US Open 2012 -- Final Results
The USACO 2012 US Open Contest featured algorithmic programming problems covering a wide range of techniques and levels of difficulty. As the "national championship" contest for the USACO, the US Open is one of the key factors used to determine the set of finalists to be invited to the USACO summer training camp.
Click here to see the contest problems and solutions.
A total of 632 participants competed, from 63 different countries:
294 USA 66 CHN 24 VNM 21 GEO 19 IRN 16 CAN 13 ARM 12 TUR 11 BLR 10 UKR 9 KAZ 9 BGR 9 BEL 7 RUS 6 VEN 6 HKG 6 FRA 5 TKM 4 IDN 4 GRC 4 CUB 4 AUS 3 TJK 3 SRB 3 MKD 3 MEX 3 DEU 3 BGD 2 ZAF 2 TWN 2 SYR 2 SWE 2 ROU 2 POL 2 ITA 2 IND 2 CZE 2 BRA 2 AUT 2 ARG 1 THA 1 SVK 1 SHN 1 SGP 1 PRT 1 PER 1 LVA 1 LTU 1 KOR 1 JAP 1 ISR 1 IRL 1 IRI 1 IMN 1 GRL 1 GBR 1 EST 1 DOM 1 COL 1 CHL 1 BRN 1 AZE 1 AFG
The average participant submitted solutions for 2.5 problems. In total, there were 1617 graded submissions, broken down by language as follows:
909 C++
499 Java
116 Pascal
64 Python
29 C
Gold Division Results
The Gold division had 127 total participants, of whom 96 were pre-college students.
This was one of our most challenging contests to date, with three difficult problems to solve in five hours. Congratulations to our top 10 student participants listed below for their fantastic results, especially to our three perfect scores: Scott Wu from the USA, Mingda Qiao from China, and Gennady Korotkevich from Belarus!
| Country | Grad | Name | Score |
|---|---|---|---|
| USA | 2015 | Scott Wu | 1000 |
| CHN | 2014 | Mingda Qiao | 1000 |
| BLR | 2012 | Gennady Korotkevich | 1000 |
| USA | 2014 | Steven Hao | 857 |
| USA | 2013 | Johnny Ho | 824 |
| CHN | 2013 | Ruosong Wang | 802 |
| CHN | 2013 | QiLin Dong | 788 |
| UKR | 2012 | Vitaliy Herasymiv | 784 |
| BLR | 2013 | Sergey Kulik | 772 |
| CZE | 2013 | Stepan Simsa | 762 |
The top 10 results in the observer category included two perfect scores as well:
| Country | Name | Score |
|---|---|---|
| DEU | Fabian Gundlach | 1000 |
| ZAF | Bruce Merry | 1000 |
| RUS | Egor Kulikov | 968 |
| UKR | Yaroslav Tverdokhlib | 879 |
| VNM | Dat NguyenThanh | 794 |
| THA | Visit Pataranutaporn | 762 |
| VNM | Thinh FanVan | 727 |
| CAN | Jacob Plachta | 664 |
| CHN | Zechao Shang | 664 |
| USA | John Nevard | 625 |
Silver Division Results
The silver division had 122 total participants, of whom 105 were pre-college students.
Like the gold division, the silver division also proved to be quite challenging, with only 2 perfect scores in the pre-college group. The top 10 pre-college participants are listed below -- congratulations to all for their excellent results!| Country | Grad | Name | Score |
|---|---|---|---|
| SRB | 2014 | Ivan Stosic | 1000 |
| USA | 2015 | Andrew He | 1000 |
| CHN | 2014 | Kefan Lv | 939 |
| CHN | 2013 | Zhizhi Chen | 848 |
| USA | 2013 | Cheng Zhang | 806 |
| USA | 2014 | Brian Shimanuki | 800 |
| USA | 2013 | Sunny Nahar | 782 |
| USA | 2014 | Qingqi Zeng | 762 |
| VNM | 2012 | Yên Thanh Lê | 762 |
| CHN | 2013 | Jiayu sun | 758 |
One perfect score also appears in the top 10 list of observers:
| Country | Name | Score |
|---|---|---|
| CUB | Ramon Alejandro Reyes Fajardo | 1000 |
| HKG | KN Hung | 782 |
| CUB | Leandro Castillo | 673 |
| VNM | Trung Dinh | 578 |
| HKG | Hackson Leung | 578 |
| CHN | Jacob Jiang | 578 |
| CHN | Jiang Jying | 467 |
| MKD | Vasja Pavlov | 412 |
| GBR | Robin Lee | 378 |
| ZAF | Ashraf Moolla | 364 |
All participants with scores at least 667 will be automatically promoted to the gold division for future contests (starting next season).
Bronze Division Results
[Note: the scores on the 3lines problem have changed slightly due to 4 buggy test cases that have now been corrected.]
A total of 383 participants competed in the bronze division, 328 of them pre-college students.
Congratulations to the 2 pre-college students with perfect scores: Alejandra Alfonso from Chile and Johan Sannemo from Sweden! The top 10 pre-college bronze participants are:
| Country | Grad | Name | Score |
|---|---|---|---|
| CHL | 2013 | Alejandra Alfonso | 1000 |
| SWE | 2014 | Johan Sannemo | 1000 |
| AUS | 2012 | Yujin Wu | 977 |
| CHN | 2014 | Minyang Jiang | 966 |
| CHN | 2014 | Xinyan Hong | 942 |
| USA | 2015 | Hariank Muthakana | 932 |
| USA | 2014 | Andrew Bent | 932 |
| USA | 2015 | Matthew Savage | 919 |
| SRB | 2013 | Bojan Rosko | 917 |
| VNM | 2014 | Hung Cao Xuan | 886 |
| LVA | 2013 | Ojārs Vilmārs Ratnieks | 886 |
The top 10 bronze observers are:
| Country | Name | Score |
|---|---|---|
| CHN | Wei ZiQing | 988 |
| VNM | Minh-Hoàng Lê | 977 |
| KAZ | Nurlan Zhusupov | 886 |
| CHN | Chao Fang | 864 |
| CHN | Carl Pan | 864 |
| CHN | Tiny Lic | 781 |
| CAN | Paul Liu | 746 |
| IRN | Armin Vakily | 733 |
| USA | Zoli K | 686 |
| CHN | Tong Pei | 682 |
All participants with scores at least 667 will be automatically promoted to the silver division for future contests (starting next season).
Final Remarks
This contest brings to a close what I think has been a very successful season of USACO contests. The US Open was definitely one of the more challenging contests we have ever offered, but students certainly managed to rise to the occasion and come up with strong results. I am glad that there were a few (but not too many) perfect scores in each division -- exactly the sort of distribution we were hoping to see. Technically, everything went smoothly during the contest. Our new infrastructure has matured to the point where it is now mostly stable, and ready to finally see enhancements (evaluation mode, more problem types like interactive and output-only problems, batching of test cases, etc.). Now that the season is finally winding down, we will have plenty of time to tackle these enhancements, as well as moving the training pages to the new site.
This contest would not have been possible -- and it certainly would not have been nearly as high-quality -- if not for the help of a number of remarkable individuals on our coaching staff. Thanks especially to Neal Wu, Mark Gordon, Fatih Gelgi, Travis Hance, Bruce Merry, Richard Peng, and Eric Price for helping with problems, solutions, and test data. These folks did a fantastic and thorough job; for example, they developed more than a dozen solutions to the "balanced subsets" gold problem to make sure they had strong test data. 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 also to Chad Waters and the Clemson CCIT staff for their help with our contest infrastructure, 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.
The decision on which finalists are to be invited to the USACO summer training camp will be announced very soon.
Happy coding!
- Brian Dean ([email protected])
Director, USA Computing Olympiad