LeoChan2022's blog

Is Div2 planning to be ABC?
By LeoChan2022, history, 2 months ago, In English

What the hell is the Div2 last night? It had A $$$\to$$$ E having much less difficult of thinking than before with a quite hard but typical(I heard from those who got accepted) F(actually ex $$$\to$$$ G)) math problem. I just thought I was do a ABC.

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

Auto comment: topic has been updated by LeoChan2022 (previous revision, new revision, compare).

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2 months ago, # |
← Rev. 3   Vote: I like it +17 Vote: I do not like it

maybe you are getting better actually

edit:

well actually by looking at your solved problems rating you are better

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2 months ago, # |
  Vote: I like it +3 Vote: I do not like it

Div.2 nowdays are more likely to Div.3

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2 months ago, # |
  Vote: I like it +16 Vote: I do not like it

Nope. You're just getting better

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2 months ago, # |
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Everything seems to be easier when ur getting better.

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

You are just getting better bro.

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

real

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7 weeks ago, # |
  Vote: I like it +16 Vote: I do not like it

Well I have the same feeling. Though I didn't take part in it, after viewing these problems I felt superised that I can find out how to solve E so easily.

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

The problem with E is quite interesting. Authors, testers and most importantly coordinators just didn't come up with the simplest solution possible (dp[prefix][xor_sum]), but still lowered the constraints because "well, we reduced the bound on A to make sure nlog^2A passes". This was their rookie mistake, the better solution here would be to lower $$$n$$$ to something like $$$10^4$$$ and increase $$$A$$$ to $$$10^9$$$. Or just be cruel to unoptimized code and leave it as is. If you are able to solve Div2E problems, you should be familiar with code optimization. The fact that this happened is a lesson to coordinators and authors and I hope they will learn. Otherwise, not a gigantic issue, just an easy Div2E, that's all.

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7 weeks ago, # |
  Vote: I like it +16 Vote: I do not like it

Although I think your point is valid, "planning to be ABC" is going too far. It's just this one round and there are various types of contests. Also, it's a sad overlook that the writers didn't find out the easy solution for E, but with their intended solution it's more or less of a proper E. I agree the set involved too little thought process and it was quite math-heavy though.

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