sshwyR's blog

By sshwyR, history, 6 weeks ago, In English

Hello Codeforces! We (dqa2020, Xiejiadong, xryjr233, ZZZZZZZZZZZZZZZZZZ and me) are excited to invite you to take part in Codeforces Round #664 (Div. 1) and Codeforces Round #664 (Div. 2), which will happen on Aug/12/2020 17:35 (Moscow time).

Huge thanks to:

There will be 5 problems in Div.1 round and 6 problems in Div.2 round. You'll be given 2 hours to solve them.

The story of this round is about that man. Instead of displaying his name, I prefer telling one of his legends (or joke):

"I have a 'friend', who makes lots of money every day, earning a billion in the blink of eyes. With a wave of his hand, OIers all over the world will follow him."

You can post your guesses in the comments.

UPD: Score Distribution:

  • Div.1: 500 — 1000 — 1500 — 1750 — 2500
  • Div.2: 500 — 750 — 1000 — 1250 — 1750 — 2250

Good luck!

UPD: Congratulations to the winners!

Div.1:

  1. Benq
  2. ecnerwala
  3. nick452
  4. kefaa2
  5. neal

Div.2:

  1. C.S.T.T
  2. MyLoveKUN
  3. Rchen3
  4. JuRuo_sjy
  5. evilbuggy
 
 
 
 
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6 weeks ago, # |
  Vote: I like it +12 Vote: I do not like it

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

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    5 weeks ago, # ^ |
      Vote: I like it +60 Vote: I do not like it

    What's the point of declaring top 5 people in Div.2, after all they are just Div.1 guys who registered with their alternative account, isn't this unfair? for example just look at the person who is placed 3rd in Div.2, this guy was newbie, like seriously? This disrupts entire rating distribution.

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6 weeks ago, # |
Rev. 4   Vote: I like it +410 Vote: I do not like it

I am tester, please upvote for me! :)

( I'M CUTE, GIVE ME CONTRIBUTION )

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6 weeks ago, # |
  Vote: I like it +9 Vote: I do not like it

Is the man is Bill Gates? :D

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6 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

is that man Jack Ma? just a random guess

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6 weeks ago, # |
  Vote: I like it +149 Vote: I do not like it

We don't want stories please, as they come in the way of easily comprehending the problem statement. :(

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    6 weeks ago, # ^ |
      Vote: I like it +77 Vote: I do not like it

    Oh don't worry. The statement is not long and we just use the main character to describe it. The story itself is easy to comprehend :)

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      6 weeks ago, # ^ |
        Vote: I like it -8 Vote: I do not like it

      Maybe you could highlight the formal statement or something to separate it from the story.

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

      For me who is afraid of number theory, this is good news to be happy about. If there is a math problem, I am also ready to change to the alternate.

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6 weeks ago, # |
  Vote: I like it +280 Vote: I do not like it

Tester — Planning to participate in the next div 1.
sshwyR — You already tested it.
Tester -

Spoiler
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    6 weeks ago, # ^ |
      Vote: I like it +65 Vote: I do not like it

    MeToo

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    6 weeks ago, # ^ |
      Vote: I like it +78 Vote: I do not like it

    This contest was put on hold for a long time due to the difficult Di2A.

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      6 weeks ago, # ^ |
        Vote: I like it +70 Vote: I do not like it

      difficult Di2A

      Thank you , now excuse me while I go to sleep for 35 hours real quick

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        6 weeks ago, # ^ |
          Vote: I like it +10 Vote: I do not like it

        Go for 40 , than that would be sacrilegious

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          6 weeks ago, # ^ |
            Vote: I like it +22 Vote: I do not like it

          Two set violin = small pp

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            6 weeks ago, # ^ |
              Vote: I like it +4 Vote: I do not like it

            Bass = pp large

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

              What? You bass gang, had some arguments before, but now is just butthurt, VIOLIN > bass. TwoSet responded to all Davie's videos, but Davie just ignored the "bass diss track" (which was asking for a livestream at the end) and the "davie fakes playing the violin". Brett played bass poorly, but it was REAL, but Davie, on the other hand, FAKED playing it. So what side is winning, huh?

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      6 weeks ago, # ^ |
        Vote: I like it +1 Vote: I do not like it

      Oops, difficult Di2A. So scary....

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

      Is this difficult div2A? Then what about the contest, which was for Russian elementary school students, with a 1700 rating problem A. (it was like 10 contests before) :D

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

    Feeling sad for such testers but they will get contribution.

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

      Well I knew I wont participate in one div1 when I was testing. Anyways I did participated but in unrated mode. Just that I didnt knew I wont be participating on 12 Aug.

      Spoiler
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6 weeks ago, # |
  Vote: I like it +60 Vote: I do not like it

Another Chinese Round! This round has special and interesting stories.Good luck and have fun for every contestants. Some information in advance:Those stories may all be about one mysterious person.

[O)]-[(O]/

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6 weeks ago, # |
  Vote: I like it +7 Vote: I do not like it

Is the man @MikeMirzayanov ? <3 i have not any guess about his income but i love him and want to see his name in the problem statement ..

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6 weeks ago, # |
  Vote: I like it +9 Vote: I do not like it

Mukesh Ambani???

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6 weeks ago, # |
  Vote: I like it +32 Vote: I do not like it

Boss Cai!!

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6 weeks ago, # |
  Vote: I like it +15 Vote: I do not like it

I am almost sure this man is Jack Ma.

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6 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

I want to know what is Polygon platform ? Strange word for me

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    6 weeks ago, # ^ |
      Vote: I like it +4 Vote: I do not like it

    A platform for making problems

    https://polygon.codeforces.com/

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    6 weeks ago, # ^ |
      Vote: I like it +1 Vote: I do not like it

    Polygon in basically the platform for creation of programming contest problems. It also supports problem statement writing, test data preparing, model solutions, judging and automatic validation.

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    5 weeks ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    The mission of Polygon is to provide platform for creation of programming contest problems. Polygon supports the whole development cycle: - problem statement writing - test data preparing (generators supported) - model solutions (including correct and wittingly incorrect) - judging - automatic validation

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6 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

I know! The man is Cai Rui[user:Boboniu]!

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6 weeks ago, # |
Rev. 2   Vote: I like it +7 Vote: I do not like it

Intersting fact: tourist will set a new best rating ever on codeforces if he wins this round!

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6 weeks ago, # |
  Vote: I like it -7 Vote: I do not like it

What are you talking about ???

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6 weeks ago, # |
  Vote: I like it -18 Vote: I do not like it

Chinese Round?

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6 weeks ago, # |
Rev. 2   Vote: I like it +199 Vote: I do not like it

Fun fact: seeing MiFaFaOvO can't participate in this round, if he doesn't in the next global round, he will vanish from the live standings xD

And "poof": he is gone xD

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    6 weeks ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    Excuse my ignorance, but what is the rule exactly you're talking about?

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      6 weeks ago, # ^ |
      Rev. 2   Vote: I like it +52 Vote: I do not like it

      Only the users which participated in a rated round within $$$6$$$ months will be included in the Rating Standing.

      The last rated round for him took place on $$$Feb^{17th}$$$.

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6 weeks ago, # |
  Vote: I like it +70 Vote: I do not like it

I guess it's CCF

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6 weeks ago, # |
  Vote: I like it -22 Vote: I do not like it

I guess this man is BINOD- Richest man of NEPAL.
You can just google it out.

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6 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

I do CP for fun.. What about you guys?

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6 weeks ago, # |
Rev. 3   Vote: I like it -13 Vote: I do not like it

Billie Jean is not my love

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6 weeks ago, # |
  Vote: I like it -118 Vote: I do not like it

BINOD !

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    6 weeks ago, # ^ |
      Vote: I like it +46 Vote: I do not like it

    Please don't spam Codeforces at least. There are many who don't know the context and it gets annoying after a while.

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6 weeks ago, # |
  Vote: I like it -40 Vote: I do not like it

hope to vecome will be legendary grandmaster this contest

please dont cheat everyone

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6 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

It's Mr-Cai!!! Hahahaha

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6 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

When I see Chinese round, I think of Mathforces.

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6 weeks ago, # |
Rev. 2   Vote: I like it 0 Vote: I do not like it

so... Yet another maximizing profit problems ... or Yet another guessing name problems :v

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6 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

Ronan Ryan?

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6 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

interestingLSY Time for your picture about boboniu!

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6 weeks ago, # |
Rev. 3   Vote: I like it -14 Vote: I do not like it

Ah-oh, MiFaFaOvO as a tester, which means we can't see his competition with tourist this time. A huge pity!

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    6 weeks ago, # ^ |
      Vote: I like it -71 Vote: I do not like it

    Either way ,he will never compete against tourist ,after the time he gained 1st spot . He just prays for some bad luck for tourist ,so that he can remain on top.

    Before that ,i Never thought ,such legendary grandmaster would ever fear to directly compete against someone. But anyway that someone tourist is not ordinary guy.

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    6 weeks ago, # ^ |
      Vote: I like it +49 Vote: I do not like it

    But It's still an interesting and exciting contest

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6 weeks ago, # |
  Vote: I like it +69 Vote: I do not like it

He must be Zide Du(杜子德) from the CCF.

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    6 weeks ago, # ^ |
      Vote: I like it +38 Vote: I do not like it

    China Computer Federation or China Collecting-money Federation?

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6 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

Is him, right ?

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6 weeks ago, # |
  Vote: I like it -7 Vote: I do not like it

Please provide short statements for problems and understandable english,I am learning english .Thanks

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

    Copy to baidu translate (

    Website: fanyi.baidu.com

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6 weeks ago, # |
Rev. 11   Vote: I like it -64 Vote: I do not like it

[Deleted]

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    6 weeks ago, # ^ |
      Vote: I like it +39 Vote: I do not like it

    You take slander as freedom?

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    6 weeks ago, # ^ |
      Vote: I like it +30 Vote: I do not like it

    You should know it's not polite to comment others like that

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    6 weeks ago, # ^ |
      Vote: I like it +37 Vote: I do not like it

    Freedom is not your excuse for slandering.

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    6 weeks ago, # ^ |
      Vote: I like it +29 Vote: I do not like it

    Although it is your right to express your own ideas,but your last comment was unsuitable indeed in some way.And codeforces delete your comment for a great many people downvote you.I think it is reasonable.

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6 weeks ago, # |
  Vote: I like it +49 Vote: I do not like it

See this 89567737

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

What's happening to "timeanddate.com"? :|

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    6 weeks ago, # ^ |
    Rev. 2   Vote: I like it +11 Vote: I do not like it

    The website works well for me, probably it's because of your network problem.

    And I don't think these sorts of comments are meaningful here

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      6 weeks ago, # ^ |
      Rev. 5   Vote: I like it -29 Vote: I do not like it

      This comment has been edited. Don't dislike me anymore! D: leave me alone!

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        6 weeks ago, # ^ |
          Vote: I like it +63 Vote: I do not like it

        Excuse me is there anything wrong?

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6 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

How to Mukesh ambani here?

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6 weeks ago, # |
  Vote: I like it +24 Vote: I do not like it

Boss Cai -- boboniu

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6 weeks ago, # |
Rev. 2   Vote: I like it +6 Vote: I do not like it

Makes lots of money everyday. That must be dzd from CCF(China Collecting-money Foundation)!

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6 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

I became psychopath because of the little pony, please make sure that the problems have short statements. with appreciation to your great story.

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6 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

I really hope that the problems are not as hard as the quiz.....

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6 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

He must be Zhang Aiqin ?

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6 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

Is this Gennady Korotkevich? Lol

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6 weeks ago, # |
  Vote: I like it +11 Vote: I do not like it

How many number of common problems ?

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6 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

Richie Rich?

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6 weeks ago, # |
  Vote: I like it +10 Vote: I do not like it

It could be suneo's dad from doraemon xD

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6 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

is it jeff bezos ?

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6 weeks ago, # |
  Vote: I like it -11 Vote: I do not like it
My guess
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    6 weeks ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    Asia's richest man, Worlds 4th. He is definitely very rich but I don't think it the right answer. Suneo's dad and Richie Rich are much more likely candidates.

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6 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

please what's the difficulty fo this contest because i'm a beginer and i want to take a part

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    6 weeks ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    It's better for you to test your skills in Division 4 or 3. However, this is Division 2 so you can still be able to maybe solve the first problem or who knows, maybe even the second one! Good luck to you!

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6 weeks ago, # |
Rev. 2   Vote: I like it 0 Vote: I do not like it

I'm the man y'all are talking about. admin please don't put me on read only again plix.)

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6 weeks ago, # |
  Vote: I like it +7 Vote: I do not like it

Olers?

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6 weeks ago, # |
  Vote: I like it +1 Vote: I do not like it

Is that man Mark Zuckerberg??

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6 weeks ago, # |
Rev. 2   Vote: I like it +13 Vote: I do not like it
The Man is:
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6 weeks ago, # |
  Vote: I like it +9 Vote: I do not like it

Is the man Mike Mirzayanov ?

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6 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

JPow?

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6 weeks ago, # |
  Vote: I like it +41 Vote: I do not like it

If there are unnecessary stories, please, do mark them in Italic or any other way. I've faced a lot of issues about bad storytelling in Codeforces. :)

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6 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

boboniu LGM.
rating 3117 in Codeforces
rating 10000 in Hearthstone War Chess.
%%%%%%%

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6 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

ALIBABA

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6 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

is it Mukesh Ambani ?

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

What are "Olers"?

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    6 weeks ago, # ^ |
      Vote: I like it +14 Vote: I do not like it

    The people like us. Take part in OI. OI, Olympics Information. OIer, the people learn OI. OIers is plural form of OIer. Understand? :)

    I'm not good at English. I hope you can understand xD

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    6 weeks ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    OIers are coders who participate in programming competitions (mostly used in China I guess). OI = Olympiad Informatics

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    6 weeks ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    It's what Chinese called people who participate in Olympic in Informatics contests.

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    5 weeks ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    The goalkeeper of RCD Espanyol, click the link for more details.

    https://www.transfermarkt.de/oier-olazabal/profil/spieler/8176

    Since Wu Lei (the best football player in China) is also in this team, we use the word "Oier" to show our respect to RCD Espanyol so that they pay Wu Lei on time.

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6 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

I think he is clb(boboniu)/cy/kel

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6 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

I love Money :B

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6 weeks ago, # |
Rev. 11   Vote: I like it -12 Vote: I do not like it

Its Jack Ma I guess- cofounded ALIBABA- China's richest person!

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6 weeks ago, # |
  Vote: I like it -14 Vote: I do not like it

i guess Jack Ma .

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6 weeks ago, # |
  Vote: I like it -15 Vote: I do not like it

tourist? Pretty sure it's him :)

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6 weeks ago, # |
  Vote: I like it +5 Vote: I do not like it

I guess he's kkksc03, head of Luogu(an oj in China). For every monthly contest in Luogu, if you want to watch the video tutorial, you must pay 10¥ first. And what's more there's lots of OI online lesson made by Luogu in every summer and they're not free! So he can make lots of money in this way.

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    6 weeks ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    Actually, according to himself, the money is not paid to him directly and a lot of money is spent in maintaining Luogu's website. And the lessons' money will be given to the teachers. So I'm very sure that it's not him.

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6 weeks ago, # |
  Vote: I like it +14 Vote: I do not like it

Any hint about no of common problems or score distribution ?

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6 weeks ago, # |
  Vote: I like it +19 Vote: I do not like it

Score Distribution?

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6 weeks ago, # |
Rev. 2   Vote: I like it -35 Vote: I do not like it

Binod

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6 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

Obviously,the man is DUZIDE:P

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6 weeks ago, # |
  Vote: I like it -13 Vote: I do not like it

Codeforces Round #664 ~ Made in China

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

I guess the person is a CODER. :>

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6 weeks ago, # |
  Vote: I like it +14 Vote: I do not like it

Score Distribution?

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    6 weeks ago, # ^ |
      Vote: I like it +8 Vote: I do not like it

    Sorry for the late publishment of score distribution :)

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6 weeks ago, # |
Rev. 2   Vote: I like it -9 Vote: I do not like it

I have a request for MikeMirzayanov.. can we have TEAM contest at codeforces.

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6 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

how are you talking about me??

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6 weeks ago, # |
  Vote: I like it +4 Vote: I do not like it

It's €€£

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6 weeks ago, # |
Rev. 3   Vote: I like it -34 Vote: I do not like it

.

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6 weeks ago, # |
  Vote: I like it +7 Vote: I do not like it

sshwyr how many problems will be common in both divisions?

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    6 weeks ago, # ^ |
    Rev. 2   Vote: I like it -12 Vote: I do not like it

    I guess there are 4.

    D2A->D2B->D1A/D2C->D1B/D2D->D1C/D2E->D1D/D2F->D1E

    upd: When I saw the scoreboard I knew there are only 3 but I forgot to update QAQ

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    6 weeks ago, # ^ |
      Vote: I like it +8 Vote: I do not like it

    3

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6 weeks ago, # |
  Vote: I like it +4 Vote: I do not like it

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

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6 weeks ago, # |
  Vote: I like it +36 Vote: I do not like it

Today's tester busy with increasing their contribution .

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6 weeks ago, # |
  Vote: I like it +13 Vote: I do not like it

Div2 Problem E with 1750 (^_^)...it should be solvable

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

iam not a tester, but please upvote for my pp :).......

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6 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

The man must be, President of IOI: Richard Forster

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6 weeks ago, # |
  Vote: I like it +8 Vote: I do not like it

Zhengru IOI will be internationalized.

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6 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

Karuna! :D

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6 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

An off-topic question: how can I view the past contests right before contests?

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6 weeks ago, # |
  Vote: I like it +8 Vote: I do not like it
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6 weeks ago, # |
  Vote: I like it +1 Vote: I do not like it

Too much if else... :(

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6 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

Normal Div1:

Try to solve more problems

Horrible Round #664 Div1:

Try to solve the first problem faster

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    5 weeks ago, # ^ |
      Vote: I like it +27 Vote: I do not like it

    No,you should try to avoid FST instead of solving problems faster. It's my final standing: xjpbmbrm.png

    (I was rk128 before the system test...)

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6 weeks ago, # |
  Vote: I like it 0 Vote: I do not like it

If I accept no question am i still rated?

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6 weeks ago, # |
  Vote: I like it +10 Vote: I do not like it

why they set so hard

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6 weeks ago, # |
  Vote: I like it +12 Vote: I do not like it

Was this the "Single Test Case" Contest?

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6 weeks ago, # |
  Vote: I like it -7 Vote: I do not like it

Really nice problems and clear statements. Enjoyed taking this contest :D

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6 weeks ago, # |
  Vote: I like it -8 Vote: I do not like it

Codeforces rounds are great, they teach us how to look at a problem in a simple manner, without overcomplicating it. orz Great contest.

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6 weeks ago, # |
  Vote: I like it +9 Vote: I do not like it

Well well well, once again someone posted solutions on youtube during the contest, you can even see his username in the video, i wonder if these guys are shameless or what Video link Username: Khayrulmithu

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    6 weeks ago, # ^ |
      Vote: I like it +4 Vote: I do not like it

    I don't know why but that video sounds exactly like an airline pilot's announcement.

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

    And he got it wrong on test 10 :D

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

I really liked d1 B, but...

Starting from any vertex u

This would be much more understandable if it said from all vertices. Wasted lots of time solving the wrong problem.

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    6 weeks ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    That could confuse people into thinking that it's possible to start from multiple vertices simultaneously, I think the clearest is "for all vertices u, starting from u, ..."

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    5 weeks ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    I'm pretty sure that "any" was actually used correctly here

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6 weeks ago, # |
  Vote: I like it -14 Vote: I do not like it

What was the point of swapping X and Y in Div2B?

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6 weeks ago, # |
  Vote: I like it +10 Vote: I do not like it

Does this works for Div-2 E — Make a graph $$$g[i][j][k]$$$ = how many edges exist such that its head is on node with $$$i$$$ outgoing edges and tail is in node with $$$j$$$ outgoing edges and it is $$$k'th$$$ smallest one. Then we brute force every $$$c_i$$$. That will be $$$O(k!k^2)$$$

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6 weeks ago, # |
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The whole round is like an ingenuous play of MiFaFaOvO to get back his first place in the rating (though unsuccessful). Chinese people are really good at the art of war. My respect.

(please don't take this very seriously)

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    6 weeks ago, # ^ |
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    "There are two ways to go higher, self improvement, and sabotaging literally the entire community"

    He has made his choice.

    (Jk no offense pls :)

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    5 weeks ago, # ^ |
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    Seems his plan worked

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6 weeks ago, # |
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Why the "non-empty" in C? I guess it has to do with printing the output but it reduced problem quality by like 30%.

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    6 weeks ago, # ^ |
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    could u plz xplain how to solve todays div2 C problem

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      6 weeks ago, # ^ |
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      You do realize that I haven't read Div 2C?

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        6 weeks ago, # ^ |
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        ok..if someone other can help..bcz..i am very curious about it..that why my logic was wrong..even on sample test cases ..i know i was completely wrong.can not wait till editorial..xD

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          6 weeks ago, # ^ |
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          rank 1 guys code is very clean to understand.

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      5 weeks ago, # ^ |
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      This is very easy implementation. DIV2 C LINK

      Just coz I am a newbie don't think that the solution is worthless. :)

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    6 weeks ago, # ^ |
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    Might as well allow output of negative length to boost problem quality?

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      6 weeks ago, # ^ |
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      Empty strings make sense, strings of negative length don't.

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    5 weeks ago, # ^ |
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    OH SHIT I missed it. Even my starting answer is an empty string. Luckily my code goes for large strings first when improving the cost in binsearch, so I got AC.

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6 weeks ago, # |
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Problem D Wrong answer on pretest 5 :(

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6 weeks ago, # |
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Is C checking if a cube like shape fits all of the given points by binary search / math?

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    6 weeks ago, # ^ |
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    Yes!But I am too weak at geometry,I come up with this idea quickly but don't know how to compute the area covered by several polygon...

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      6 weeks ago, # ^ |
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      Maintain the minimum and maximum values of $$$N$$$, $$$B$$$, and $$$N - B$$$.

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        6 weeks ago, # ^ |
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        Yes,but does it turn into a geometry problem??

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          6 weeks ago, # ^ |
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          Depends on your definition of "geometry" I guess. I didn't really use any "geometric" techniques. But yeah, you can visualize the things as hexagons.

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          6 weeks ago, # ^ |
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          No need to compute the area. Just find a point inside it.

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            5 weeks ago, # ^ |
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            Yes,But how to compute the point inside it?

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      6 weeks ago, # ^ |
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      Several polygons? I think it reduces to finding the minimum side length of the square in a shape like this that can fit all the points, which should be fairly easy. But I spent most of the contest thinking I had to minimize the sum of distances instead of the maximum, so I couldn't implement it in time.

      cube

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    6 weeks ago, # ^ |
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    Rather diamond-like (with top-left and bottom-right edges cut). Math seems awful there.

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6 weeks ago, # |
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How to solve Div2C? Also, where does the N^2 check all pairs approach go incorrect?

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    6 weeks ago, # ^ |
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    Final Answer can be at most $$$2 ^ {9}$$$, so just brute force for every possible value, and pick the smallest.

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      6 weeks ago, # ^ |
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      Thanks.

      Do you think there a polynomial-time solution in case final answer is large?

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        5 weeks ago, # ^ |
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        I have O(n^2 log m), where m is the size of the largest input integer.

        Figure out how many leading zeroes we can get by picking greedily the pairs where the bitwise-and has the most leading zeroes, using O(n^2) time. The next bit has to be a 1 in any solution, so we can add that bit the the answer. Since the bit will be a 1 in any case, we can ignore is from now on: we set it to zero and find out again how many leading zeroes we can now get. Repeat until we can get all zeroes.

        https://codeforces.com/contest/1395/submission/89696109

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      6 weeks ago, # ^ |
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      Well, I did that but, the o/p for test 3 came out to be 179. How did you do it?

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      5 weeks ago, # ^ |
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      Your implementation is too elegant :)

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    6 weeks ago, # ^ |
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    I solve this way
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      5 weeks ago, # ^ |
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      Now I feel like an idiot,spend half an hour in implementing an dp solution..:/

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      5 weeks ago, # ^ |
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      can you explain why you did if((a[i]&[b[j])|k)==k) cnt++,break;

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      5 weeks ago, # ^ |
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      Can you explain this approach?

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        5 weeks ago, # ^ |
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        My english is so bad.sorry.if you understand its my pleasure <3
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      5 weeks ago, # ^ |
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      Very clean aproach, fix the answer and check there are N pairs a[i]&b[j] that has the same bit positions. I spend 1 hour until I reach my dp aproach...

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    5 weeks ago, # ^ |
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    This is very easy implementation. DIV2 C LINK

    Just coz I am a newbie don't think that the solution is worthless. :)

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6 weeks ago, # |
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Is 1C a geometry problem? I thought it just need to binary_search and compute the area covered by several polygon..

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6 weeks ago, # |
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I passed the pretests in Div2B with a backtracking solution, how is that a thing?

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6 weeks ago, # |
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Hints for $$$Div 2 E$$$ Please?

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    5 weeks ago, # ^ |
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    Assume you have selected a tuple. Of course, you can now reduce the initial graph to one such that each node has out-degree of 1. Realise that for each node to be in a cycle in this resulting graph (and thus be possible to reach back to it in finite time), each node must also have an in-degree of 1.

    For each node (let it be Q), traverse over all nodes that point to it, let's call these set of nodes P. You can easily determine that for which value in the tuple will these nodes in P be pointing to Q. Also, this means that these values can not co exist in the tuple, since that would mean that multiple nodes point to Q in the resulting graph. Thus, you make a list of all these invalid combinations.

    Iterate over all K! tuples, and for each check if they consist of an invalid combination. If not, then it is valid.

    Sadly, was a bit late while implementing in contest :(

    Here's my AC code: https://codeforces.com/contest/1395/submission/89731507

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      5 weeks ago, # ^ |
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      What's the upper bound of the number of those invalid combinations?

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        5 weeks ago, # ^ |
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        By an invalid combination, I mean pairs $$$((i, j), (k, l))$$$ such that value $$$j$$$ at index $$$i$$$ in the tuple, and value $$$k$$$ at index $$$l$$$ in the tuple, are incompatible. So the maximum number of such invalid combinations are $$$K!(K!+1) / 2$$$.

        You just have to store all these pairs in a $$$K*K*K*K$$$ matrix.

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6 weeks ago, # |
  Vote: I like it +24 Vote: I do not like it

1250 not enough points for Div.2D

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6 weeks ago, # |
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Long Long in problem A just ruined my whole contest.I almost wasted 50min behind it.

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6 weeks ago, # |
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In Div2C, Sample test 3, what combinations get the final result as 147? The minimum I could get was 177.

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    6 weeks ago, # ^ |
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    so true... There should be a greedy approach to solve this problem...

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    6 weeks ago, # ^ |
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    I think you applied the dp approach. I did the same thing at first and waste a lot of time. just brute force the answer

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    6 weeks ago, # ^ |
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    I think this was the combination

    Spoiler

    these are indices of the element from array a and b

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    6 weeks ago, # ^ |
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    I also got the same error during the contest but now I understand. Well, let's say our solution consists of two parts, 1 and 2. I am not going to explain the second part assuming you already know it.

    But in the first part, u must be choosing a minimum c1 among all possible c1 and then doing part 2 of the solution but we are doing a mistake here. Actually, part 1 of the solution has n possibilities. Choosing minimum c1 is just one of the possibilities. A second possibility, for example, can be choosing a minimum c2 and then doing part 2 of the solution. Similarily choosing a minimum c3 among all possible c3 can be the third possibility and so on. So there are n possibilities.
    So the solution is O(n^3) and not O(n^2). wicardobeth

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    5 weeks ago, # ^ |
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    This is very easy implementation. DIV2 C LINK

    Just coz I am a newbie don't think that the solution is worthless. :)

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6 weeks ago, # |
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i will fst in d,One detail was not considered,shit.

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6 weeks ago, # |
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That was implementationforces, I like that. Should be enough to become blue again :)

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    6 weeks ago, # ^ |
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    What was the solution to D?

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      6 weeks ago, # ^ |
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      Greedy.

      Edit, more understandable: We devide $$$a[]$$$ into set $$$a[]$$$ and $$$b[]$$$, where all $$$b[i]<=m$$$ and all $$$a[i]>m$$$

      Sort both sets biggest element first.

      Then choose consecutevly to use i elements from a[]. Foreach i we can calculate how much elements from b[] can be used then, and using prefix-sum calc in O(1) the funfactor of that i.

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        6 weeks ago, # ^ |
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        If only I had two more minutes to fix my implementation

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        6 weeks ago, # ^ |
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        Figured that, but couldn't implement. Thanks, will wait till I can see your submission.

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    6 weeks ago, # ^ |
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    I am used to see you in blue ;)

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6 weeks ago, # |
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How to solve div2 D?

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    6 weeks ago, # ^ |
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    1) Make 2 lists: one of all greater than m (let us call it gr), second all less than m(let us call it sm). 2) Sort gr reverse and sm normally. 3) Now compare highest unused of gr with sum of d consecutive of sm. If gr highest is greater than simply add that to ans(in other words muzzle d smallest elements of sm). Take care of these things: 1) Do the above only till you have atleast 1 element left in gr, cause you can add it in the end. 2) If you encounter condition like less than d elements remaining in sm, then dont compare with gr greatest element as you can add all remaining along with greatest, if greatest goes in the end. 3) In the end try to put all remaining elements of gr in the end of the permutation seperated by d elements each. For details see the code: 89725326 If I fail system test ignore this comment :D

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6 weeks ago, # |
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Can anyone please tell me what's wrong in my code? Problem A https://ide.codingblocks.com/s/308173

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6 weeks ago, # |
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Can someone tell me why this solution to 1C is wrong?89722745

I can't find the mistake :(

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    6 weeks ago, # ^ |
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    Oh now I find it

    I forgot one line if(zmin>zmax) return 0; :(

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6 weeks ago, # |
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Boboniu stands nowhere in front of Binod

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6 weeks ago, # |
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Did anybody else got more than one "Wrong Answer in Pretext 2" in Div2 A

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6 weeks ago, # |
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Any Idea of Test 16, Div1 B ?

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How to solve Div-1 B??

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6 weeks ago, # |
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Need help, why did my solution for Div2B did not pass ? I have used dfs- https://codeforces.com/contest/1395/submission/89714645

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    6 weeks ago, # ^ |
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    I don't know dfs but this can be done with simple traversing.

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      6 weeks ago, # ^ |
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      yes, but the first think that came to my mind was this solution so I implemented it. But my question is that, what's wrong with this DFS approach, should work right ?

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        5 weeks ago, # ^ |
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        Because the DFS might not find a suitable move e.g it moves in a corner and both adjacent cells are already visited then it backtracks and moves from some previous suitable position.

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    6 weeks ago, # ^ |
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    I solved it first printing the (short)path sx, sy to 0, 0 which is moving up until the border and moving left until the border, and also save this path to an array.

    Then move to the end of row and move 1 row down and back to the beginning of the second row.

    Print there values while moving if they are not in the array you saved before.

    Then do this steps until reach (n-1, m-1).

    Here is an image of clarification, start from (sx, sy):

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    6 weeks ago, # ^ |
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    Dfs is wrong because it uses backtracking(after using a path you go back to the last intersection in that path and complete the search.) although in this problem you can't go back to the same square.