US Open 2016 Contest -- Final Results

This was our final (and perhaps most challenging!) contest of the 2015-2016 season, serving as our national championship.

A total of 1545 users logged into the contest during its 4-day span. Of those, 1214 participants submitted at least one solution, hailing from 66 different countries:

  661 USA  101 CHN   39 VNM   25 BLR   18 IRN   18 BGD   17 TUR
   16 ROU   16 IND   15 POL   14 MEX   14 KAZ   13 TKM   13 BGR
   12 GEO   12 CAN   12 AUS   11 KOR   11 FRA    9 TUN    9 JPN
    9 EST    9 ARM    8 RUS    8 GRC    8 BRA    6 UKR    6 TJK
    6 THA    6 ITA    6 HKG    6 FIN    6 COL    6 ARG    5 MYS
    5 IDN    5 DEU    4 NLD    4 HUN    4 GBR    4 CUB    3 SRB
    3 SGP    3 ISR    3 AUT    2 TWN    2 HRV    2 ESP    2 AZE
    1 ZAF    1 SVN    1 SVK    1 SGS    1 PRT    1 PER    1 MKD
    1 MDA    1 MAC    1 LVA    1 LBN    1 KGZ    1 EGY    1 CZE
    1 CYP    1 BIH    1 BEL

The average participant submitted solutions for 1.9 problems. In total, there were 2333 graded submissions, broken down by language as follows:

  770 C++11
  712 Java
  658 C++
   57 Python 3.4.0
   51 Python 2.7.6
   51 Pascal
   26 C

Below are the detailed results for each of the platinum, gold, silver, and bronze contests. You will also find solutions and test data for each problem, and by clicking on any problem you can practice re-submitting solutions in "analysis mode". If you are logged in, you will also see your own specific results below alongside the contest(s) you took.

USACO 2016 US Open Contest, Platinum

The Platinum division had 401 total participants, of whom 312 were pre-college students. Our top 10 pre-college participants were:

Country   Grad   Name Score
JPN  2018    Yuta Takaya933
USA  2016    Suchir Balaji867
USA  2017    Daniel Chiu811
USA  2016    Alexander Wei756
KOR  2017    Jaehyun Koo694
IRN  2017    Mohammad Nematollahi    689
USA  2017    Bryan Chen672
CZE  2017    Václav Volhejn672
VNM  2016    Anh Duc Le667
FRA  2016    François Sellier667

The top 10 observers were:

Country   Name Score
JPNUwi Tenpen833
TWNShik Chen772
FINTuukka Korhonen733
MEXDiego Gutierrez Yepiz   667
RUSMikhail Ipatov644
USAMichael Kirsche644
HKGJohn Chan644
FINAntti Laaksonen567
FRAFélix Breton533
POLMateusz Radecki528

As you can see from the scores above, the platinum division contest was quite challenging, with no perfect scores. In particular, nobody received full marks for the "Bull in a China Shop" problem, and only 7 participants fully solved the "Landscaping" problem (Takaya, Balaji, Le, Sellier, Tenpen, Korhonen, and Yepiz). Congratulations to all of our high-scoring individuals for their strong showing on this very difficult contest, and in particular congratulations to Suchir Balaji, our national champion within the USA!

1

262144
View problem  |   Test data   |   Solution

2

Bull in a China Shop
View problem  |   Test data   |   Solution

3

Landscaping
View problem  |   Test data   |   Solution

USACO 2016 US Open Contest, Gold

The Gold division had 383 total participants, of whom 309 were pre-college students.

All competitors who scored 600 or higher on this contest are automatically promoted to the platinum division -- congratulations to you all! Detailed results for those promoted are here.

1

Splitting the Field
View problem  |   Test data   |   Solution

2

Closing the Farm
View problem  |   Test data   |   Solution

3

248
View problem  |   Test data   |   Solution

USACO 2016 US Open Contest, Silver

The Silver division had 430 total participants, of whom 368 were pre-college students.

All competitors who scored 600 or higher on this contest are automatically promoted to the gold division. Detailed results for those promoted are here.

1

Field Reduction
View problem  |   Test data   |   Solution

2

Diamond Collector
View problem  |   Test data   |   Solution

3

Closing the Farm
View problem  |   Test data   |   Solution

USACO 2016 US Open Contest, Bronze

The Bronze division had 458 total participants, of whom 341 were pre-college students.

All competitors who scored 600 or higher on this contest are automatically promoted to the silver division -- to all who were promoted, congratulations! Detailed results for those promoted are here.

1

Diamond Collector
View problem  |   Test data   |   Solution

2

Bull in a China Shop
View problem  |   Test data   |   Solution

3

Field Reduction
View problem  |   Test data   |   Solution

Final Remarks

The 2015-2016 season has now reached its end, and I think it has been a very successful season for our contests -- particularly our newly re-configured divisions (bronze through platinum), which has hopefully made it easier for new participants to get started and make progress upward via promotion. The US Open contest this time was designed to be challenging at all levels, especially in platinum, where results are a large determinant of who is selected to attend our summer training camp as a finalist. Promotion cutoffs were reasonably generous due to the difficulty of the contest. Many were promoted, who will therefore start in higher divisions at the beginning of next season. I'm happy also that the contest ran quite smoothly, with no technical issues and only a small handful of clarification requests.

For those still waiting to achieve promotion, remember that USACO contests are designed to challenge even the very best students, and it can take a good deal of hard work to excel at them. Remember that the more practice you get, the better your algorithmic coding skills will become! To help you fix any bugs in your code, you are encouraged to consult the official solutions above and to make use of "analysis mode" to re-submit improved versions of your solutions.

A large number of people contribute towards the quality and success of USACO contests. Those who helped with this contest include Mark Gordon, Richard Peng, Nick Wu, Travis Hance, Yang Liu, and Mark Chen. Thanks also to Amy Quispe for helping to maintain our social media presence (Facebook: https://www.facebook.com/UsacoContests, Twitter: (https://twitter.com/UsacoContests), our translators for allowing us to offer this contest in five additional languages, to Clemson CCIT for providing our main contest server, and to our sponsors for their generous support: Usenix, Dropbox, D.E. Shaw, and Ansatz Capital.

We will announce our selection of the 2015-2016 finalists soon. To all who participated this season, I hope you have enjoyed improving your coding and problem-solving skills through participation in the USACO, and I look forward to seeing you all again when our next season starts in the fall!

Happy coding!

- Brian Dean ([email protected])
Director, USA Computing Olympiad
Dean's Professor in the School of Computing, Clemson University

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