msg555's blog

By msg555, 5 years ago, In English,

After TLE'ing this problem in the contest I've been unable to come up with a satisfactory explanation as for why it does so. The mystery is why does my solution behave so much worse on case 65 than any of the other previous max sized cases. Since I cannot clearly see a reason why I feel it's possible this could happen again. I'm not looking for suggestions on how to make my code faster.

My solution is listed at http://codeforces.com/contest/498/submission/9250377

I've noticed other solutions that did manage to pass using essentially the same algorithm are also significantly slower on case 65 than any of the other cases. For example http://codeforces.com/contest/498/submission/9251777

Link to problem — http://codeforces.com/problemset/problem/498/B

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By msg555, 5 years ago, In English,

Did you miss the IOI? Were you competing in the IOI? Did you think it was really just so great you want to watch it again at 500 times speed? Do you wish that all the contestants were visualized as cows racing towards a barn? Do you want to be subjected to my rudimentary web skills?

Then you're in luck! I originally built this to amuse myself and other USA coaches but it seems like other people might be interested, so take it for what it is. Change the highlight field to select any contestants you are interested in (the links below highlight the winners).

IOI 2014 — http://dolphin.eecs.umich.edu/contest/ioi.html?nosound&year=2014&speed=500&highlight=USA4,AUS3,CHN3

IOI 2013 — http://dolphin.eecs.umich.edu/contest/ioi.html?nosound&year=2013&speed=500&highlight=CHN1

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By msg555, 5 years ago, In English,

In the interest of learning a bit about Codeforces' Polygon and Gym services, I have set up and made available a contest that I worked on a few years ago. The contest was created with the help of Richard Peng, Danny Sleator, Dennis Matveyev, and Krzysztof Onak.

I believe the average problem difficulty should be relatively easy for strong teams although there's at least one fairly tricky problem in the set. Good luck!

As an aside, this contest actually has a bit of a story behind it:

This was an invitational contest hosted by the University of Michigan during the 2011-2012 ICPC season. With help from the contests' sponsor, Jump Trading, we were able to invite several of the teams from around our area for a contest prior to regionals.

While I personally found the logistics of setting up such a contest a bit frustrating to manage, lucky for North America, one of the teams we invited was the University of Chicago coached by Borja Sotomayor. Running with the idea, Borja has created something much bigger and much more meaningful with the NAIPC contests (which many of us hope will become an official NA super regional) from the past three years (thank you Borja and everyone else involved!).

You can check out these past NAIPC contests at the links below

http://icpc.cs.uchicago.edu/invitational2012/

http://icpc.cs.uchicago.edu/invitational2013/

http://naipc.uchicago.edu/2014/

Anyway, enough story time. Good luck solving problems! (And see if you can spot all the Pixies references)

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By msg555, 5 years ago, In English,

Hi everyone, I saw PavelKunyavskiy post a link to a JSON file and decided to put it through a tracking script mostly written by jonathanpaulson.

Here are the results -- 2014 ICPC Contestant Tracking

The link is updated every 8 hours (although presumably not much will change between now and finals). You can view university and country (when given) aggregates in addition to individuals.

If you would like me to add any individuals please use the following format and either message me or comment and I can add them for the next update.

name,country,university,cf_handle,tc_handle

You can grab the configuration file I'm using from http://dolphin.eecs.umich.edu/contest/icpc.csv

Edit: Added IOI information and filled in missing country information (apologies if I made a mistake)

Edit: Fixed the omission of Tsinghua handles

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By msg555, 6 years ago, In English,

USACO's US Open contest is now live at http://www.usaco.org/ through April 8. As USACO's signature end of season contest, playing a significant role in finalist selection, you will have 5 hours from when you start to solve 3 or 4 problems.

Good luck and enjoy the problems!

-Mark

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