| Problem Name | Online Judge | Contest | Difficulty Level | |
|---|---|---|---|---|
| 1 | Registration System | Codeforces | Codeforces Beta Round #4 (Div. 2 Only) | 1 |
| 2 | Vitaliy and Pie | Codeforces | Codeforces Round #297 (Div. 2) | 1 |
| 3 | Winner | Codeforces | Codeforces Beta Round #2 | 1 |
| 4 | OR in Matrix | Codeforces | Codeforces Round #277 (Div. 2) | 1 |
| 5 | Bear and Three Musketeers | Codeforces | Codeforces Round #318 [RussianCodeCup Thanks-Round] (Div. 2) | 2 |
| 6 | Password | Codeforces | Codeforces Beta Round #93 (Div. 1 Only) & Codeforces Beta Round #93 (Div. 2 Only) | 2 |
| 7 | FIGUREFUL | SPOJ | 2 | |
| 8 | Equivalent Strings | Codeforces | Codeforces Round #313 (Div. 1) & Codeforces Round #313 (Div. 2) | 2 |
| 9 | Simple Minded Hashing | UVA | 2 | |
| 10 | Good Substrings | Codeforces | Codeforces Round #166 (Div. 2) | 3 |
| 11 | Gargari and Bishops | Codeforces | Codeforces Round #264 (Div. 2) | 3 |
| 12 | VOI 2013 - Trao ?ổi thông tin | SPOJ Vietnam | 3 | |
| 13 | Common Divisors | Codeforces | Codeforces Round #117 (Div. 2) | 3 |
| 14 | Watto and Mechanism | Codeforces | Codeforces Round #291 (Div. 2) | 3 |
| 15 | Long Jumps | Codeforces | Codeforces Round #274 (Div. 2) & Codeforces Round #274 (Div. 1) | 3 |
| 16 | Almost Arithmetical Progression | Codeforces | Codeforces Round #156 (Div. 2) & Codeforces Round #156 (Div. 1) | 4 |
| 17 | Queries for Number of Palindromes | Codeforces | CROC-MBTU 2012, Elimination Round (ACM-ICPC) | 4 |
| 18 | King's Path | Codeforces | Codeforces Round #149 (Div. 2) | 4 |
| 19 | Tavas and Malekas | Codeforces | Codeforces Round #299 (Div. 2) & Codeforces Round #299 (Div. 1) | 4 |
| 20 | Train and Peter | Codeforces | Codeforces Beta Round #8 | 4 |
| 21 | Replacing Digits | Codeforces | VK Cup 2012 Round 2 (Unofficial Div. 2 Edition) | 5 |
| 22 | Correcting Mistakes | Codeforces | VK Cup 2015 - Round 2 (unofficial online mirror, Div. 1 only) | 5 |
| 23 | Fibonacci-ish | Codeforces | Manthan, Codefest 16 | 5 |
| 24 | Spy Syndrome 2 | Codeforces | Manthan, Codefest 16 | 5 |
| 25 | Petr# | Codeforces | Codeforces Beta Round #86 (Div. 1 Only) & Codeforces Beta Round #86 (Div. 2 Only) | 5 |
| 26 | Sets | Codeforces | Yandex.Algorithm 2011 Qualification 2 | 5 |
| 27 | New Year and Ancient Prophecy | Codeforces | Good Bye 2015 | 5 |
| 28 | Palindrome Degree | Codeforces | Codeforces Beta Round #7 | 5 |
| 29 | Kefa and Watch | Codeforces | Codeforces Round #321 (Div. 2) | 6 |
| 30 | Fedor and Essay | Codeforces | Codeforces Round #267 (Div. 2) | 6 |
| 31 | Double Profiles | Codeforces | Codeforces Round #109 (Div. 1) & Codeforces Round #109 (Div. 2) | 6 |
| 32 | Spelling Check | Codeforces | School Team Contest #1 (Winter Computer School 2010/11) | 6 |
| 33 | Bear and Polynomials | Codeforces | VK Cup 2016 - Round 1 | 6 |
| 34 | String | Codeforces | Codeforces Beta Round #94 (Div. 1 Only) & Codeforces Beta Round #94 (Div. 2 Only) | 6 |
| 35 | Om Nom and Necklace | Codeforces | ZeptoLab Code Rush 2015 | 6 |
| 36 | Test | Codeforces | Codeforces Beta Round #25 (Div. 2 Only) | 6 |
| 37 | Messenger | Codeforces | Codeforces Round #344 (Div. 2) | 6 |
| 38 | Caesar Cipher | UVA | 6 | |
| 39 | Beaver | Codeforces | Codeforces Beta Round #71 | 6 |
| 40 | LIS of Sequence | Codeforces | Codeforces Round #277 (Div. 2) | 6 |
| 41 | Acyclic Organic Compounds | Codeforces | Codeforces Round #333 (Div. 1) | 7 |
| 42 | Encoding | Codeforces | VK Cup 2015 - Round 2 (unofficial online mirror, Div. 1 only) | 7 |
| 43 | Peterson Polyglot | Codeforces | Codeforces Round #402 (Div. 1) & Codeforces Round #402 (Div. 2) | 7 |
| 44 | Good Substrings | Codeforces | ABBYY Cup 3.0 | 7 |
| 45 | President and Roads | Codeforces | Codeforces Round #Pi (Div. 2) | 7 |
| 46 | The Untended Antiquity | Codeforces | Codeforces Round #439 (Div. 2) | 7 |
| 47 | The angry professor | SPOJ | 7 | |
| 48 | Sereja and Squares | Codeforces | Codeforces Round #243 (Div. 1) | 7 |
| 49 | Tree-String Problem | Codeforces | Croc Champ 2013 - Qualification Round | 7 |
| 50 | Counter Attack | Codeforces | Codeforces Round #120 (Div. 2) | 7 |
| 51 | Marbles | Codeforces | Codeforces Round #336 (Div. 1) & Codeforces Round #336 (Div. 2) | 7 |
| 52 | Cutting Jigsaw Puzzle | Codeforces | Codeforces Beta Round #50 | 8 |
| 53 | Tricky and Clever Password | Codeforces | Codeforces Beta Round #30 (Codeforces format) | 8 |
| 54 | Permutation | Codeforces | MemSQL Start[c]UP 2.0 - Round 1 | 8 |
| 55 | Fractal Detector | Codeforces | Codeforces Round #141 (Div. 2) | 8 |
| 56 | Don't fear, DravDe is kind | Codeforces | Codeforces Beta Round #28 (Codeforces format) | 8 |
| 57 | DZY Loves Strings | Codeforces | Codeforces Round #254 (Div. 1) | 8 |
| 58 | Two Permutations | Codeforces | Codeforces Round #131 (Div. 1) | 8 |
| 59 | Restoring the Expression | Codeforces | Codeforces Round #451 (Div. 2) | 8 |
| 60 | Deletion of Repeats | Codeforces | Codeforces Beta Round #19 | 8 |
| 61 | Have You Ever Heard About the Word? | Codeforces | Codeforces Round #189 (Div. 1) | 9 |
| 62 | Timofey and a flat tree | Codeforces | Codeforces Round #395 (Div. 1) | 9 |
| 63 | String Transformation | Codeforces | Codeforces Beta Round #90 | 9 |
| 64 | Superhero's Job | Codeforces | VK Cup 2015 - Round 3 (unofficial online mirror, Div. 1 only) | 9 |
| 65 | And Yet Another Bracket Sequence | Codeforces | VK Cup 2015 - Round 1 | 9 |
| 66 | Polycarpus is Looking for Good Substrings | Codeforces | VK Cup 2012 Finals (unofficial online-version) | 9 |
| 67 | Largest Submatrix 3 | Codeforces | Codeforces Round #239 (Div. 1) | 9 |
| 68 | The Next Good String | Codeforces | Codeforces Round #124 (Div. 1) | 9 |
| 69 | Simplified Nonogram | Codeforces | Codeforces Round #298 (Div. 2) | 9 |
| 70 | Xenia and String Problem | Codeforces | Codeforces Round #207 (Div. 1) | 9 |
| 71 | Harry Potter and the Sorting Hat | Codeforces | Codeforces Beta Round #60 | 9 |
| 72 | Berland Local Positioning System | Codeforces | Codeforces Round #298 (Div. 2) | 9 |
| 73 | Rap God | Codeforces | Codeforces Round #406 (Div. 1) | 10 |
| 74 | Puzzle Lover | Codeforces | Codeforces Round #339 (Div. 1) | 10 |
| 75 | Misha and LCP on Tree | Codeforces | Codeforces Round #285 (Div. 1) | 10 |
| 76 | Looking for Owls | Codeforces | Codeforces Round #203 (Div. 2) | 10 |