USACO January 2013 Contest -- Final Results

The USACO January 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 1022 participants submitted at least one solution, hailing from 69 different countries:

 486 USA  55 CHN  30 BLR  29 IRN  27 CAN  25 MEX  18 RUS
  16 VNM  16 DEU  15 BGR  14 UKR  14 BGD  13 TUR  12 SRB
  11 GEO  10 TKM   9 VEN   9 MYS   9 LTU   9 JPN   9 HRV
   9 AUS   9 ARM   8 BRA   7 ROU   7 IDN   7 FRA   6 POL
   6 NLD   6 LVA   6 ITA   6 CUB   6 COL   5 KOR   5 KAZ
   5 IND   5 EGY   4 SGP   4 ISR   4 GRC   4 AZE   3 ZAF
   3 THA   3 SVK   3 GBR   3 EST   3 DOM   2 YUG   2 MNE
   2 AUT   2 ARG   1 TWN   1 TJK   1 SYR   1 SVN   1 RSA
   1 PER   1 MSA   1 MKD   1 MDA   1 LKA   1 KGZ   1 HUN
   1 HKG   1 ESP   1 CZE   1 CYP   1 BIH   1 BEL

The average participant submitted solutions for 2.2 problems. In total, there were 2290 graded submissions, broken down by language as follows:

1360 C++
 667 Java
 155 Pascal
  64 Python
  44 C

Gold Division Results

The Gold division had 188 total participants, of whom 140 were pre-college students.

Full Gold Results

Very impressive results this time in the gold division, including 13 perfect scores in the pre-college category:

Country   Grad   Name Score
USA  2014    Joshua Brakensiek1000
BLR  2013    Vlad Podtelkin1000
IRN  2013    Hamed Valizadeh1000
SRB  2015    Marko Stankovic1000
CHN  2013    Lei Xu1000
BLR  2013    Constantine Sokol1000
AUS  2014    Joshua Lau1000
USA  2015    Scott Wu1000
USA  2014    Stanley Cen1000
BLR  2013    Sergey Kulik1000
RUS  2013    Dmitry Gorbunov1000
ROU  2014    Andrei Heidelbacher1000
USA  2015    Videh Seksaria1000

and 9 in the observers category:

Country   Name Score
LTUKarolis Kusas1000
HUNBalazs Kezes1000
ZAFBruce Merry1000
GBRRobin Lee1000
JPNMakoto Soejima1000
CUBAlfonso Peterssen1000
POLAdam Karczmarz1000
RUSNiyaz Nigmatullin1000
UKRYaroslav Tverdokhlib1000

Congratulations to these and all other high-scoring participants!

Silver Division Results

[Note: results have changed very slightly after re-grading the "squares" problem due to a bug in two test cases.]

The silver division had 295 total participants, of whom 245 were pre-college students.

Full Silver Results

The silver problems in this contest ended up being reasonably approachable, with a number of high scores. Congratulations especially to the 16 perfect scores in the pre-college division:

Country   Grad   Name Score
RUS  2013    Kirill Borozdin1000
RUS  2014    Nikolay Kalinin1000
AUS  2014    Austin Tankiang1000
BEL  2013    Floris Kint1000
MYS  2013    Ying Hong1000
TUR  2014    Semih Basrik1000
CAN  2014    Stella Lau1000
RUS  2013    Alexander Logunov1000
RUS  2013    Ivan Belonogov1000
BLR  2013    Maxim Rusak1000
USA  2013    Davis Wang1000
MEX  2014    Diego Roque1000
ARM  2013    Albert Sahakyan1000
VNM  2014    Truong Nam Nguyen Huy1000
LVA  2015    Alexey Zayakin1000
USA  2014    Jakob Weisblat1000

and also to the 5 perfect scores in the observer category. Top observers were:

Country   Name Score
USAPeter Liu1000
CHNChun Wu1000
SVKMichal Anderle1000
ARGPablo Blanc1000
CHNSiyi Yang1000
EGYMahmoud Radwan933
USAFred Code867
MEXYomero Meroyo833
HRVTomislav Gracin833
SGPTao Guo833

All participants with scores at least 750 will be automatically promoted to the gold division for future contests.

Bronze Division Results

A total of 539 participants competed in the bronze division, 473 of them pre-college students.

Full Bronze Results

Just as with the December contest, the bronze division proved to be quite challenging. Only 2 pre-college participants and 2 observers earned perfect scores, and the overall score distribution dropped off relatively quickly from these top results (this may also be a partial side-effect though of the large number of bronze-to-silver promotions from the previous two contests). Top pre-college participants in the bronze division were:

Country   Grad   Name Score
RUS  2015    Vladimir Smykalov1000
RUS  2013    Artem Rakhov1000
JPN  2018    Yuta Takaya933
BLR  2015    Barbara Kuskova900
EGY  2013    Mostafa Hammad767
CHN  2014    Chenxi Qiu733
IRN  2015    Erfan Loghmani733
USA  2014    Arshdeep Sabharwal700
EST  2013    Janno Veeorg700
USA  2013    Steven Vorbrich700
USA  2017    David Zhu700

Top scores in the observer category were:

Country   Name Score
UKRRoman Bilyi1000
JPNMinoru Fujita1000
LTUArtūras Lapinskas967
JPNTakaya Doki967
USAZachary Wheeler933
JPNKeigo Oka933
JPNKensuke Imanishi933
CHNYang Cao900
KORJineon Back900
IRNKayvan Mazaheri767

All participants with scores at least 700 will be automatically promoted to the silver division for future contests.

Final Remarks

I am pleased to see a steady stream of promotions over the course of this season, resulting in a healthy increase in numbers for gold and silver. This contest also led to a good number of promotions, despite its relative difficulty, particularly at the bronze level. 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, Bruce Merry, Fatih Gelgi, Jonathan Paulson, and Neal Wu. 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 hope to see everyone again soon for the February contest!

Happy coding!

- Brian Dean (
Director, USA Computing Olympiad