly and stopped using it, because CLion is perfectly capable of automatically adding std:: to anything from std. For example, I type set, press Enter, and CLion completes it as std::set. I think this is a cool coding style.

But this does not always work. Moreover, at some point it broke in CLion, and I even submitted an issue about it on YouTrack after which JetBrains fixed it.

But obviously, in CP, using std:: is not always convenient, especially when you stop participating in rounds frequently. So in harder problems I often just stop caring about it and use using namespace std so that I have enough time to write all the problems.

You can also notice that I try to fit the first problems into the minimum possible number of lines, but problems where I need to be able to easily change or debug the code have to be much more spread out. This is also very noticeable and quite obvious.

Regarding

for (int i = 1; t--; ++i) {

apparently, in some problem before that round I had to use the test case number. Moreover, you yourself pointed out that this happened only in one round.

I often delete everything from main during a round. I don’t think this is even remotely a strong reason to think that I’m a cheater.

Regarding "strange c++98-styled template class clarification".

Cmd + Option + L is Reformat Code in CLion. It adds those spaces itself. I’m simply too lazy to dig through clang-tidy/code style settings to fix this.

This, by the way, also explains the occasional lack of spaces after my one-line fors.

Someone also wrote about O(Tn^2) in one of the problems involving Pascal’s triangle.

Well, this is basic stuff. Over time, you realize that in competitive programming it is important to write code quickly, not optimally.

For example, I can often allow myself to do some simple counting of the number of elements in an array in O(n^2), simply because it is trivially more convenient to write.

Obviously, C(n, k) is not some super complicated function, but I write code from scratch, and spending an extra minute building two arrays f and nf and then writing the formula seemed pointless to me that time, when the problem constraints allowed me to write an O(Tn^2) solution that easily passes the TL.

I consider this accusation especially meaningless.

Regarding ps = 10. It wasn’t obvious to me. Even IGMs can sometimes fail to notice obvious things :)

This accusation also seems absurd to me, simply because — why?

In general, I consider everything I responded to above completely pulled out of thin air.

Seriously, sometimes there is using namespace std / sometimes there isn’t, sometimes I write Pascal’s triangle in quadratic time — cheater?

The only thing that I actually consider a fair question is 2129D.

Here the answer is ridiculously simple: I was just having fun. I just wanted to write funny code.

This is literally one problem out of more than 100 rounds that I have participated in.

Moreover, I wrote this problem incorrectly 3 times in a row, and at some point it pissed me off. I had very little time left, so I decided to write the shortest code I could while also making it as ugly as possible.

Seems like I succeeded.

I also don’t really understand what unfair advantage this could have given me, considering that, as far as I remember, this was before LLMs learned to solve problems this difficult.

Also, we discussed this problem with my friends, and everyone laughed at my submission :)

Thank you very much for not being indifferent and, just like me, trying to find cheaters on Codeforces :)

Larping final boss:

nah I don't think that cheater would post blogs to expose others *remembering about ShulkerBox* oops nvm

Why are so many bot-named users targeting plagues (TemperanceAlouette6042, MatildaDamaris6674 and PiaElka37401).

Note: all of them are unrated and registered 2 days ago (pls don't call me racist).

Auto comment: topic has been updated by HubRis504 (previous revision, new revision, compare).

The only thing that I actually consider a fair question is 2129D.

Here the answer is ridiculously simple: I was just having fun. I just wanted to write funny code.

Right. plagues switched from his usual ++i to i++ because he was “having fun.”

Right. plagues changed the Fenwick tree function name from void modify(int i, int x) in 2129B to void upd(int i, int v) in 2129E because he was “having fun.”

And this is seriously considered an acceptable explanation on Codeforces?

If exactly the same answer had come from someone without an International Grandmaster title next to their name, I strongly doubt people would be nearly as charitable. It would probably have been downvoted into the ground.

Cheaters, are you taking notes? Next time someone points out something suspicious in your code, just say you were “having fun.”

So yes, you did achieve your goal.

Have fun.

Racist bum turns out to be a cheater omd the jokes write themselves

This is an outrageous stretch. I fully agree the original blog of plagues should've been written without AI, and had removed some accusations, but on this matter, he has my full endorsement.

Most of the stuff here can be explained by copying template code, and a lot of ADHD. This is not how the community should go forward, looking for minor details and asking to defend themselves.

After reading the blog and the comments, I don't still get whether this is a troll blog or a serious one...

i seriously want to know why there is so many bot accounts downvoting and attacking plagues?
Even they said focus on the main thing which is the cheating allegations, why could not you guys use your true identity? Or is it that you do not want to or are you also cheating?
Let see if this get downvoted to like -10, that would confirm my suspicions further.

At this point it's CF vs some alt accounts