| 1086 | Cryptography | Spring School Contest 2001 | 12615 | 105 |
| 1049 | Brave Balloonists | USU Local Contest. March 2000 | 6010 | 246 |
| 1104 | Don’t Ask Woman about Her Age | Tetrahedron Team Online Contest May 2001 | 5172 | 94 |
| 1118 | Nontrivial Numbers | Autumn School Contest 2001 | 4734 | 103 |
| 1352 | Mersenne Primes | Spring School Contest 2005 | 3913 | 130 |
| 1091 | Tmutarakan Exams | USU Local Contest. March 2001 | 2423 | 520 |
| 1355 | Bald Spot Revisited | Spring School Contest 2005 | 2408 | 211 |
| 1133 | Fibonacci Sequence | NEERC 2001 Central Subregional | 2194 | 222 |
| 1204 | Idempotents | USU Local Contest. March 2002 | 2148 | 228 |
| 1356 | Something Easier | Spring School Contest 2005 | 1717 | 295 |
| 1261 | Tips | Autumn School Contest 2003 | 1507 | 331 |
| 1748 | The Most Complex Number | Petrozavodsk Summer 2009. Ufa SATU Contest | 1390 | 262 |
| 2102 | Michael and Cryptography | Ural FU Junior Championship 2016 | 1376 | 135 |
| 2138 | The Good, the Bad and the Ugly | Ural School Programming Contest 2019 | 1196 | 101 |
| 1430 | Crime and Punishment | Timus Top Coders: First Challenge | 1070 | 462 |
| 2070 | Interesting Numbers | Ural Regional School Programming Contest 2015 | 966 | 219 |
| 1286 | Starship Travel | USU Personal Contest 2004 | 755 | 659 |
| 1554 | Multiplicative Functions | Petrozavodsk Summer 2007. NSU Contest | 687 | 633 |
| 1456 | Jedi Riddle 2 | Timus Top Coders: Second Challenge | 650 | 745 |
| 1698 | Square Country 5 | Petrozavodsk Winter 2009. USU Contest | 611 | 633 |
| 1560 | Elementary Symmetric Functions | Petrozavodsk Summer 2007. NSU Contest | 464 | 931 |
| 2117 | Polyphemus' triples | University academic school olympiad in informatics 2019 | 246 | 521 |
| 1807 | Cartridges for Maxim | NEERC 2010 Eastern Subregional | 230 | 1434 |
| 2124 | Algebra on Segment | Petrozavodsk Summer 2018. umnik_team Contest | 93 | 1275 |
