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

As an author, I hope you'll enjoy the problems!

Best of luck to everyone — hoping you all see a nice rating increase !

Problems are really cool… would suggest everyone to give this contest and hope you enjoy it…

Participate or you will miss some truly beautiful problems.

As a tester, I can confirm this problem set is "beautiful".

As a tester, I was forced to write an as a tester comment

As a tester, -. . ...- . .-. / --. — -. -. .- / --. .. ...- . / -.-- — ..- / ..- .--.

As a tester, I can confidently say that this problem set is beautifully designed — it’s genuinely fun and a joy to attempt.

As a tester, regarding questions I would say only one thing, think DP but apply greedy, or maybe vice versa, hope everyone has fun solving problem, all the best :)

Excited to participate and get some positive delta

Hey all these days I dont understand what is specific color testing and what they do in general ?

As a tester, I can confirm you’re gonna have a great time giving this contest. Don’t miss it!

As a tester, I made a video of solving all the problems. I'll put the stream very soon on Codeforces, don't miss it.

A contest with Interactive Problems , its going to be GREAT again

18o3 the tester OTZ

As a tester, the problems are really cool and fun to attempt. I hope you all have a beautiful increase in rating.

what about the recent decrease?(rollback)

All the best everyone! Hope everyone gets +ve delta.

As a participant , seems interesting.

Is cry's basement already full?

As a participant, SHAW!

cout << "Best of luck CODERS for this round!" << endl;

Be Ready for one INTERACTIVE Problem. there will be one.

Here is guide for Interactive Problems.

According to the poor situation of QueueForces's submission now, will it be rated?

really excited to give an unrated round after a pathetic performance in last round.

hope to reach lgm this contest

div.3 ❌ div.2 ✅

All — Beautiful

How beautiful the problem are !

ConstructiveForces

how to H?

Oh my god. Please ban all unrated participants, I almost shocked when I see the common standings.

Multiple valid answers everywhere

Please ban the Unrated cheaters

the interactive snuffed me out, i hate those questions

constructive forces

No way G went from 200 to 700 in like 5 minutes. Regardless a good contest.

Is problem D not just binary searching over smallest L and largest R, where the condition is checking if query "1 mid mid" yields a different value from query "2 mid mid"?

Was E that easy? Please give some hints.

lol what is this standing?

Why did no sample case for B have a solution with a subsequence rather than a subarray?

я свел задачу H к следующему:

$$$f(a, x, l, r)$$$ будет однёркой если $$$x \le \text{min}$$$ || $$$\text{max} \le c$$$, иначе если x находится между мин и макс, тогда функция вернёт 0

тогда зная этот факт, можно для каждого X хранить 3 числа ls (кол-во чисел которые меньше чем i), eq(кол-во чисел которые равны i), bg(кол-во чисел которые больше чем i) (ls + eq + bg = n)

если существуют такие отрезоки [l1, r1] & [l2, r2] что (l1 <= l2 <= r2 <= r1) тогда [l2, r2] можно просто удалить и сделать m-1

если 2 отрезка пересекаются, то должно выполнятся одн из следующих условий: 1) назовем отрезок меньшим если все числа в нем <= i, иначе большим. Тогда оба отрезка должны быть либо большими, либо маленькими

2) если у них разные состояния, то все числа которые лежат на переечинии этих отрезков должны быть равны i

а дальше как решать я уже не знаю, только придумал как решить за $$$2^n$$$

Beautiful Permutation — Can someone help me in finding the issue with this code. I'm using binary search to find L and R.

#include<bits/stdc++.h>
using namespace std;
using ll = long long;

ll ask(int type , int L , int R){
    cout << type << " " << L << " " << R << endl;
    cout.flush();
    ll sum ; cin >> sum;
    return sum;
}

int main(){
    int t ; cin >> t;

    while(t--){
        int N ; cin >> N;
        int L = 1 , R = N;

        int low = 1 , high = N;
        while(low <= high){
            int mid = (low + high) >> 1;
            ll original = ask(1 , 1 , mid);
            ll modified = ask(2 , 1 , mid);
            if(original != modified) high = (L = mid) - 1;
            else low = mid + 1;
        }

        low = 1 , high = N;
        while(low <= high){
            int mid = (low + high) >> 1;
            ll original = ask(1 , mid , N);
            ll modified = ask(2 , mid , N);
            if(original != modified) low = (R = mid) + 1;
            else high = mid - 1;
        }

        cout << "! " << L << " " << R << endl;
    }

    return 0;
}

bro, i was just lost in life after failing C for like the 10th time, and then i read "u gotta use the current a not initial" pmo

So many bots! How will CF handle this? Will this game still be rated?

Really great problems. Enjoyed!

Open the status page, and set the filters as follows: Problem G, Verdict Accepted, Language Python3. Look at the submissions that were made just before the contest ended. All of them (literally ALL) are unrated (black) people, and the running time and consumed memory of those submissions are mostly uniform. I looked at some submissions and they looked all AI-generated. They are almost all cheaters.

Coordinators and admins, please look into them.

UPD: I've found that other problems are in the similar situation; generally Python 3 submissions are filled with cheaters.

Hello, Constructiveforces!

CHEATFORCES Today,left after solving 4 problems at a ~3.5k rank came back and saw my rank to be 4.9k changed within last 12 minutes of the contest wow , so so many cheaters so annoying dont know how to keep myself motivated having these things

This is my code for problem C:

// this is code


#include <bits/stdc++.h>
using namespace std;

int t, n;
int a,b;

int main(int argc, char const *argv[])
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cin >> t;
    for(int q=0;q<t;++q){
        cin>>a>>b;
        if(b==0){
            cout<<1<<"\n"<<"0\n";
            continue;
        }
        if(a<b) {
            cout<<"-1\n";
            continue;
        }
        if(a==b){
            cout<<"0\n";
            continue;
        }
        int kq=a^b;
        if(kq<=a) cout<<1<<"\n"<<kq<<"\n";
        else{
            int k1=kq^a;
            int k2=k1^b;
            cout<<2<<"\n"<<b<<" "<<a<<"\n";
        }
    }
    return 0;
}

I need an explaination why it is wrong:(((( Anybody please help me:((((

Beautiful contest, we should have more mainly constructive contests!

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What a coincidence that they have the same code and the same comments

how to prove that we always have a solution for problem G except when n=2?

is it related to pigeonhole principle?

Video Solution of A,B,C,D,E with C++ code of Codeforces Round 1059 (Div. 3): https://youtu.be/ty5y1geayPI

I was doing hacking and got the following message

Recently, your account was used to crawl. Please change your password to prevent your account from being used for unauthorized activities.

what can i do to avoid it??

Cause till now i have made only 26 hacks (15 successful)

on the other hand i have seen people make 300+ hacks , is there any trick

Just look at the rank list from 150 to 400, a very high density of black people. Submission pattern so random. I think someone made bot to submit with so many account or maybe a very mass cheating group.

the standing looks so strange. so many unrated participants with high score.

so cool that hundreds of xxxxxxx people had a stroke of genius​ in a few minutes and completed A-G, and their solutions are exactly the same. in early time you can find that every page of top ranks are full of these fk guys

Any idea why this logic is wrong for E?

Submission

In a nutshell, I am appending an element that is different from last two distinct elements.

As a Contestant, I still don't understand interactive problems. But very nice questions.

thanks for the contest!!!

Is Codeforces planning a roll back due to such obvious and impactful cheating?

I dont get it why my solution does not work, WA on testcase 2/53, can somebody have a look? Thanks

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