| Problem Name | Online Judge | Year | Contest | Difficulty Level | |
|---|---|---|---|---|---|
| 1 | Marbles | SPOJ | 1 | ||
| 2 | Combinations | UVA | 1 | ||
| 3 | Wooden Sticks | PKU | 1 | ||
| 4 | Number Sequence | PKU | 1 | ||
| 5 | DNA Sorting | PKU | 1 | ||
| 6 | Cipher | PKU | 1 | ||
| 7 | Round Numbers | PKU | 1 | ||
| 8 | Paths on a Grid | PKU | 1 | ||
| 9 | Permutations | SPOJ | 1 | ||
| 10 | Triangle Counting | UVA | 1 | ||
| 11 | Brick Wall Patterns | UVA | 1 | ||
| 12 | Lucky Numbers | Codeforces | Experimental Educational Round: VolBIT Formulas Blitz | 1 | |
| 13 | Wet Shark and Bishops | Codeforces | Codeforces Round #341 (Div. 2) | 1 | |
| 14 | Chocolate | Codeforces | Codeforces Round #340 (Div. 2) | 1 | |
| 15 | Pasha and Stick | Codeforces | Codeforces Round #337 (Div. 2) | 1 | |
| 16 | Random Teams | Codeforces | Codeforces Round #273 (Div. 2) | 1 | |
| 17 | Dreamoon and WiFi | Codeforces | Codeforces Round #272 (Div. 2) | 1 | |
| 18 | Mashmokh and ACM | Codeforces | Codeforces Round #240 (Div. 1) & Codeforces Round #240 (Div. 2) | 1 | |
| 19 | Pocket Book | Codeforces | Codeforces Round #108 (Div. 2) | 2 | |
| 20 | The World is a Theatre | Codeforces | Codeforces Beta Round #95 (Div. 2) | 2 | |
| 21 | Permutations | UVA | 2 | ||
| 22 | Yet another Number Sequence | UVA | 2 | ||
| 23 | Choose and divide | UVA | 2 | ||
| 24 | Safe Salutations | UVA | 2 | ||
| 25 | Count the Trees | UVA | 2 | ||
| 26 | How many nodes ? | UVA | 2 | ||
| 27 | How Many Trees? | UVA | 2 | ||
| 28 | Trees Made to Order | PKU | 2 | ||
| 29 | Code | PKU | 2 | ||
| 30 | Necklace of Beads | PKU | 2 | ||
| 31 | Let it Bead | PKU | 2 | ||
| 32 | Color | PKU | 2 | ||
| 33 | Candy Distribution | PKU | 2 | ||
| 34 | Ciel and Flowers | Codeforces | Codeforces Round #190 (Div. 2) | 2 | |
| 35 | Kolya and Tanya | Codeforces | Codeforces Round #324 (Div. 2) | 2 | |
| 36 | Modulo Sum | Codeforces | Codeforces Round #319 (Div. 2) | 2 | |
| 37 | Kyoya and Colored Balls | Codeforces | Codeforces Round #309 (Div. 1) & Codeforces Round #309 (Div. 2) | 2 | |
| 38 | Points on Line | Codeforces | Codeforces Round #153 (Div. 1) & Codeforces Round #153 (Div. 2) | 2 | |
| 39 | Mr. Kitayuta's Gift | Codeforces | Codeforces Round #286 (Div. 1) & Codeforces Round #286 (Div. 2) & Codeforces Round #286 (Div. 1) & Codeforces Round #286 (Div. 2) | 2 | |
| 40 | Leha and Function | Codeforces | Codeforces Round #429 (Div. 1) & Codeforces Round #429 (Div. 2) | 2 | |
| 41 | Little Elephant and Interval | Codeforces | Codeforces Round #129 (Div. 1) & Codeforces Round #129 (Div. 2) | 3 | |
| 42 | Card Game | SPOJ | 3 | ||
| 43 | Burger | UVA | 3 | ||
| 44 | Binomial Theorem | UVA | 3 | ||
| 45 | Expression Bracketing | UVA | 3 | ||
| 46 | A decorative fence | PKU | 3 | ||
| 47 | Lucky tickets | PKU | 3 | ||
| 48 | Cow Sorting | PKU | 3 | ||
| 49 | Magic Bracelet | PKU | 3 | ||
| 50 | Connected Graph | PKU | 3 | ||
| 51 | Longge's problem | PKU | 3 | ||
| 52 | Selection of Personnel | Codeforces | Experimental Educational Round: VolBIT Formulas Blitz | 3 | |
| 53 | Hamming Distance Sum | Codeforces | Codeforces Round #336 (Div. 2) | 3 | |
| 54 | Ilya and Escalator | Codeforces | Codeforces Round #293 (Div. 2) | 3 | |
| 55 | Unbearable Controversy of Being | Codeforces | Codeforces Round #277.5 (Div. 2) | 3 | |
| 56 | Pashmak and Buses | Codeforces | Codeforces Round #261 (Div. 2) | 3 | |
| 57 | Star | Codeforces | April Fools Day Contest | 4 | |
| 58 | Quantity of Strings | Codeforces | Codeforces Round #107 (Div. 1) & Codeforces Round #107 (Div. 2) | 4 | |
| 59 | Dima and Sequence | Codeforces | Codeforces Round #167 (Div. 2) | 4 | |
| 60 | FUN WITH NUMBERS | SPOJ | 4 | ||
| 61 | CARDS | PKU | 4 | ||
| 62 | Leonardo's Notebook | PKU | 4 | ||
| 63 | The Stable Marriage Problem | PKU | 4 | ||
| 64 | Difference between Triplets | PKU | 4 | ||
| 65 | Weather | Codeforces | Codeforces Round #145 (Div. 2, ACM-ICPC Rules) | 4 | |
| 66 | Benches | Codeforces | Experimental Educational Round: VolBIT Formulas Blitz | 4 | |
| 67 | Gerald and Giant Chess | Codeforces | Codeforces Round #313 (Div. 1) & Codeforces Round #313 (Div. 2) | 4 | |
| 68 | Vanya and Triangles | Codeforces | Codeforces Round #308 (Div. 2) | 4 | |
| 69 | New Year Santa Network | Codeforces | Good Bye 2014 | 4 | |
| 70 | Inna and Nine | Codeforces | Codeforces Round #220 (Div. 2) | 4 | |
| 71 | Matrix | Codeforces | Codeforces Round #213 (Div. 1) & Codeforces Round #213 (Div. 2) | 4 | |
| 72 | Tourist Problem | Codeforces | Codeforces Round #198 (Div. 2) & Codeforces Round #198 (Div. 1) | 4 | |
| 73 | Magic Five | Codeforces | Codeforces Round #191 (Div. 2) | 4 | |
| 74 | Beautiful Numbers | Codeforces | Codeforces Round #181 (Div. 2) | 4 | |
| 75 | Polo the Penguin and Houses | Codeforces | Codeforces Round #177 (Div. 1) | 4 | |
| 76 | The Intriguing Obsession | Codeforces | Codeforces Round #439 (Div. 2) | 4 | |
| 77 | Ralph And His Magic Field | Codeforces | Codeforces Round #447 (Div. 2) | 4 | |
| 78 | Directed Roads | Codeforces | Codeforces Round #369 (Div. 2) | 4 | |
| 79 | Cycles | Codeforces | Codeforces Round #144 (Div. 1) & Codeforces Round #144 (Div. 2) | 5 | |
| 80 | Games with Rectangle | Codeforces | Codeforces Beta Round #94 (Div. 1 Only) & Codeforces Beta Round #94 (Div. 2 Only) | 5 | |
| 81 | Permutations | Codeforces | Codeforces Beta Round #92 (Div. 2 Only) | 5 | |
| 82 | Basketball Team | Codeforces | Codeforces Beta Round #83 (Div. 1 Only) & Codeforces Beta Round #83 (Div. 2 Only) | 5 | |
| 83 | How many trees? | Codeforces | Codeforces Beta Round #9 (Div. 2 Only) | 5 | |
| 84 | Prime Factors | Live Archive | 1997 | North America - East Central NA | 5 |
| 85 | The shuffle Problem | PKU | 5 | ||
| 86 | Regetni | PKU | 5 | ||
| 87 | Jerry's Protest | Codeforces | 8VC Venture Cup 2016 - Elimination Round | 5 | |
| 88 | Lengthening Sticks | Codeforces | Codeforces Round #317 [AimFund Thanks-Round] (Div. 1) & Codeforces Round #317 [AimFund Thanks-Round] (Div. 2) | 5 | |
| 89 | Symmetric and Transitive | Codeforces | Codeforces Round #315 (Div. 1) & Codeforces Round #315 (Div. 2) | 5 | |
| 90 | Vitaly and Cycle | Codeforces | Codeforces Round #311 (Div. 2) | 5 | |
| 91 | Kyoya and Permutation | Codeforces | Codeforces Round #309 (Div. 1) & Codeforces Round #309 (Div. 2) | 5 | |
| 92 | Increase Sequence | Codeforces | Codeforces Round #266 (Div. 2) | 5 | |
| 93 | Mashmokh and Reverse Operation | Codeforces | Codeforces Round #240 (Div. 1) & Codeforces Round #240 (Div. 2) | 5 | |
| 94 | Roman and Numbers | Codeforces | Codeforces Round #235 (Div. 2) | 5 | |
| 95 | Two Heaps | Codeforces | Codeforces Round #205 (Div. 2) | 5 | |
| 96 | Jeff and Furik | Codeforces | Codeforces Round #204 (Div. 1) & Codeforces Round #204 (Div. 2) | 5 | |
| 97 | Iahub and Permutations | Codeforces | Codeforces Round #198 (Div. 2) & Codeforces Round #198 (Div. 1) | 5 | |
| 98 | Malek Dance Club | Codeforces | Codeforces Round #189 (Div. 1) & Codeforces Round #189 (Div. 2) | 5 | |
| 99 | Shaass and Lights | Codeforces | Codeforces Round #178 (Div. 2) | 5 | |
| 100 | Dima and Two Sequences | Codeforces | Codeforces Round #167 (Div. 2) & Codeforces Round #167 (Div. 1) | 5 | |
| 101 | Weird journey | Codeforces | Codeforces Round #407 (Div. 1) & Codeforces Round #407 (Div. 2) | 5 | |
| 102 | Square Subsets | Codeforces | Codeforces Round #448 (Div. 2) | 5 | |
| 103 | Winter is here | Codeforces | Codeforces Round #428 (Div. 2) | 5 | |
| 104 | Anton and School - 2 | Codeforces | Codeforces Round #404 (Div. 2) | 5 | |
| 105 | Little Elephant and Elections | Codeforces | Codeforces Round #157 (Div. 1) & Codeforces Round #157 (Div. 2) | 6 | |
| 106 | Table | Codeforces | Codeforces Round #144 (Div. 1) & Codeforces Round #144 (Div. 2) | 6 | |
| 107 | Triangles | Codeforces | Codeforces Round #142 (Div. 1) & Codeforces Round #142 (Div. 2) | 6 | |
| 108 | Partial Sums | Codeforces | Codeforces Round #138 (Div. 1) & Codeforces Round #138 (Div. 2) | 6 | |
| 109 | Numbers | Codeforces | Codeforces Round #131 (Div. 1) & Codeforces Round #131 (Div. 2) | 6 | |
| 110 | Cipher | Codeforces | Codeforces Round #110 (Div. 1) & Codeforces Round #110 (Div. 2) | 6 | |
| 111 | Lucky Subsequence | Codeforces | Codeforces Round #104 (Div. 1) & Codeforces Round #104 (Div. 2) | 6 | |
| 112 | Lucky Permutation | Codeforces | Codeforces Beta Round #91 (Div. 1 Only) & Codeforces Beta Round #91 (Div. 2 Only) | 6 | |
| 113 | Array | Codeforces | Codeforces Beta Round #53 | 6 | |
| 114 | ETS Problem setting | UVA | 6 | ||
| 115 | Birthday Cake | PKU | 6 | ||
| 116 | Sum of powers | PKU | 6 | ||
| 117 | Parking Lot | Codeforces | Experimental Educational Round: VolBIT Formulas Blitz | 6 | |
| 118 | Challenge Pennants | Codeforces | Experimental Educational Round: VolBIT Formulas Blitz | 6 | |
| 119 | Bots | Codeforces | Bubble Cup 8 - Finals [Online Mirror] | 6 | |
| 120 | Pig and Palindromes | Codeforces | Codeforces Round #316 (Div. 2) | 6 | |
| 121 | GukiZ and Binary Operations | Codeforces | Codeforces Round #307 (Div. 2) | 6 | |
| 122 | Pluses everywhere | Codeforces | Codeforces Round #295 (Div. 2) & Codeforces Round #295 (Div. 1) | 6 | |
| 123 | Special Matrices | Codeforces | Codeforces Round #277.5 (Div. 2) | 6 | |
| 124 | Magic Trick | Codeforces | MemSQL Start[c]UP 2.0 - Round 1 | 6 | |
| 125 | Devu and Flowers | Codeforces | Codeforces Round #258 (Div. 2) | 6 | |
| 126 | Jzzhu and Numbers | Codeforces | Codeforces Round #257 (Div. 1) | 6 | |
| 127 | Random Task | Codeforces | Codeforces Round #247 (Div. 2) | 6 | |
| 128 | Compartments | Codeforces | Codeforces Round #207 (Div. 1) & Codeforces Round #207 (Div. 2) | 6 | |
| 129 | Greg and Friends | Codeforces | Codeforces Round #179 (Div. 1) & Codeforces Round #179 (Div. 2) | 6 | |
| 130 | Permutation Sum | Codeforces | Codeforces Round #175 (Div. 2) | 6 | |
| 131 | Little Elephant and LCM | Codeforces | Codeforces Round #157 (Div. 1) & Codeforces Round #157 (Div. 2) | 6 | |
| 132 | Unusual Sequences | Codeforces | Codeforces Round #450 (Div. 2) | 6 | |
| 133 | Mike and Geometry Problem | Codeforces | Codeforces Round #361 (Div. 2) | 6 | |
| 134 | Memory and Scores | Codeforces | Codeforces Round #370 (Div. 2) | 6 | |
| 135 | The table | Codeforces | Codeforces Round #140 (Div. 1) | 7 | |
| 136 | Chessboard Billiard | Codeforces | Codeforces Beta Round #68 | 7 | |
| 137 | Right Triangles | Codeforces | Codeforces Testing Round #1 | 7 | |
| 138 | On Number of Decompositions into Multipliers | Codeforces | Codeforces Round #232 (Div. 1) & Codeforces Round #232 (Div. 2) | 7 | |
| 139 | Plato's Blocks | PKU | 7 | ||
| 140 | ????? | PKU | 7 | ||
| 141 | Fence Divercity | Codeforces | Codeforces Round #346 (Div. 2) | 7 | |
| 142 | Square Root of Permutation | Codeforces | Educational Codeforces Round 4 | 7 | |
| 143 | Devu and Birthday Celebration | Codeforces | Codeforces Round #251 (Div. 2) | 7 | |
| 144 | Beautiful Pairs of Numbers | Codeforces | Codeforces Round #236 (Div. 1) | 7 | |
| 145 | Levko and Strings | Codeforces | Codeforces Round #210 (Div. 1) & Codeforces Round #210 (Div. 2) | 7 | |
| 146 | Vasily the Bear and Beautiful Strings | Codeforces | Codeforces Round #195 (Div. 2) | 7 | |
| 147 | Axis Walking | Codeforces | Codeforces Round #191 (Div. 2) | 7 | |
| 148 | Yaroslav and Two Strings | Codeforces | Codeforces Round #179 (Div. 2) | 7 | |
| 149 | Dima and Horses | Codeforces | Codeforces Round #167 (Div. 2) & Codeforces Round #167 (Div. 1) | 7 | |
| 150 | Ski Base | Codeforces | Codeforces Beta Round #75 (Div. 1 Only) & Codeforces Beta Round #75 (Div. 2 Only) | 7 | |
| 151 | On the Bench | Codeforces | Codeforces Round #429 (Div. 1) & Codeforces Round #429 (Div. 2) | 7 | |
| 152 | String Mark | Codeforces | Codeforces Round #448 (Div. 2) | 7 | |
| 153 | Number Challenge | Codeforces | Codeforces Round #146 (Div. 1) | 8 | |
| 154 | Gifts | Codeforces | Codeforces Round #142 (Div. 1) | 8 | |
| 155 | Periodical Numbers | Codeforces | Codeforces Round #132 (Div. 2) | 8 | |
| 156 | Playing with Superglue | Codeforces | Croc Champ 2012 - Round 2 | 8 | |
| 157 | Clues | Codeforces | Codeforces Round #110 (Div. 1) | 8 | |
| 158 | New Year Garland | Codeforces | Codeforces Round #100 | 8 | |
| 159 | Brackets | Codeforces | Codeforces Beta Round #92 (Div. 1 Only) & Codeforces Beta Round #92 (Div. 2 Only) | 8 | |
| 160 | Petya and Coloring | Codeforces | Codeforces Beta Round #85 (Div. 1 Only) | 8 | |
| 161 | Bath Queue | Codeforces | Codeforces Beta Round #28 (Codeforces format) | 8 | |
| 162 | Tickets | Codeforces | Codeforces Beta Round #26 (Codeforces format) | 8 | |
| 163 | Parquet | Codeforces | Codeforces Beta Round #26 (Codeforces format) | 8 | |
| 164 | Positions in Permutations | Codeforces | Codeforces Round #175 (Div. 2) | 8 | |
| 165 | Hexagonal Routes | PKU | 8 | ||
| 166 | Different Subsets For All Tuples | Codeforces | Educational Codeforces Round 11 | 8 | |
| 167 | Cowslip Collections | Codeforces | CROC 2016 - Elimination Round | 8 | |
| 168 | Misha and Palindrome Degree | Codeforces | Codeforces Round #285 (Div. 2) & Codeforces Round #285 (Div. 1) | 8 | |
| 169 | The Child and Binary Tree | Codeforces | Codeforces Round #250 (Div. 1) | 8 | |
| 170 | Vowels | Codeforces | Codeforces Round #225 (Div. 1) | 8 | |
| 171 | Sereja and Intervals | Codeforces | Codeforces Round #215 (Div. 1) | 8 | |
| 172 | Black-and-White Cube | Codeforces | Testing Round #7 | 8 | |
| 173 | Olya and Graph | Codeforces | Codeforces Round #184 (Div. 2) | 8 | |
| 174 | Greg and Caves | Codeforces | Codeforces Round #179 (Div. 1) | 8 | |
| 175 | Distinct Paths | Codeforces | Croc Champ 2013 - Round 2 | 8 | |
| 176 | Polo the Penguin and Trees | Codeforces | Codeforces Round #177 (Div. 1) | 8 | |
| 177 | Cow Tennis Tournament | Codeforces | Codeforces Round #174 (Div. 1) | 8 | |
| 178 | Number Table | Codeforces | Codeforces Beta Round #39 | 8 | |
| 179 | Codeword | Codeforces | Codeforces Round #349 (Div. 1) | 8 | |
| 180 | Find a car | Codeforces | Codeforces Round #415 (Div. 1) & Codeforces Round #415 (Div. 2) | 8 | |
| 181 | An unavoidable detour for home | Codeforces | Codeforces Round #418 (Div. 2) | 8 | |
| 182 | Little Elephant and Triangle | Codeforces | Codeforces Round #136 (Div. 1) | 9 | |
| 183 | Bitonix' Patrol | Codeforces | Codeforces Round #134 (Div. 1) | 9 | |
| 184 | Thoroughly Bureaucratic Organization | Codeforces | Codeforces Round #127 (Div. 1) | 9 | |
| 185 | Lucky Pair | Codeforces | Codeforces Round #104 (Div. 1) | 9 | |
| 186 | Pentagon | Codeforces | Codeforces Beta Round #48 | 9 | |
| 187 | Lesson Timetable | Codeforces | Codeforces Beta Round #37 | 9 | |
| 188 | Triangles | Codeforces | Codeforces Beta Round #15 | 9 | |
| 189 | Flags | Codeforces | Codeforces Beta Round #76 (Div. 1 Only) | 9 | |
| 190 | Move by Prime | Codeforces | IndiaHacks 2016 - Online Edition (Div. 1 + Div. 2) | 9 | |
| 191 | Transforming Sequence | Codeforces | AIM Tech Round (Div. 1) | 9 | |
| 192 | Present for Vitalik the Philatelist | Codeforces | Codeforces Round #325 (Div. 1) | 9 | |
| 193 | Randomizer | Codeforces | Codeforces Round #313 (Div. 1) | 9 | |
| 194 | Pasha and Pipe | Codeforces | Codeforces Round #293 (Div. 2) | 9 | |
| 195 | Random Function and Tree | Codeforces | Codeforces Round #275 (Div. 1) | 9 | |
| 196 | On Sum of Number of Inversions in Permutations | Codeforces | Codeforces Round #232 (Div. 1) | 9 | |
| 197 | Yet Another Number Sequence | Codeforces | Codeforces Round #230 (Div. 1) & Codeforces Round #230 (Div. 2) | 9 | |
| 198 | Ksenia and Combinatorics | Codeforces | Codeforces Round #224 (Div. 2) | 9 | |
| 199 | Sereja and Cinema | Codeforces | Codeforces Round #223 (Div. 1) | 9 | |
| 200 | The Red Button | Codeforces | MemSQL start[c]up Round 1 | 9 | |
| 201 | White, Black and White Again | Codeforces | Testing Round #6 | 9 | |
| 202 | Research Rover | Codeforces | Intel Code Challenge Elimination Round (Div. 1 + Div. 2, combined) | 9 | |
| 203 | Singer House | Codeforces | Codeforces Round #424 (Div. 1, rated, based on VK Cup Finals) | 9 | |
| 204 | Karen and Cards | Codeforces | Codeforces Round #419 (Div. 1) | 9 | |
| 205 | Lust | Codeforces | Codeforces Round #446 (Div. 1) | 9 | |
| 206 | Weak Subsequence | Codeforces | Codeforces Beta Round #97 (Div. 1) | 10 | |
| 207 | Sleeping | Codeforces | Codeforces Beta Round #86 (Div. 1 Only) | 10 | |
| 208 | Toys | Codeforces | School Team Contest #2 (Winter Computer School 2010/11) | 10 | |
| 209 | Bingo! | Codeforces | MemSQL Start[c]UP 2.0 - Round 2 | 10 | |
| 210 | Drawing Circles is Fun | Codeforces | Codeforces Round #219 (Div. 1) | 10 | |
| 211 | Vasily the Bear and Painting Square | Codeforces | Codeforces Round #195 (Div. 2) | 10 | |
| 212 | Nephren Runs a Cinema | Codeforces | Codeforces Round #449 (Div. 1) | 10 | |
| 213 | Shake It! | Codeforces | Codeforces Round #431 (Div. 1) | 10 | |
| 214 | Numbers on the blackboard | Codeforces | Codeforces Round #443 (Div. 1) | 10 | |
| 215 | Days of Floral Colours | Codeforces | Codeforces Round #431 (Div. 1) | 10 |