| 1102 | Strange Dialog | Tetrahedron Team Online Contest May 2001 | 2910 | 167 |
| 1158 | Censored! | NEERC 2001 Northern Subregional | 965 | 505 |
| 1177 | Like Comparisons | USU Personal Contest 2002 | 388 | 1240 |
| 1297 | Palindrome | Spring School Contest 2004 | 6199 | 82 |
| 1354 | Palindrome. Again Palindrome | Spring School Contest 2005 | 3678 | 139 |
| 1423 | String Tale | Timus Top Coders: First Challenge | 2903 | 172 |
| 1517 | Freedom of Choice | Timus Top Coders: Third Challenge | 1868 | 250 |
| 1590 | Bacon’s Cipher | NEERC 2007 Eastern Subregional | 2310 | 190 |
| 1677 | Monkey at the Keyboard | Petrozavodsk Summer 2008. USU Contest | 246 | 1567 |
| 1684 | Jack's Last Word | USU Personal Contest 2009 | 1492 | 264 |
| 1713 | Key Substrings | NEERC 2009 Eastern Subregional | 601 | 619 |
| 1723 | Sandro's Book | Ural Regional School Programming Contest 2009 | 6134 | 61 |
| 1842 | Local Roots | Petrozavodsk Summer 2010. USU Contest | 38 | 6708 |
| 1937 | Davy Jones’s Organ | Ural FU Championship 2012 | 232 | 1202 |
| 1954 | Five Palindromes | Petrozavodsk Winter 2013. Kontur Cup. ChU 2013 Selection | 61 | 3877 |
| 1960 | Palindromes and Super Abilities | Petrozavodsk Winter 2013. Kontur Cup. ChU 2013 Selection | 632 | 429 |
| 2040 | Palindromes and Super Abilities 2 | Petrozavodsk Summer 2014. Ural FU Dandelion Contest | 270 | 855 |
| 2044 | 31 Palindromes | Petrozavodsk Summer 2014. Ural FU Dandelion Contest | 83 | 2574 |
| 2045 | Richness of words | Petrozavodsk Summer 2014. Ural FU Dandelion Contest | 511 | 459 |
| 2077 | Reductions | Qualification of Eastern Subregional 2015 | 17 | 7729 |
| 2118 | Cipher Message 4 | Petrozavodsk Summer 2018. umnik_team Contest | 84 | 1436 |
| 2131 | Open Cup | Later is better than never | 11 | 6211 |
| 2137 | Dynamic string complexity | Later is better than never | 10 | 6521 |
| 2168 | Runes in the Field | Ural School Programming Contest 2022 | 6 | 3008 |