2018 December Contest -- Final Results

The 2018 December contest featured algorithmic programming problems covering a wide range of techniques and levels of difficulty.

A total of 5290 distinct users logged into the contest during its 4-day span -- a new record for participation!. A total of 4724 participants submitted at least one solution, hailing from 72 different countries:

 2882 USA  838 CHN   86 CAN   69 MYS   68 VNM   66 GEO   60 ROU
53 BLR   48 IND   43 KOR   38 FRA   31 IRN   30 RUS   28 TWN
23 ARM   21 MNG   20 SGP   20 DEU   20 AUS   18 UKR   15 AZE
13 COL   11 GBR   11 BGR   10 TUR   10 TUN   10 KGZ   10 JPN
10 HRV    9 TKM    9 SLV    9 BRA    8 MEX    8 LTU    8 ARG
7 IDN    7 EST    6 ZAF    6 KAZ    6 EGY    5 SWE    5 POL
5 HKG    5 GRC    4 SRB    4 NLD    4 HUN    4 FIN    4 CUB
3 NZL    3 ITA    3 DOM    3 BGD    3 BEL    2 UZB    2 THA
2 SAU    2 NGA    2 MDA    2 CYP    1 TJK    1 SYR    1 SVN
1 SVK    1 PRT    1 PHL    1 PAK    1 NPL    1 ISL    1 IRL
1 BHS    1 ALB

In total, there were 15470 graded submissions, broken down by language as follows:

 5223 Java
4995 C++11
3302 C++
1595 Python 3.4.0
263 Python 2.7.6
78 C
14 Pascal


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 2018 December Contest, Platinum

The platinum division had 458 total participants, of whom 319 were pre-college students. The platinum contest this time arounde proved to be quite challenging, with only four perfect scores in the pre-college division. Congratulations to all of the top scorers for their excellent results! Results for all participants are here. Note that the coaches decided to add some extra test cases to the last problem before computing final scores, since the original test data was not as exhaustive as hoped (recall that as per our rules, the coaches can always add or remove test cases prior to final grading if needed, so you should always test your code thoroughly and not assume it will earn perfect marks just because it solves the test cases present in the contest itself).

1

Balance Beam
View problem  |   Test data   |   Solution

2

Sort It Out
View problem  |   Test data   |   Solution

3

The Cow Gathering
View problem  |   Test data   |   Solution

USACO 2018 December Contest, Gold

The gold division had 842 total participants, of whom 672 were pre-college students. All competitors who scored 750 or higher on this contest are automatically promoted to the platinum division. Detailed results for all those promoted are here.

1

Fine Dining
View problem  |   Test data   |   Solution

2

Cowpatibility
View problem  |   Test data   |   Solution

3

Teamwork
View problem  |   Test data   |   Solution

USACO 2018 December Contest, Silver

The silver division had 1967 total participants, of whom 1614 were pre-college students. All competitors who scored 750 or higher on this contest are automatically promoted to the gold division. Detailed results for all those promoted are here.

1

Convention
View problem  |   Test data   |   Solution

2

Convention II
View problem  |   Test data   |   Solution

3

Mooyo Mooyo
View problem  |   Test data   |   Solution

USACO 2018 December Contest, Bronze

The bronze division had 3784 total participants, of whom 3103 were pre-college students. All competitors who scored 750 or higher on this contest are automatically promoted to the silver division. Detailed results for all those promoted are here.

1

Mixing Milk
View problem  |   Test data   |   Solution

2

The Bucket List
View problem  |   Test data   |   Solution

3

Back and Forth
View problem  |   Test data   |   Solution

Final Remarks

Another year with record levels of participation! More than 5000 participants joined this contest, an impressive milestone for the USACO (next goal: 10,000!). At its peak level of participation, the number of simultaneous participants in this contest was twice that of the most recent IOI. Nonetheless, things went quite smoothly with the contest from a technical standpoint. Many were promoted to higher divisions (as is typical for the first contest of the season), and overall the score distributions looked very reasonable.

For those not yet promoted, remember that the more practice you get, the better your algorithmic coding skills will become -- please keep at it! 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. To help you fix any bugs in your code, you can now re-submit your solutions and get feedback from the judging server using "analysis mode".

A large number of people contribute towards the quality and success of USACO contests. Those who helped with this contest include Mark Gordon, Nathan Pinsker, Dhruv Rohatgi, Nick Wu, Travis Hance, Grace Cai, Yang Liu, Franklyn Wang, and Spencer Compton. 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: D.E. Shaw, Jump Trading, and Ansatz Capital. As we have recently lost one or two key sponsors, we are actively looking for additional sponsors who might be interested in supporting our efforts to contribute to the computing talent pipeline -- please feel welcome to send me a note if you know any good prospects I should consider contacting.

We look forward to seeing everyone again for the next contest in January.

Happy coding!

- Brian Dean (bcdean@clemson.edu)