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)
6551	Codeforces 1451E1: Bitwise Queries (Easy Version)
6550	Codeforces 1451D: Circle Game
6549	Codeforces 1451C: String Equality
6548	Codeforces 1451B: Non-Substring Subsequence
6547	Codeforces 1451A: Subtract or Divide
6546	Codeforces 1450H2: Multithreading (Hard Version)
6545	Codeforces 1450H1: Multithreading (Easy Version)
6544	Codeforces 1450G: Communism
6543	Codeforces 1450F: The Struggling Contestant
6542	Codeforces 1450E: Capitalism
6541	Codeforces 1450D: Rating Compression
6540	Codeforces 1450C2: Errich-Tac-Toe (Hard Version)
6539	Codeforces 1450C1: Errich-Tac-Toe (Easy Version)
6538	Codeforces 1450B: Balls of Steel
6537	Codeforces 1450A: Avoid Trygub
6536	Codeforces 1447B: Numbers Box
6535	Codeforces 1447A: Add Candies
6534	Codeforces 1446F: Line Distance
6533	Codeforces 1446E: Long Recovery
6532	Codeforces 1446D2: Frequency Problem (Hard Version)
6531	Codeforces 1446D1: Frequency Problem (Easy Version)
6530	Codeforces 1446C: Xor Tree
6529	Codeforces 1446B: Catching Cheaters
6528	Codeforces 1446A: Knapsack
6527	Codeforces 1445B: Elimination
6526	Codeforces 1445A: Array Rearrangment
6525	Codeforces 1444E: Finding the Vertex
6524	Codeforces 1444D: Rectangular Polyline
6523	Codeforces 1444C: Team-Building
6522	Codeforces 1444B: Divide and Sum
6521	Codeforces 1444A: Division
6520	Codeforces 1443E: Long Permutation
6519	Codeforces 1443C: The Delivery Dilemma
6518	Codeforces 1443B: Saving the City
6517	Codeforces 1443A: Kids Seating
6516	Codeforces 1442F: Differentiating Games
6515	Codeforces 1442E: Black, White and Grey Tree
6514	Codeforces 1442D: Sum
6513	Codeforces 1442C: Graph Transpositions
6512	Codeforces 1442B: Identify the Operations
6511	Codeforces 1442A: Extreme Subtraction
6510	Codeforces 1440B: Sum of Medians
6509	Codeforces 1440A: Buy the String
6508	Codeforces 1439E: Cheat and Win
6507	Codeforces 1439D: INOI Final Contests
6506	Codeforces 1439C: Greedy Shopping
6505	Codeforces 1439B: Graph Subset Problem
6504	Codeforces 1439A2: Binary Table (Hard Version)
6503	Codeforces 1439A1: Binary Table (Easy Version)
6502	Codeforces 1438F: Olha and Igor

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

6551

Codeforces 1451E1: Bitwise Queries (Easy Version)

6550

Codeforces 1451D: Circle Game

6549

Codeforces 1451C: String Equality

6548

Codeforces 1451B: Non-Substring Subsequence

6547

Codeforces 1451A: Subtract or Divide

6546