maroonrk's blog

AtCoder Regular Contest 166 Announcement
By maroonrk, history, 3 years ago, In English

We will hold AtCoder Regular Contest 166.

The point values will be 400-400-600-600-800-1100.

We are looking forward to your participation!

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3 years ago, hide # |
 
Vote: I like it +16 Vote: I do not like it

Hope that I can get rating.

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3 years ago, hide # |
 
Vote: I like it -20 Vote: I do not like it

Wow, hope this round can be friendly to me noob :)

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3 years ago, hide # |
 
Vote: I like it -7 Vote: I do not like it

Plz plz give me 2 Dan I solved 4

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3 years ago, hide # |
← Rev. 2  
Vote: I like it +5 Vote: I do not like it

Let me show how I solve problem C.

I stare at the screen for 30 minutes and have no idea about it. Then I write a brute force solution at first.

Then I print down each answer of 1x1, 1x2, 1x3 ... 1xn, find it is geometric progression. For 2x2, 2x3...2xn, 3x3 ... 3xn feel the same

Then I observe the ratio, wait, Fiobnacci?

Then I calculate the product, and found it is the square of product of Fiobnacci.

Finally I get AC by last moment.

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    3 years ago, hide # ^ |
     
    Vote: I like it 0 Vote: I do not like it

    How to compute $$$F_2 F_4 \dots F_n$$$ for $$$n \leq 10^{18}$$$?

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      3 years ago, hide # ^ |
       
      Vote: I like it 0 Vote: I do not like it

      Thank you for correction, I haven't find a solution yet, my previous thought about using matrix multiplication is wrong.

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3 years ago, hide # |
 
Vote: I like it 0 Vote: I do not like it

how to solve B using dp? the editorial says so but doesn't give much details.

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3 years ago, hide # |
 
Vote: I like it +10 Vote: I do not like it

there's a mistake in C — LU / RD Marking Editorial.Assume $$$n\leq m$$$,it's not $$$(a_2a_4...a_{2n})^2a_{2n+1}^m$$$ but $$$(a_2a_4...a_{2n})^2a_{2n+1}^{m-n}$$$.

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3 years ago, hide # |
 
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hey Guys! So I was going through the editorial of problem C and didn't understand how exactly the formula in the last step is derived. I understand how to answer for each individual component, that is the Fibonacci number, and multiply the results of each component together as they are independent. But why are we squaring the result of the multiplication of each component? and why is the term (a2n+1)^m there in the end? I enjoyed the explanation so far and really want to understand it completely. Thanks!

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

My rating rose to 2042 from 2028 but today I found it returned to 2028. Is my rating rolled back? I found no evidence that the contest will be unrated.

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