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)
9301	AtCoder ABC128: E. Roadwork
9300	AtCoder ABC128: D. equeue
9299	AtCoder ABC128: C. Switches
9298	AtCoder ABC128: B. Guidebook
9297	AtCoder ABC128: A. Apple Pie
9296	AtCoder ABC127: F. Absolute Minima
9295	AtCoder ABC127: E. Cell Distance
9294	AtCoder ABC127: D. Integer Cards
9293	AtCoder ABC127: C. Prison
9292	AtCoder ABC127: B. Algae
9291	AtCoder ABC127: A. Ferris Wheel
9290	AtCoder ABC126: F. XOR Matching
9289	AtCoder ABC126: E. 1 or 2
9288	AtCoder ABC126: D. Even Relation
9287	AtCoder ABC126: C. Dice and Coin
9286	AtCoder ABC126: B. YYMM or MMYY
9285	AtCoder ABC126: A. Changing a Character
9284	AtCoder ABC125: D. Flipping Signs
9283	AtCoder ABC125: C. GCD on Blackboard
9282	AtCoder ABC125: B. Resale
9281	AtCoder ABC125: A. Biscuit Generator
9280	AtCoder ABC124: D. Handstand
9279	AtCoder ABC124: C. Coloring Colorfully
9278	AtCoder ABC124: B. Great Ocean View
9277	AtCoder ABC124: A. Buttons
9276	AtCoder ABC123: D. Cake 123
9275	AtCoder ABC123: C. Five Transportations
9274	AtCoder ABC123: B. Five Dishes
9273	AtCoder ABC123: A. Five Antennas
9272	AtCoder ABC122: D. We Like AGC
9271	AtCoder ABC122: C. GeT AC
9270	AtCoder ABC122: B. ATCoder
9269	AtCoder ABC122: A. Double Helix
9268	AtCoder ABC121: D. XOR World
9267	AtCoder ABC121: C. Energy Drink Collector
9266	AtCoder ABC121: B. Can you solve this?
9265	AtCoder ABC121: A. White Cells
9264	AtCoder ABC120: D. Decayed Bridges
9263	AtCoder ABC120: C. Unification
9262	AtCoder ABC120: B. K-th Common Divisor
9261	AtCoder ABC120: A. Favorite Sound
9260	AtCoder ABC119: D. Lazy Faith
9259	AtCoder ABC119: C. Synthetic Kadomatsu
9258	AtCoder ABC119: B. Digital Gifts
9257	AtCoder ABC119: A. Still TBD
9256	AtCoder ABC118: D. Match Matching
9255	AtCoder ABC118: C. Monsters Battle Royale
9254	AtCoder ABC118: B. Foods Loved by Everyone
9253	AtCoder ABC118: A. B +/- A
9252	AtCoder ABC117: D. XXOR

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

9301

AtCoder ABC128: E. Roadwork

9300

AtCoder ABC128: D. equeue

9299

AtCoder ABC128: C. Switches

9298

AtCoder ABC128: B. Guidebook

9297

AtCoder ABC128: A. Apple Pie

9296