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)
6550 Codeforces 1451D: Circle Game
6549 Codeforces 1451C: String Equality
6548 Codeforces 1451B: Non-Substring Subsequence
6547 Codeforces 1451A: Subtract or Divide
6546 Codeforces 1450H2: Multithreading (Hard Version)
6545 Codeforces 1450H1: Multithreading (Easy Version)
6544 Codeforces 1450G: Communism
6543 Codeforces 1450F: The Struggling Contestant
6542 Codeforces 1450E: Capitalism
6541 Codeforces 1450D: Rating Compression
6540 Codeforces 1450C2: Errich-Tac-Toe (Hard Version)
6539 Codeforces 1450C1: Errich-Tac-Toe (Easy Version)
6538 Codeforces 1450B: Balls of Steel
6537 Codeforces 1450A: Avoid Trygub
6536 Codeforces 1447B: Numbers Box
6535 Codeforces 1447A: Add Candies
6534 Codeforces 1446F: Line Distance
6533 Codeforces 1446E: Long Recovery
6532 Codeforces 1446D2: Frequency Problem (Hard Version)
6531 Codeforces 1446D1: Frequency Problem (Easy Version)
6530 Codeforces 1446C: Xor Tree
6529 Codeforces 1446B: Catching Cheaters
6528 Codeforces 1446A: Knapsack
6527 Codeforces 1445B: Elimination
6526 Codeforces 1445A: Array Rearrangment
6525 Codeforces 1444E: Finding the Vertex
6524 Codeforces 1444D: Rectangular Polyline
6523 Codeforces 1444C: Team-Building
6522 Codeforces 1444B: Divide and Sum
6521 Codeforces 1444A: Division
6520 Codeforces 1443E: Long Permutation
6519 Codeforces 1443C: The Delivery Dilemma
6518 Codeforces 1443B: Saving the City
6517 Codeforces 1443A: Kids Seating
6516 Codeforces 1442F: Differentiating Games
6515 Codeforces 1442E: Black, White and Grey Tree
6514 Codeforces 1442D: Sum
6513 Codeforces 1442C: Graph Transpositions
6512 Codeforces 1442B: Identify the Operations
6511 Codeforces 1442A: Extreme Subtraction
6510 Codeforces 1440B: Sum of Medians
6509 Codeforces 1440A: Buy the String
6508 Codeforces 1439E: Cheat and Win
6507 Codeforces 1439D: INOI Final Contests
6506 Codeforces 1439C: Greedy Shopping
6505 Codeforces 1439B: Graph Subset Problem
6504 Codeforces 1439A2: Binary Table (Hard Version)
6503 Codeforces 1439A1: Binary Table (Easy Version)
6502 Codeforces 1438F: Olha and Igor
6501 Codeforces 1438E: Yurii Can Do Everything
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