PC2021: Intermediate results, Problem 4, week 8

By 16th May 2021, there are 1053 registered participants from 71 countries (the list of countries is given below). During the first eight weeks, 43 solutions were submitted, out of which 20 had at least one correct part, a or b, see the 0-th hint.

There will be no more hints, but you’ll have time until 23:59 GMT, 15th June to submit a solution for Problem 5. I recommend doing it before 13:00 GMT, 13th June as in that case  you’ll get a feedback and will be having one more chance to correct your solution if it is not correct.

Problem 4 is now closed for submissions, the results and best solutions of Problem 4 will be published within a couple of days. The overall winners will be announced and the best solutions of Problem 5 will be published by 19th June (when the EuPhO-2021 will start).

Correct solutions for the part a of Problem 4 were submitted by:

First NameSurnameCountrySchool/Universitydatetime
HuiyuanWangChinaUniversity of Cambridge28/03/202121:28
ZheningLiCanadaSir John A. Macdonald Secondary School29/03/202104:23
LotusChenChinaNo.2 High School Shijiazhuang30/03/202115:56
AntoniaGhitaRomaniaInternational Computer High School of Bucharest01/04/202114:29
OliwierUrbańskiPolandLiceum Ogólnokształcące nr 7 w Poznaniu03/04/202111:52
JoshuaTeoSingaporeNUS High School04/04/202112:27
NikitaSemeninRussiaMoscow Institute of Physics and Technology05/04/202115:55
M. SubhiAbo RdanSyriaKnowledge private schools08/04/202108:56
Caio AugustoSiqueira da SilvaBrazilColégio Objetivo Integrado13/04/202102:16
Vlad-ȘtefanOrosRomania“Grigore Moisil” Informatics High School13/04/202116:00
QianLinChinaUniversity of Oxford01/05/202114:47
YanjunZhouUnited KingdomUniversity of Oxford02/05/202123:29
Ameya VikramaSinghIndiaFIITJEE Junior College03/05/202110:58
DanielSchillerGermanyRuprecht-Karls-Universität Heidelberg08/05/202121:44
VukHipSerbiaMathematical grammar school11/05/202108:56
Sebastián AndrésArévalo AguirreEl SalvadorInstituto Emiliani16/05/202106:38
AlexandarRoussevBulgariaFirst Language School16/05/202111:21
RicardsKnipsisLatviaUniversity of Manchester20/05/202118:04
JieWangChinaZhangjiakou No.1 Middle School25/05/202115:52

Correct solutions for the part b were submitted by:

First NameSurnameCountrySchool/Universitydatetime
ZheningLiCanadaSir John A. Macdonald Secondary School29/03/202104:23
NikitaSemeninRussiaMoscow Institute of Physics and Technology29/03/202109:07
OliwierUrbańskiPolandLiceum Ogólnokształcące nr 7 w Poznaniu29/03/202112:18
TevžLotričSloveniaUniversity of Oxford29/03/202122:28
HuiyuanWangChinaUniversity of Cambridge05/04/202100:23
Vlad-ȘtefanOrosRomania“Grigore Moisil” Informatics High School13/04/202116:00
JaroslavHermanCzechiaCharles University28/04/202122:04
YanjunZhouUnited KingdomUniversity of Oxford02/05/202123:29
QianLinChinaUniversity of Oxford08/05/202116:02
RicardsKnipsisLatviaUniversity of Manchester20/05/202118:04
Sebastián AndrésArévalo AguirreEl SalvadorInstituto Emiliani23/05/202106:33
AlexandarRoussevBulgariaFirst Language School23/05/202112:20

Participating countries: Algeria, Azerbaijan, Australia, Bangladesh, Belarus, Belgium, Bosnia and Herzegovina, Bolivia, Brazil, Bulgaria, Cambodia, Canada, China, Croatia, Czechia, Egypt, El Salvador, Estonia, Finland, Georgia, Germany, Greece, Hungary, India, Indonesia, Iran, Israel, Italy, Japan, Kazakhstan, Kenya, Korea, Kyrgyzstan, Latvia, Lebanon, Lithuania, Macedonia, Malaysia, Mexico, Moldova, Mongolia, Nepal, Nigeria, North Macedonia, Pakistan, Peru, Philippines, Poland, Romania, Russia, Saudi Arabia, Serbia, Singapore, Slovakia, Slovenia, South Africa, South Korea, Spain, Sri Lanka, Sweden, Switzerland, Syria, Taiwan, Thailand, Turkey, Turkmenistan, United Arab Emirates, United Kingdom, United States, Uzbekistan, Vietnam.

RicardsKnipsisLatviaUniversity of Manchester20/05/202118:04
Sebastián AndrésArévalo AguirreEl SalvadorInstituto Emiliani23/05/202106:33
AlexandarRoussevBulgariaFirst Language School23/05/202112:20