maroonrk's blog

AtCoder Grand Contest 072 Announcement
By maroonrk, history, 12 months ago, In English

We will hold AtCoder Grand Contest 072. This contest counts for GP30 scores.

The point values will be 900-1100-1100-1400-1400.

We are looking forward to your participation!

  • Vote: I like it
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12 months ago, hide # |
 
Vote: I like it 0 Vote: I do not like it

Is there no one around? Good luck to everyone!

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12 months ago, hide # |
← Rev. 8  
Vote: I like it -56 Vote: I do not like it

This AGC was quite challenging, perhaps the hardest one I've participated in so far. The first problem involved an advanced DP approach, which was tough for me but likely engaging for more experienced coders. Despite the difficulty, I really appreciate the problem writers' effort and thoughtfulness in crafting such a well-prepared contest.

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12 months ago, hide # |
 
Vote: I like it +38 Vote: I do not like it

Thank you for participating AGC072. We are sorry for the high difficulty, but I'm glad if you enjoyed some of the problems.

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12 months ago, hide # |
 
Vote: I like it +41 Vote: I do not like it

Thank you for the motivationpill

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12 months ago, hide # |
 
Vote: I like it +38 Vote: I do not like it

Knowing 1733E - Conveyor is pretty helpful for solving C on this contest, particularly the idea of computing a table counting the number of visits from the first $$$k$$$ paths (though the specific mechanics are different).

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12 months ago, hide # |
 
Vote: I like it +37 Vote: I do not like it

Today's contest for 2000-2100 rated people be like, let's register for the contest and get free delta ;)

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12 months ago, hide # |
 
Vote: I like it +55 Vote: I do not like it

Solved 0 problems, and my rating still increased

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12 months ago, hide # |
 
Vote: I like it +40 Vote: I do not like it

My solution to C has 0 common observations with the editorial solution lol. In particular I even have a different complexity (O(n^3))

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12 months ago, hide # |
 
Vote: I like it +18 Vote: I do not like it

How much time it took for authors to prepare this excellent problemset?

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    12 months ago, hide # ^ |
     
    Vote: I like it +43 Vote: I do not like it

    It depends on how we measure the time:

    If you consider about preparing problem statements, solutions, testcases, and testing problems, we started from early April and spent full 2 weeks.

    If you consider about problem idea, the first of 5 problems we've came up with is Problem B "AGC Language", which was proposed on January 2023 — which is over 2 years before this AGC. We could gradually pile up AGC-quality problems, as the last of 5 problems is Problem D "Magician", which was proposed on December 2024.

    If you consider about the entire pathway towards writing AGC, we started competitive programming in 2015, we wrote the first contest in 2016, first ABC in 2018, first ARC in 2021, first AHC in this March. During the pathway, writing AGC in some future was one of our goal. Considering this, this contest is depended on lots of years.

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12 months ago, hide # |
 
Vote: I like it +13 Vote: I do not like it

These problems are amazing. It would probably take me more like a week to solve them all though, lol.

The only one I figured out how to solve so far is E, which was a really beautiful problem. I needed a cool general observation about Djikstra-style algorithms I've never seen before: if you do not know which vertex is the unhandled settled one, but know it is one of a small set of vertices, you can run the Djikstra step on each of them. You might have to run a Djikstra step on all but one of them again in the future, but you still eliminated one vertex.

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12 months ago, hide # |
 
Vote: I like it +15 Vote: I do not like it

This maybe the hardest AGC I've ever participated. It maybe great for the grands,not for me.

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