December 2011 Contest -- Final Results
The USACO 2011 December Contest featured algorithmic programming problems covering a wide range of techniques and levels of difficulty. Click here to see the contest problems and solutions.
A total of 1102 participants competed, from 68 different countries:
438 USA 79 VNM 76 CHN 40 IRN 34 ROU 31 GEO 27 RUS 27 KAZ 26 BLR 22 MEX 16 LTU 16 AUS 15 ARM 14 IDN 14 CAN 13 BGR 11 UKR 11 TWN 11 KOR 10 ITA 10 DEU 9 YUG 8 TUR 8 SRB 8 HRV 7 TJK 7 MKD 7 FRA 7 EGY 7 BRA 6 TKM 6 GRC 6 COL 6 BGD 5 VEN 5 POL 5 LVA 5 CUB 4 PER 3 SYR 3 LKA 3 IND 3 DOM 3 CZE 2 ZAF 2 THA 2 SWE 2 SVK 2 PRT 2 AUT 2 ARG 1 SVN 1 SGP 1 NZL 1 MNG 1 MDA 1 LUX 1 JPN 1 ISL 1 GER 1 GBR 1 FIN 1 ESP 1 DNK 1 BEN 1 ARE
The average participant submitted solutions for 2.1 problems. In total, there were 2351 graded submissions, broken down by language as follows:
1375 C++ 592 Java 294 Pascal 55 C 35 Python
Gold Division Results
The Gold division had 130 total participants, of whom 80 were pre-college students.
The gold problems in this contest proved to be quite challenging, with both time and memory constraints creating difficulties for many participants. The only perfect score in the gold division this time belongs to observer Lovro Puzar from Croatia. Congratulations, Lovro, on this remarkable feat! There were no perfect scores among the pre-college participants, but many still turned in impressive scores. The top ten pre-college participants in the gold divison are:
| Country | Grad | Name | Score |
|---|---|---|---|
| VNM | 2012 | Huy Tran | 897 |
| USA | 2012 | Mitchell Lee | 846 |
| TWN | 2015 | Peter Yu | 833 |
| CHN | 2015 | Yuetong Wang | 831 |
| CHN | 2012 | Wenhan Huang | 806 |
| BLR | 2012 | Gennady Korotkevich | 769 |
| CHN | 2012 | Martin Token | 752 |
| SYR | 2013 | Kinan Sarmini | 722 |
| USA | 2013 | Johnny Ho | 701 |
| CHN | 2014 | Silly Cross | 638 |
The top ten observers are:
| Country | Name | Score |
|---|---|---|
| HRV | Lovro Puzar | 1000 |
| POL | Adam Karczmarz | 974 |
| UKR | Yaroslav Tverdokhlib | 923 |
| BGD | Nazmul Hasan | 897 |
| CZE | Filip Hlasek | 897 |
| CAN | Jacob Plachta | 703 |
| KAZ | Ali-Amir Aldan | 703 |
| VNM | VuongLinh Nguyen | 679 |
| DEU | Alexander Rass | 667 |
| DEU | Fabian Gundlach | 667 |
Silver Division Results
The silver division saw 217 total participants, of whom 175 were pre-college students.
The three silver problems in this contest required a mixture of standard algorithmic techniques plus "out of the box" thinking. Five pre-college students are to be congratulated for their perfect scores:
| Country | Grad | Name |
|---|---|---|
| USA | 2013 | Yimo Chen |
| IRN | 2013 | Daniyal Mehrjerdi |
| CHN | 2013 | Lei Xu |
| POL | 2012 | Bartek Dudek |
| RUS | 2012 | Egor Suvorov |
along with 3 observers:
| Country | Name |
|---|---|
| UKR | Ivan Mistreanu |
| RUS | Mikhail Mayorov |
| MKD | Igor Kulev |
Congratulations on achieving a perfect score on this very difficult contest! All of you are promoted to the gold division for future contests. Promotion to gold is also available if desired for any participant receiving a score of 850 or higher -- please email [email protected] if you fit into this category and wish to participate in the gold contest in January. (As a note to those who are wondering how promotion criteria are set: every contest is different, so we carefully choose criteria for promotion in each contest after reviewing the problems and results in order to make sure that those who are promoted are fully ready for the challenges of the next division).
Bronze Division Results
A total of 755 participants competed in the bronze division, 597 of them pre-college students.
Congratulations to the 14 pre-college students and 4 observers with perfect scores! The pre-college bronze winners are:
| Country | Grad | Name |
|---|---|---|
| USA | 2014 | Brian Shimanuki |
| VNM | 2013 | Tung Tran |
| GEO | 2013 | Tornike Mandzzulashvili |
| GEO | 2014 | Nika Nadiradze |
| ROU | 2017 | Pavel Ori |
| CHN | 2013 | Pu Chen |
| TWN | 2015 | Wei Chen Liao |
| AUS | 2015 | Michael Chen |
| USA | 2013 | Wenkai Lei |
| KOR | 2014 | Yechan Bae |
| VNM | 2014 | Linh To Ngoc |
| CHN | 2016 | Zhouxing Shi |
| USA | 2014 | Douglas Chen |
| RUS | 2012 | Alex Gordeev |
The bronze observers with perfect scores are:
| Country | Name |
|---|---|
| CHN | Shimi Zhang |
| USA | Nick Buelich |
| VNM | Phong Duong Thanh |
| DNK | Anders Roy Christiansen |
All participants with perfect scores will be automatically promoted to the silver division for future contests. Those with scores of 900 or greater can also be promoted, if desired; please contact [email protected] if so.
Final Remarks
This contest appears to have been slightly more challenging than the previous contest, especially at the gold level. However, I am still quite happy with the overall distributions in all three divisions.
Our contest infrastructure continues to improve, with only minor technical issues appearing in the contest. The main technical issue we encountered was a sporadic database connection error between our grader machine and our main server, mostly causing long wait times for feedback for some participants; this should be fixed by the next contest, but to make sure everything is set up properly, we need to take the grader machine off-line for the time being, meaning that "analyis mode" (where you can re-submit your solutions to old contests) will not be available quite yet. Look for this feature after the January contest.
I had a lot of excellent help setting up and running this contest. Many thanks go to Nathan Pinsker and Albert Gu for helping to set up the gold contest, Alex Chen for helping with the silver contest, and Kalki Seksaria for helping with bronze. Other members of the coaching staff who contributed time and expertise include Neal Wu, Mark Gordon, Richard Peng, Ben Cousins, Travis Hance, Chris Corsi, and Chad Waters. As always, if you would like to contribute to USACO contests as well by sending me high-quality problems, please do not hesitate to do so! Thanks are also due to our translators, who help increase the reach of our contests dramatically, and finally to our sponsors, whose support is absolutely crucial and much appreciated: IBM, Usenix, TwoSigma, and Jump Trading.
I'll see you all again in the January contest!
- Brian Dean ([email protected])
Director, USA Computing Olympiad