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)
9351	AtCoder ABC137: A. +-x
9350	AtCoder ABC136: F. Enclosed Points
9349	AtCoder ABC136: E. Max GCD
9348	AtCoder ABC136: D. Gathering Children
9347	AtCoder ABC136: C. Build Stairs
9346	AtCoder ABC136: B. Uneven Numbers
9345	AtCoder ABC136: A. Transfer
9344	AtCoder ABC135: F. Strings of Eternity
9343	AtCoder ABC135: E. Golf
9342	AtCoder ABC135: D. Digits Parade
9341	AtCoder ABC135: C. City Savers
9340	AtCoder ABC135: B. 0 or 1 Swap
9339	AtCoder ABC135: A. Harmony
9338	AtCoder ABC134: F. Permutation Oddness
9337	AtCoder ABC134: E. Sequence Decomposing
9336	AtCoder ABC134: D. Preparing Boxes
9335	AtCoder ABC134: C. Exception Handling
9334	AtCoder ABC134: B. Golden Apple
9333	AtCoder ABC134: A. Dodecagon
9332	AtCoder ABC133: F. Colorful Tree
9331	AtCoder ABC133: E. Virus Tree 2
9330	AtCoder ABC133: D. Rain Flows into Dams
9329	AtCoder ABC133: C. Remainder Minimization 2019
9328	AtCoder ABC133: B. Good Distance
9327	AtCoder ABC133: A. T or T
9326	AtCoder ABC132: F. Small Products
9325	AtCoder ABC132: E. Hopscotch Addict
9324	AtCoder ABC132: D. Blue and Red Balls
9323	AtCoder ABC132: C. Divide the Problems
9322	AtCoder ABC132: B. Ordinary Number
9321	AtCoder ABC132: A. Fifty-Fifty
9320	AtCoder ABC131: F. Must Be Rectangular!
9319	AtCoder ABC131: E. Friendships
9318	AtCoder ABC131: D. Megalomania
9317	AtCoder ABC131: C. Anti-Division
9316	AtCoder ABC131: B. Bite Eating
9315	AtCoder ABC131: A. Security
9314	AtCoder ABC130: F. Minimum Bounding Box
9313	AtCoder ABC130: E. Common Subsequence
9312	AtCoder ABC130: D. Enough Array
9311	AtCoder ABC130: C. Rectangle Cutting
9310	AtCoder ABC130: B. Bounding
9309	AtCoder ABC130: A. Rounding
9308	AtCoder ABC129: F. Takahashi's Basics in Education and Learning
9307	AtCoder ABC129: E. Sum Equals Xor
9306	AtCoder ABC129: D. Lamp
9305	AtCoder ABC129: C. Typical Stairs
9304	AtCoder ABC129: B. Balance
9303	AtCoder ABC129: A. Airplane
9302	AtCoder ABC128: F. Frog Jump

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

9351

AtCoder ABC137: A. +-x

9350

AtCoder ABC136: F. Enclosed Points

9349

AtCoder ABC136: E. Max GCD

9348

AtCoder ABC136: D. Gathering Children

9347

AtCoder ABC136: C. Build Stairs

9346