tibinyte's blog

By tibinyte, history, 3 months ago, In English

Hello, Codeforces! Or, as we like to say in Romania: Nu îmi amintesc să fi adresat întrebări, Codeforces!

I am glad to finally invite you to participate in CodeTON Round 3 (Div. 1 + Div. 2, Rated, Prizes!), which will start on Nov/06/2022 17:35 (Moscow time). You will be given 8 problems and 2 hours and 30 minutes to solve them. It is greatly recommended to read all the problems, statements are short and straight to the point.

I would like to thank:

Scoring Distribution: 500-750-1250-1750-2250-2500-3250-3500

The editorial has been published here!

And here are our winners!

And here is the information from our title sponsor:

Hello, Codeforces!

We, the TON Foundation team, are pleased to support CodeTON Round 3.

The Open Network (TON) is a fully decentralized layer-1 blockchain designed to onboard billions of users to Web3.

Since July, we have been supporting Codeforces as a title sponsor. This round is another way for us to contribute to the development of the community.

The winners of CodeTON Round 3 will receive valuable prizes.

The first 1,023 participants will receive prizes in TON cryptocurrency:

  • 1st place: 1,024 TON
  • 2–3 places: 512 TON each
  • 4–7 places: 256 TON each
  • 8–15 places: 128 TON each
  • 512–1,023 places: 2 TON each

We wish you good luck at CodeTON Round 3 and hope you enjoy the contest!

 
 
 
 
  • Vote: I like it
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  • Vote: I do not like it

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3 months ago, # |
  Vote: I like it -8 Vote: I do not like it

Good luck in LeafTON round 3.

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3 months ago, # |
  Vote: I like it +83 Vote: I do not like it

omg green round

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3 months ago, # |
  Vote: I like it +31 Vote: I do not like it

As a tester, I am sure you will find some interesting problems whatever rating you have and I wish you good luck and high rating!

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3 months ago, # |
  Vote: I like it +38 Vote: I do not like it

First of all, as a tester, I tested. Secondly, I strongly recommend this round!!!

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3 months ago, # |
Rev. 2   Vote: I like it +12 Vote: I do not like it

As a tester, I'm already yellow, not purple!

Upd: Good luck to all participants! tibinyte orz

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3 months ago, # |
  Vote: I like it +45 Vote: I do not like it

The contest's duration is 2.5 hours in blog but 2 hours in Current or upcoming contests?

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3 months ago, # |
  Vote: I like it +61 Vote: I do not like it

As a tester I suggest everyone to participate in this contest. Even I want to participate in it but I obviously can't :(

I wish everyone good luck and a good experience

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    3 months ago, # ^ |
      Vote: I like it +9 Vote: I do not like it

    As a sad I can't participate in the round myself I'm a tester too!

    good luck everyone! hope you find some interesting problems and have a good time

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3 months ago, # |
  Vote: I like it +18 Vote: I do not like it

As a tester, Problem A is one of the problems of all time.

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3 months ago, # |
  Vote: I like it +4 Vote: I do not like it

GREEN>>CYAN

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3 months ago, # |
  Vote: I like it +39 Vote: I do not like it

statements are short and straight to the point. finally it's in the blog. Thanks

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3 months ago, # |
  Vote: I like it +5 Vote: I do not like it

As a newbie , it will be more fun to participant in a green author round . Best of luck all.

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3 months ago, # |
  Vote: I like it +12 Vote: I do not like it

As a tester I tested

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3 months ago, # |
  Vote: I like it +13 Vote: I do not like it

Leaf forces

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3 months ago, # |
  Vote: I like it +10 Vote: I do not like it

Excited for a green round :)

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3 months ago, # |
  Vote: I like it 0 Vote: I do not like it

what is the starting difficulty range of the question ??

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3 months ago, # |
  Vote: I like it -55 Vote: I do not like it

Well, it's obvious that tibinyte is a talented programmer, but he just managed to get negative deltas to become green to pretend to be weak. Also, he is just the blog sender, not one of the problem setters.

So, I wish you guys get positive deltas & have fun!

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    3 months ago, # ^ |
      Vote: I like it +97 Vote: I do not like it

    As a tester, tibinyte is the main author of this round. Please do not spread misinformed opinions.

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    3 months ago, # ^ |
      Vote: I like it +27 Vote: I do not like it

    Capital L

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    3 months ago, # ^ |
      Vote: I like it +21 Vote: I do not like it

    As a Tibinyte's friend I can tell you that he has been developing this round since long time ago and he's the main author of round. Please do not spread misinformed opinions. (and reach master)

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    3 months ago, # ^ |
      Vote: I like it +8 Vote: I do not like it

    As a Leafeon supremacist, I can confirm that this claim is baseless. Also green is the best color because Leafeon is the best Pokemon

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    3 months ago, # ^ |
      Vote: I like it +11 Vote: I do not like it

    Okay I'm sorry for that, I apologize for this.

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    3 months ago, # ^ |
      Vote: I like it +48 Vote: I do not like it

    Personally, a round is the result of everyone's joint efforts. Whoever thinks of the idea, who thinks the solution, who proves the correctness of the algorithm, who perfects the statement, who creates the powerful test data, and who fixes the issue is actually unnecessary so clearly. What matters is our joint efforts and our friendship.

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      3 months ago, # ^ |
        Vote: I like it +13 Vote: I do not like it
      LLLL
      LLLL
      LLLL
      LLLL
      LLLL
      LLLL
      LLLL
      LLLLLLLLLLLLLLLL
      LLLLLLLLLLLLLLLL
      
      
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    3 months ago, # ^ |
      Vote: I like it +3 Vote: I do not like it

    I believe you had a huge surprise...

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3 months ago, # |
  Vote: I like it 0 Vote: I do not like it

Good Luck everyone!!!

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3 months ago, # |
  Vote: I like it -32 Vote: I do not like it

Is it rated?

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3 months ago, # |
  Vote: I like it +11 Vote: I do not like it

How do they'll send cryptocurrency? We have to have crypto wallet?

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3 months ago, # |
  Vote: I like it +4 Vote: I do not like it

As a tester I have nothing more to add than "Good luck!" and "May the God have mercy on you", because the problem setters surely don't know the definition of this word.

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    3 months ago, # ^ |
      Vote: I like it +35 Vote: I do not like it

    I assure you, tibinyte knows what mercy is, it is the only hero I can play on overwatch

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3 months ago, # |
  Vote: I like it 0 Vote: I do not like it

Wish for positive delta Good luck everyone<3!

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3 months ago, # |
  Vote: I like it 0 Vote: I do not like it

Time to become CM now ;)

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3 months ago, # |
  Vote: I like it 0 Vote: I do not like it

G Gaming

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3 months ago, # |
  Vote: I like it -6 Vote: I do not like it

Time for Remontad

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3 months ago, # |
  Vote: I like it +1 Vote: I do not like it

Oooh wow! 58 people contribute to making this round happen.

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3 months ago, # |
  Vote: I like it 0 Vote: I do not like it

Aiming green in the green round... Wish me luck :)

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    3 months ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    Solve A and B problems very quickly and you will become pupil. Also don't make any wrong answers. All the best bro!

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3 months ago, # |
  Vote: I like it +3 Vote: I do not like it

Wish me luck hope i become green after this contest.

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3 months ago, # |
  Vote: I like it 0 Vote: I do not like it

Please downvote me please

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3 months ago, # |
  Vote: I like it +31 Vote: I do not like it

Hope I will get GM. :)

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    3 months ago, # ^ |
      Vote: I like it +33 Vote: I do not like it

    Oh.. you are close to 2400. Wish you luck for today's contest, hope you become GM..

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    3 months ago, # ^ |
      Vote: I like it +23 Vote: I do not like it

    Same D:

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      3 months ago, # ^ |
        Vote: I like it 0 Vote: I do not like it

      Frate, iti zic io, ajungi si tu (grand)master.

      Marinush

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        3 months ago, # ^ |
        Rev. 2   Vote: I like it +14 Vote: I do not like it

        I have just realized that I read statement of problem E incorrectly, I thought that we can shift only whole string D:

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    3 months ago, # ^ |
      Vote: I like it +11 Vote: I do not like it

    Congratulations on reaching GM!!

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3 months ago, # |
  Vote: I like it 0 Vote: I do not like it

I wish good luck to all to this contest !!

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3 months ago, # |
Rev. 2   Vote: I like it -41 Vote: I do not like it

round need to be unrated, because it is round

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3 months ago, # |
  Vote: I like it +6 Vote: I do not like it

How do they'll send cryptocurrency? We have to have crypto wallet? someone can answer to this question plz!

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    3 months ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    Create a wallet on this app; this'll give you a wallet address

    https://tonkeeper.com/

    P.S. Checkout the TON username market on telegram : https://fragment.com/ where you buy and sell in TONs

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      2 months ago, # ^ |
        Vote: I like it 0 Vote: I do not like it

      I've created my wallet address and update my profile but did not receive the prize yet. Would you like to tell me the reason or what should I do to receive the prize?

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    3 months ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    Yes, you'll have to provide your wallet address to receive prize.
    Here is the list of TON wallet applications: https://ton.app/wallets

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      3 months ago, # ^ |
        Vote: I like it 0 Vote: I do not like it

      Who should I provide my wallet address to?

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        3 months ago, # ^ |
          Vote: I like it 0 Vote: I do not like it

        In CodeTON Round 2 there was a Codeforces message from System, containing link to form. So I think you should wait for that message (it will be visible in notifications panel).

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3 months ago, # |
  Vote: I like it +12 Vote: I do not like it

Will score distribution be announced briefly before the beginning of the round?

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    3 months ago, # ^ |
      Vote: I like it +17 Vote: I do not like it

    It will be posted along with the editorial as to not spoil anything about the round

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3 months ago, # |
  Vote: I like it +1 Vote: I do not like it

Hope that I will be Pupil after this round

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    3 months ago, # ^ |
      Vote: I like it -8 Vote: I do not like it

    you have not submitted a single problem coward

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      3 months ago, # ^ |
        Vote: I like it 0 Vote: I do not like it

      Sorry I am completing my assignment for my cllg .As Tommorow is the last day

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      3 months ago, # ^ |
        Vote: I like it 0 Vote: I do not like it

      And Finally Somebody who noticed me

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3 months ago, # |
  Vote: I like it +4 Vote: I do not like it

Score distribution?

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3 months ago, # |
  Vote: I like it 0 Vote: I do not like it

Hopefully it will be great contest because of short statements and straight to the point.

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3 months ago, # |
  Vote: I like it 0 Vote: I do not like it

In the previous CodeTON rounds, I lost my rating. Hope Today I will gain plus point.

Love to see short statements and straight to the point.

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3 months ago, # |
  Vote: I like it -8 Vote: I do not like it

let's go

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3 months ago, # |
  Vote: I like it -8 Vote: I do not like it

time to + 100

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3 months ago, # |
  Vote: I like it -9 Vote: I do not like it

When Life gives you a match with Zimbabwe... Let's be India! All the best for the Contest!

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3 months ago, # |
  Vote: I like it 0 Vote: I do not like it

Good Luck!!!!!!!!!

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3 months ago, # |
  Vote: I like it -49 Vote: I do not like it

Please, don't make rounds again. Thanks.

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3 months ago, # |
  Vote: I like it +10 Vote: I do not like it

Last few contests gave me cancer

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3 months ago, # |
  Vote: I like it -16 Vote: I do not like it

What is the conversion ration TON to INR ??

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3 months ago, # |
  Vote: I like it 0 Vote: I do not like it

How to solve D?

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3 months ago, # |
  Vote: I like it +14 Vote: I do not like it

How to optimize E from O(n^2) to O(n) or O(nlogn) ?

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3 months ago, # |
  Vote: I like it -10 Vote: I do not like it

Good problems, very good D and E was easy

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3 months ago, # |
  Vote: I like it -8 Vote: I do not like it

How to calculate the number of numbers from 1 to M coprime to N ?

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3 months ago, # |
  Vote: I like it -8 Vote: I do not like it

Took me 40 minutes to search and read about Mobius function(Problem D). Not sure if there is any solution that doesn't utilize it.

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    3 months ago, # ^ |
      Vote: I like it +5 Vote: I do not like it

    Use the Inclusion-Exclusion Principle.

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      3 months ago, # ^ |
        Vote: I like it 0 Vote: I do not like it

      Yeah, I thought about that one too. But I believe that I won't be able to implement in time.

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      3 months ago, # ^ |
        Vote: I like it 0 Vote: I do not like it

      I thought that would maybe time out. Took me an eternity to get the Mobius solution to work.

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        3 months ago, # ^ |
          Vote: I like it 0 Vote: I do not like it

        It won't be time out. Think about this, this principle works on a[i]/a[i+1], and the product of them is a[1]/a[n] which isn't more than 1e9.

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        3 months ago, # ^ |
          Vote: I like it 0 Vote: I do not like it

        It won't time out because, you will apply factorization and inclusion exclusion stuff only when $$$a[i] != a[i-1]$$$. The prefix gcd can only change $$$O(log(m))$$$ times, because everytime the gcd changes, it has to reduce at least by a factor of $$$2$$$.

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3 months ago, # |
  Vote: I like it 0 Vote: I do not like it

What was logic for C , Solved D but was not able to process C's logic.

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    3 months ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    Consider the xor of the two arrays, you will notice something ...

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    3 months ago, # ^ |
      Vote: I like it +4 Vote: I do not like it

    Some useful observations are:

    1. If every index is equal/unequal in both strings, then it's possible.
    2. When an operation is performed, either bit in string a, or bit in string b changes, so if all of the index were equal in both, then it becomes unequal, and vice-versa.
    3. You just have to make all index 0 in string a, let's say. So, string b can be all 0's or all 1's. If all 0's then we're done.
    4. If not, then just add 3 extra operations: (1,1) (2,N) (1,N)
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3 months ago, # |
  Vote: I like it 0 Vote: I do not like it

better luck next time for all ****

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3 months ago, # |
  Vote: I like it 0 Vote: I do not like it

Tough contest for me :((

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3 months ago, # |
  Vote: I like it -6 Vote: I do not like it

How to solve problem D ?

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3 months ago, # |
  Vote: I like it -8 Vote: I do not like it

How to round number in D?

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    3 months ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    If you think of the number I think of, you have to round it down :)

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3 months ago, # |
  Vote: I like it 0 Vote: I do not like it

Is it ObservationForces now?

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3 months ago, # |
Rev. 2   Vote: I like it +25 Vote: I do not like it

Upvoted the contest for the story behind Problem E. I couldn't focus on the Problem, because I had to show the story to my fiancée and my brother and needed to hype it. Beautiful Daemon Targaryen. I would upvote more if I could.

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3 months ago, # |
  Vote: I like it 0 Vote: I do not like it

Did anyone solve D using Euler's totient function?

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3 months ago, # |
Rev. 2   Vote: I like it +10 Vote: I do not like it

I used about 10 minutes to think about the conclusion of problem E but used more than an hour on coding. Anyway, I think this round is the best round I've ever participated.

UPD: after I solved problem D I got rk20. :) (though my final rank is 200 :(

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3 months ago, # |
  Vote: I like it 0 Vote: I do not like it

omg green round

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3 months ago, # |
  Vote: I like it -13 Vote: I do not like it

Literally dying atm. Could get a grasp on D (Yes, I did think of inclusion-exclusion here and there but did not find a way to preprocess the values of the mobius function. Did I want to copy paste an overkill $$$O(n^\frac{2}{3})$$$ method to preprocess prefix sums of the mobius function? Hell no.) but couldn't finish. C felt hard, like, very hard. Might be even convinced that C > D if C was after D.

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3 months ago, # |
Rev. 2   Vote: I like it +8 Vote: I do not like it
is it the approach for problem c ?
If A^B == 0000 or 11111 then answer exists 
Then we shift all ones to left side and zeros to right for A and do same operations for B also.
which makes A as 00001111 and B as 11110000 something like this
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    3 months ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    The answer is only possible if for all i either a[i]=b[i] or a[i]!=b[i]. Just make all a[i]=1,you'll observe that all b[i] become either 0 or 1.If they are all 0 just do 1,n so all a will be 0 and b will remain 0,else if all b are 1 then do (1,1) (2,n)

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    3 months ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    Yes. I did operations on $$$[i,n]$$$ for all $$$i$$$ such that $$$b_i$$$ and $$$b_{i-1}$$$ are different. Then $$$b$$$ consists only of $$$1$$$s or only of $$$0$$$s. The same goes for $$$a$$$. Then you just need to look at $$$a_1$$$ and $$$b_n$$$ (they did not get changed yet) an accordingly make everything $$$0$$$.

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    3 months ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    Let me Explain by example

    Example 1:
    
    A -> 110010, B -> 001101  (Initially Given)
    
    A -> 001110  B->  001110  (1-4 index operation)
    
    A -> 000001  B->  111110  (2-4 index operation)
    
    Example 2:
    
    A -> 10101  B-> 01010     (Initially Given)
    
    A->  01101  B-> 01101     (1-2 index operation)
    
    A->  00011  B-> 11100     (1-3 index operation)
    

    I think the above approach was harder for implementing atleast to me. I guess making all equal to one was simpler than this. Instead of making x 0's and y 1's as above.

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3 months ago, # |
  Vote: I like it 0 Vote: I do not like it

I always lose rating in div 1+ div2 contest any suggestions…?

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    3 months ago, # ^ |
      Vote: I like it +1 Vote: I do not like it

    I guess, in div 1 + div 2 contests it is more important to solve the earliest problems fast enough (since there will be more people solving the same amount of problems, relatively speaking). Interestingly, for me it is the other way round: I always win rating in the joint contests...

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3 months ago, # |
  Vote: I like it +8 Vote: I do not like it

How to solve E ?

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    3 months ago, # ^ |
    Rev. 5   Vote: I like it +11 Vote: I do not like it

    Take a segment. Let's call $$$C$$$ the number of closing brackets and $$$O$$$ the number of opening brackets. Let's call $$$M$$$ the minimum value the prefix sum of the segment reaches (Opening bracket is $$$+1$$$, closing is $$$-1$$$). The cost of a segment then is $$$max(0, O-C)+min(0, M)=max(0, O-C)+M$$$.

    Explanation

    You can calculate both parts of this sum for all segments idependently by iterating and doing confusing calculations. See 179633595 the two blocks after long long ans=0;.

    For me it was easier to visualise the bracket sequence as a graph of the prefix sum and then look at area on the graph which both of the terms contribute.

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      3 months ago, # ^ |
        Vote: I like it +8 Vote: I do not like it

      Very clean code and solution, thank you! I knew that the solution is very clean, but did not have the skill to find it tho.

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3 months ago, # |
Rev. 2   Vote: I like it 0 Vote: I do not like it

I think Problem B is based more on implementation side rather than observation.

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    3 months ago, # ^ |
    Rev. 2   Vote: I like it 0 Vote: I do not like it

    my sol : just find longest substring with same character let k be the longest length substring

    and x=no of 0's and y=no of 1's in whole string

    our ans is max of (k*k , x*y)

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    3 months ago, # ^ |
    Rev. 2   Vote: I like it 0 Vote: I do not like it

    I don't think so... This was just 10 lines of code

    solve :: String -> Int
    solve str = max count (ind * ind)
      where
      x = length $$$ filter (=='0') str y = length $$$ filter (=='1') str
      count
        | x > 0 && y > 0 = x * y
        | x > 0 = x * x
        | otherwise = y * y
      ind = maximum $$$ length &lt;$$$> group str
    
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3 months ago, # |
  Vote: I like it +65 Vote: I do not like it

E was nice. Until the last 40 minutes, I thought that the first operation can be only applied to the entire string. That led to a much more complicated problem. :(

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    3 months ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    Wow... I was thinking and thinking with that misunderstanding of the first operation for the whole contest. I got to read the statement a bit more carefully.

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    3 months ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    Me too, I have written two brute-forces to understand that it's not the case...

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    3 months ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    And I realized only after reading your comments that we can apply to any substring :(

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3 months ago, # |
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How to solve problem E? The most I can do is a brute force O(n^3) solution.

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3 months ago, # |
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Great contest!Congrats to the authors!Cool problem D, unfortunately I didn't solve it.I'm waiting for editoiral!Thanks!

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3 months ago, # |
  Vote: I like it +2 Vote: I do not like it

Me After Solving A & B :')

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3 months ago, # |
  Vote: I like it -10 Vote: I do not like it

Can anyone please explain how to solve problem C with intution?

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    3 months ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    Consider A^B. Every time we conduct an operation A^B would be XORed by 111...1. So for a YES case, A^B would either be 000...0 or 111...1 after whatever operations. Now you just need to make A to 000...0. In the end, B is either 000...0 or 111...1. Then it's easy to make a few more operations to get job done.

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    3 months ago, # ^ |
      Vote: I like it 0 Vote: I do not like it
    Hint1
    Hint2
    Tutorial
    Solution
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      3 months ago, # ^ |
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      im not able to understand the hint1 and hint 2,can you please explain by taking examples?

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3 months ago, # |
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Why the time limit of G is 3s... My FFT solution passes. It does not seem to be the intended solution.

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3 months ago, # |
  Vote: I like it +149 Vote: I do not like it

Congratulations to conqueror_of_tourist for not only living up to their username, but also becoming LGM with Python!

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    3 months ago, # ^ |
      Vote: I like it +8 Vote: I do not like it

    you also achieved the goal of your username with python only. Screenshot-2022-11-06-200424

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3 months ago, # |
  Vote: I like it +29 Vote: I do not like it

Countforces

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3 months ago, # |
  Vote: I like it 0 Vote: I do not like it

I wasn't able to solve A, with just looking at the problem and understanding it, I saw that in the correct cases, position 0 had an 1 or position 1 had a 2, so intuitively I went on and did an algorithm that checks that case. Too bad for me it was just when it started with 1.

But can someone explain why is it when it starts with 1? I did it so if it's 1 or 2 at the first 2 positions, i.e. arr[0] == 1 or arr[1] == 2 then yes, else then "No".

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    3 months ago, # ^ |
      Vote: I like it +1 Vote: I do not like it

    before u completely look at my answer read the question once for clarity..... constraint : i < j < k 1st position element has to smaller than kth position element element at 1st position cannot be changed.... but using 1st position you can swap any positions of j and k .

    so the smallest possible element that can take 1st position must be one .

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    3 months ago, # ^ |
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    Because when it starts with 1 you will always be able to make it sorted, suppose you have 1,5,4 you just select i=1, j= 2 and k=3 so that you can swap 5,4, similarly for every other wrong pair you just can choose those pair as j and k and by selecting i as 1 you are ensuring the 2nd operation which is swap

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      3 months ago, # ^ |
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      But then, what happens with 2,4,3 for example? You can sort it, but at the start there is a 2.

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        3 months ago, # ^ |
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        But since there is no 1 at first place, it is not possible to sort the list, so ans for this is No, one thing 2.3,4 this input is not possible, read carefully the list is permutation, that means you will always have 1,2,...n

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        3 months ago, # ^ |
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        Array is a permutation so there must be a 1

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          3 months ago, # ^ |
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          I didn't know what was a permutation, that was the problem....

          Thank you very much guys! Next time i hope to do better, meanwhile i'll be learning and doing problems.

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3 months ago, # |
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So finally....

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3 months ago, # |
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can someone explain C logic

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3 months ago, # |
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Problem D is similar to this problem which I proposed to codechef before.

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3 months ago, # |
  Vote: I like it -25 Vote: I do not like it

Sorry, but I didn't like this round at all:
A: just one simple observation
B: just one simple observation
C: just one simple observation
D: just find number of coprime with n not greater than m (testers in comments, is it interesting? Really?)
E: closed this problem as soon as I've read. Yet another "count some *** for all subsegments"
Can say nothing about F+, because didn't read
No, don't misunderstand me, each problem is good. But as set of problems in one contest...

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    3 months ago, # ^ |
    Rev. 5   Vote: I like it +38 Vote: I do not like it

    I'm sorry that you found the first 2 problems of the contest(which are supposed to be easy) too easy for a candidate master / master, I will talk to tibinyte and kindly ask him to give out some smart and well hidden minimum cost maximum flow with a lot of observations and implementation details for problems A and B in his future rounds. As of C, consider it a simple observation for you, judging by the counter of solves it was just as hard as it had to be and I also needed some time to figure it out(but I might also have some skill issues so ignore me if you want). I really liked problem D because of its "smooth" solution that included some simple math and observations, so I found it interesting and I am sorry that this does not fit your view. Your argument about problem E is probably by far the dumbest thing I read on the internet today and this really means something as I've seen a lot of dumb memes today. Anyway, I am sorry that you didn't enjoy the round and wish you good luck in the next ones.

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      3 months ago, # ^ |
      Rev. 2   Vote: I like it +3 Vote: I do not like it

      First and foremost, L

      Second, this is not how you argue, this is how you correctly argue this is satire, by all means the purpose is not to offend anyone

      Dear contestant,

      Please don't worry if you had to little to no observations to pass some problems that were set to not cater to you. In a Codeforces round, the mechanics employed by some problem do not by any means determine the quality of any problem*. Apologies if this does not fit your view.

      Thanks for the feedback,

      Tester of Codeton Round 3

      *: (although, admittedly, it can determine the quality of the round as you stated-- I won't argue with that because I am not in the mood for jejune disputes)

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      3 months ago, # ^ |
        Vote: I like it +3 Vote: I do not like it

      you found the first 2 problems of the contest too easy for a candidate master / master

      Where have I said this?

      consider it a simple observation for you

      It's my point: this is "one observation problem". You either find this observation->"ez ac" or you don't find this observation at all->you can't solve problem. This argument is applied to A and B

      I really liked problem D

      It's your personal opinion and I've shared mine.

      Your argument about problem E

      It's not argument, it's my personal opinion. I don't find problems which require some counting on all subsegments interesting. I didn't solve D incontest because I'm dumb, but if I solved D, I would skip E.

      The dumbest thing is "This contest is the most bad/good/... contest ever" comments without any details. I tried to share my opinion about whole problemset why I didn't like this contest. And seems that you misunderstood my initial comment. Once more: every problem is good. But you don't find problemset good if every problem is about, for example, geometry, do you?

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        3 months ago, # ^ |
        Rev. 5   Vote: I like it +8 Vote: I do not like it

        "you found the first 2 problems of the contest too easy for a candidate master / master" — I just wanted to point out that it is a normal fact that you found them easy because you have a higher rating than the people that should find them challenging, I didn't want to say that you mentioned this, because you didn't.

        "It's my point: this is "one observation problem". You either find this observation->"ez ac" or you don't find this observation at all->you can't solve problem. This argument is applied to A and B" — I find this quite common in the modern day competitive programming where problems are more and more based on tricky observations, I wouldn't say that I love it, but we should adapt to these kind of problems if we want to do CP, and if not, as we say in Romania, "ayaye".

        "It's your personal opinion and I've shared mine." — I respect that.

        "I don't find problems which require some counting on all subsegments interesting." — I get that, but in a contest(especially in a serious one with a higher stake like OI or ICPC) you can't just say that you don't like a problem, you just have to try to solve it because you wanted to take part in that competition(I will assume that no one can force you to take a contest if you do not want that).

        "I didn't solve D in contest because I'm dumb" — I know this is a bad feeling, but you probably just missed out on something, it happened to all of us, no need to be so harsh about it.

        "The dumbest thing is "This contest is the most bad/good/... contest ever" comments without any details" — I agree that this is usually toxic and people tend to say that after a round that got them positive delta, but my opinion as a tester was just that the round was good and recommended others to try it.

        "But you don't find problemset good if every problem is about, for example, geometry, do you" — No, I do not. I also recommend that you spend some time analysing the problems with editorials and realize that they are not just some combinatorics / dp problems, but also require some clever observations. Also, A-C are not counting at all and E and H are not combinatorics / dp(as I know).

        Anyway, I think we discussed more about this than it was necessary. The contest is done and others will come.

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          3 months ago, # ^ |
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          Thank you for discussion!

          Just one correction: in ICPC you have wider set of topics to choose from and what is more important you have teammates. This allow you to skip/delegate some problems if you don't like it more often, than in personal contests.

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    3 months ago, # ^ |
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    and you could just solve simple observations problems didn't notice something?

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Why is my output on the code I wrote when run on my compiler different from the one used in the contest ?

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Great contest

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3 months ago, # |
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as newbie downvote me

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3 months ago, # |
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Tourist in 10th place wow

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3 months ago, # |
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Ratings updated preliminarily. We will remove cheaters and update the ratings again soon!

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    3 months ago, # ^ |
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    Hope updated ratings would changed my rating by 2 points

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      3 months ago, # ^ |
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      Hope updated ratings would change my rating by 54 points

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3 months ago, # |
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problem : https://codeforces.com/problemset/problem/1750/D

input : 4 1000000000 60 30 1 1

output: 595458194

how? can anyone explain?

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3 months ago, # |
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Personally, I think this E is very good. I can use BIT or segment tree, or even deduce the expression O(n) directly. I really like this problem

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3 months ago, # |
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Hey, is it possible to pass problem B with python?

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3 months ago, # |
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in problem D

if m was <= 1e6 , could we solve the problem using Möbius Function?

something similar to this problem
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3 months ago, # |
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How to claim TON cryptocurrency after winning in this contest?

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3 months ago, # |
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My friend rating is 1110 and rank in contest is 9000 by solving only problem and by rating is 926 and got 8200 rank by solving 2 questions...But the worst things my rating decreases only by 6 and my rating decreases by 28....How is it even possible.....Please help anyone

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    3 months ago, # ^ |
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    You get more rating points than you should first 5 or 6 contests you participate in, which is most likely to be the situation with your friend.

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3 months ago, # |
Rev. 2   Vote: I like it 0 Vote: I do not like it

I see that in recent contests the questions don't get difficulty tags!!

Why is it so? Anyone?

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3 months ago, # |
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Alsalam Alykom,My solution for A,B is skipped and i swear i didn't use ideone or another account or anything its my clear solution ! I swear to god i didn't cheat why something like that happen to me ? how to avoid this MikeMirzayanov tibinyte

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3 months ago, # |
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How do I receive my money?

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3 months ago, # |
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Where is my ton please?

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3 months ago, # |
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How can I receive my money?

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2 months ago, # |
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Has anyone received the prize yet?

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2 months ago, # |
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Has anyone received their TON yet? The deadline was supposed to be on Nov 26.

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    2 months ago, # ^ |
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    Hi. The wallets were collected and sent to TON. Of course, they need several days to process the data.

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2 months ago, # |
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Is the team still in the process of sending prizes? Or is it already finished and I didn't receive anything due to some mistake from my side?

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2 months ago, # |
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I just received my prize a minute ago. Maybe you guys will receive it soon

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3 weeks ago, # |
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Will this round send NFT trophies? Like the kind of NFT trophy in round 1 and round 2.