USACO March 2013 Contest -- Final Results

The USACO March 2013 contest featured algorithmic programming problems covering a wide range of techniques and levels of difficulty.

Click here to see the contest problems and official solutions, or to practice re-submitting solutions.

A total of 1154 participants submitted at least one solution, hailing from 78 different countries:

 474 USA  77 CHN  58 IRN  50 VNM  44 BLR  42 CAN  31 TUR
  24 GEO  20 ARM  19 RUS  16 BGR  14 MYS  13 IND  13 DEU
  12 ROU  11 GRC  10 UKR  10 TKM   9 VEN   9 THA   9 SRB
   9 MEX   9 KOR   9 KAZ   9 AUS   8 TJK   8 POL   8 JPN
   8 CUB   7 TWN   7 GBR   6 LTU   5 SYR   5 HRV   5 DOM
   5 BGD   4 YUG   4 NLD   4 FRA   4 FIN   4 COL   3 TUN
   3 SGP   3 MKD   3 LVA   3 ESP   3 BRA   3 AZE   2 ZAF
   2 SVK   2 ISR   2 IDN   2 HKG   2 EGY   2 BIH   2 BEL
   2 AUT   2 ARG   1 ZWE   1 SRM   1 SAR   1 RSA   1 PRT
   1 PER   1 MUS   1 MDA   1 KWT   1 KGZ   1 ITA   1 IMN
   1 HUN   1 GER   1 EST   1 CZE   1 CYP   1 CRO   1 BGN
   1 BDI

The average participant submitted solutions for 2.6 problems. In total, there were 3016 graded submissions, broken down by language as follows:

1852 C++
 799 Java
 261 Pascal
  56 C
  48 Python

Gold Division Results

The Gold division had 235 total participants, of whom 194 were pre-college students.

Full Gold Results

The gold contest this month proved to be quite challenging despite the inclusion of several problems (cowrun and necklace) that have appeared in very similar forms on contests some time ago. There were 10 perfect scores in the pre-college group:

Country   Grad   Name Score
RUS  2013    Artem Rakhov1000
CHN  2015    Xu Yinzhan1000
RUS  2013    Ivan Belonogov1000
BLR  2013    Sergey Kulik1000
USA  2015    Scott Wu1000
USA  2014    Steven Hao1000
ROU  2014    Andrei Heidelbacher1000
USA  2015    Videh Seksaria1000
USA  2014    Joshua Brakensiek1000
USA  2013    Kalki Seksaria1000

as well as 6 perfect scores from observers:

Country   Name Score
POLAdam Karczmarz1000
RUSNiyaz Nigmatullin1000
VNMTuanAnh TranDang1000
JPNMinoru Fujita1000
GBRRobin Lee1000
CHNYang Xiao1000

Congratulations to these and all other high-scoring participants!

Silver Division Results

The silver division had 237 total participants, of whom 208 were pre-college students.

Full Silver Results

Despite a fairly challenging contest, 6 pre-college competitors earned perfect scores (and several others would have as well if they had been slightly more careful to use 64-bit ints instead of 32-bit ints on the "poker" problem):

Country   Grad   Name Score
CHN  2014    Nasri D1000
RUS  2013    Edvard Davtyan1000
CHN  2013    Fan Wang1000
IRN  2014    Alireza Nasri1000
TUR  2015    Ikbal Kazar1000
VNM  2015    Phúc Thái1000

There were also 4 perfect scores in the observer group:

Country   Name Score
BGDNafis Sadique1000
NLDRaymond van Bommel1000
HRVMarin Tomic1000
CHNMark Fan1000

All participants with scores at least 800 will be automatically promoted to the gold division for future contests.

Bronze Division Results

(Note: Results have been updated since re-grading the "cowrace" problem due to a small bug in one test case)

A total of 691 participants competed in the bronze division, 580 of them pre-college students.

Full Bronze Results

As in the February contest, we saw quite a few high scores in the bronze division. Congratulations in particular to the following perfect scores in the pre-college group:

Country   Grad   Name Score
USA  2014    Michael Lin1000
GBR  2016    Kyle Walker1000
TUR  2016    Ersan Çolak1000
BLR  2014    Andrew Raukut1000
VNM  2015    Khanh Do Ngoc1000
TUR  2015    Abdullah Enes Oncu1000
CAN  2014    Austin Tripp1000
USA  2015    Kevin Li1000
CHN  2017    Lihuang Ding1000
TUR  2014    Kamil Toraman1000
USA  2016    Horace He1000
USA  2015    James Lennon1000
TUR  2018    Edward Newgate1000
IND  2013    Abhishek Kumar1000
TUR  2015    Enes Keles1000
TUR  2014    Kartal Savascisi1000
BGR  2018    Radostin Chonev1000
GBR  2014    Felix Chapman1000
ROU  2014    Radu Visan1000
HRV  2018    Vilim Lendvaj1000
IRN  2015    Milad R1000
TKM  2015    Bayram Berdiyev1000
EST  2015    Magnus Teekivi1000
CHN  2014    Renne Bright1000
USA  2014    John Smith1000
USA  2014    Jacob Naranjo1000
GEO  2015    Alexandre Tskhovrebovi1000
TJK  2015    Mehrubon Turaev1000
USA  2016    Vineet Kosaraju1000
BLR  2013    Dima Popov1000
TKM  2013    Nurmyrat Atamedow1000
KAZ  2013    Roman Chesnokov1000
VNM  2014    Bac Nguyen Cong1000
CHN  2014    Zecong Hu1000
USA  2014    Edgar Chen1000
GEO  2016    Lasha Bukhnikashvili1000
USA  2015    Alvin Kao1000
CHN  2014    Zijue Li1000
CUB  2015    Marcos Perez1000
USA  2015    Mike Smith1000
USA  2015    Timothy Deng1000
MEX  2016    Jordan Alexander1000
BGR  2017    Encho Mishinev1000
BLR  2014    Aliaksandr Siarhei1000
KAZ  2014    Miras Mirzakerey1000
IRN  2015    Milad Rezaei1000
USA  2014    Arnav Sastry1000

Also a round of congratulations to the observers with perfect scores:

Country   Name Score
IRNYashar Dabiran1000
ROUSebastian Claici1000
USAJon Gibson1000
CHNJiajun Liang1000
IRNRoham Heidari1000
POLJarosław Czekalski1000
YUGRadenko Pavlovic1000
USABảo Nguyễn Quang1000
CANYasushi Yamamoto1000
RUSNikolay Kuznetsov1000
USAChrs Zlg1000
USAAlex Anderson1000
CHNKevin Jiang1000
THATeerapat Jenrungrot1000
USAJun Park1000

All participants with scores at least 850 will be automatically promoted to the silver division for future contests.

Final Remarks

Distributions in the March contest all looked good. It appears the problems were neither substantially harder nor substantially easier than most other contests. In the gold contest especially, I was quite impressed by the large number of students who earned very high scores -- the upcoming US Open contest should be quite competitive this year! Even at this point late in the season, it is also still very nice to see so many promotions to higher divisions. 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, Richard Peng, Travis Hance, John He, Chris Tzamos, Neal Wu, Fatih Gelgi, Jonathan Paulson, Yan Gu, and Nathan Pinsker. 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.

We are looking forward to the US Open -- our "national championship" contest for the season! (All are welcome to participate in this contest, even students outside the USA)

Happy coding!

- Brian Dean (
Director, USA Computing Olympiad