| 1104 | Don’t Ask Woman about Her Age | Tetrahedron Team Online Contest May 2001 | 4867 | 93 |
| 2138 | The Good, the Bad and the Ugly | Ural School Programming Contest 2019 | 631 | 99 |
| 1118 | Nontrivial Numbers | Autumn School Contest 2001 | 4457 | 102 |
| 1086 | Cryptography | Spring School Contest 2001 | 11470 | 108 |
| 2102 | Michael and Cryptography | Ural FU Junior Championship 2016 | 1066 | 124 |
| 1352 | Mersenne Primes | Spring School Contest 2005 | 3695 | 129 |
| 2070 | Interesting Numbers | Ural Regional School Programming Contest 2015 | 800 | 200 |
| 1355 | Bald Spot Revisited | Spring School Contest 2005 | 2208 | 215 |
| 1133 | Fibonacci Sequence | NEERC 2001 Central Subregional | 2076 | 218 |
| 1204 | Idempotents | USU Local Contest. March 2002 | 2024 | 225 |
| 1049 | Brave Balloonists | USU Local Contest. March 2000 | 5727 | 239 |
| 1748 | The Most Complex Number | Petrozavodsk Summer 2009. Ufa SATU Contest | 1263 | 255 |
| 1261 | Tips | Autumn School Contest 2003 | 1386 | 336 |
| 1356 | Something Easier | Spring School Contest 2005 | 1365 | 347 |
| 1430 | Crime and Punishment | Timus Top Coders: First Challenge | 1000 | 461 |
| 2117 | Polyphemus' triples | University academic school olympiad in informatics 2019 | 150 | 476 |
| 1091 | Tmutarakan Exams | USU Local Contest. March 2001 | 2287 | 512 |
| 1698 | Square Country 5 | Petrozavodsk Winter 2009. USU Contest | 575 | 604 |
| 1554 | Multiplicative Functions | Petrozavodsk Summer 2007. NSU Contest | 629 | 633 |
| 1286 | Starship Travel | USU Personal Contest 2004 | 682 | 681 |
| 1456 | Jedi Riddle 2 | Timus Top Coders: Second Challenge | 597 | 755 |
| 1560 | Elementary Symmetric Functions | Petrozavodsk Summer 2007. NSU Contest | 403 | 979 |
| 2124 | Algebra on Segment | Petrozavodsk Summer 2018. t.me/umnik_team Contest | 49 | 1253 |
| 1807 | Cartridges for Maxim | NEERC 2010 Eastern Subregional | 215 | 1337 |
