Recontest clashes with the cf div1 round, please consider moving the contest to a different day or to a different time on the same day.

My problem was proposed on 21 Jan 2022.

Can you teach me how to win a div.1 round with some 1E+ difficulty ad-hoc problems? I'm willing to pay $200/hour or even more.

Curious: how much would you be willing to pay?

So you would pay even less than 10$ for 7 days of lectures?

Thank you for participation! We hope you enjoyed the problems.

You can access the solution slides (ordered according to the difficulty level, or at least how we perceived it) here: in Russian, in English.

By looking at the title I thought, why would a GM need a coach??

ask if the contest is rated

How to know the exact numbers for each size ?

I think 24th should also work

Your code should be available on your profile on https://www.facebook.com/codingcompetitions/profile

Tagging random community members who participate in contests is not going to fix the underlying infrastructure being broken.

Many colleges have exams till the evening (both my teammates got till 8). So, keeping it in the night makes more sense. 24th night seems like a valid time too though.

In fact, I have an exam till 6pm on 23rd and I didn't know it at the time of writing that comment 💀. Given the rarity of div1s these days, it would be great if they could avoid the clash, and 24th night seems like a good option for it.

Did you see the "N/A" with a slow connection (i.e. you saw that exact message and it's not just that the submission window didn't open)?

I throttled my network connection speed to simulate GPRS and it still doesn't happen. Then I logged in as an unrated alt account and it happened immediately, with a fast connection. And indeed, even the response from https://codeforces.net/data/submitSource contains "N/A" in the source field.

I think that seeing "N/A" has nothing to do with your network connection. Instead, Codeforces simply doesn't show source code to unrated accounts. This is further corroborated by the fact that everyone who has complained in this thread is unrated (or was unrated at the time of complaining).

And this is probably not a bug at all: source code viewing has probably been intentionally disabled for unrated accounts to reduce scraping.

bro pls dont flood cf with blogs, by this some useful ones got missed..

Apple every year be like:

it is not forbidden to participate in teams of smaller/*larger size*

Codeforces tells me "You should select between 1 and 3 team members" :thinking:

It's enough

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

Since your rank is master, you should be able to uphack any solution, but unfortunately, the case won't be added

It's pretty opaque. Some community members, such as the great Monogon have reverse-engineered it. Blog upvotes are weighted more heavily than comment upvotes (~10x or something), and your displayed contribution is some nonlinear function of your total score (like squareroot). Specifically getting twice as many upvotes does not correspond to twice as much contribution; it's something less than that.

Also there's exponential decay in your total score, and surprisingly it's not smoothly applied. We think it's like every 6 months. So if you make a blog post and get a lot of upvotes, your contribution will increase, and then 6 months later it'll suddenly drop.

This causes a weird side effect where even if you post blogs forever that always get lots of upvotes, your contribution will flatten, even if you keep posting those blogs.

The whole system is very unusual and could likely be improved.

Should we add our team?

waiting for Lebanon and Jordan teams to comment

The uphacking window is actually just one week after the contest, I just checked some submissions for older contests and that doesn't seem to be changed. And if it's successful it is added for later submissions. Since the problem is more than a year old, it's considered frozen and won't update unless Mike or the authors decide to move with it.

Me too found it a bit surprising it's this short, I thought it is something less than a month like 1-2 weeks before finally confirming it's just a week.

There's already one

D is a nice problem, really enjoyed it in contest.

Also, L is nicer to do if you count count the number of 2 squares divided by a vertical line and horizontal line, and subtract overcounts.

rutgers orz

Where is Editorial ?

‎

skibidi sorta fellow

There is one actually which you get access to after hitting CM

Is there any t-shirt size charts that we can take a look at for more info ?

GOOD lUCK

Can F be solved without FFT? Otherwise I find it really weird that so many teams solved it in contest. Like, how is this about as solved as problem I which could have been literally done with some simple hashes??

‎

H is quite cool

Same design as last year?

I don't see Kazakhstan in the list of delivery countries. Is it an error?

For sure they must add a report button for those kind of blogs that u just waist time reading it for nothing (chatGPT comments !!).

This is frustratingly bad. Even though after a while (in order of 10 seconds) it always end up loading, 10 seconds is quite a lot. It is bad enough that I need to think "do I really need to read that submission" quite often. This is worse when attempting to read more than one submissions.

Stop begging for money

I'm now interested if "minimal lectures and maximum practice" a good or bad thing according to you

Can you share the measurement chart pls? :)

you mean JOO91 when you said shoo91? UPD: I found a banned account JOO_91 in his profile team XD Upd2: it seems like all users in his profile team are his alt's.

Why when I try to view the Editorial, it says 'You are not allowed to view the requested page'?

ys i ment him

So smart !

Matters went from Egypt to Russia.. Good cheating reputation JOO91 and

?

ماا بورااااحه

MikeMirzayanov, when can we expect a fix for this problem? It's really frustrating not being able to open submissions from the past contests.

Can you dm me your rates please for future reference? Maybe someday we'll able to offer you an interesting deal

But I can only hack the solutions in recent 2 contests, I can't find the button "hack it" on earlier contest's submissions.

Poor fellow! It's so sad that you weren't able to cheat and remain undetected! I wish you luck next time! Try using a better AI model called "YourBrainsGPT" — it is said that it solves problems better, and it never produces code that gets disqualified!

Why is the Editorial!!! not allowed to view.

It's Nov.18 now.

Looks like the editorial has been taken down. Please fix cry

SB.

Ooops, sorry! I'll publish the results ASAP

the implementation part should be 2nd nature

My language skill (as my "1st nature") completely sucks. I feel impossible to explain the solution any problem more than 2200 rated. Sometimes I try to explain something and end up messing it up. Don't know if your problem is same as mine.

I find it helpful to formulate the solution in my head, not as abstract ideas but as a clear sequence of steps. I also try to logically / mathematically prove to myself why the solution would work. It does take a while, and in contests it does slow me down significantly. I do that intentionally. While intuition and making leaps in logic intuitively can make me solve faster, it also often leads to inaccurate conclusions. Or even worse, correct solutions, but I cannot explain to myself how certain corner cases get handled by that solution. Thinking about implementation details early on is also a slippery slope, as we may end up spending too much mental effort in the nitty gritties of a wrong solution. I encourage you to try practicing restraint before you jump to the editor. To spend time explaining to yourself why something works, finding confidence in your own approach, before you implement it.

Weights are the points we score for making blocks of X = 4, 8, 16, 32, .. 2 ^ n, then just use knapsack with repetition.

Just add #undef _GLIBCXX_HAVE_ICONV before #include <bits/extc++.h>, and it passes: 292337691.

nice handle bro

There was a recent comment about this:

https://codeforces.net/blog/entry/136182#comment-1218231

"If you need a size exchange, update your shipping address, or have any questions, please email [email protected] and use the subject heading "Hacker Cup 2024 — Shirt Order Confirmation #xxxxx". Please allow 2-3 business days for a reply to account for time differences as we're based in California, USA."

Is this completely offline or can we participate online?

It's offline. Offline camps are more fun and participants gets a sense of belonging in the community.

But, yes. We will do some more online camps too after this.

Total_sum can be big, as a_i <= 10^9. When you do targets array it can be humongous it seems

The size of targets array would be 10^9

masterpiece

I was hoping for the designs to be different from last year's. ¯_(ツ)_/¯
Anyway, it's finally here. Thanks!

"-and not reading the rules of the contest properly" Bro participated in 65 rounds, have you ever seen a contest which allowed you to cheat, it is obvious that using ChatGPT is prohibited, if you wanna lie at least do it convincingly.

But I respect you for actually publicly apologizing, we all were in that situation, just avoid doing it again.

why is editorial not available?

Till now, I haven't spent any money on learning competitive programming, I have been learning myself. I just want to experience the camp and I am also curious if It can made improvements in my skills. So, that's is why I am not willing to pay much but if it upto 150 dollars, I may try to participate.

Don't use Chinese to reply in CodeForces.

Damn man:)))

No way people find that funny. If you consider writing that in a place like codeforces funny, you had fallen below ape level intelect.

Honestly, they should add a report button for these kind of blogs

https://codeforces.net/blog/entry/135457

I was told that it goes up to like 30 seconds, and it probably differs from person to person, because for me it's always around 10 to 15 seconds.

Approach : We consider moving each column either to left or right, the first one will move to right and last one will move to left (consider this as base case), now if the current column moves left then it can collide with previous two if they move right else we move current column to right. This is what me and my friend coded but couldn't submit.

`
#include <bits/stdc++.h>
using namespace std;
#define int long long
#define endl "\n"
const int N = 1e6 + 10;
const int MOD = 1e9 + 7;

void solve()
{
    int n; cin >> n;
    int a[n];
    for(int i = 0;i < n; i++) cin >> a[i];
    int ans = 0;
    vector<vector<int>>v(n);
    for(int i = 0;i < n; i++){
        int sz = a[i];
        for(int j = 0;j < sz; j++){
            int x; cin >> x;
            v[i].push_back(x);
        }
        sort(v[i].begin(),v[i].end());
    }
    auto calcInt = [&](vector<int>&v1,vector<int>&v2)->int{
        int i = 0,j = 0;
        int count = 0;
        while(i < v1.size() && j < v2.size()){
            if(v1[i] < v2[j]){i++;}
            else if(v1[i] > v2[j]){j++;}
            else{
                count++;
                i++;j++;
            }
        }
        return count;
    };
    vector<vector<int>>match(n,vector<int>(2,0));
    for(int i = 0;i < n; i++){
        if(i - 2 >= 0) match[i][0] = calcInt(v[i - 2],v[i]);
        if(i - 1 >= 0) match[i][1] = calcInt(v[i - 1],v[i]);
    }
    auto f = [&](int i,char ch1,char ch2,auto &&f)->int{
        if(i == n - 1) return ((ch2 == 'R') ? match[i][0] : 0) + ((ch1 == 'R') ? match[i][1] : 0);
        int ans = 1e9;
        ans = min(ans,((ch2 == 'R') ? match[i][0] : 0) + ((ch1 == 'R') ? match[i][1] : 0) + f(i + 1,'L',ch1,f));
        ans = min(ans,f(i + 1,'R',ch1,f));
        return ans;
    };
    cout << f(1,'R','.',f);
}

signed main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    int t = 1;
    // cin >> t;
    while (t--)
    {
        solve();
    }
}
`

here is the editorial.

ABC Editorial meanwhile

https://mathmodel2.github.io/ex/cf1.html

Can teams that haven't registered before register for this one?

That depends on the RCD, I guess their deadline has already passed.

if its minimal lectures and maximum practice, I would pay 10$.

bro got downvoted :)

I dont think anyone will need any advice on being PUPIL, ITS TOO EZ UNLESS YOU CHEAT AND GET CAUGHT LIKE ME 2 YEARS AGO

Syria

Damascus University

Tkhla 3n 7lmk w mt

Khaled_Al_Awad, Wael_Zaiback, Rj3i_Flicker

What about changing the timings? I guess 4.30 to 7 in the evening should be fine?

But not messages advising the same, it seems...

We are thinking of hosting a practice round with the problems from cancelled prelims, so you will be able to submit them soon.

this is refactored code from telegram, congrats on getting caught cheater!

How to prove K? That there exists an optimal path passing through x, y, where x, y are maximal coordinates such that gcd(a,x) = 1 and gcd(b,y) = 1.

Turned out to be a problem in my internet network. I tried to open it with a VPN and it worked.

There are some OI style tasks in oj.uz to practice. Check out the later years of IOI or APIO for examples.

I don't know how to $$$\tt{properly}$$$ run grader.cpp and the task.cpp file, usually I just change the #include "task.h" to #include "task.cpp" in the grader file and run the grader file. This works well enough for me.

In case of having even more files to submit (two-step communicative for example), you can #include all the related files in the grader.cpp

When submitting, just submit the task.cpp file.

Also, if the task is in OI format then subtasks will probably exist on that task too. Depending on the grader, you might need to if-else each subtask to get many subtasks with different partial solns, or you might be able to just submit for each subtask separately if they use max for each subtask scoring.

damn, thanks.

Jordan : PSUT

TEAM NAME : AAA

baboby , Aziz.Ammourah , ayoooy

everytime a one occurs, the element next to it can be 1 or 0. in a string where there is 0 at last, no of 1s = no of 10 + no of 11 follows. in a string where there is 1 at last, the sum will be no of ones -1

Is there a blog that discussed all the questions from the ICPC Preliminary Contest held on November 16, 2024, which was later canceled?