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)
4351	Codeforces 1012D: AB-Strings
4350	Codeforces 1012C: Hills
4349	Codeforces 1012B: Chemical table
4348	Codeforces 1012A: Photo of The Sky
4347	Codeforces 1011B: Planning The Expedition
4346	Codeforces 1011A: Stages
4345	Codeforces 1010F: Tree
4344	Codeforces 1010E: Store
4343	Codeforces 1010D: Mars rover
4342	Codeforces 1010C: Border
4341	Codeforces 1010B: Rocket
4340	Codeforces 1010A: Fly
4339	Codeforces 1009G: Allowed Letters
4338	Codeforces 1009F: Dominant Indices
4337	Codeforces 1009E: Intercity Travelling
4336	Codeforces 1009D: Relatively Prime Graph
4335	Codeforces 1009C: Annoying Present
4334	Codeforces 1009B: Minimum Ternary String
4333	Codeforces 1009A: Game Shopping
4332	Codeforces 1008B: Turn the Rectangles
4331	Codeforces 1008A: Romaji
4330	Codeforces 1007E: Mini Metro
4329	Codeforces 1007D: Ants
4328	Codeforces 1007C: Guess two numbers
4327	Codeforces 1007B: Pave the Parallelepiped
4326	Codeforces 1007A: Reorder the Array
4325	Codeforces 1006F: Xor-Paths
4324	Codeforces 1006E: Military Problem
4323	Codeforces 1006D: Two Strings Swaps
4322	Codeforces 1006C: Three Parts of the Array
4321	Codeforces 1006B: Polycarp's Practice
4320	Codeforces 1006A: Adjacent Replacements
4319	Codeforces 1005F: Berland and the Shortest Paths
4318	Codeforces 1005E2: Median on Segments (General Case Edition)
4317	Codeforces 1005E1: Median on Segments (Permutations Edition)
4316	Codeforces 1005D: Polycarp and Div 3
4315	Codeforces 1005C: Summarize to the Power of Two
4314	Codeforces 1005B: Delete from the Left
4313	Codeforces 1005A: Tanya and Stairways
4312	Codeforces 1004F: Sonya and Bitwise OR
4311	Codeforces 1004E: Sonya and Ice Cream
4310	Codeforces 1004D: Sonya and Matrix
4309	Codeforces 1004C: Sonya and Robots
4308	Codeforces 1004B: Sonya and Exhibition
4307	Codeforces 1004A: Sonya and Hotels
4306	Codeforces 1003F: Abbreviation
4305	Codeforces 1003E: Tree Constructing
4304	Codeforces 1003D: Coins and Queries
4303	Codeforces 1003C: Intense Heat
4302	Codeforces 1003B: Binary String Constructing

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

4351

Codeforces 1012D: AB-Strings

4350

Codeforces 1012C: Hills

4349

Codeforces 1012B: Chemical table

4348

Codeforces 1012A: Photo of The Sky

4347

Codeforces 1011B: Planning The Expedition

4346