atcoder_official's blog

By atcoder_official, history, 3 months ago, In English

We will hold AtCoder Beginner Contest 444.

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3 months ago, hide # |
 
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675 pointer G!! Seems like it's going to be speed run for problems A-F :(

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Hope everyone good luck!

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Rev. 2  
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Hardest G ever...

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good

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Hope everybody luck in all the contest!

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Good luck!

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Why do I get a 403 ERROR? The server is busy?

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Why there's a 403 ERROR?I haven't submitted the problem A for the first 30 minutes

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Good Luck!

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hey i have been automatically registered as unrated how can i switch to rated

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omg

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I preemptively award F "most annoying problem of the year" for 2026.

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Rev. 2  
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I couldn’t join the contest because I had a physics class... :<

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The gap between E and F is TOOOOOOOOOOO large. 2411 participants passed A~E (scoring 1500), but only 54 participants passed F (including AI?). The sample input for F is also very weak. I coded a solution for F with all my might but it ended up getting a verdict of AC×40 and TLE×10.

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Can someone please help with C. This is my submission. https://atcoder.jp/contests/abc444/submissions/73102557 I basically tried two cases after sorting — one where the last element==l and then I make sure other pairs exist.

And case two with even pair after sorting such that I sum i th element from both start and end and see if their sums are equal.

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    3 months ago, hide # ^ |
     
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    8
    4 2 6 2 2 10 2 8 
    

    Consider this case, the output should be empty, but your code prints $$$10$$$. I know the problem guarantees that at least one solution exists, but any correct implementation would produce no output for this case, which indicates that your code may print an invalid answer in real tests.

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      3 months ago, hide # ^ |
       
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      Thanks a lot. I debugged with it and found the issue.

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F and G is soooooooo hard. It took me 75 min to solve G and i don't have time to solve F.

Probably hardest F ever, I don't have any idea when i read the problem statement. It would be better if F is easier.

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not so good round, i think.

Prob D is a little bit easier than Prob C, and the gap between E and F is too big that solving A-E may have perf from 1200 to 2300

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What a F

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https://atcoder.jp/contests/abc444/editorial/15843

For the end of the problem G editorial, what does the periodicity of $$$\pi_p^k\pmod C$$$ say about the periodicity of $$$p^{k_p}\pi_p^{e_p-2k_p}\pmod C$$$?

Upd: If you split $$$C$$$ into the portion divisible by $$$p$$$ and the other portion, then $$$p^{k_p}\pi_p^{e_p-2k_p}$$$ will be zero modulo the first portion for all but some small values of $$$k_p$$$, and purely periodic modulo the second portion.

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SpeedCoder. Gap between E and F is too much

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Problem F : In the following submission why am I getting WA. Don't worry about TLE.

My submission

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ZJG Contest

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Is there a way to apply the idea behind Problem G to non-math problems?

I learned a lot about Gaussian integers and filled some gaps in my number theory knowledge. However, I am curious how this knowledge can be apply to CP problems.

Of course, this might not actually exist, but knowledge is always useful, and it better to learn it than not.

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Can we talk AWC there?