Topcoder_Updates's blog

By Topcoder_Updates, 4 months ago, In English

It's that time again and we are excited! The first Online Round of the 2022 Topcoder Open Algorithm Competition has arrived and is open to all!

Details:

Up to 750 of the highest scorers from each Round 1 will advance to Round 2 of the Algorithm Competition.

If you're unable to make it or don't advance, there will be one more Round 1 — Round 1B on Wednesday, April 27, 2022 at 07:00 UTC -4.

Best of luck to you in the Arena!

PS: Please help our research friends with this survey if you have time! Takes a few minutes!

- The Topcoder Community Team

 
 
 
 
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4 months ago, # |
Rev. 2   Vote: I like it +20 Vote: I do not like it

CodeChef_admin

conflict with April Lunchtime :(

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4 months ago, # |
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How can we check the rankings for people who participated in the past year (to see who skips directly to round 2 by being top 250)? I can only find this, which is for probably for people acitve in the past 6 months only

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4 months ago, # |
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I am new in topcoder.I have registered for TCO 1A. Somewhere I read that allowed participant is 2500 not more than that, so I have to register early.Why is that? And what is TCO 1A parallel round?Is it for participants who doesn't want to give real round or not qualified to give real round and is it rated ?

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    4 months ago, # ^ |
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    I think the 2500 limit is related to how much the server can handle and it's rarely, if ever, an issue. The parallel round is for the people who get to skip round 1 (e.g. they are very highly rated so they are auto-qualified for round 2). And based on previous years, I expect it to be rated!

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

    Only 320 registered with less than half hour to go, so the 2500 limit is very theoretical.

    In fact, I'm trying to remember when a TCO round had more registrants than the cutoff for advancing. (Currently the cutoff is 750 so everybody who gets any points will advance).

    It's been like that for some years... Unfortunately, Topcoder destroyed their wonderful CP community. Still a good place though.

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

I have certain troubles with logging in Web Arena now.

First I see

this login form

, where I type my login and password. This authentificates me at TopCoder site.

Then I see

a second form

, which keeps telling me that either username or password is wrong. But I can successfully log in to Applet Arena with those. Both "register" and "reset password" links lead nowhere.

UPD: And when I'm trying to open arena.topcoder.com after log in topcoder.com site, it results in an infinite loop striving to load https://accounts-auth0.topcoder.com/?retUrl=https:%2F%2Farena.topcoder.com%2Findex.html

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    4 months ago, # ^ |
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    Please email support at support@topcoder.com with details so they can help you out.

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    4 months ago, # ^ |
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    As far as I know, they just banned some Russian accounts (mine as well)

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      4 months ago, # ^ |
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      I asked them yesterday about this problem, they responded with the following (I think it is okay to publish it here):

      Hi Alexander,

      While I still have some questions, for example, why don't they publish (anything about) this russian policy on their website, I do not really want that much to write SRMs, therefore I have not tried to know any further details.

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4 months ago, # |
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First topcoder round in almost two years, excited to see all the fixed bugs!

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

    Division leaderboard still doesn't work in webarena.

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    4 months ago, # ^ |
    Rev. 2   Vote: I like it +110 Vote: I do not like it

    Is it intended, that the following strategy exists?

    -Open 250

    -Read 250

    -Solve 250

    -Submit 250

    -Read 1000's title

    -Solve 1000

    -Open 1000

    -Submit 1000

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

I found second problem challenging.Editorial out when? Topcoder_Updates

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    4 months ago, # ^ |
    Rev. 2   Vote: I like it +4 Vote: I do not like it

    After the challenge phase is over :)

    Edit: now that it is, here's the draft of the editorial

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      4 months ago, # ^ |
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      thanks

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      4 months ago, # ^ |
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      Nice problem. I got the DP part to calculate pA & pB but didn't know the technique of writing an equation for probability "p" in terms of itself, to simulate the infinite process, and then solving for "p". Very nice general technique to know:

      p = pA*1 + pB*pA*1 + pB*pB*0 + (1-pA-pB*pA-pB*pB)*p
      

      In that equation, what do the "*1" and "*0" indicate? I'm familiar with multiplying probabilities by values to compute expected value, but unclear what probabilities the "1" and "0" represent here.

      (I liked the 250 also — thank you for making it a little bit harder than a division-2 250, as we have had in many recent TCO opening rounds. This was more like a division-2 450 so everybody had a chance but took a little thought).

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        4 months ago, # ^ |
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        You are writing an expression for the probability that Alice wins. Whenever you reach a state where she has already won, she wins from that state with probability 1. And whenever you reach a state where she has already lost, she wins from that state with probability 0. That's where the 1 and 0 in this formula come from.

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          4 months ago, # ^ |
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          Excellent.. so, including the *0 along with the *1 thus allows us to explicitly enumerate all the possible outcomes (both positive and negative), without missing one by accident. Thanks!

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4 months ago, # |
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The third problem was similar to this one.

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    4 months ago, # ^ |
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    Seem lower constraint make the problem harder :)

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4 months ago, # |
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Joke here is unlucky to get bye ticket as competing in Round 1 will easily get more rating.

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4 months ago, # |
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Can someone please help me with this error that I get while opening the arena: "Fatal: Launch Error: Could not launch JNLP file. The application has not been initialized, for more information execute javaws/browser from the command line and send a bug report."

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3 months ago, # |
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I have encountered a problem: I registered for TCO 1B recently, but now I can't find a section where I actually did that. And overall I roughly can see any information about an upcoming round (1B). Could somebody explain me please where I can find all stated information? When I go to TopCoder Arena I can only see recently finished SRM. There is no further data.

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3 months ago, # |
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EDIT: Just managed.

I cannot login in the arena, requests keep timing out.

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    3 months ago, # ^ |
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    I could not open web arena. Can you please send the link to java applet?

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3 months ago, # |
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When I am choosing a problem, the applet says: "You are not assigned to this room." How to fix it?