November 2011 Contest -- Final Results

The USACO 2011 November Contest featured algorithmic programming problems covering a wide range of techniques and levels of difficulty. Click here to see the contest problems and solutions.

A total of 1450 participants competed in the contest -- a new record! We saw participants from 74 different countries:

  566 USA   99 CHN   66 VNM   42 IRN   40 BLR   39 IDN   38 GEO   37 CAN   34 ROM   
   33 KAZ   31 MEX   28 TUR   23 RUS   22 BRA   21 ITA   20 TWN   16 KOR   16 HRV
   14 ROU   14 LTU   14 DEU   14 BGR   13 MKD   13 GRC   13 EGY   12 IND   11 YUG
   11 COL   11 AUS   10 TKM    9 POL    8 FRA    7 UKR    6 VEN    6 ARM    5 TJK
    5 SRB    5 SGP    5 LVA    5 LKA    5 CUB    5 BGD    4 SVN    4 PER    3 THA
    3 NZL    3 GBR    3 EST    3 DOM    2 ZAF    2 SYR    2 PRT    2 MNG    2 LUX
    2 INA    2 HKG    2 DNK    2 AUT    2 ARG    1 TUV    1 SVK    1 NED    1 MDA
    1 MAR    1 LBN    1 JPN    1 JAM    1 ISL    1 IRL    1 GER    1 FIN    1 CZE
    1 CYP    1 ARE

The average participant submitted solutions for 2.6 problems. In total, there were 3878 graded submissions, broken down by language as follows (this was our first time ever supporting Python as a competition language):

 2264 C++
 1041 Java
  330 Pascal
  173 C
   70 Python

Gold Division Results

The Gold division had 167 total participants, of whom 98 were pre-college students.

Full Gold Results

A total of 13 pre-college students achieved perfect scores; congratulations on this superb achievement! The pre-college gold winners are:

Country   Grad   Name Country   Grad   Name
VNM  2012    Huy Tran SYR  2013    Kinan Sarmini
ROM  2013    Gavrila Vlad BLR  2012    Gennady Korotkevich
CHN  2012    Martin TokenBGR  2012    Rumen Hristov
BLR  2012    Adam BardashevichCHN  2016    Yuetong Wang
CHN  2013    LiJie ChenCHN  2012    Wenhan Huang
USA  2013    Johnny HoIRN  2013    SeyedHamed Valizadeh
CHN  2014    Nanxin Chen

Congratulations also to the 17 observers in the gold division with perfect scores:

Country   NameCountry   NameCountry   Name
LVAEduard KalinicenkoEGYHamza IbrahimCHNZechao Shang
KAZAli-Amir AldanBLRAleksey RopanVNMNguyenTS Nguyen
CHNQu PengIRNSaeed IlchiROMPaul-Dan Baltescu
DEUDaniel KirchZAFBruce MerryCHNNeal Zane
DEUThomas FerschUKRYaroslav TverdokhlibCANTyson Andre
DEUAlexander RassCHNKuan Yang

Silver Division Results

The silver division saw 200 total participants, of whom 166 were pre-college students.

Full Silver Results

The three problems in this division required clever algorithmic thinking and proved challenging for most of the competitors. Although there were many high scores, only three participants (all three of them pre-college students) turned in perfect scores:

Country   Grad   Name
USA  2014    Steven Hao
USA  2013    Calvin Deng
CHN  2013    Grace Tsai

Congratulations on achieving a perfect score on this very difficult contest! All three of you are promoted to the gold division for future contests. Promotion to gold is also available if desired for any participant receiving a perfect score on two of the three problems -- please email if you fit into this category and wish to participate in the gold contest in December.

Bronze Division Results

A total of 1083 participants competed in the bronze division, 829 of them pre-college students.

Full Bronze Results

Congratulations to the 79 pre-college students and 38 observers with perfect scores! All of you have been promoted to the silver division for future contests. The pre-college bronze winners are:

Country   Grad   NameCountry   Grad   Name
RUS  2013    Alexander MokinCHN  2014    Chen Jianing
RUS  2013    Danil MedvedevUSA  2013    Davis Wang
VNM  2013    Dat DuongLTU  2013    Vladimir Daglis
LTU  2013    Edgaras LiberisUSA  2013    Albert Chu
GEO  2016    George SkhirtladzeROU  2016    Paul Gramatovici
USA  2013    Derek LouROM  2014    Olariu Ciprian
FRA  2012    Simon MaurasUSA  2013    Sunny Nahar
CHN  2013    Xiang WuDEU  2012    Julian Labeit
TWN  2013    Jhih Bang HsiehTWN  2012    Shao-Chuan Lee
USA  2013    Jeffrey YanKAZ  2013    Eldar Aimakov
USA  2012    Scott DellaTorreVNM  2013    ThnhAn Hng
USA  2013    Cody SilvermanMEX  2014    Daniel Talamas
USA  2013    Yimo ChenVNM  2012    Bao Chiem Duy
MEX  2013    Edgar Augusto Santiago NievesAUS  2014    Ray Li
VNM  2013    Linh TaUSA  2014    Jakob Weisblat
VNM  2012    Thanh NguyenBRA  2013    Kahn Slap
BRA  2014    Igor Wolff ResplandeCHN  2013    Peter Lee
LKA  2012    Hirantha SubasingheRUS  2013    Kirill Borozdin
ROM  2012    Cristian LambruRUS  2013    Vladimir Polushin
VNM  2013    Tu├ín Anh NguyenRUS  2012    Oleg Ivanov
USA  2013    Bo MoonMKD  2015    Vasil Kuzevski
CAN  2014    Stella LauUKR  2012    Valentin Lukyanets
IRN  2013    Sobhan MiryoosefiPER  2012    Dennis Huillca
RUS  2012    Gerald AgapovUSA  2013    Allan Sadun
VNM  2012    Shin DoyleMEX  2013    Freddy Roman
USA  2014    Abhay GoelIDN  2013    Jonathan Irvin Gunawan
HRV  2014    Martin GluhakISL  2012    Bjarki Agust Gudmundsson
RUS  2012    Egor SuvorovRUS  2012    Petr Mayorov
CAN  2013    Mehwar RazaTUR  2012    Mustafa Erdogan
VNM  2013    Life KeeperKAZ  2012    Ilya Dronov
KAZ  2012    Dias AbdraimovSRB  2014    Ivan Stosic
IRN  2013    Daniyal MehrjerdiINA  2012    Setiadi Alvin
ITA  2013    Davide PallottiITA  2013    Andrea Battistello
IDN  2013    Pusaka Kaleb SetyabudiITA  2013    Matteo Almanza
AUT  2012    Markus HasenohrlTUR  2012    Safa Andac
IDN  2013    M Aji MuharromCAN  2014    Henry Wu
VNM  2013    Bao Nguyen LeUSA  2015    Andrew He
IDN  2013    Vincent TheINA  2012    Amanda Pratama
IDN  2012    Jennifer SantosoITA  2012    Gabriele Farina
ITA  2013    Daniele Del Giudice

The bronze observers with perfect scores are:

Country   Name Country   Name Country   Name
IRNHooman HashemiMDALuncasu VictorCANRobert Xiao
CHNBaoer YuVNMQViet KyVNMHoang Le
CHNShijian LiuIRNShahriar HeshmatCUBErnesto Carvajal
CHNYuwen LiIDNDavid ChristopherAUSAndrew Haigh
KORGyeongGeun KimARGFederico PousaUSACheng Pan
DNKGert HansenCANAlex VelazquezCHNGuodong Feng
CHNLei HuangROMAndrei -GBRSean Quah
CHNDerrick ChouFRAZamato LasstsPERJohann Cortez
RUSMikhail MayorovGBRRobin LeeCHNTianyu Lou
COLAlejandro AlejandroROMLaurentiu Cristian IonSGPMark Theng
DEUFlorin-Cristian GhesuCHNHan ZhuBRALeonardo Conegundes
KORMyungwoo ChunCHNW JnTWNHow Jing

Final Remarks

I'm quite happy with the overall results in each division -- the distribution of scores indicates that the problems were indeed quite challenging, but hopefully not to a point of being frustratingly difficult. If you are new to the USACO, you now have a good sense what to expect in terms of difficulty from our contests.

This contest was the first to run on our brand new web infrastructure; we are continuing to add features and improvements, so the next contest should have all the features you are used to with past USACO contests, including real-time feedback during the contest on whether your program answers the sample input correctly, the ability to view previous submissions, analysis mode after the contest ends, the ability to run your program on the grading server with your own input for timing purposes, and more. I appreciate everyone bearing with us during the migration, and I appreciate all the feedback you have given me to help improve the system for the next contest.

I am glad that cheating seemed to be at a minimum during this contest, and I hope it stays this way. I did unfortunately have to remove several participants for cheating on the contest (mostly by using multiple accounts during the contest -- don't do this!). Cheating is never really to your advantage, and it will result in your being banned from all future USACO contests. Also, please use your actual name in your account; although I respect the refined sense of humor of participants such as "Gangster Veggies" and "Fuzzy Fuzzy", I will generally remove entries from the final results until they come from accounts with legitimate names.

Thanks are due to a number of folks for their help getting this contest off the ground. The USACO coaching staff -- Neal Wu, Nathan Pinsker, Mark Gordon, Richard Peng, Albert Gu, Jacob Steinhardt, and Ben Cousins, were instrumental in helping with solutions and test data. Thanks to Rob Kolstad for helping with the website transition, and to Chad Waters for his help with the new back-end grading system. Excellent problems were contributed by Ray Li and Rob Seay (if you have good ideas for problems, please send them my way -- we are always looking for high-quality problems!). Thanks to the folks at Clemson CCIT, who have provided our new server. Finally, a huge round of thanks are due to our sponsors, whose support is absolutely crucial and much appreciated: IBM, Usenix, TwoSigma, and Jump Trading.

Thanks, and I hope to see all of you again in the December contest!

- Brian Dean (
Director, USA Computing Olympiad