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)
10601	AtCoder ABC312: A. Chord
10600	AtCoder ABC311: Ex. Many Illumination Plans
10599	AtCoder ABC311: G. One More Grid Task
10598	AtCoder ABC311: F. Yet Another Grid Task
10597	AtCoder ABC311: E. Defect-free Squares
10596	AtCoder ABC311: D. Grid Ice Floor
10595	AtCoder ABC311: C. Find it!
10594	AtCoder ABC311: B. Vacation Together
10593	AtCoder ABC311: A. First ABC
10592	AtCoder ABC310: Ex. Negative Cost
10591	AtCoder ABC310: G. Takahashi And Pass-The-Ball Game
10590	AtCoder ABC310: F. Make 10 Again
10589	AtCoder ABC310: E. NAND repeatedly
10588	AtCoder ABC310: D. Peaceful Teams
10587	AtCoder ABC310: C. Reversible
10586	AtCoder ABC310: B. Strictly Superior
10585	AtCoder ABC310: A. Order Something Else
10584	AtCoder ABC309: Ex. Simple Path Counting Problem
10583	AtCoder ABC309: G. Ban Permutation
10582	AtCoder ABC309: F. Box in Box
10581	AtCoder ABC309: E. Family and Insurance
10580	AtCoder ABC309: D. Add One Edge
10579	AtCoder ABC309: C. Medicine
10578	AtCoder ABC309: B. Rotate
10577	AtCoder ABC309: A. Nine
10576	AtCoder ABC308: Ex. Make Q
10575	AtCoder ABC308: G. Minimum Xor Pair Query
10574	AtCoder ABC308: F. Vouchers
10573	AtCoder ABC308: E. MEX
10572	AtCoder ABC308: D. Snuke Maze
10571	AtCoder ABC308: C. Standings
10570	AtCoder ABC308: B. Default Price
10569	AtCoder ABC308: A. New Scheme
10568	AtCoder ABC307: Ex. Marquee
10567	AtCoder ABC307: G. Approximate Equalization
10566	AtCoder ABC307: F. Virus 2
10565	AtCoder ABC307: E. Distinct Adjacent
10564	AtCoder ABC307: D. Mismatched Parentheses
10563	AtCoder ABC307: C. Ideal Sheet
10562	AtCoder ABC307: B. racecar
10561	AtCoder ABC307: A. Weekly Records
10560	AtCoder ABC306: Ex. Balance Scale
10559	AtCoder ABC306: G. Return to 1
10558	AtCoder ABC306: F. Merge Sets
10557	AtCoder ABC306: E. Best Performances
10556	AtCoder ABC306: D. Poisonous Full-Course
10555	AtCoder ABC306: C. Centers
10554	AtCoder ABC306: B. Base 2
10553	AtCoder ABC306: A. Echo
10552	AtCoder ABC305: Ex. Shojin

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

10601

AtCoder ABC312: A. Chord

10600

AtCoder ABC311: Ex. Many Illumination Plans

10599

AtCoder ABC311: G. One More Grid Task

10598

AtCoder ABC311: F. Yet Another Grid Task

10597

AtCoder ABC311: E. Defect-free Squares

10596