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)
601	Codeforces 124A: The number of positions
600	Codeforces 123E: Maze
599	Codeforces 123D: String
598	Codeforces 123C: Brackets
597	Codeforces 123B: Squares
596	Codeforces 123A: Prime Permutation
595	Codeforces 122B: Lucky Substring
594	Codeforces 122A: Lucky Division
593	Codeforces 121E: Lucky Array
592	Codeforces 121D: Lucky Segments
591	Codeforces 121C: Lucky Permutation
590	Codeforces 121B: Lucky Transformation
589	Codeforces 121A: Lucky Sum
588	Codeforces 120J: Minimum Sum
587	Codeforces 120I: Luck is in Numbers
586	Codeforces 120H: Brevity is Soul of Wit
585	Codeforces 120G: Boom
584	Codeforces 120F: Spiders
583	Codeforces 120E: Put Knight!
582	Codeforces 120D: Three Sons
581	Codeforces 120C: Winnie-the-Pooh and honey
580	Codeforces 120B: Quiz League
579	Codeforces 120A: Elevator
578	Codeforces 119E: Alternative Reality
577	Codeforces 119D: String Transformation
576	Codeforces 119C: Education Reform
575	Codeforces 119B: Before Exam
574	Codeforces 119A: Epic Game
573	Codeforces 118E: Bertown roads
572	Codeforces 118D: Caesar's Legions
571	Codeforces 118C: Fancy Number
570	Codeforces 118B: Present from Lena
569	Codeforces 118A: String Task
568	Codeforces 117E: Tree or not Tree
567	Codeforces 117D: Not Quick Transformation
566	Codeforces 117C: Cycle
565	Codeforces 117B: Very Interesting Game
564	Codeforces 117A: Elevator
563	Codeforces 116B: Little Pigs and Wolves
562	Codeforces 116A: Tram
561	Codeforces 115E: Linear Kingdom Races
560	Codeforces 115D: Unambiguous Arithmetic Expression
559	Codeforces 115C: Plumber
558	Codeforces 115B: Lawnmower
557	Codeforces 115A: Party
556	Codeforces 114B: PFAST Inc.
555	Codeforces 114A: Cifera
554	Codeforces 113E: Sleeping
553	Codeforces 113D: Museum
552	Codeforces 113C: Double Happiness

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

601

Codeforces 124A: The number of positions

600

Codeforces 123E: Maze

599

Codeforces 123D: String

598

Codeforces 123C: Brackets

597

Codeforces 123B: Squares

596