| 1049 | Brave Balloonists | USU Local Contest. March 2000 | 6106 | 249 |
| 1086 | Cryptography | Spring School Contest 2001 | 12860 | 106 |
| 1091 | Tmutarakan Exams | USU Local Contest. March 2001 | 2464 | 525 |
| 1104 | Don’t Ask Woman about Her Age | Tetrahedron Team Online Contest May 2001 | 5277 | 95 |
| 1118 | Nontrivial Numbers | Autumn School Contest 2001 | 4854 | 103 |
| 1133 | Fibonacci Sequence | NEERC 2001 Central Subregional | 2239 | 224 |
| 1204 | Idempotents | USU Local Contest. March 2002 | 2194 | 229 |
| 1261 | Tips | Autumn School Contest 2003 | 1553 | 329 |
| 1286 | Starship Travel | USU Personal Contest 2004 | 772 | 661 |
| 1352 | Mersenne Primes | Spring School Contest 2005 | 3968 | 131 |
| 1355 | Bald Spot Revisited | Spring School Contest 2005 | 2463 | 211 |
| 1356 | Something Easier | Spring School Contest 2005 | 1751 | 297 |
| 1430 | Crime and Punishment | Timus Top Coders: First Challenge | 1094 | 464 |
| 1456 | Jedi Riddle 2 | Timus Top Coders: Second Challenge | 666 | 747 |
| 1554 | Multiplicative Functions | Petrozavodsk Summer 2007. NSU Contest | 698 | 644 |
| 1560 | Elementary Symmetric Functions | Petrozavodsk Summer 2007. NSU Contest | 478 | 934 |
| 1698 | Square Country 5 | Petrozavodsk Winter 2009. USU Contest | 631 | 638 |
| 1748 | The Most Complex Number | Petrozavodsk Summer 2009. Ufa SATU Contest | 1430 | 266 |
| 1807 | Cartridges for Maxim | NEERC 2010 Eastern Subregional | 233 | 1487 |
| 2070 | Interesting Numbers | Ural Regional School Programming Contest 2015 | 1014 | 229 |
| 2102 | Michael and Cryptography | Ural FU Junior Championship 2016 | 1455 | 143 |
| 2117 | Polyphemus' triples | University academic school olympiad in informatics 2019 | 281 | 537 |
| 2124 | Algebra on Segment | Petrozavodsk Summer 2018. umnik_team Contest | 104 | 1352 |
| 2138 | The Good, the Bad and the Ugly | Ural School Programming Contest 2019 | 1324 | 109 |
| 2184 | Flint's Favorite Number | Ural School Programming Contest 2024 | 17 | 1523 |
