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.

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)
3651	Codeforces 855D: Rowena Ravenclaw's Diadem
3650	Codeforces 855C: Helga Hufflepuff's Cup
3649	Codeforces 855B: Marvolo Gaunt's Ring
3648	Codeforces 855A: Tom Riddle's Diary
3647	Codeforces 854B: Maxim Buys an Apartment
3646	Codeforces 854A: Fraction
3645	Codeforces 853E: Lada Malina
3644	Codeforces 853D: Michael and Charging Stations
3643	Codeforces 853C: Boredom
3642	Codeforces 853B: Jury Meeting
3641	Codeforces 853A: Planning
3640	Codeforces 852I: Dating
3639	Codeforces 852H: Bob and stages
3638	Codeforces 852G: Bathroom terminal
3637	Codeforces 852F: Product transformation
3636	Codeforces 852E: Casinos and travel
3635	Codeforces 852D: Exploration plan
3634	Codeforces 852C: Property
3633	Codeforces 852B: Neural Network country
3632	Codeforces 852A: Digits
3631	Codeforces 851B: Arpa and an exam about geometry
3630	Codeforces 851A: Arpa and a research in Mexican wave
3629	Codeforces 850F: Rainbow Balls
3628	Codeforces 850E: Random Elections
3627	Codeforces 850D: Tournament Construction
3626	Codeforces 850C: Arpa and a game with Mojtaba
3625	Codeforces 850B: Arpa and a list of numbers
3624	Codeforces 850A: Five Dimensional Points
3623	Codeforces 849B: Tell Your World
3622	Codeforces 849A: Odds and Ends
3621	Codeforces 848E: Days of Floral Colours
3620	Codeforces 848D: Shake It!
3619	Codeforces 848C: Goodbye Souvenir
3618	Codeforces 848B: Rooter's Song
3617	Codeforces 848A: From Y to Y
3616	Codeforces 847M: Weather Tomorrow
3615	Codeforces 847L: Berland SU Computer Network
3614	Codeforces 847K: Travel Cards
3613	Codeforces 847J: Students Initiation
3612	Codeforces 847I: Noise Level
3611	Codeforces 847H: Load Testing
3610	Codeforces 847G: University Classes
3609	Codeforces 847F: Berland Elections
3608	Codeforces 847E: Packmen
3607	Codeforces 847D: Dog Show
3606	Codeforces 847C: Sum of Nestings
3605	Codeforces 847B: Preparing for Merge Sort
3604	Codeforces 847A: Union of Doubly Linked Lists
3603	Codeforces 846F: Random Query
3602	Codeforces 846E: Chemistry in Berland

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

3651

Codeforces 855D: Rowena Ravenclaw's Diadem

3650

Codeforces 855C: Helga Hufflepuff's Cup

3649

Codeforces 855B: Marvolo Gaunt's Ring

3648

Codeforces 855A: Tom Riddle's Diary

3647

Codeforces 854B: Maxim Buys an Apartment

3646