| 1049 | Brave Balloonists | USU Local Contest. March 2000 | 5420 | 238 |
| 1086 | Cryptography | Spring School Contest 2001 | 10419 | 112 |
| 1091 | Tmutarakan Exams | USU Local Contest. March 2001 | 2222 | 496 |
| 1104 | Don’t Ask Woman about Her Age | Tetrahedron Team Online Contest May 2001 | 4510 | 94 |
| 1118 | Nontrivial Numbers | Autumn School Contest 2001 | 4398 | 97 |
| 1133 | Fibonacci Sequence | NEERC 2001 Central Subregional | 2330 | 184 |
| 1204 | Idempotents | USU Local Contest. March 2002 | 1885 | 228 |
| 1261 | Tips | Autumn School Contest 2003 | 1284 | 343 |
| 1286 | Starship Travel | USU Personal Contest 2004 | 647 | 679 |
| 1352 | Mersenne Primes | Spring School Contest 2005 | 3450 | 131 |
| 1355 | Bald Spot Revisited | Spring School Contest 2005 | 2012 | 224 |
| 1356 | Something Easier | Spring School Contest 2005 | 1263 | 355 |
| 1430 | Crime and Punishment | Timus Top Coders: First Challenge | 930 | 469 |
| 1456 | Jedi Riddle 2 | Timus Top Coders: Second Challenge | 551 | 771 |
| 1554 | Multiplicative Functions | Petrozavodsk Summer 2007. NSU Contest | 592 | 625 |
| 1560 | Elementary Symmetric Functions | Petrozavodsk Summer 2007. NSU Contest | 373 | 982 |
| 1698 | Square Country 5 | Petrozavodsk Winter 2009. USU Contest | 540 | 586 |
| 1748 | The Most Complex Number | Petrozavodsk Summer 2009. Ufa SATU Contest | 1100 | 264 |
| 1807 | Cartridges for Maxim | NEERC 2010 Eastern Subregional | 194 | 1312 |
| 2070 | Interesting Numbers | Ural Regional School Programming Contest 2015 | 612 | 196 |
| 2102 | Michael and Cryptography | Ural FU Junior Championship 2016 | 788 | 116 |
