Please, try EDU on Codeforces! New educational section with videos, subtitles, texts, and problems. ×

By ICPCNews1, 3 weeks ago, In English,

text

UPD: You can predownload tests as an encrypted zip-archive by the links https://test1.codeforces.com/icpc-challenge-2020-tests.zip or https://test4.codeforces.com/icpc-challenge-2020-tests.zip (~80MB). The password is 64e00d81811bbc463e1e636af.

Hello everyone!

Live broadcast

Announcing the ICPC Graph Mining Challenge, Powered by Huawei and brought to you by ICPC U. Graphs are a powerful mechanism for representing many aspects of our daily lives, from mobile call routing to disease tracking. Answering various graph-related questions enables solutions to some of the most challenging, modern problems. The ICPC Challenge presents a problem from some area in computing. The area and problem style may be very different from the standard ICPC problems. Previous contests included new programming languages, multi-agents, parallel programming, etc. The ICPC Challenge provides a platform for ICPC to experiment with new problem types. It also provides participants with experience in some new area and problem type.

The ICPC Graph Mining Challenge will take place online during ICPC Day Zero on 27 June, 2020, 11:00-14:00 UTC. This round is unrated for all participants. Day Zero is a celebration of the 2020 ICPC World Finals, hosted by the Moscow Institute of Physics and Technology (MIPT). Everybody is welcome to participate. This is an individual competition. Participants will be divided into three groups: 2020 ICPC World Finals Contestant, 2020 ICPC World Finals Coach (includes co-coaches), and Participants. The 2020 ICPC World Finals Contestants and Coaches with the best graph solutions will be recognized as ICPC Challenge Winners. The top-scoring participants will also receive great prizes.

Join ICPC Challenge Warm-up Join ICPC Challenge

Both rounds are unrated for all participants

Huawei will provide prizes to the 12 winners in each group accordingly:

  • Group 1: 3 hour Challenge — ICPC 2020 World Finalists
  • Group 2: 3 hour Challenge — ICPC Coaches and Co-Coaches
  • Group 3: 3 hour Challenge — All participants
Group 1-3 Winners Quantity per place Prize
ICPC Challenge / 1-4th place 1 HUAWEI P40 PRO
ICPC Challenge / 5-8th place 1 HUAWEI MATEPAD PRO LTE
ICPC Challenge / 9-12th place 1 HUAWEI WATCH GT 2E

Each participant may win at most one prize for this Challenge.

All participants must agree to follow the 2020 ICPC Graph Mining Challenge Rules.

Participation Instructions:

  1. Read and agree to follow the rules.
  2. Create a Codeforces account if you don’t already have one.
  3. Associate your Codeforces account with your ICPC account if you have one. Though optional, this is necessary if you want to compete as a 2020 ICPC World Finalist or Coach.
  4. Register for the contest here.
  5. Please, make sure to complete the Warm-up at least 24 hours before the event to test your access, etc.
  6. There will be large input files. They will be available here at least 24 hours in advance. We recommend you to download them before the event.
  7. Go here at least 20 minutes prior to the start of the contest.

Good luck to all participants!

Announcement of ICPC Challenge 2020
 
 
 
 
  • Vote: I like it
  • +408
  • Vote: I do not like it

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

Great news!

Thanks for arranging it on Codeforces and making it open for all participants.

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

Thanks for arranging a warmup contest before the main contest.

»
2 weeks ago, # |
  Vote: I like it -61 Vote: I do not like it

i think i dont understand

what is this contest

is it the acm-icpc that was suppose to be this month or it is another contest ?

Because i heard that acm-icpc will be online but in 13/7/2020

»
2 weeks ago, # |
  Vote: I like it -54 Vote: I do not like it

ICPC is a team contest, the practice contest should allow team participation.

»
2 weeks ago, # |
Rev. 3   Vote: I like it -117 Vote: I do not like it

.

»
2 weeks ago, # |
  Vote: I like it +135 Vote: I do not like it

Who the hell has an account named ICPCnews that he forced the real ICPCnews to name themselves ICPCnews1?

  • »
    »
    2 weeks ago, # ^ |
      Vote: I like it +27 Vote: I do not like it

    They could use a _ like ICPC_News instead adding 1 in the last.

  • »
    »
    2 weeks ago, # ^ |
      Vote: I like it +112 Vote: I do not like it

    they just forgot the password lol

  • »
    »
    13 days ago, # ^ |
      Vote: I like it +2 Vote: I do not like it

    They can reclaim that username on this new year if ICPCnews1 participates in 10 rated contests. xd

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

who has their handle as "ICPCNews" ??

  • »
    »
    2 weeks ago, # ^ |
      Vote: I like it +87 Vote: I do not like it
    • »
      »
      »
      13 days ago, # ^ |
        Vote: I like it +11 Vote: I do not like it

      I suppose you're right...

      On the bright side, they have no submissions, no comments/blog posts, and haven't been active for years, so Mike might allow the real ICPC News to take their handle next Magic season

      • »
        »
        »
        »
        13 days ago, # ^ |
          Vote: I like it 0 Vote: I do not like it

        I thought you can't change when another user has taken the nickname

        • »
          »
          »
          »
          »
          13 days ago, # ^ |
            Vote: I like it +10 Vote: I do not like it

          You can if that user has no submissions, comments etc and has not been logged in for many years.

          • »
            »
            »
            »
            »
            »
            13 days ago, # ^ |
              Vote: I like it +24 Vote: I do not like it

            A surprise twist would be that ICPCNews is actually the real ICPCNews but forgot their password

»
2 weeks ago, # |
  Vote: I like it -33 Vote: I do not like it

HW NB!

»
2 weeks ago, # |
  Vote: I like it +51 Vote: I do not like it

Whoa, guys, it's just a CP contest, nothing to do with political stuff! Altough CCP might've done some offensive things, it doesn't necessarily mean that everything about CN's bad, okay???

  • »
    »
    2 weeks ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    What's CCP & CN?

    • »
      »
      »
      13 days ago, # ^ |
      Rev. 2   Vote: I like it +14 Vote: I do not like it

      CCP = Chinese Communist Party

      and

      CN = Peoples' Republic of China (Top Level Domain abbreviation)

  • »
    »
    2 weeks ago, # ^ |
      Vote: I like it -162 Vote: I do not like it

    CCP might've done some offensive things

    Well, maybe this is not true. I always agree with CCP. Don't say these words anymore. How can China become such a brilliant country if CCP is not a good party?
    While I was walking on Wall Street, I saw an old Chinese lady who was shouting to express her bad feelings about CCP. I think, if we, the Chinese can't believe in our government ourselves, then how can the foreigners respect our party?

    • »
      »
      »
      2 weeks ago, # ^ |
        Vote: I like it +35 Vote: I do not like it

      I respect your idea, but I still hold my own opinion. CCP didn't created good education & cultural evironment. The idea of propogating things are unacceptable nowadays. I don't mean to deny everything CCP had ever done, but the method of international-communication they took was definitely causing conflicts, yet these conflicts intensify when we Chinese poeple know. The major voice is about forbidden all from foreign. That's what I mentioned offensive.

      • »
        »
        »
        »
        2 weeks ago, # ^ |
          Vote: I like it -65 Vote: I do not like it

        The major voice is about forbidden all from foreign.

        I agree with you except this sentence. Did't you read the news about it?

      • »
        »
        »
        »
        13 days ago, # ^ |
          Vote: I like it +1 Vote: I do not like it

        Yes, you're right at some points.

        But in my opinion, we should do that or we must do that. You just go to youtube or twitter or somewhere out of the GFW, when they talk about CN or CCP everything seems to be bad. They might think we're living in the hell. And those who has migrated abroard to the US or some else western countries, some of them just deny everything CCP has done using the Chinese! If we dont have the GFW, most of people who only play Tiktok or kuaishou will accept their "US the bset, CN the worst" opinion, which will cause many problems because they dont know English and dont have the way to figure out the news.

        And for our programmer, that's true, very inconvinient sometimes. If we want to search something about CP or just computer, using local search protocol sometimes is useless, and if you can't use the Google many problems seem never be solved. I know this feeling because I had some questions before which local search cant solve, and I used Google and found a conmmunity referenced to the problem and I just asked the conmmunity and solved.

        So, in conclusion, this is a double-edged sword policy. But most of people in CN even dont know the exist of the GFW, so for most of people there seems to be nothing wrong.

        • »
          »
          »
          »
          »
          13 days ago, # ^ |
            Vote: I like it -13 Vote: I do not like it

          Yeah, I kinda agree with you. Some of the mistook perspectives were caused by lack of global view.

          • »
            »
            »
            »
            »
            »
            13 days ago, # ^ |
              Vote: I like it 0 Vote: I do not like it

            LOL, you nickname is very interesting. but when you really "da tie", you will feel bad for days. I just did it in Xuzhou regional contest. The disdance to the last of the bronze medal is 10 teams. Very upset.

            • »
              »
              »
              »
              »
              »
              »
              13 days ago, # ^ |
                Vote: I like it -19 Vote: I do not like it

              Ah, Fe is just part of OI/ACM career. So as Au or Ag. It's not the medal what really matters, its the friendship and knowledge we had had.

    • »
      »
      »
      2 weeks ago, # ^ |
        Vote: I like it +14 Vote: I do not like it

      First, I think the brilliance of one country should be due to the workers. Second, I don't think people must respect the parties in other countries, or know which parties exist in other countries. For example, do you know about the parties in India?

      • »
        »
        »
        »
        2 weeks ago, # ^ |
        Rev. 2   Vote: I like it -25 Vote: I do not like it

        I think so.

      • »
        »
        »
        »
        13 days ago, # ^ |
        Rev. 2   Vote: I like it +27 Vote: I do not like it

        Why the HELL are you talking about politics, this is a coding website, not a politics website. Please talk on other websites or chatrooms, not here.

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

Wow the contest is from 4am to 7am PDT. Amazing!

  • »
    »
    2 weeks ago, # ^ |
      Vote: I like it -36 Vote: I do not like it

    Absolutely. We all know this is powered by a Chinese high-tech company. So it mainly depends on OIers in China. In a word, it's the best arrangement for the Chinese like me!

    P.S. OIer means people who study OI.

  • »
    »
    2 weeks ago, # ^ |
      Vote: I like it +29 Vote: I do not like it

    I (completely seriously and unironically) think early in the morning is the best time for a contest.

    Pros:

    1. You'll solve the problems just after waking up. The brain is well-rested, you are able to think unbelievably clearly and concentrate easily. If you participate after a day of work half of your brain has already turned to mush.

    2. Nothing else is ever scheduled at 4am. You'll never need to make decisions like "do I participate or do this other thing?".

    That said, being at 4am on a Saturday morning weakens both points somewhat.

    • »
      »
      »
      2 weeks ago, # ^ |
        Vote: I like it +19 Vote: I do not like it

      These are maybe pros of a contest at 7 am, not in the middle of night when people sleep.

      Do you really want to be wakened up after 4 hours of sleep and take some quiz or exam?

      • »
        »
        »
        »
        2 weeks ago, # ^ |
          Vote: I like it +21 Vote: I do not like it

        Well, maybe 4 am is too early, but 7 is already too late if you're expected to be somewhere at 9.

        If there is a contest at 4 am (a rare thing but it happens, TopCoder had more of them a few years ago), I would plan for it for going to bed earlier, it's not a big deal.

        Of course that's just my opinion, I don't expect many people to agree with me :P

        • »
          »
          »
          »
          »
          13 days ago, # ^ |
            Vote: I like it -15 Vote: I do not like it

          My biggest issue with early-morning rounds is Atcoder rounds Sunday mornings because they are early enough that I would be tired competing on a normal sleep schedule, but they aren't CF rounds, so they aren't important enough to me to actively change my sleep schedule ahead of time.

          I suppose the easy solution to that is to change my priorities and just get up earlier though.

          • »
            »
            »
            »
            »
            »
            13 days ago, # ^ |
              Vote: I like it +52 Vote: I do not like it

            They should be important enough to you. Problem: solved.

        • »
          »
          »
          »
          »
          12 days ago, # ^ |
            Vote: I like it 0 Vote: I do not like it

          The main problem is for the people where according to their timezone the contest is at midnight.

»
2 weeks ago, # |
  Vote: I like it -21 Vote: I do not like it

everyone knows who will be the winner

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

What would be the average diffuculty of the contest ?

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

what kind of problems comes in ICPC ? Any Link to the problems.

  • »
    »
    13 days ago, # ^ |
      Vote: I like it +8 Vote: I do not like it

    These aren't actually ICPC problems. ICPC problems are usually like longer CF problems. These are more optimization challenges, so they are a different category really.

    There is a practice contest going on which should give you a good idea of the problem types.

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

Is it something like Google hashcode but individual instead of a team competition?

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

Just a logistical question — are Groups 1/2 considered as a subset of Group 3, or a seperate group?

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

what kind of problems? graph theory?

»
2 weeks ago, # |
Rev. 2   Vote: I like it -27 Vote: I do not like it

.

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

What does it mean when the following is the case Partial result: 300000 points ?

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

I think that a lot of ICPC contestants (including myself) didn't connect their codeforces/ICPC correctly (the scoreboard for ICPC contestants contain only one TheLostCookie ) so how to connect both accounts correctly ?

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

    Visit https://codeforces.com/settings/general and connect your account with ICPC ID. If you are not in the list of finalists/coaches, it means that ICPC didn't return your correct role. I'll ask ICPC to check it.

    • »
      »
      »
      2 weeks ago, # ^ |
        Vote: I like it 0 Vote: I do not like it

      Mine is already connected as well, and I'm not in the list — so there could be an issue in the linking.

      • »
        »
        »
        »
        2 weeks ago, # ^ |
          Vote: I like it +62 Vote: I do not like it

        Yes, there is some issue around roles in WF. Just wait, it will be fixed before the main contest. Thanks!

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

sorry. i was making a stupid mistake

»
13 days ago, # |
  Vote: I like it 0 Vote: I do not like it

These practice problems seems not very hard,but someone maybe rusty with file input&output.

  • »
    »
    13 days ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    what to do with subtask, i mean how to append subtask output to a file

    • »
      »
      »
      13 days ago, # ^ |
        Vote: I like it 0 Vote: I do not like it

      You could create a txt file and paste your answer in it. Different subtask should upload different file,not append all in one.

  • »
    »
    13 days ago, # ^ |
    Rev. 2   Vote: I like it -21 Vote: I do not like it

    How can you say that they are NOT VERY HARD? The independent set problem is a NP-hard problem that nobody knows how to solve it in polinomial time! It is EXTREMELY HARD! Making a bad heuristics and randomized algorithims is quite easy, but solving the problem is REALLY HARD

    • »
      »
      »
      11 days ago, # ^ |
        Vote: I like it 0 Vote: I do not like it

      I mean it's not difficult to find a passible answer to the problems.

      I agree with you on the opinion that it's hard to find the best answer.

      So it's the reason to hold a contest.No one knows the best answer,one just need to give a better answer than others.

»
13 days ago, # |
  Vote: I like it +28 Vote: I do not like it

How to download my submission?

»
13 days ago, # |
  Vote: I like it +8 Vote: I do not like it

When I tried to submit, I got this message: "The program is too long [size=1985279 bytes]." I tried sending a compressed .zip file, but that didn't work. How am I supposed to submit for this contest?

  • »
    »
    13 days ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    I had this verdict too. It turned out that my output did not satisfy the requirement in the problem.

  • »
    »
    12 days ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    I am facing the same issue, can someone help what we need to do?

    • »
      »
      »
      12 days ago, # ^ |
        Vote: I like it +3 Vote: I do not like it

      Just send the outputs (output files). "The program is too long..." means that you can't preview your code in web-interface, it is too huge to be displayed.

»
13 days ago, # |
  Vote: I like it -38 Vote: I do not like it

What's the purpose of this 2-day warmup? Letting people without CF accounts learn how to submit a solution here?

There's no special format of input or output. There are no special scoring rules. Omitting the first problem wouldn't hurt anything, it serves no additional purpose. The content of the problems is "one well-known problem", which is fine to solve, but multiple real problems (instead of lol A) would give it some substance. People have a lot of time that they won't have in the serious version.

»
12 days ago, # |
  Vote: I like it +17 Vote: I do not like it

"There will be large input files. They will be available here at least 24 hours in advance. We recommend you to download them before the event" So it's less than 20 hours left and where is the input?

»
12 days ago, # |
  Vote: I like it +23 Vote: I do not like it

You can predownload tests as an encrypted zip-archive by the link https://test1.codeforces.com/icpc-challenge-2020-tests.zip (~80MB). We will publish the password when the contest begins.

»
12 days ago, # |
  Vote: I like it -30 Vote: I do not like it

Is the practise contest rated?

  • »
    »
    12 days ago, # ^ |
      Vote: I like it +15 Vote: I do not like it
    "Both rounds are unrated for all participants"
    Please read the announcement properly first .
    
»
12 days ago, # |
  Vote: I like it 0 Vote: I do not like it

i have a problem with input. if i want to input a test case let say an array 3 4 5 4 i have to give input like
3
4
5
4
otherwise it shows error '3' is not recognized as an internal or external command,operable program or batch file.

»
12 days ago, # |
  Vote: I like it 0 Vote: I do not like it

This is my first ICPC Challenge. I solved the first problem of the practice contest and the verdict is showing "partial result". What does it mean?

»
12 days ago, # |
  Vote: I like it +16 Vote: I do not like it

Can you share the warmup problem prepared on Polygon with me?

  • »
    »
    11 days ago, # ^ |
      Vote: I like it +15 Vote: I do not like it

    +1, it should be public for educational reasons (so it would be easier to prepare optimization problems)

»
12 days ago, # |
  Vote: I like it +42 Vote: I do not like it

Since the warm-up challenge is over and the official is going to start soon. Can we quickly discuss the solution everyone else used? I wonder what algorithm was used by the guy who came first.

  • »
    »
    11 days ago, # ^ |
    Rev. 2   Vote: I like it +30 Vote: I do not like it

    I did simulated annealing:

    Repeatedly add an un-chosen vertex to our independent set; remove all neighbors of that vertex from our set; let the score change be D: if D>=0, we definitely keep this change: otherwise, we might still keep this change with probability e^(D/temp), where temp is our "temperature". Temperature has a certain value at the start of the SA (manually controlled; usually I did 0.5, 0.25, or 1.0 for long SA's) and decays linearly to 0 at the end of the SA.

    I ran multiple SA for various lengths of time (ex. 100 sec, 200 sec, 1000 sec, 7 hrs). In the beginning I always started with no vertices chosen. Later I took previous solutions and ran SA on them.

»
12 days ago, # |
  Vote: I like it +14 Vote: I do not like it

Anyone else facing problems downloading the tests? Mines failing after a couple of minutes.

»
12 days ago, # |
  Vote: I like it 0 Vote: I do not like it

It intersects with atcoder beginner contest

»
12 days ago, # |
  Vote: I like it +5 Vote: I do not like it

Just for the curious: ICPC finalists (who linked account) in Global Round 8: https://codeforces.com/contest/1368/standings/split/contestants

»
11 days ago, # |
  Vote: I like it 0 Vote: I do not like it

What were peoples' solutions to the practice contest?

»
11 days ago, # |
  Vote: I like it +5 Vote: I do not like it

What were people's solutions to the real contest.

  • »
    »
    11 days ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    Write weird greedy solution once, for the rest of the time -- change parameters and submit.

    • »
      »
      »
      11 days ago, # ^ |
        Vote: I like it -11 Vote: I do not like it

      Worked for me. I passed tons of masters and some GM's using that.

  • »
    »
    11 days ago, # ^ |
      Vote: I like it +16 Vote: I do not like it

    My solution (12th place) was standard "generate random initial state and do hill climbing until converges" I couldn't get good scores until I started generating skewed initial states: lots of states having size 1 and the rest evenly distributed. Hill climbing was just moving one element from a set to another.

»
11 days ago, # |
  Vote: I like it 0 Vote: I do not like it

As of now I cannot seem to access other people's solutions to the practice contest, even though it has already ended. Is this a mistake or is it intentional?

  • »
    »
    11 days ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    They don't submit the codes anyways. What will you do looking at the output?

»
11 days ago, # |
  Vote: I like it +96 Vote: I do not like it

Why there were two different values with same name "modularity" in the statement?

  • »
    »
    11 days ago, # ^ |
    Rev. 2   Vote: I like it +10 Vote: I do not like it

    That was incredibly dumb, plus the modularity calculated in the explanation of the third example is not the modularity used for getting the scores (it is the second modularity without adding the regularization), and I guess this was not intentional. I believe that even the setters got confused with the multiple modularities.

»
11 days ago, # |
  Vote: I like it +57 Vote: I do not like it

Better not discuss your solutions guys as there is week long upsolving with prizes as well

»
11 days ago, # |
  Vote: I like it -7 Vote: I do not like it

I want to know more about the background of the official problems.

The goal to optimize is intricate.

3 hours are too little to comprehend the official,so why 48 hours for the warm-up?

»
11 days ago, # |
  Vote: I like it +67 Vote: I do not like it

Congrats yashChandnani orz !!!

»
4 days ago, # |
  Vote: I like it 0 Vote: I do not like it

Can i solve problems after ICPC Challenge 2020 and ICPC Challenge 2020: Marathon?