Starlight

Over 20,000 problems available: AMC 8/10/12 and AIME problems from 2010-2024; USAJMO/USAMO problems from 2002-2024; USACO problems from 2014 to 2024 (all divisions); all Codeforces, AtCoder and DMOJ problems. If you leave the search field blank, it returns all problems with the specified type.

Reset

Need help searching? Click for format/examples of problems
  • AMC 8: [year] AMC 8 Problem #, Ex: 2013 AMC 8 Problem 1
  • AMC 10: [year] AMC 10A Problem # OR [year] AMC 10B Problem #, Ex: 2015 AMC 10A Problem 16
  • AMC 12: [year] AMC 12A Problem # OR [year] AMC 12B Problem #, Ex: 2021 AMC 12B Problem 25
  • AIME: [year] AIME I Problem # OR [year] AIME II Problem #, Ex: 2013 AIME I Problem 8
  • USAJMO/USAMO: [year] USAJMO/USAMO Problem #, Ex: 2023 USAJMO Problem 1
  • Codeforces: Codeforces [contest id (e.g. 101)][problem id (e.g. A, B, C)]: [Codeforces problem name], Ex: Codeforces 1336F: Journey
  • AtCoder: AtCoder [contest id (e.g. ABC314, ARC164, ZONE2021)]: [problem id (A, B, C)]. [Problem name], Ex: AtCoder ZONE2021: E. Sneaking
  • DMOJ: DMOJ [contest name (if applicable)] [problem number (e.g. P1)] - [Problem name], Ex: DMOJ Yet Another Contest 3 P1 - Shell Swap Scam
  • USACO: [year] [contest month (e.g. January, US Open)], [division (e.g. Gold)]: [Problem name], Ex: USACO 2023 US Open Contest, Bronze: Rotate and Shift

ID Problem Name (click to add insights/hints, view summary of insights/hints and similar problems)
24485 Codeforces 1919D: 01 Tree
24484 Codeforces 1919C: Grouping Increases
24483 Codeforces 1919B: Plus-Minus Split
24482 Codeforces 1919A: Wallet Exchange
24481 Codeforces 1917F: Construct Tree
24480 Codeforces 1917E: Construct Matrix
24479 Codeforces 1917D: Yet Another Inversions Problem
24478 Codeforces 1917C: Watering an Array
24477 Codeforces 1917B: Erase First or Second Letter
24476 Codeforces 1917A: Least Product
24475 Codeforces 1916H2: Matrix Rank (Hard Version)
24474 Codeforces 1916H1: Matrix Rank (Easy Version)
24473 Codeforces 1916G: Optimizations From Chelsu
24472 Codeforces 1916F: Group Division
24471 Codeforces 1916E: Happy Life in University
24470 Codeforces 1916D: Mathematical Problem
24469 Codeforces 1916C: Training Before the Olympiad
24468 Codeforces 1916B: Two Divisors
24467 Codeforces 1916A: 2023
24466 Codeforces 1915G: Bicycles
24465 Codeforces 1915F: Greetings
24464 Codeforces 1915E: Romantic Glasses
24463 Codeforces 1915D: Unnatural Language Processing
24462 Codeforces 1915C: Can I Square?
24461 Codeforces 1915B: Not Quite Latin Square
24460 Codeforces 1915A: Odd One Out
24459 Codeforces 1914G2: Light Bulbs (Hard Version)
24458 Codeforces 1914G1: Light Bulbs (Easy Version)
24457 Codeforces 1914F: Programming Competition
24456 Codeforces 1914E2: Game with Marbles (Hard Version)
24455 Codeforces 1914E1: Game with Marbles (Easy Version)
24454 Codeforces 1914D: Three Activities
24453 Codeforces 1914C: Quests
24452 Codeforces 1914B: Preparing for the Contest
24451 Codeforces 1914A: Problemsolving Log
24450 Codeforces 1913F: Palindromic Problem
24449 Codeforces 1913E: Matrix Problem
24448 Codeforces 1913D: Array Collapse
24447 Codeforces 1913C: Game with Multiset
24446 Codeforces 1913B: Swap and Delete
24445 Codeforces 1913A: Rating Increase
24444 Codeforces 1912L: LOL Lovers
24443 Codeforces 1912K: Kim's Quest
24442 Codeforces 1912J: Joy of Pokémon Observation
24441 Codeforces 1912I: Innovative Washing Machine
24440 Codeforces 1912H: Hypercatapult Commute
24439 Codeforces 1912G: Great City Saint Petersburg
24438 Codeforces 1912F: Fugitive Frenzy
24437 Codeforces 1912E: Evaluate It and Back Again
24436 Codeforces 1912D: Divisibility Test
View links to all pages 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192

About • Privacy Notice • Rules • Problems list • Journal • Your profile • GitHub

Moon Symbol icon by Icons8 • Sun icon by Icons8 • Emojis from Twemoji by Twitter under CC by 4.0