| Problem Name | Online Judge | Contest | Difficulty Level | |
|---|---|---|---|---|
| 1 | Password | Codeforces | Codeforces Beta Round #93 (Div. 1 Only) & Codeforces Beta Round #93 (Div. 2 Only) | 2 |
| 2 | Watto and Mechanism | Codeforces | Codeforces Round #291 (Div. 2) | 3 |
| 3 | Tavas and Malekas | Codeforces | Codeforces Round #299 (Div. 2) & Codeforces Round #299 (Div. 1) | 4 |
| 4 | Prefixes and Suffixes | Codeforces | Codeforces Round #246 (Div. 2) | 4 |
| 5 | MUH and Cube Walls | Codeforces | Codeforces Round #269 (Div. 2) | 4 |
| 6 | Spy Syndrome 2 | Codeforces | Manthan, Codefest 16 | 5 |
| 7 | Om Nom and Necklace | Codeforces | ZeptoLab Code Rush 2015 | 6 |
| 8 | Match & Catch | Codeforces | Codeforces Round #244 (Div. 2) | 6 |
| 9 | Martian Strings | Codeforces | Codeforces Round #106 (Div. 2) | 6 |
| 10 | Messenger | Codeforces | Codeforces Round #344 (Div. 2) | 6 |
| 11 | String | Codeforces | Codeforces Beta Round #94 (Div. 1 Only) & Codeforces Beta Round #94 (Div. 2 Only) | 6 |
| 12 | Cyclical Quest | Codeforces | Codeforces Round #146 (Div. 1) & Codeforces Round #146 (Div. 2) | 7 |
| 13 | Valera and Swaps | Codeforces | Codeforces Round #252 (Div. 2) | 7 |
| 14 | Encoding | Codeforces | VK Cup 2015 - Round 2 (unofficial online mirror, Div. 1 only) | 7 |
| 15 | Votka and String | SPOJ | 7 | |
| 16 | Ann and Half-Palindrome | Codeforces | Codeforces Round #311 (Div. 2) | 7 |
| 17 | Mike and Friends | Codeforces | Codeforces Round #305 (Div. 1) | 8 |
| 18 | Three strings | Codeforces | MemSQL Start[c]UP 2.0 - Round 1 | 8 |
| 19 | Deletion of Repeats | Codeforces | Codeforces Beta Round #19 | 8 |
| 20 | Paper task | Codeforces | IndiaHacks 2016 - Online Edition (Div. 1 + Div. 2) | 8 |
| 21 | Little Elephant and Strings | Codeforces | Codeforces Round #129 (Div. 1) | 8 |
| 22 | String | Codeforces | Codeforces Beta Round #92 (Div. 1 Only) | 8 |
| 23 | Good Substrings | Codeforces | ABBYY Cup 3.0 | 8 |
| 24 | Genetic engineering | Codeforces | Yandex.Algorithm 2011 Round 2 | 8 |
| 25 | Fence | Codeforces | Codeforces Round #144 (Div. 1) | 9 |
| 26 | Forensic Examination | Codeforces | Codeforces Round #349 (Div. 1) | 9 |
| 27 | Cool Slogans | Codeforces | Codeforces Round #364 (Div. 1) | 9 |
| 28 | And Yet Another Bracket Sequence | Codeforces | VK Cup 2015 - Round 1 | 9 |
| 29 | Xenia and String Problem | Codeforces | Codeforces Round #207 (Div. 1) | 9 |
| 30 | Expensive Strings | Codeforces | Educational Codeforces Round 5 | 9 |
| 31 | Have You Ever Heard About the Word? | Codeforces | Codeforces Round #189 (Div. 1) | 9 |
| 32 | Good Substrings | Codeforces | ABBYY Cup 3.0 | 9 |
| 33 | Arpa’s abnormal DNA and Mehrdad’s deep interest | Codeforces | Codeforces Round #383 (Div. 1) | 10 |
| 34 | Cutting the Line | Codeforces | Codeforces Round #330 (Div. 1) | 10 |
| 35 | Misha and LCP on Tree | Codeforces | Codeforces Round #285 (Div. 1) | 10 |