atcoder_official's blog

By atcoder_official, history, 5 weeks ago, In English

We will hold AtCoder Regular Contest 231.

We are looking forward to your participation!

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5 weeks ago, hide # |
 
Vote: I like it +11 Vote: I do not like it

I hope I can AC AB

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← Rev. 19  
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no……Awa,Bwaeeeeeeeeeeeeeee

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← Rev. 2  
Vote: I like it +5 Vote: I do not like it
A 'wrong?' solution for D which passed the tests

Anyone hack for this qwq

btw, D's samples gave me a wrong impression that when N=3,K=2 the first wins... Until I wrote a brute force and discovered that it's wrong. wtf...

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← Rev. 5  
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Slightly different wrong solution to D that passes tests
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    5 weeks ago, hide # ^ |
     
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    My solution was based on that, but specially dealt with the case when $$$M=1$$$ (in this case we have an obvious winning strategy). I don't know whether that is correct.

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An alternative interpretation to "D — Choose Your Role" https://atcoder.jp/contests/arc231/editorial/26560

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4 weeks ago, hide # |
 
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How would one solve B if the constraints only allowed the elements of sets to be < 1024

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4 weeks ago, hide # |
 
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In problem D, I noticed that there are only $$$N-1$$$ stones in each pile. So I wondered why it wasn't $$$N$$$. Since $$$N \times (N-1)$$$ is even, I guessed that maybe the second player should choose the number of piles depending on the number of stones the first player chose in the last turn. So this can make sure that the number of stones in total will always be even after the move of the second player. So I guessed that the second player can always win. In addition, if there are $$$N$$$ stones in each pile at first, if the first player chose to remove $$$N$$$ stones in a pile, the second player couldn't remove the same number. Those give me the idea to remove the same number as the first player, starting from biggest pile to smaller.

Sadly, I didn't think I could solve 700-points problem during the contest. So I only solved A and B, and losed a lot of ratings. ^_^

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4 weeks ago, hide # |
 
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In D, it seems removing stones from the $$$K$$$ largest piles almost works. This submission gets AC and passes hundreds of thousands of small stresstests where the 1st player moves randomly.

solution