manish.17's blog

Codeforces Round #836 (Div. 2)
By manish.17, 2 years ago, In English

Hi again, Codeforces!

fishy15, flamestorm, ScarletS, saarang and I are glad to invite you to our second Constructiveforces round, Codeforces Round 836 (Div. 2), which will be held on Nov/25/2022 18:35 (Moscow time). The round will be rated for participants with rating lower than 2100.

Please note the unusual time!

We'd especially like to thank:

You will have 2 hours to work on (and solve!) 6 problems. At most one of the problems will be interactive. Make sure to read this blog and familiarize yourself with these types of problems before the round! You are highly encouraged to read all the problems ;).

The scoring distribution is $$$500-1000-1500-1750-2250-3000$$$.

Good luck, and see you on the scoreboard!

UPD1: Thanks to ak2006 for making video editorials for some of the problems.

UPD2: Editorial is out!

UPD3: Congrats to the winners:

Div. 1 + 2:

  1. jiangly
  2. SSRS_
  3. kotatsugame [tie]
  4. Maksim1744 [tie]
  5. March_7th

Div. 2:

  1. March_7th
  2. is_this_Furry
  3. puffins
  4. DongXuelian
  5. ouqI
  • Vote: I like it
  • +95
  • Vote: I do not like it

Comments Comments (189)
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2 years ago, # |
  Vote: I like it +78 Vote: I do not like it

omg saarang round

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    2 years ago, # ^ |
      Vote: I like it +58 Vote: I do not like it

    omg saarang round

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      2 years ago, # ^ |
        Vote: I like it +71 Vote: I do not like it

      omg saarang round

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        2 years ago, # ^ |
          Vote: I like it +73 Vote: I do not like it

        omg saarang round

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          2 years ago, # ^ |
            Vote: I like it +46 Vote: I do not like it

          omg saarang round

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            2 years ago, # ^ |
              Vote: I like it +35 Vote: I do not like it

            omg saarang round

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              2 years ago, # ^ |
                Vote: I like it +32 Vote: I do not like it

              omg saarang round

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                2 years ago, # ^ |
                  Vote: I like it +22 Vote: I do not like it

                omg saarang round

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                  2 years ago, # ^ |
                    Vote: I like it +22 Vote: I do not like it

                  omg saarang round

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                  2 years ago, # ^ |
                    Vote: I like it +9 Vote: I do not like it

                  omg saarang round

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                  2 years ago, # ^ |
                    Vote: I like it +9 Vote: I do not like it

                  omg saarang round

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

                  Who is saarang ?

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                  2 years ago, # ^ |
                    Vote: I like it +126 Vote: I do not like it

                  Who is saarang? 🤔 For the blind, 🦇 it is light. 💡 For the hungry 😣 , it is bread. 🍞 For the sick, 💉 it is the cure. ⚕️ For the sad 😢 , it is joy. 😂 For the poor 🚫💰 , it is the treasure; 💰 ⛏️ for the debtor ➖ 💰 , it is forgiveness. 🙏 For the face 😶 , it is the lips 👄

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                  2 years ago, # ^ |
                    Vote: I like it +42 Vote: I do not like it

                  Who is saarang? 🤔 For the blind, 🦇 it is light. 💡 For the hungry 😣 , it is bread. 🍞 For the sick, 💉 it is the cure. ⚕️ For the sad 😢 , it is joy. 😂 For the poor 🚫💰 , it is the treasure; 💰 ⛏️ for the debtor ➖ 💰 , it is forgiveness. 🙏 For the face 😶 , it is the lips 👄

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                  2 years ago, # ^ |
                    Vote: I like it +33 Vote: I do not like it

                  Who is saarang? 🤔 For the blind, 🦇 it is light. 💡 For the hungry 😣 , it is bread. 🍞 For the sick, 💉 it is the cure. ⚕️ For the sad 😢 , it is joy. 😂 For the poor 🚫💰 , it is the treasure; 💰 ⛏️ for the debtor ➖ 💰 , it is forgiveness. 🙏 For the face 😶 , it is the lips 👄

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

                  And for a 30 year old bachelor man?

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

                  omg saarang round

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        2 years ago, # ^ |
          Vote: I like it -11 Vote: I do not like it

        lol

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2 years ago, # |
  Vote: I like it +13 Vote: I do not like it

OMG the moment has come. The best round ever is here. I really enjoyed a lot testing it, I'm very proud of y'all, you're great problemsetters ;) Hopefully you'll enjoy it as much as I did.

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2 years ago, # |
  Vote: I like it +13 Vote: I do not like it

oh eem gee guysss!!!? how did saarang, a blue coder set a div2????⊙＿⊙?? im literally shaking and crying in disbelief..!

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    2 years ago, # ^ |
      Vote: I like it +34 Vote: I do not like it

    oh eem gee guysss!!!? how did tibinyte, a Leafeon. coder set a div1????⊙＿⊙?? im literally shaking and crying in disbelief..!

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2 years ago, # |
← Rev. 2   Vote: I like it +5 Vote: I do not like it

As a tester I can assure you that the problems have very good quality and are fun, you can't miss the opportunity to participate in this contest :)

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2 years ago, # |
  Vote: I like it +16 Vote: I do not like it

As a tester, I'm sad because I can't participate

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

Among us

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

"At most one of the problems will be interactive." That feeling when the number of interactive problems is in the range of $$$[1,1]$$$

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2 years ago, # |
  Vote: I like it +18 Vote: I do not like it

As a non non-tester I have not not tested and the problems were not not good.

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2 years ago, # |
  Vote: I like it +78 Vote: I do not like it

As a tester I must say that one of the authors, namely ScarletS, has a huge skill issue when it comes to Codenames.

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    2 years ago, # ^ |
      Vote: I like it +35 Vote: I do not like it

    As an author I must say that one of the testers, namely AlperenT, has a huge skill issue when it comes to Codenames.

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2 years ago, # |
  Vote: I like it +55 Vote: I do not like it

As a tester, I must say that atodo and AlperenT are the most based codenames spymasters ever.

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

omg saarang round

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2 years ago, # |
  Vote: I like it +9 Vote: I do not like it
Meme
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2 years ago, # |
  Vote: I like it 0 Vote: I do not like it

When there are multiple problem setters, how do people decides who makes the announcement post and gets the contribution? Coin toss may be?

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

seemed like a joke but not.

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2 years ago, # |
  Vote: I like it +1 Vote: I do not like it

omg indian round

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2 years ago, # |
  Vote: I like it +39 Vote: I do not like it

As a tester, atodo didn't test.

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2 years ago, # |
  Vote: I like it +6 Vote: I do not like it

manish.17 orz

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2 years ago, # |
  Vote: I like it +10 Vote: I do not like it

As a Tester please give me contribution.

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2 years ago, # |
  Vote: I like it +1 Vote: I do not like it

thanks for the round

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

manish.17-fan-club

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2 years ago, # |
  Vote: I like it -20 Vote: I do not like it

I hope the constructiveforces part is a joke

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2 years ago, # |
  Vote: I like it +5 Vote: I do not like it

As a tester

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2 years ago, # |
  Vote: I like it -38 Vote: I do not like it

The round clashes with Ecuador vs Netherlands, can it please be postponed?

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    2 years ago, # ^ |
      Vote: I like it +42 Vote: I do not like it

    The round does not clash with Ecuador vs Netherlands.
    Ecuador vs Netherlands clashes with the round.

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      2 years ago, # ^ |
        Vote: I like it -16 Vote: I do not like it

      The world cup happens once every 4 years, contests happen 4 times a week

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        2 years ago, # ^ |
          Vote: I like it +5 Vote: I do not like it

        There have been 21 World Cups plus the current one, but there have only been 2 saarang rounds.

        Spoiler
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2 years ago, # |
  Vote: I like it 0 Vote: I do not like it

As a tester, this round was pretty fun to test. Hope the same holds for participants too!

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

Hope this round will make expert.

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

Note the unusual timing.

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2 years ago, # |
  Vote: I like it +5 Vote: I do not like it

As a former POTUS, I sure hope this round is good.

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2 years ago, # |
  Vote: I like it +34 Vote: I do not like it

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2 years ago, # |
  Vote: I like it +9 Vote: I do not like it

This is my first round . Good luck to everyone :)

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    2 years ago, # ^ |
      Vote: I like it +9 Vote: I do not like it

    Do you have any previous history in competitive programming? I mean do you participate on other websites?

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

Hope to get to Master.

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

    Hey. Where did you practice from May 2021 to July 2022? I mean which website? You grew up very very fast.

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

    Hi, I have solved around 400 problems on codeforces

    I want to know how to improve more. what are the things I am doing wrong

    Please check my profile- https://mirror.codeforces.com/profile/NamanKedia

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

      how old are you?

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

      Half of this 400 problems are problems with raiting 800. Try to solve more interesting and harder problems)

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2 years ago, # |
← Rev. 2   Vote: I like it +1 Vote: I do not like it

Please note that this contest (div 2) is start from an unusual time!

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    2 years ago, # ^ |
      Vote: I like it -11 Vote: I do not like it

    Yeah. It's written in bold in the announcement. No need to put useless comments down here.

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2 years ago, # |
  Vote: I like it +6 Vote: I do not like it

Good luck to all participants of this round, hope to positive delta

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

Good luck everyone! Time to grind

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2 years ago, # |
  Vote: I like it +57 Vote: I do not like it

omg Ali_ZaiBug round

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2 years ago, # |
  Vote: I like it +24 Vote: I do not like it

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2 years ago, # |
  Vote: I like it +6 Vote: I do not like it

omg Ali_ZaiBug round

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

omg Ali_ZaiBug round

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2 years ago, # |
← Rev. 2   Vote: I like it 0 Vote: I do not like it

omg Ali_ZaiBug round

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2 years ago, # |
  Vote: I like it +1 Vote: I do not like it

SpeedforcesAB

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2 years ago, # |
← Rev. 2   Vote: I like it +5 Vote: I do not like it

Samples are quite nice. ;)

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2 years ago, # |
  Vote: I like it -8 Vote: I do not like it

Contest=Xor

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2 years ago, # |
  Vote: I like it +33 Vote: I do not like it

Cool, unorthodox problems. Good job and thanks setters! Had fun.

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2 years ago, # |
  Vote: I like it -35 Vote: I do not like it

I really hate constructing sequence problems, and no one can convince me that these types of problems are useful for competitive programming. They are basically hit or miss. Shit problems!

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2 years ago, # |
  Vote: I like it +6 Vote: I do not like it

There was hardly any implementation before E ...

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2 years ago, # |
  Vote: I like it +9 Vote: I do not like it

Constructive Round ^^

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

Div1Forces

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

Any hint for D?

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

    Take the sum of the sequence to be $$$k^2n^2$$$ and then take the elements of the sequence to be $$$a, a+1, a+2, \dots, a+\frac n2 - 1$$$ along with $$$a+kn, a+kn-1, \dots, a+kn-\frac n2 + 1$$$ for some $$$a$$$. (I know I've added an extra term if $$$n$$$ is odd, feel free to remove it from either side) Now try to find ways to determine the value for $$$k$$$ and $$$a$$$.

    Hint 2: Consider cases where $$$n$$$ is even and odd seperately.

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    2 years ago, # ^ |
      Vote: I like it +4 Vote: I do not like it

    Solution for D:

    If $$$n$$$ is even:

    Let $$$\Sigma a[i]=n^2$$$.

    $$$a[]=...,n-2,n-1,n+1,n+2,...$$$.

    Sample:

    $$$n=6$$$

    $$$a[]=3,4,5,7,8,9$$$

    If $$$n$$$ is odd:

    Let $$$\Sigma a[i]={(n+1)}^2=n^2+2n+1$$$.

    $$$a[]=(n-n/2)+1,...,(n-2)+2,(n-1)+2,n+2,(n+1)+2,(n+2)+2,...,(n+n/2-1)+3,(n+n/2)+3$$$.

    Sample:

    $$$n=5$$$

    $$$a[]=4,6,7,9,10$$$

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

how to solve B what's the idea ?

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

for problem C if n%k != 0 then we can't form a permutation . but or we can simply place n in kth index and we'll be done

why wouldn't this work anyone ?

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

    Take for example 8 2

    Your method would give 2 8 3 4 5 6 7 1

    But I can also construct 2 4 3 8 5 6 7 1 which is lexicographically smaller due to having 4 instead of 8.

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

    This is not the lexicographically minimal solution For example n=12,x=3 you can form a_3=6,a_6=12, others equal to i

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

    The statement asks you to get the smallest lexicographical answer.

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

I submitted 5 sec before for Q3 but it said that contest over can you kindly accept the solution. Since it didn't compile in time it didn't accept

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

The problems were really fun!

However, I suspect the solutions for A,B, and C were leaked. While hacking, I noticed a bunch of grey coders with the same mistake in C: returning -1 if n>>16 == x, which doesn't seem related to the problem at all. This fails for testcase

1
199998 3
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2 years ago, # |
  Vote: I like it +15 Vote: I do not like it

Is this Construct forces? What is your fetish with construct the sequence folks ?

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2 years ago, # |
  Vote: I like it +6 Vote: I do not like it

ConstructiveForces

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2 years ago, # |
  Vote: I like it +18 Vote: I do not like it

Similar but not same problem for E: here

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2 years ago, # |
← Rev. 2   Vote: I like it +8 Vote: I do not like it

Nice round thanks!

I will agree with other people that ABCD all being constructive is slightly boring, but I would rather have 6 good constructives than 6 varied but mediocre problems (also I guess im slightly biased lol).

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

When will upsolving be opened?

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

Nice contest of constructives Thx for this amazing contest.

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2 years ago, # |
← Rev. 2   Vote: I like it +1 Vote: I do not like it

For those who are unable to solve C, try finding the ans for n=60, x=2

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

Why is it wrong? Problem C https://mirror.codeforces.com/contest/1758/submission/182533063

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2 years ago, # |
← Rev. 2   Vote: I like it 0 Vote: I do not like it

For the problem D, I got the answer when n is even , but for the odd n , I tried a lot but didn't get. I was trying to use the seq: (sum of 1st n odd numbers ) = n*n , and to maintain the max-min diff, I manipulated this odd numbers sequence like I made this diff to be equal to n so that n*n matches with the sum but failed when n is odd , in this case 1 value was always repeating. Can someone please help for odd n.

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2 years ago, # |
← Rev. 4   Vote: I like it 0 Vote: I do not like it

my solution for D:

if n is even, let say max — min is 2n then we can have half 5n and half 3n, if you do the sum it is exactly 4n^2. 5n * n/2 + 3n * n/2 = 4n^2 = (2n)^2.

if n is odd, we can compute for cases where n >= 7. add another 3n and reduce 3n from the 5ns. Sum is still 4n^2

if n is 3 or 5, then just find some cases that work. Example already has case 5.

To make number distinct just add minus from the first half, and add the same thing in the second half. They are guaratee to be distinct because 5n and 3n is a large range and we only have n/2 numbers This solution is very tedious. Is there a better solution than this?

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

    There is this. But I don't think it's pretty.

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

    I solved D by two pointers technique about min and max of array.

    Let's call the minimum and maximum of $$$A$$$ are $$$m$$$ and $$$M$$$, respectively.

    Then the minimum sum occurs at [ $$$m$$$, $$$m+1$$$, $$$m+2$$$, ..., $$$m+N-2$$$, $$$M$$$ ], and the maximum sum occurs at [ $$$m$$$, $$$M-N+2$$$, $$$M-N+3$$$, ..., $$$M-1$$$, $$$M$$$ ].

    Hence,

    $$$ \dfrac{(N - 1)(2m + N - 2)}{2} + m \le (M - m)^2 = s \le \dfrac{(N - 1)(2M - N + 2)}{2} + M $$$

    where $$$s$$$ is the sum of $$$A$$$.

    So run a while loop until find the inequality above met. In each loop, increase $$$m$$$ by $$$1$$$ if $$$(M - m)^2$$$ is lower than range, or increase $$$M$$$ by $$$1$$$ otherwise.

    After finding $$$m$$$ and $$$M$$$, it's easy to find the solution. (Just equally increase the elements of $$$A$$$ starting from the minimum sum case, until the sum meets $$$(M-m)^2$$$)

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2 years ago, # |
  Vote: I like it +5 Vote: I do not like it

Sir, prease give my rating beck. What do I have to do with your nonsense?

Deepesson You give my rating back imediately

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    2 years ago, # ^ |
      Vote: I like it +24 Vote: I do not like it

    I should be the one asking: why did you ping me with your nonsense?

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

    Y'll get around -135 from this round

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

https://mirror.codeforces.com/contest/1758/submission/182524851 I literally can't find what's wrong in my solution, can anyone please show why this solution is wrong?

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

Yeah, it was very good, i like it

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

Can some please explain to me why my solution — 182545721, is giving a time limit exceeded error? While this solution is not 182533564.

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

my solution for C :

If n%x != 0 then there is no answer, else p[x]=n. Let j be the current index of n in the permutation, iterate from x+1 to n-1 and , when you find an integer i such that n%i == 0 and i%j==0 swap(i,j).

Unfortunately the solution is wrong, can anyone help me find the mistake ?

Submission : https://mirror.codeforces.com/contest/1758/submission/182515365

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

    You have to set $$$p[n] = 1$$$ at the end after $$$p[x]=n$$$, otherwise you are overwriting it when $$$x == n$$$

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

      the case where n==x is handled by the if statement already

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

        you're right, your problem is the break, you should have pushed more the n to the last position you could so that the solution is lexicographically the smallest

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          2 years ago, # ^ |
            Vote: I like it +1 Vote: I do not like it

          OMG it was never intended to put it there, I forgot to delete it after changing the solution. OMG that's tragic. Thank you for your help!

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

    It’s not a “solution”, if it’s giving wrong answer

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

      It is indeed a solution, I just made a mistake while coding it (forgot to delete a break statement). It got AC in the end.

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2 years ago, # |
  Vote: I like it +1 Vote: I do not like it
Meme
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2 years ago, # |
  Vote: I like it +12 Vote: I do not like it

Screencast with commentary

Also, problem E should not appear in rated contests.

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

    Why?Is it because there is a known problem very similar to it?

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      2 years ago, # ^ |
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      Yes, this is a very well-known setup, and there wasn't any new spin on it.

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

Feeling sad that I almost solved d but couldn't able to submit within time otherwise it was very good contest as per my side!!! My problem D sol.n: 182548322 It was random approach i get to by trying some no.s i get that for every n , 2*n + 1 could a valid difference of maximum of a[i] — minimum of a[i]. If you know the explanation pls let me know!!!

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2 years ago, # |
  Vote: I like it +14 Vote: I do not like it

Alternative solution for D

It works only for $$$n > 3$$$, so cases then $$$n=2$$$ or $$$n=3$$$ should be solved by hand (or bruteforce)

It is well known that $$$1 + 3 + \dots + 2\cdot n - 1 = n^2$$$ and $$$max - min$$$ in this case is equal to $$$2\cdot n -2$$$.

Let's decrease second and third numbers by 1 and increment last number by 2, so we will have: $$$1,2,4,7 \dots 2\cdot n-3, 2\cdot n+1$$$ and now $$$max - min = 2\cdot n$$$.

How to get the sum equals to $$$4\cdot n^2$$$? We can add $$$3\cdot n$$$ to every number!

Thus, we have $$$sum = n^2 + 3\cdot n \cdot n = 4\cdot n^2$$$ and $$$max-min$$$ will not change.

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

This channel leaked ABC during contest. Can we find all the cheaters who copied problem C and just perma ban them? Close to 1k views on problem C

https://www.youtube.com/watch?v=vGpNQQo-NPI

I think their solution C is unique enough to id the cheaters

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    2 years ago, # ^ |
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    @MoreAnyNot really? I'm asking myself how do you know that? Maybe you submitted it yourself?

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2 years ago, # |
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Really nice problem E.

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2 years ago, # |
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I don't understand why problem D was included in the contest especially at the rank of D and the cut off point for most participants, it doesn't take any algorithm to solve nor can any interesting observations be made. otherwise great contest.

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

Loved the contest, thinking 1,3 in problem B was helpful. Saw C, tried, failes :D.

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

Please help me figure out what's wrong with my C https://mirror.codeforces.com/contest/1758/submission/182541955

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

    Why do you think multiply only by 2 is enough? x=3,n=27 will hack your solution. Output isn't even a permutation.

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

Simple greedy solution for D:

  1. To give ourselves a bit of wiggle room let Max-Min be equal to 10*n, Then let the square of this expression be x
  2. Initialize the array from 1 to n as you normally would with a[i]=i for 1<=i<=n-1 and a[n]=1+10*n, let the cost of this initialization be MIN .
  3. Then we can increment every element by 1 and reduce the leftover of x by ((x-MIN)/n)*n.
  4. Now we can greedily spend the rest of X incrementing elements starting from the back.

it is easy to see that 10*n difference is more than enough because after step 3 x will be strictly less than n which is less than the difference between the sum of numbers from (10*n-n+1, 10*n-n+2..., 10*n); — (1, 2..., n).

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

Maybe it's impossible for an expert to solve only 2 problems during Div2, but today i realized it. Thanks to this round, I will practice more to improve myself. :)

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    2 years ago, # ^ |
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    I don't think it's an indication of how good you really are at solving problems. Indeed, no one expected so many constructs in a row

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2 years ago, # |
  Vote: I like it +20 Vote: I do not like it

Finally, Candidate Master, thank you for the contest.)

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2 years ago, # |
  Vote: I like it +9 Vote: I do not like it

Problem description was very short and clear. I like it. Problem set was also logical and efficient. Just wow round.❤️

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2 years ago, # |
  Vote: I like it +8 Vote: I do not like it

Reached expert with master performance today. Thank you for the constructiveforces round.

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2 years ago, # |
  Vote: I like it +1 Vote: I do not like it

Please consider that their is a YouTube channel that post the problems code during contest time https://youtu.be/vGpNQQo-NPI

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

182612492

can anyone tell me why i am getting runtime error! i tried with prime factorization and swapping

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

    Line 19. p -= p // i looks wierd. Shouldn't it be p = p // i ? As a result, list b contains much more numbers than it should, thus you get index-out-of-range error later.

    Edit: Fix this error and get accepted.

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

What is expectation raitong for C and D

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2 years ago, # |
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Hi ,this contest had a different style than other codeforces contests. Other codeforce contexts are more algorithmic. But this contest had a more creative style. If this style of contest is going to be held again, please have its own type. Thankful

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2 years ago, # |
← Rev. 5   Vote: I like it 0 Vote: I do not like it

An awesome round it was.

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