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)
10351	AtCoder ABC280: G. Do Use Hexagon Grid 2
10350	AtCoder ABC280: F. Pay or Receive
10349	AtCoder ABC280: E. Critical Hit
10348	AtCoder ABC280: D. Factorial and Multiple
10347	AtCoder ABC280: C. Extra Character
10346	AtCoder ABC280: B. Inverse Prefix Sum
10345	AtCoder ABC280: A. Pawn on a Grid
10344	AtCoder ABC279: Ex. Sum of Prod of Min
10343	AtCoder ABC279: G. At Most 2 Colors
10342	AtCoder ABC279: F. BOX
10341	AtCoder ABC279: E. Cheating Amidakuji
10340	AtCoder ABC279: D. Freefall
10339	AtCoder ABC279: C. RANDOM
10338	AtCoder ABC279: B. LOOKUP
10337	AtCoder ABC279: A. wwwvvvvvv
10336	AtCoder ABC278: Ex. make 1
10335	AtCoder ABC278: G. Generalized Subtraction Game
10334	AtCoder ABC278: F. Shiritori
10333	AtCoder ABC278: E. Grid Filling
10332	AtCoder ABC278: D. All Assign Point Add
10331	AtCoder ABC278: C. FF
10330	AtCoder ABC278: B. Misjudge the Time
10329	AtCoder ABC278: A. Shift
10328	AtCoder ABC277: Ex. Constrained Sums
10327	AtCoder ABC277: G. Random Walk to Millionaire
10326	AtCoder ABC277: F. Sorting a Matrix
10325	AtCoder ABC277: E. Crystal Switches
10324	AtCoder ABC277: D. Takahashi's Solitaire
10323	AtCoder ABC277: C. Ladder Takahashi
10322	AtCoder ABC277: B. Playing Cards Validation
10321	AtCoder ABC277: A. ^{-1}
10320	AtCoder ABC276: Ex. Construct a Matrix
10319	AtCoder ABC276: G. Count Sequences
10318	AtCoder ABC276: F. Double Chance
10317	AtCoder ABC276: E. Round Trip
10316	AtCoder ABC276: D. Divide by 2 or 3
10315	AtCoder ABC276: C. Previous Permutation
10314	AtCoder ABC276: B. Adjacency List
10313	AtCoder ABC276: A. Rightmost
10312	AtCoder ABC275: Ex. Monster
10311	AtCoder ABC275: G. Infinite Knapsack
10310	AtCoder ABC275: F. Erase Subarrays
10309	AtCoder ABC275: E. Sugoroku 4
10308	AtCoder ABC275: D. Yet Another Recursive Function
10307	AtCoder ABC275: C. Counting Squares
10306	AtCoder ABC275: B. ABC-DEF
10305	AtCoder ABC275: A. Find Takahashi
10304	AtCoder ABC274: Ex. XOR Sum of Arrays
10303	AtCoder ABC274: G. Security Camera 3
10302	AtCoder ABC274: F. Fishing

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

10351

AtCoder ABC280: G. Do Use Hexagon Grid 2

10350

AtCoder ABC280: F. Pay or Receive

10349

AtCoder ABC280: E. Critical Hit

10348

AtCoder ABC280: D. Factorial and Multiple

10347

AtCoder ABC280: C. Extra Character

10346