yaro's blog

Codeforces Beta Round #51
By yaro, 14 years ago, translation, In English
Good morning (day, evening, night)!

Today's round problems authors are we — Rei and yaro. We've been thoroughly selecting the problemset, so hope you'll enjoy the final edition.

Thanks to problem coordinator Artem Rakhov for invaluable help in round preparation, and to those, who makes codeforces more comfortable, functional and stable.

Wish you good luck!

UPD. Analysis: A B C D E
Announcement of Codeforces Beta Round 51
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Comments Comments (22)
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14 years ago, # |
  Vote: I like it +5 Vote: I do not like it
Thanks for a contest. Problem D is pretty good =).
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14 years ago, # |
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Problem C is very interesting. I got the correct idea in almost one and half an hour, but mistakenly typed coord <= 4 instead of coord <= 5, then got challenged =)
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  • 14 years ago, # ^ |
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    Same here! But luckily I didn't lock the problem, so I could resubmit and lose only ~400 points as opposed to ~1200 ;)
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14 years ago, # |
← Rev. 2   Vote: I like it 0 Vote: I do not like it

In problem C , almost everyone wrote same 2 line solution.

Alas, I did not give it a try.(the idea could have struck me too :( )


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14 years ago, # |
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C is really interesting.
Firstly I thought it should be coord <= 2.
But it shows WA.
After thinking more , I realized that it should be coord <= 4.

As for problem D:
The time limit is quite strict for my solution.
My solution got TLE, but when I change the language to MS C++ , I got Accepted.

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14 years ago, # |
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How long will take the analysis to be posted? (just by curiosity)

By the way, excelent contest, nice problems.
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14 years ago, # |
← Rev. 2   Vote: I like it +5 Vote: I do not like it
C is really interesting.I play this game for many times to get the right idea.But I think E is somewhat similar to a problem in TopCoder..
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  • 14 years ago, # ^ |
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    You mean it has been already offered in some srm round? Hmm, would be great if you give a prooflink.
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    • 14 years ago, # ^ |
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      Actually E is somewhat similar to E in last Codeforces Round
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    • 14 years ago, # ^ |
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      I have seen this problem many times~ USACO APIO srm codeforces & ACMICPC tianjin site...
      http://ace.delos.com/TESTDATA/OPEN10.tricount.htm
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      • 14 years ago, # ^ |
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        Anyway we apologize for any similarity with another problems. We weren't sure that idea is original, but believed that statement certainly is.
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    • 14 years ago, # ^ |
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      Here it is : Div 1 1000. The idea is explained in the wiki.
      http://www.topcoder.com/wiki/display/tc/TCO'10+Online+Round+4
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  • 14 years ago, # ^ |
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    It's easier than the problem E in last Round, although I also can't pass it by mistake.
    I think this one is similar to the last problem of APIO2010.
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14 years ago, # |
← Rev. 3   Vote: I like it +5 Vote: I do not like it
You wrote Ananysis instead of Analysis
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14 years ago, # |
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It seems the best solution to problem E is to calculate the triangles that don't contain the point and has the time complexity O(n). But I wrote a program that directly calculate the triangles that contain the point with time complexity O(nlogn) which also got Accepted.
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14 years ago, # |
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Expecting English tutorial :)

UPD: I see.
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14 years ago, # |
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can you put English Analysis, because every one didn't know Russian. please!
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  • 14 years ago, # ^ |
    ← Rev. 3   Vote: I like it 0 Vote: I do not like it
    There are links to the english analyses of all the problems in the post.
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    • 14 years ago, # ^ |
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      I'm sorry, I found English analyses but links are to Russian analyses
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14 years ago, # |
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Hi all,

may I know if there is a proof for problem C? I am not sure how you can derive the answer.

Thanks!
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