USACO US Open 2013 Contest -- Final Results
The USACO US Open 2013 contest, our national champtionship, featured three divisions worth of challenging algorithmic programming problems.
Click here to see the contest problems and official solutions, or to practice re-submitting solutions.
A total of 779 participants submitted at least one solution, hailing from 65 different countries:
362 USA 45 CHN 41 IRN 33 VNM 28 CAN 26 BLR 15 TUR 15 IDN 14 RUS 13 GEO 12 VEN 11 JPN 10 BEL 7 MYS 7 BGR 7 BGD 7 ARM 6 UKR 6 THA 6 NLD 6 AUS 5 TJK 5 ROU 5 KAZ 5 FIN 4 TKM 4 IND 4 FRA 4 DEU 4 BRA 3 ZAF 3 POL 3 MEX 3 LVA 3 LTU 3 GRC 3 GBR 3 CUB 2 TWN 2 SYR 2 SVK 2 SIN 2 MKD 2 KOR 2 DOM 2 CZE 2 AZE 1 YUG 1 SRB 1 SGP 1 SAU 1 RSA 1 MDA 1 ISR 1 ISL 1 IMN 1 HUN 1 HRV 1 GER 1 ESP 1 CYP 1 COL 1 BIH 1 AUT 1 ARG
The average participant submitted solutions for 2.6 problems. In total, there were 2004 graded submissions, broken down by language as follows:
1215 C++ 570 Java 115 Pascal 64 Python 38 C
Gold Division Results
The Gold division had 183 total participants, of whom 159 were pre-college students.
The gold division contained three very difficult problems -- quite a bit more challenging than the average USACO contest! There was no easy problem, and as a result, the overall score distribution was quite unforgiving. Nonetheless, four participants earned perfect scores: three pre-college students (Daniyal Mehrjerdi, Ray Li, and Nikolay Kalinin) and one observer (Yaroslav Tverdokhlib). Congratulations to these individuals and all others who turned in impressive scores on this extremely challenging contest! The top pre-college participants were:
| Country | Grad | Name | Score |
|---|---|---|---|
| AUS | 2014 | Ray Li | 1000 |
| RUS | 2014 | Nikolay Kalinin | 1000 |
| IRN | 2013 | Daniyal Mehrjerdi | 1000 |
| USA | 2015 | Scott Wu | 967 |
| RUS | 2013 | Dmitry Gorbunov | 900 |
| USA | 2013 | Johnny Ho | 900 |
| CHN | 2014 | Honghua Dong | 867 |
| USA | 2015 | Andrew He | 833 |
| JPN | 2014 | Kohji Liu | 833 |
| ARM | 2013 | Albert Sahakyan | 767 |
| USA | 2013 | Ray Li | 767 |
and the top observers were:
| Country | Name | Score |
|---|---|---|
| UKR | Yaroslav Tverdokhlib | 1000 |
| RUS | Egor Kulikov | 933 |
| CAN | Jacob Plachta | 767 |
| RUS | Artem Rakhov | 733 |
| GBR | Robin Lee | 700 |
| DEU | Maximilian J | 633 |
| POL | Adam Karczmarz | 567 |
| FIN | Antti Laaksonen | 567 |
| VNM | Khanh NguyenXuan | 500 |
| VNM | Minh-Hoang Le | 500 |
Silver Division Results
The silver division had 210 total participants, of whom 184 were pre-college students.
(Note: we've recently re-graded the 'fuel' problem after fixing a small issue with the test data).
Like the gold contest, the silver contest was also quite challenging, with no single problem being particularly easy. Only four participants earned perfect scores: Stefano Chiesa in the pre-college category and Nick Buelich, Alex Anderson, and Topi Talvitie in the observer category. Congratulations to these individuals as well as all our other top scorers. In the pre-college group, top scorers were:
| Country | Grad | Name | Score |
|---|---|---|---|
| IDN | 2014 | Stefano Chiesa | 1000 |
| USA | 2015 | James Bloxham | 967 |
| BEL | 2013 | Victor Lecomte | 967 |
| IDN | 2013 | Rakina Zata Amni | 967 |
| USA | 2014 | Dan Fu | 967 |
| JPN | 2017 | Kotomi Tachibana | 967 |
| IRN | 2014 | Mohammad Amin Khashkhashi Moghaddam | 900 |
| CHN | 2016 | Zhao Shengyu | 900 |
| TUR | 2014 | Kartal Savascisi | 900 |
| TUR | 2014 | Metehan Kaya | 900 |
The top observers were:
| Country | Name | Score |
|---|---|---|
| USA | Alex Anderson | 1000 |
| USA | Nick Buelich | 1000 |
| FIN | Topi Talvitie | 1000 |
| RUS | Nikolay Kuznetsov | 967 |
| CHN | Peichen Xie | 700 |
| COL | Chrs Zlg | 667 |
| DEU | Fabian Henneke | 667 |
| SYR | Ijo Ivram | 667 |
| JPN | Fiend Friend | 633 |
| CHN | Jinglun Li | 633 |
All participants with scores at least 700 will be automatically promoted to the gold division for future contests.
Bronze Division Results
A total of 390 participants competed in the bronze division, 327 of them pre-college students.
The bronze contest contained 4 problems of varying levels of difficulty. The most difficult problem, haywire, required very clever insight in order to design a solution fast enough to solve all test cases! Top scorers in the bronze division were the following:
| Country | Grad | Name | Score |
|---|---|---|---|
| UKR | 2015 | Yury Monastyrshyn | 1000 |
| RUS | 2014 | Nikita Uvarov | 1000 |
| JPN | 2017 | Kazumi Kasaura | 1000 |
| CHN | 2013 | Yanpei Liu | 1000 |
| RUS | 2013 | Ivan Fefer | 1000 |
| VNM | 2013 | Hieu Lang | 1000 |
| FIN | 2015 | Sami Kalliomäki | 979 |
| IDN | 2013 | Joshua Aristo | 938 |
| IDN | 2013 | Ammar Fathin Sabili | 917 |
| BEL | 2013 | Nathan Meynaert | 917 |
Also a round of congratulations to the observers with top scores:
| Country | Name | Score |
|---|---|---|
| RUS | Danil Osherov | 1000 |
| JPN | Ryoga Tanaka | 1000 |
| NLD | Jan Elffers | 1000 |
| USA | Daidai Lanlan | 1000 |
| USA | Cal Che | 979 |
| USA | Bob Suffern | 917 |
| CHN | Xia Jiazhen | 917 |
| BRA | Gustavo Segovia | 900 |
| USA | Jonathan Paulson | 875 |
| BLR | Vlad Sobol | 863 |
All participants with scores at least 750 will be automatically promoted to the silver division for future contests.
Final Remarks
This is the final contest of the 2012-2013 USACO season, and perhaps the most challenging as well. I believe it's been a very successful season overall, with contest problems that have been unique, fun, intellectually stimulating, and of the highest quality, thanks mostly to our top-notch coaching staff. I am always impressed at the large number of young participants in our contests who can solve problems that would often be a challenge even to graduate-level university computer science students. To all who have competed this season, you should be proud of your achievements and the commitment you have invested to improve your programming and problem-solving skills.
As I mentioend earler, the US Open is designed to be -- even more than a typical USACO contest -- supremely challenging, even to the very best participants. Do not feel discouraged if your score is not as high as you had hoped! Becoming a world-class algorithmic problem-solver requires patience and practice, and you will certainly improve your skills the longer you keep at it. An excellent way to get more practice is to make use of analysis mode to submit solutions to problems from the past two seasons.
A large number of people contribute towards the quality and success of USACO contests. Those who helped with this contest include Mark Gordon, John Pardon, Richard Peng, Travis Hance, Fatih Gelgi, Jonathan Paulson, Nathan Pinsker, and Josh Alman. Thanks also to our translators and to Clemson CCIT for providing our contest infrastructure. Finally, we are grateful to the USACO sponsors for their generous support: IBM, Usenix, TwoSigma, and Jump Trading.
Based on the results of this season, we will shortly be announcing the list of finalists who will be invited to attend the USACO 2013 summer training camp.
I hope everyone enjoyed the US Open and the entire 2012-2013 season, and I hope to see you back next fall!
- Brian Dean ([email protected])
Director, USA Computing Olympiad