Instructions

	Rankings

	MARCH 2007 LEVEL 1 CONTEST RESULTS These are the final results of the USACO MARCH 2007 LEVEL 1 programming contest. The next contest is the USACO U S OPEN 2007 contest to be held 26-31 April. Our goal in these contests is to cultivate interest in computer programming among pre-college students and recognize those who are outstanding performers. This contest had 55 valid competitors and 28 observers, a total of 83 legal entrants. Everyone is welcome to solve problems, but results are not reported (and participation is not counted) for those who successfully solve an elite problem (e.g., in the Bronze competition). Six more contestants were disqualified: four for unacceptable names and two for copying solutions. The 83 contestants and observers came from these 27 countries: 1 AUS 4 BRA 1 ESP 2 IND 2 MNG 17 USA 1 AUT 3 CAN 1 FRA 1 IRN 5 POL 1 ZAF 1 BGD 18 CHN 3 GEO 1 KAZ 1 POR 2 BGR 1 DEU 1 HRV 1 KGZ 1 TUR 4 BLR 1 EGY 3 IDN 5 LTU 1 UKR The grading system accepted 0.8 MB of text (mostly programs but the occasional binary), a total of 1,050 submissions. Here's a summary of how the final graded submissions looked (including observers): Program Subs C Pascal Java pfact 65 34/52% 20/31% 11/17% stat3 61 28/46% 22/36% 11/18% snarf 38 22/58% 14/37% 2/ 5% The contest ran with no flaws other than starting late. Test data and sample solutions are available at http://ace.delos.com/MAR07LEVEL1 . ### LEVEL 1 RESULTS #################################################### For this contest, the 'snarf' problem was judged to be the most difficult; we used the modified IOI scoring method this time: points weight 1 2 3 4 5 6 7 8 9 a ----------------------------------------------- pfact: 270 273.4 27 27 27 27 27 27 27 27 27 27 snarf: 400 400.0 40 40 40 40 40 40 40 40 40 40 stat3: 330 326.6 33 33 33 33 33 33 33 33 33 33 Apparently, the 'snarf' problem was just incredibly challenging. No competitor properly solved the last two test cases; I expect numerical overflows fooled several more. It is a problem I was given when I was in high school. I did not expect it to be quite so challenging. Juniors dominate the entries (but just by a bit): Distribution by grade: Grde # Percent 2007 10 (18.2%) *********** 2008 15 (27.3%) **************** 2009 11 (20.0%) *********** 2010 7 (12.7%) ***** 2011 8 (14.5%) ******* 2012 4 ( 7.3%) * Very challenging contest this time, only six scores above 800. ===== Distribution of scores ===== 951..1000 0 901.. 950 0 851.. 900 2 801.. 850 3 *** 751.. 800 1 * 701.. 750 0 651.. 700 2 ** 601.. 650 1 * 551.. 600 7 ***** 501.. 550 3 * 451.. 500 1 * 401.. 450 0 351.. 400 5 *** 301.. 350 10 ****** 251.. 300 4 201.. 250 3 * 151.. 200 1 * 101.. 150 0 51.. 100 6 **** 1.. 50 2 0.. 0 4 ** The curve is very much affected by the scoring algorithm used. USACO scores spread out from 0..1000 instead of being packed into the 900..1000 range. This can be disconcerting! Don't let it bother you -- it's just a number that is mechanically calculated to yield a large spread. Six scores above 700 -- an outright winner in USA's James Ide: 2007 USA James Ide 871 * Winner *** 2007 LTU Eduard Prochorenko 871 2012 CHN john zhang 810 2009 BRA Leonardo Conegundes 810 2007 CHN Wu Zheng Ren 810 2010 LTU Andrius Dagys 773 Congrats to all these fine competitors! ############################## GENERAL ################################### ## About the USACO Internet Programming Contests These contests (the elite GOLD division in particular) are just incredibly hard. Level 1 is a bit easier than the elite division. Winners must master not only algorithmic techniques like dynamic programming but also the ability to write bug-free code quickly. This requires practice and skill. Don't despair if you didn't get a perfect score this time -- it is hard! Furthermore, the scoring mechanism is set up so that a huge percentage of finishers scores in the 0..500 range -- different from many contests where everyone finishes in the 800..1000 range and the 0..800 range is empty. If we don't do this, we can't distinguish among the top competitors. ## Want to Learn More? Check out the USACO training pages at http://ace.delos.com/usacogate . They provide practice challenges that can help you move up in the rankings. ## How the Scoring Works The complete score results are shown below. I used a program to determine how much each problem was worth and how much each test case was worth. Basically, it counts how many people got test cases and problems wrong and uses that to estimate a difficulty and choose a weight. Each problem has a certain number of test cases along with a "weight" that tells how many of the 1,000 points come from that program. The test cases are also weighted; here is an example: points weight 1 2 3 4 5 6 ------------------------------ probname: 39 396.6 6 5 6 5 6 11 If you score full marks on cases 1, 2, 3, and 4, you'd have 6+5+6+5=22 out of 39 points for this problem and you receive: 22/39 * 396.6 = 223.7 total points out of 396.6 possible. The sum of each problem's points is your total score. ## Closing (Thanks and Solicitation) Thanks to the USACO coaches who helped bring this contest together. Special thinks to our translators. USACO accepts -- and uses -- problem submissions from anyone! You have a real leg up in the contest if we use your problem. Feel free to send programming tasks to me. We now have a staff of 20 coaches and assistant coaches who vet the problems and create prototype solutions. This enables us to have many contests throughout the year with at least some level of predictable quality. ==================================================================== ((__)) Rob Kolstad USACO Head Coach (00) kolstad@sage.org +1 719-481-6542 -nn--(o__o)--nn- http://www.usaco.org Colorado Springs, CO ==================================================================== ################################################################################################# 2007 FEBRUARY LEVEL 1 CONTEST RESULTS ################################################################################################# ========================= Test Case Weights ======================== points weight 1 2 3 4 5 6 7 8 9 a ----------------------------------------------- pfact: 270 273.4 27 27 27 27 27 27 27 27 27 27 snarf: 400 400.0 40 40 40 40 40 40 40 40 40 40 stat3: 330 326.6 33 33 33 33 33 33 33 33 33 33 Total score = sum of earned_prob_points[i]/possible_points[i]weight[i] ============================ Scoring Legend ============================ = correct t = time exceeded 0-9 = 0%-90% e = bad exit status x = wrong s = bad signal . = no entry GRAD CTR Name................ ID........ ---- pfact ---- ---- snarf ---- ---- stat3 ---- TOTAL ---------------------------------------------------------------------------------------------- 2007 USA James Ide lifestr1 *** * 270 *** xtxt 240 ** * 330 840 2007 LTU Eduard Prochorenko mrdocent1 * * 270 *** xtxx 240 ** * 330 840 2012 CHN john zhang johnzha1 * * 270 * ttttt 200 * * 330 800 2009 BRA Leonardo Conegundes leonard8 * * 270 * txttt 200 * * 330 800 2007 CHN Wu Zheng Ren wu_zhen1 * * 270 * ttttt 200 * * 330 800 2010 LTU Andrius Dagys andrius2 * t 243 * ttttx 200 * * 330 773 2011 CAN Saravannan Shaan saravan1 *** ttxs 162 ** ttttt 200 * * 330 691 2007 DEU Johann Felix von So jf.sode1 * * 270 xxx xxxxx 80 *** * 330 680 2009 BGR Stanislav Manilov spookyb1 * *** 270 tttt ttttt 40 ** * 330 640 2010 USA Daniel Ranard danrana1 x xxxxx 108 *** txttt 200 * * 330 636 2008 USA Christian Schenkelb archaic1 * * 270 * ttttt 200 xx* xxxx* 132 604 2009 ZAF Imtiaz Mangerah cool1231 *** * 270 ..... ..... 0 * * 330 600 2008 USA Frank Xiao frankxi1 * * 270 ..... ..... 0 * * 330 600 2008 CAN Devin Kwok scholar-o1 * * 270 ..... ..... 0 * * 330 600 2007 UKR Yuriy Konovalyuk stratocod2 * * 270 ..... ..... 0 * * 330 600 2008 CHN peng ziliang xpksupe1 * * 270 * xx 320 ..... ..... 0 593 2011 CHN Norman Ya normanyah1 *t *tt 189 * ttttt 200 xx* xx* 198 587 2007 IDN Dwika Putra dephe_phe1 ..... ..... 0 * ttttt 200 * * 330 527 2011 POL Alan Kutniewski alan.kutn1 * ss 216 **** tttt 240 xxxx xxxxx 33 491 2009 CHN kong weihao kongwei1 *** * 270 * ttttt 200 ..... ..... 0 473 2012 MNG Janchiv Bat-Erdene janchiv2 x ttttt 108 ..... ..... 0 *** * 330 436 2008 BRA Caio Valentim kakaio91 x xxxxx 108 ..... ..... 0 *** * 330 436 2008 POL Albert Bogdanowicz abogdan2 * * 270 ..... ..... 0 xx* xxxx* 132 404 2009 USA Ashton Grimball agrimki2 *** * 270 ..... ..... 0 xx* xxxx* 132 404 2011 POL Jakub Woyke jwoyke1 *** * 270 ..... ..... 0 xx* xxxx* 132 404 2012 MNG Munkhbayar Battogto b_munkhba1 ..... ..... 0 xxxx xxxxx 40 ** * 330 367 2010 LTU Max Belousov maxlabora1 *** xx 216 ..... ..... 0 xx xxxx* 132 349 2010 BLR Sergey Konoplich ___seryog1 ..... ..... 0 ..... ..... 0 *** * 330 327 2009 USA Emma Conner econner_k1 ..... ..... 0 ..... ..... 0 * * 330 327 2008 BLR Alexander Zelchan emerald661 ..... ..... 0 ..... ..... 0 * * 330 327 2008 USA Eric Fischer ericfis1 ..... ..... 0 ..... ..... 0 * * 330 327 2008 USA Osbert Bastani hypo34001 ..... ..... 0 ..... ..... 0 * * 330 327 2011 BLR Vlad Mickitich mikluke1 ..... ..... 0 ..... ..... 0 * * 330 327 2008 USA Mike Mu moo.mike.1 ..... ..... 0 ..... ..... 0 * * 330 327 2010 USA Darren Jindal quantus2 ..... ..... 0 ..... ..... 0 * * 330 327 2008 POL Wojciech Langiewicz wojtek2 * *** 270 ..... ..... 0 xxxx xxxxx 33 306 2009 CHN brad bu buyuan23 *x xxxtt 108 ***t ttttt 160 xxxx xxxxx 33 302 2008 IRN azadeh moosavi naneh_n2 *** * 270 ..... ..... 0 ..... ..... 0 273 2011 GEO zura tsilosani z-z1 * * 270 ..... ..... 0 ..... ..... 0 273 2007 AUS Dimaz Putra dimazp1 x xxxx 135 ..... ..... 0 xx xxxx* 132 267 2010 USA Aryan Khojandi worlddomi1 x * 243 ..... ..... 0 ..... ..... 0 246 2009 CHN Daniel Cao cnj19911 * tt 216 ..... ..... 0 ..... ..... 0 219 2011 USA Favyen Bastani faba5592 ** tt 216 ..... ..... 0 ..... ..... 0 219 2011 CHN Tong Shi stone191 xx xtttt 81 xxxx xxxxx 40 xxxx xxxxx 33 155 2007 LTU Michail Zarechenski rostov931 ..... ..... 0 ..... ..... 0 *xx xxxx* 132 131 2007 USA Juan Bustos juan_bu1 xx* xxxtt 81 ..... ..... 0 xxxx xxxxx 33 115 2012 GEO vaja asatiani beboiko1 *x xtttt 108 ..... ..... 0 ..... ..... 0 109 2008 CHN chenxing liu congmin1 **x xxxxx 108 ..... ..... 0 ..... ..... 0 109 2007 FRA desclaux christophe descl31 **t ttxtt 108 ..... ..... 0 ..... ..... 0 109 2008 USA Chris Wagner ghettom1 **x xxxtt 108 ..... ..... 0 ..... ..... 0 109 2009 GEO Vano Gurgenishvili gurgen3 **x xxxtt 108 ..... ..... 0 ..... ..... 0 109 2010 HRV Izabela Gucunsk bella101 ..... ..... 0 xxxx xxxxx 40 xxxx xxxxx 33 73 2009 USA Hannah Flynn hflynn_1 ..... ..... 0 xxxx xxxxx 40 ..... ..... 0 40 2008 USA Eric Woo airwoo1 ..... ..... 0 ..... ..... 0 xxxx xxxxx 33 33 2009 IDN Helen Angmalisang kuroika1 ..... ..... 0 ..... ..... 0 xxxx xxxxx 33 33 9999 CHN xiaobo zhou 46161171 ** * 270 * tt 320 ** *** 330 920 1999 CHN song symbol sxb1 x * 243 * tt 320 ** * 330 893 2005 CHN xianghong luo lxhimo1 * * 270 * xxx 280 *** * 330 880 2006 ESP Ximo Planells x_ximo1 * * 270 *** xttt 240 ** * 330 840 9999 CHN Du Peng meiilov1 * * 270 xx xxx 200 ** * 330 800 2005 IND Siddharth S mitsidd1 * * 270 * ttttt 200 * * 330 800 2002 CHN Jianshu Sun bigtree1 * * 270 * *** 400 xxxx xxxxx 33 706 2003 BLR Sergey Tatyanenko statyanen1 ** * 270 xxx xtttt 80 *** * 330 680 2002 IND barath krishnan k_barat1 x xxxxx 108 *** tttxx 200 * * 330 636 2005 TUR Deniz Yörükoðlu efoja871 * * 270 ..... ..... 0 * * 330 600 9999 CHN li xiaoyong my-lxy1 *** eeee 162 xxxx xtttx 40 *** * 330 531 9999 BRA Henrique Rennó henriqu4 * * 270 *** ttttt 200 xxxx xxxxx 33 506 2006 BGR Desislava Hristova desi.hris1 **** ssss 162 ..... ..... 0 ** * 330 491 2006 IDN Winardi Kurniawan winardi3 x xxxxx 108 ***** xtxx 240 xx xxxx* 132 480 2004 CHN CAI allen allen_c1 *** * 270 * ttttt 200 ..... ..... 0 473 2005 BGD Wasima Haque mouri_w1 * * 270 * ttttx 200 ..... ..... 0 473 2005 EGY shady youssef bronko61 x xxxxt 108 ..... ..... 0 *** *** 330 436 2005 BRA Alfredo Sandes alfredo2 x tt 189 ** tttxx 200 ..... ..... 0 391 2006 AUT Martin Jörg martin_1 ..... ..... 0 ..... ..... 0 * * 330 327 9999 CHN Chen Chen aflyhor2 * *** 270 xtxt ttttt 40 ..... ..... 0 313 2006 POR João Carreira jokarre1 ** *** 270 xxxx xxxxx 40 ..... ..... 0 313 2006 CHN Kai Chen remlost1 ** *** 270 ..... ..... 0 xxxx xxxxx 33 306 9999 KGZ Alisher Abdulhayev ali_abd4 ** * 270 ..... ..... 0 ..... ..... 0 273 9999 CAN Gerry Donaldson gdonald1 *** xx 216 ..... ..... 0 ..... ..... 0 219 1997 USA Richard Lee rlee121 **t ttt* 162 ..... ..... 0 ..... ..... 0 164 2004 LTU Vytautas Astrauskas vastrau1 t** tttt 135 ..... ..... 0 ..... ..... 0 137 1988 POL Lucas Sliwa 3crhash1 ..... ..... 0 ..... ..... 0 xxxx xxxxx 33 33 9999 KAZ Erkanat Ramazanov erkanat1 ..... ..... 0 ..... ..... 0 xxxx xxxxx 33 33 ====== Distributions ===== Distribution by grade: Grde # Percent 2007 10 (18.2%) ********** 2008 15 (27.3%) **************** 2009 11 (20.0%) *********** 2010 7 (12.7%) ***** 2011 8 (14.5%) ******* 2012 4 ( 7.3%) *** Distribution by country: Cntry # Percent AUS 1 ( 1.8%) * BGR 1 ( 1.8%) * BLR 3 ( 5.5%) ** BRA 2 ( 3.6%) CAN 2 ( 3.6%) CHN 9 (16.4%) ********** DEU 1 ( 1.8%) * FRA 1 ( 1.8%) * GEO 3 ( 5.5%) **** HRV 1 ( 1.8%) * IDN 2 ( 3.6%) ** IRN 1 ( 1.8%) * LTU 4 ( 7.3%) *** MNG 2 ( 3.6%) POL 4 ( 7.3%) ***** UKR 1 ( 1.8%) * USA 16 (29.1%) ********************** ZAF 1 ( 1.8%) * ===== Distribution of scores ===== 951..1000 0 901.. 950 0 851.. 900 0 801.. 850 2 751.. 800 4 701.. 750 0 651.. 700 2 601.. 650 3 * 551.. 600 6 **** 501.. 550 1 * 451.. 500 2 401.. 450 5 *** 351.. 400 1 * 301.. 350 11 ********* 251.. 300 3 * 201.. 250 3 *** 151.. 200 1 * 101.. 150 7 ******* 51.. 100 1 * 1.. 50 3 *** 0.. 0 0 Prob * x t e s pfact.1 0 0 0 0 0 pfact.2 59 5 1 0 0 pfact.3 65 0 0 0 0 pfact.4 49 14 2 0 0 pfact.5 64 0 1 0 0 pfact.6 49 13 3 0 0 pfact.7 45 12 6 1 1 pfact.8 44 12 7 1 1 pfact.9 40 8 14 1 2 pfact.10 39 8 14 1 3 Total correct: 454 (82.55%) Prob * x t e s snarf.1 0 0 0 0 0 snarf.2 30 7 1 0 0 snarf.3 27 9 2 0 0 snarf.4 28 9 1 0 0 snarf.5 26 9 3 0 0 snarf.6 11 8 19 0 0 snarf.7 5 13 20 0 0 snarf.8 5 7 26 0 0 snarf.9 1 14 23 0 0 snarf.10 1 16 21 0 0 Total correct: 134 (24.36%) Prob * x t e s stat3.1 0 0 0 0 0 stat3.2 48 13 0 0 0 stat3.3 39 22 0 0 0 stat3.4 39 22 0 0 0 stat3.5 48 13 0 0 0 stat3.6 39 22 0 0 0 stat3.7 39 22 0 0 0 stat3.8 40 21 0 0 0 stat3.9 40 21 0 0 0 stat3.10 48 13 0 0 0 Total correct: 380 (69.09%)