maroonrk's blog

By maroonrk, history, 2 months ago, In English

We will hold AtCoder Regular Contest 149.

The point values will be 300-500-500-700-700-900.

We are looking forward to your participation!

 
 
 
 
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2 months ago, # |
Rev. 2   Vote: I like it +9 Vote: I do not like it

hope all of you have fun!

(upd: What an interesting contest! the solution of B is very interesting!)

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2 months ago, # |
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Hope you all have a good time in this competition!

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2 months ago, # |
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Hope to solve 3 problems

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2 months ago, # |
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thanks

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2 months ago, # |
Rev. 2   Vote: I like it -8 Vote: I do not like it

Problems were interesting.

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    2 months ago, # ^ |
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    Hey i have never participated in ARC rounds. Are they harder than normal beginner contests?

    What is the minimum codeforces rating one should have to solve 2 problems in most of the contests?

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      2 months ago, # ^ |
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      Yes ARCs are harder than ABC contests and it's rating range is until 2799 but ABC's rated range is until 1999, Also I don't think CF rating is a good criterion for atcoder contests so I can't answer your second question.

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2 months ago, # |
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C was a good problem, but my algorithm only works with $$$n \geq 9$$$. therefore, i have to calculate all the situations for $$$n \in [3, 8]$$$ and add it to my code :(

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    2 months ago, # ^ |
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    I am luckier than you.I have to calculate the situations for n=3&&n=5.

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      2 months ago, # ^ |
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      I'm even luckier, I only need to calculate the situation for $$$n=3$$$.

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2 months ago, # |
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D harder than normal, but it's still a great contest. Hope a more banlanced contest next time!

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

Problem D is similar to this problem.

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2 months ago, # |
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2 months ago, # |
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It is difficult for me to understand the official solution of problem D, especially the "symmetry" part and the "spanning a directed edge" part.

Would anyone like to share your editorial of this problem? Thank you so much.

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2 months ago, # |
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2 months ago, # |
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Such testcase does not exist in D, where the last move will put something to coordinate 0. Example case: 1 1 5 5

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2 months ago, # |
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In problem A, X is a positive integer less than 10^N and N can go upto 10^5 which means X is a positive integer less than 10^(10^5). What should I conclude from this?

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    2 months ago, # ^ |
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    It means X is a string of digits with string length <= 10^5.

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2 months ago, # |
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In Problem C, instead of looking for multiples of 3, I looked for getting the sum of n^2 (for n = odd cases because n^2 is odd, so the sum of 2 numbers means one of them is odd) and n^2-1 (for n = even cases because n^2-1 is odd.)

Both n^2 and n^2-1 are NOT prime.

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2 months ago, # |
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I am so happy that I've got a rating rise of more than 900 points.

(As my surprise, Atcoder's discuss in in Codeforces.)