It takes 2-3 months to accumulate 20 contests, given you don't miss a single one. I feel like this change would just make it less incentivizing for newer contestants, as one of the more fun/incentivizing aspects of CF is the rating. I find it difficult to believe many (legit) newbies will be willing to partake in 20 contests with zero feedback (rating change), especially if they are just spontaneously doing contests for fun. Furthermore, if people feel the need to cheat for a rating for validation(?) in the first place, I'm sure people will be willing to submit CE for 20 contests(especially if there are other, more concrete reasons for cheating for elo).

As for my takes on what you can do, I think its a culture/mindset issue; as long as there is demand, people will always cheat, and its especially hard to deal with on online contests without invasive anticheat or usage of real ID.

Let me know if you think otherwise, but IMO this change is negative overall.

Special thanks to ScarletS for coordinating the round (and not killing me)!

yet.

3 of the last 4 blogs on this account are about being top contributor...

As a tester, I can confirm that writers have brainrot

Rick Astley is mentioned in the blog!

I love this idea, however I want to give some small changes on this.

First of all, 20 contests are obviously too many, it take one about 4 months for that, assuming you're doing almost every contest. Maybe adjust that to 6 or 10 is more adequate.

Secondly, making first contests unrated will potentially make people just sign up a contest, solve one problem (or even just submit a random CE) and leave because they are unrated anyways. I'm afraid some kind of people would register tons of accounts, remove their restrictions at the same time, and then cheat as how they do now. I suggest just hide the rating completely (instead showing an offset value like now) in the first contests. Both of these ways increase the time cost to cheat successfully, but the second way makes more sense IMO.

Last, ban those accounts that got skipped for 2 times in a row, please. Nothing will work if this isn't implemented. I'm very shocked when I once knew some random people cheated for 6 times and still didn't get banned. Maybe not permanent, but 14/30 days temp ban will work I believe.

I'm trying to offer an English version of the statements :)

When you realize that you're rickrolled by the announcement

tbh learn from leetcode:

for the first skipped contest: make the round still rated for them but move ranking to the bottom of the leaderboard

just ban after second infraction

bro is prefiring :(

As a tester, I tested after getting to violet :)

Using bitset. :)

Build a boolean table $$$B$$$ of size $$$n\times n$$$ where $$$B_{ik}=1$$$ if and only if $$$p_i < p_{i+k}$$$. Then the number of suitable indices $$$j$$$ for a fixed $$$i$$$ is the number of ones in the bitwise $$$\texttt{AND}$$$ of the rows $$$B_i, B_{i+1}, \ldots , B_{i+m-1}$$$. You can find it for all $$$i$$$ using the approach in this blog.

As a tester, the problems are nice and you should read them all!

Did I just get rickrolled?

As a tester, I was told to farm contribution here

MikeMirzayanov Ban this account please.

As a tester，I tested.

this guy wanted retire but failed :skull:

Well-known in Krasnoyarsk

From my experience, you are incorrect, as one can easily get to Master with pure problem-solving skills. Now, I'm not stating that the person will do well in every single contest, as there are problems that involves standard techniques, but their rating will converge to Master (or higher) eventually, since the majority of contest on Codeforces is doable with only bare-minimum knowledge.

In fact, this can be pushed a bit further, to obtain a structure of size O(n) that computes any sum in O(α(n)) time. See https://arxiv.org/abs/2406.06321.

You don't need comutativity. The way you describe the query, what $$$s_i$$$ and $$$p_i$$$ mean makes comutativity not be required.

NJACK orz

As a problemsetter, all the problems are really cool and interesting. Wish all the participants a large positive delta and a fun experience.

Does it even matter? Nobody is going to choose the AI path anyways (I have only 3 candidates in mind and they are all companies)

stop farming plz

thanks

Ok time to add something meaningful to the conversation.

Although the trick detailed can be easily dismissed as unrolled queue-like undoing, the problem linked poses the same question but for 2D spaces. And so I would like to detail this scaling:

The trick here, which can be applied in the 2D case, is to assign some reference points for which we will calculate some information which will be necessary and sufficient for completing an entire query. For triangles, given an interiour reference point, we can divide the triangle by drawing lines parallel to the axis through the given reference point, and as such we divide our query to require only information for a: trapeze in NW/SE quadrants, simple cornered triangle in NE, and rectangle in SW, all computable in linear time wrt the dimensions required for a query, which is of the order of $$$k^2$$$ (sufficiency?)

Furthermore, to assure the necessity? of the construction, we can calculate only for gridpoints which have both their coordinates divisible by $$$\frac{k}{2}$$$; as such, any query has a reference point within it.

The complexity is, therefore, clearly linear.

A good CPer is good at CP.

A bad CPer is bad at CP, and accepts it.

A cheater is bad at CP, but is unable to accept it, he copes and seethes so hard that he must resolve to cheating.

I wonder, who is the real loser?

Duration: 450 minutes

But it will last for 4.5h......

What's this tag @every_LGM_IGM_GM_M_CM lol

Because he is a skipped cheater. Just wait for the ratings to be rolled back and recalculation happening.

Oh right. Thanks

I also watched movie with him yesterday. He cannot cheat as he was watching movie during contest time. The movie name was TheBhediyaOfDalalStreet

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

As a tester, f*ck the cheaters!!

No, we provide it, it could be found on eolymp. It would be published there soon.

maomao90 when he loses his top contribution spot: quick write a blog

In case those who are not able to understand the dp of the tutorial of problem D. after getting the freq array of the elements of the main array you just need to maximise the number of indices that Bob can take and then subtract it from the freq array size. Below is the simple understandable recursion + memoization code —

const int MAXN = 5001;
vector<vector<int>> dp;

int helper(vector<int>& v, int ind, int steps){
    if(ind >= v.size()){
        return 0;
    }
    if(dp[ind][steps] != -1){
        return dp[ind][steps];
    }
    int curr = 0;
    if(steps >= v[ind]){
        curr = 1 + helper(v, ind+1, steps-v[ind]);
    }
    curr = max(curr, helper(v, ind+1, steps+1));
    return dp[ind][steps] = curr;
}

void solve()
{
    int n;
    cin >> n;
    vector<int> a(n);
    map<int, int> mp;
    for(int i = 0; i < n; i++){
        cin >> a[i];
        mp[a[i]]++;
    }
    dp.assign(mp.size(), vector<int>(MAXN, -1));
    vector<int> v;
    for(auto x : mp){
        v.push_back(x.second);
    }
    int ans = helper(v, 0, 0);
    cout << v.size() - ans << "\n";
}

Thanks.

approach =First, count the number of edges in the adjacency matrix.for tree=n-1 I Use Depth-First Search (DFS) starting from the first node to check for cycles and to ensure all nodes are connected.i take care of visited and parent condiiton

The data is taken as is from the codeforces API, did you check again, there are three graph (first one includes both during and after contest, second one includes only during contest and the last one for upsolved questions).

Edit: I found the bug. (I added && while comparing instead of ||). Thanks to my Specialist ass. Btw, it is fixed.

On behalf of all the missing newbies and negative testers, I can say that this round is going to be awesome!

Reminder:

The contest will start in an hour.

Not viable. What about the false positives? What about those innocent participants whose code was copied and mass distributed by someone else mid-contest? What about coincidental symmetry between multiple solutions due to a straight-forward approach?

I think this blog can get you to the top 1 contributor again :D

As a participant, I can confirm that MrSavageVS is indeed Savage.

"Phone numbers are not as easily available as emails". Incorrect, it's easy to buy phone number for such verification and pay like 0.3$

IndianFORCES

I just want to know why your_submissions_ solved 9000+ problems and made hundreds of submissions every day.

That's not what I mean, the real one is because you're make fun of those who are trying their best to improve, and it's obviously not tolerable.

We will solve by ourselves, enjoy solving problems, improve ourselves, and will be better than you (and more often will be higher in rankings), and in the meantime you will wait for a solutions from others, like a pig waiting to be fed.

As a tester, wait I didn't tested it well I belong to IIT Patna and NJACK so I am just happy.

Look at this guy's recent submissions lol

The post was downvoted at first, just to clarify

могу обоссать тебя друг, пойдет?

As a participant, I can confirm that the testers are crazy!

get this stupid scum fucking banned

if anyone can take a SS of that telegram channel as evidence

Don't discuss about problems during the contest,bro(

Did you just rickroll us?

For this I would like to apologize, in A the error was found and updated, but not uploaded to eolymp.

Nice one! Now solve Triangle ignore the 1.5s timelimit, solve for 1s

dont you assume invertibility (and specifically, the operator being its own inverse)? i dont believe thats one of the axioms

your example doesnt solve if the operator was bitwise and for instance

We have a Discord server that practices CP, and our main language is English.

If you want to join, here is a link: https://discord.gg/kWAtZSA6

Our server is made up of Specialists and Experts that are improving, you'll fit right in.

finally SyndryVictory round

As a tester, testing this round was tasty, although I did it in hasty.

You don't need any advanced knowledge for F. Just try to optimize the brute force. There is ~$$$10^6$$$ values of x where $$$b \geq 3$$$ so you can track those values in a set to avoid overcounting. For $$$b = 2$$$ binary search on the biggest square that is less or equal to $$$N$$$. My submission: https://atcoder.jp/contests/abc361/submissions/55297768

At least cheaters have to pay for something. So that's not too bad an idea.

As of writing this comment, congratulations on reaching top 1 contributor!

With speed, expert could be reached by just knowing the stuff listed (and a little more practice on DFS/BFS) should be enough to at least slowly reach expert.

Could someone recommend more problems like Central Cutting where you need to tally the values of a certain function over partially filled combinatorial objects (a permutation of length $$$n$$$, an array of length $$$n$$$ with elements from $$$1$$$ to $$$m$$$, maybe even a node- or edge-labeled tree with some labels missing)?

ban those accounts that got skipped for 2 times in a row

I wanna add in a bit to this idea to avoid circumventing: 3 skipped contests (not consecutive) can also be qualified for a ban similarly to that for 2 consecutive skipped.

Thanks. Could you please specify or list the required knowledge and its level, if possible? A generalized explanation of your learning journey would be beneficial for us.

It's a great idea

It was a private mashup.

So what is your approach?

Okay. I don't think these topics are at a base or minimal level for the particular Codeforces rank. The learning baseline can vary from person to person, but your suggestion is noted!

I thought of tetr.io when I first saw the idea. In the game website, the users can only enter the league (i.e. official game) when they are level 10 or higher. This annoys me because getting to level 10 can take a week or more time.

The same as above, setting "unrated 20" contests for beginners isn't a good idea. They would become bored and quit cf.

Rick Astley orz

It is kind of smart brute force. Firstly we will count the number of values such that $$$i^2<=N$$$ . After this, we have to count the cubes and higher power. For doing this we can just start a loop from $$$2$$$ till $$$\sqrt[3]{n}$$$ .

We must take care to not overcount elements, for example $$$64$$$ which is both the square of 8 and the cube of 2

You can do it using Inclusion-Exclusion too. You've to basically count all squares, cubes, a^4,.. a^k less than N. Iterate from highest power to lowest power and find those values (using kth root). Then for each power k you've to exclude calculated value of its multiples.

nice rickroll.

The problems were fine but the statements were pretty bad. A's statement was wrong and I still don't understand how F works even though i got 50 points on it

I can (or will be able soon to) solve 4-6 of Div.2 problems within 2 hours without "distributing" them across people who barely can solve even Div.2 D.

I love you m3lem <3

dont help him the oa is going on he is asking for help.cheater loser

he isn't talking about buying a real phone number, he is saying you can get such phone numbers for 0.3$ for verification. There are services on internet that provide you a phone number to recieve otp for like 0.3$

Ig the prices are low but, I don't think that someone who is cheating to get better rating or overall better account(most of them are) would appreciate the access to the phone number and OTP for the account being public and easily available. plus I think it could make catching cheaters much easier, we just have to try to use public phone numbers to log into codeforces. (I think permanent numbers will cost much more than that, and not worth trying cheating on)

I don't know why this is getting downvoted so easily, since there is a lot of stuff that people don't know that could help them implementing better.

Some ideas: - Don't mix thinking and coding. What I mean is that you should have everything pretty much clear before touching the keyboard, otherwise you might make changes to the code and everything will become messy really fast. - Break down your future implementation, in paper when needed, in pieces that you understand and those that you don't understand. Those parts that you don't completely understand, well divide them even more. - Be patient, don't rush to the keyboard. Always give an extra thought, and try to think of the easiest implementation possible. - Upsolve implementation with other people's code, you can catch some ideas that you missed. but only after you have accepted!!

Codeforces problems rely more in problem-solving and intuition than in knowledge. So you might be able to get to expert.

But from expert DPs will gatekeep you from higher ratings. And graphs appear rarely in Div2 ratings, you can probably survive without learning them.

Do not cheat, and your solutions won't be skipped.

Suppose there are $$$x$$$ distinct characters, then we can simply transform $$$n$$$ into base $$$x$$$ to get the answer.

OK,thank you, maybe you have noticed, the form for filling out the award information has been sent out by the system about 5 days ago.(You can see it in "talks" page, which is near the position of your profile)

I wrote this in case that you missed it. Please note that the DDL is 7.8 24:00 :)

Here

This includes daily practice sets created by the problem setters, and a great community!

Consider this testcase: ++00-1

The answer is YES, but your code will output NO. I don't know why but you can see this: 268997262

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

From my experience, knowing your own thought process is extremely beneficial. To improve rating by 200~300, you just need to practice more, but to improve 500+ there has to be fundamental changes to one's thinking process. For example, the improvement on "recursive thinking" would be very helpful in tree DP problems, and some people just master it without actually noticing this, but some others need to be aware of it before they become proficient in this thinking manner.

how to be cm

Hi everyone. I have a question: Will they deliver T-shirts to Ukraine?

Is there an explanation as to why G isn't commonly included in official editorials?

Just remove the functionality of seeing other's solutions while the contest is on(lock and see)