Starlight: List of Problems

Over 20,000 problems available. AMC 8/10/12 and AIME problems from 2010-2023; USAJMO/USAMO problems from 2002-2023 available. USACO problems from 2014 to 2023 (all divisions). Codeforces, AtCoder, DMOJ problems are added daily around 04:00 AM UTC, which may cause disruptions.

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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)
1301	Codeforces 288A: Polo the Penguin and Strings
1300	Codeforces 287B: Pipeline
1299	Codeforces 287A: IQ Test
1298	Codeforces 286E: Ladies' Shop
1297	Codeforces 286D: Tourists
1296	Codeforces 286C: Main Sequence
1295	Codeforces 286B: Shifting
1294	Codeforces 286A: Lucky Permutation
1293	Codeforces 285E: Positions in Permutations
1292	Codeforces 285D: Permutation Sum
1291	Codeforces 285C: Building Permutation
1290	Codeforces 285B: Find Marble
1289	Codeforces 285A: Slightly Decreasing Permutations
1288	Codeforces 284B: Cows and Poker Game
1287	Codeforces 284A: Cows and Primitive Roots
1286	Codeforces 283E: Cow Tennis Tournament
1285	Codeforces 283D: Cows and Cool Sequences
1284	Codeforces 283C: Coin Troubles
1283	Codeforces 283B: Cow Program
1282	Codeforces 283A: Cows and Sequence
1281	Codeforces 282E: Sausage Maximization
1280	Codeforces 282D: Yet Another Number Game
1279	Codeforces 282C: XOR and OR
1278	Codeforces 282B: Painting Eggs
1277	Codeforces 282A: Bit++
1276	Codeforces 281B: Nearest Fraction
1275	Codeforces 281A: Word Capitalization
1274	Codeforces 280E: Sequence Transformation
1273	Codeforces 280D: k-Maximum Subsequence Sum
1272	Codeforces 280C: Game on Tree
1271	Codeforces 280B: Maximum Xor Secondary
1270	Codeforces 280A: Rectangle Puzzle
1269	Codeforces 279E: Beautiful Decomposition
1268	Codeforces 279D: The Minimum Number of Variables
1267	Codeforces 279C: Ladder
1266	Codeforces 279B: Books
1265	Codeforces 279A: Point on Spiral
1264	Codeforces 278B: New Problem
1263	Codeforces 278A: Circle Line
1262	Codeforces 277E: Binary Tree on Plane
1261	Codeforces 277D: Google Code Jam
1260	Codeforces 277C: Game
1259	Codeforces 277B: Set of Points
1258	Codeforces 277A: Learning Languages
1257	Codeforces 276E: Little Girl and Problem on Trees
1256	Codeforces 276D: Little Girl and Maximum XOR
1255	Codeforces 276C: Little Girl and Maximum Sum
1254	Codeforces 276B: Little Girl and Game
1253	Codeforces 276A: Lunch Rush
1252	Codeforces 275B: Convex Shape

Problem Name (click to add insights/hints, view summary of insights/hints and similar problems)

1301

Codeforces 288A: Polo the Penguin and Strings

1300

Codeforces 287B: Pipeline

1299

Codeforces 287A: IQ Test

1298

Codeforces 286E: Ladies' Shop

1297

Codeforces 286D: Tourists

1296