The second hint for Problem 4 will be published on 13th March 2022, 13:00 GMT .
By 27th February 2022, 13:00 GMT, there are 1114 participants from 80 countries. 35 solutions to P4 were submitted, out of which 32 were correct.
Correct solutions by university students:
| Erik | Sünderhauf | Germany | Technical University of Munich | 20/2/22 14:26 |
| Alessandro | Rezzi | Italy | University of Padova | 20/2/22 15:34 |
| Ziyue | Wang | China | Hebei University of Technology | 20/2/22 16:22 |
| Yuechen | Zhu | China | Peking University | 20/2/22 18:55 |
| Jaroslav | Herman | Czech Republic | Charles University | 20/2/22 18:58 |
| Kevin | You | United States | Carnegie Mellon University | 20/2/22 22:35 |
| Shofar | Sno | Suriname | Anton de Kom University of Suriname | 20/2/22 23:49 |
| Qian | Lin | China | University of Oxford | 21/2/22 00:15 |
| Zhening Li | Eddie Chen | Canada/United States | Massachusetts Institute of Technology | 21/2/22 02:24 |
| Ameya Vikrama | Singh | India | Indian Institute of Technology Bombay | 21/2/22 06:50 |
| Isaac | Wu | Australia | University of Melbourne | 23/2/22 10:13 |
| Bayram Alp | Sahin | Turkey | Bogazici University | 23/2/22 19:02 |
| Felix | Schwarzfischer | Germany | Technical University Munich | 27/2/22 10:31 |
| Marinus | Lehmann | Germany | University of Potsdam | 6/3/22 10:25 |
Correct solutions by pre-university students:
| Vlad-Ștefan | Oros | Romania | “Grigore Moisil” Theoretical High School | 20/2/22 15:38 |
| Luca | Milanese | Italy | Liceo “Leonardo da Vinci”, Terracina | 20/2/22 16:07 |
| Adam | Džavoronok | Slovakia | Gymnázium Poštová 9 | 20/2/22 16:30 |
| Chengkai | Yu | China | The High School Affiliated to Renmin University of China | 20/2/22 20:57 |
| Wang | Quanquan | China | Tianjin Yaohua High School | 21/2/22 02:11 |
| Yehyun | Choi | United States | Westlake High School | 21/2/22 02:19 |
| Emerson Franzua | Aldana Gavarrete | Honduras | School | 21/2/22 05:07 |
| Sebastián | Arévalo | El Salvador | Instituto Emiliani | 21/2/22 16:08 |
| Filip | Vučić | Croatia | I. gymnasium Zagreb | 21/2/22 17:03 |
| Yijun | Lin | China | High School Attached to Herbin Normal University | 22/2/22 14:25 |
| Jun Lin | Jinhua Zhang | China | Lvliang Fengshan Senior Middle School | 26/2/22 06:22 |
| Matej | Gelev | North Macedonia | Yahja Kemal | 26/2/22 12:57 |
| Vuk | Hip | Serbia | Mathematical Grammar School | 27/2/22 11:48 |
| Azimuddin | Sheikh | India | FIITJEE | 28/2/22 07:05 |
| Sarthak | Panda | India | FIITJEE Bhubaneswar | 28/2/22 10:47 |
| Felix | Yew | Malaysia | National Junior College, Singapore | 28/2/22 14:03 |
| Tomas | Babelis | Lithuania | Vilniaus jėzuitų gimnazija | 4/3/22 18:45 |
| Dženan | Midžić | Bosnia and Herzegovina | JU Gimnazija “Bihać” | 5/3/22 17:58 |
The list of countries:
Algeria, Argentina, Australia, Azerbaijan, Bahrain, Bangladesh, Belarus, Belgique, Bosnia and Herzegovina, Brazil, Brunei Darussalam, Bulgaria, Canada, China, Costa Rica, Croatia, Czech Republic, Cuba, Egypt, El Salvador, Estonia, Ethiopia, Finland, France, Georgia, Germany, Greece, Honduras, Hong Kong, Hungary, India, Indonesia, Iran, Israel, Italy, Japan, Kazakhstan, Korea, Kosovo, Kyrgyzstan, Latvia, Lebanon, Lithuania, Luxembourg, Macao, Malaysia, Mexico, Moldova, Mongolia, Nepal, Nigeria, North Macedonia, Pakistan, Peru, Philippines, Poland, Romania, Russia, Saudi Arabia, Serbia, Singapore, Slovakia, South Africa, Spain, Sri Lanka, Suriname, Sweden, Switzerland, Syria, Taiwan, Tajikistan, Tanzania, Thailand, Turkey, Turkmenistan, Ukraine, United Kingdom, United States, Uzbekistan, Vietnam