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)
10301	AtCoder ABC274: E. Booster
10300	AtCoder ABC274: D. Robot Arms 2
10299	AtCoder ABC274: C. Ameba
10298	AtCoder ABC274: B. Line Sensor
10297	AtCoder ABC274: A. Batting Average
10296	AtCoder ABC273: Ex. Inv(0,1)ving Insert(1,0)n
10295	AtCoder ABC273: G. Row Column Sums 2
10294	AtCoder ABC273: F. Hammer 2
10293	AtCoder ABC273: E. Notebook
10292	AtCoder ABC273: D. LRUD Instructions
10291	AtCoder ABC273: C. (K+1)-th Largest Number
10290	AtCoder ABC273: B. Broken Rounding
10289	AtCoder ABC273: A. A Recursive Function
10288	AtCoder ABC272: Ex. Flipping Coins 2
10287	AtCoder ABC272: G. Yet Another mod M
10286	AtCoder ABC272: F. Two Strings
10285	AtCoder ABC272: E. Add and Mex
10284	AtCoder ABC272: D. Root M Leaper
10283	AtCoder ABC272: C. Max Even
10282	AtCoder ABC272: B. Everyone is Friends
10281	AtCoder ABC272: A. Integer Sum
10280	AtCoder ABC271: Ex. General General
10279	AtCoder ABC271: G. Access Counter
10278	AtCoder ABC271: F. XOR on Grid Path
10277	AtCoder ABC271: E. Subsequence Path
10276	AtCoder ABC271: D. Flip and Adjust
10275	AtCoder ABC271: C. Manga
10274	AtCoder ABC271: B. Maintain Multiple Sequences
10273	AtCoder ABC271: A. 484558
10272	AtCoder ABC270: Ex. add 1
10271	AtCoder ABC270: G. Sequence in mod P
10270	AtCoder ABC270: F. Transportation
10269	AtCoder ABC270: E. Apple Baskets on Circle
10268	AtCoder ABC270: D. Stones
10267	AtCoder ABC270: C. Simple path
10266	AtCoder ABC270: B. Hammer
10265	AtCoder ABC270: A. 1-2-4 Test
10264	AtCoder ABC269: Ex. Antichain
10263	AtCoder ABC269: G. Reversible Cards 2
10262	AtCoder ABC269: F. Numbered Checker
10261	AtCoder ABC269: E. Last Rook
10260	AtCoder ABC269: D. Do use hexagon grid
10259	AtCoder ABC269: C. Submask
10258	AtCoder ABC269: B. Rectangle Detection
10257	AtCoder ABC269: A. Anyway Takahashi
10256	AtCoder ABC268: Ex. Taboo
10255	AtCoder ABC268: G. Random Student ID
10254	AtCoder ABC268: F. Best Concatenation
10253	AtCoder ABC268: E. Chinese Restaurant (Three-Star Version)
10252	AtCoder ABC268: D. Unique Username

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

10301

AtCoder ABC274: E. Booster

10300

AtCoder ABC274: D. Robot Arms 2

10299

AtCoder ABC274: C. Ameba

10298

AtCoder ABC274: B. Line Sensor

10297

AtCoder ABC274: A. Batting Average

10296