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)
5651	Codeforces 1272F: Two Bracket Sequences
5650	Codeforces 1272E: Nearest Opposite Parity
5649	Codeforces 1272D: Remove One Element
5648	Codeforces 1272C: Yet Another Broken Keyboard
5647	Codeforces 1272B: Snow Walking Robot
5646	Codeforces 1272A: Three Friends
5645	Codeforces 1271F: Divide The Students
5644	Codeforces 1271E: Common Number
5643	Codeforces 1271D: Portals
5642	Codeforces 1271C: Shawarma Tent
5641	Codeforces 1271B: Blocks
5640	Codeforces 1271A: Suits
5639	Codeforces 1270I: Xor on Figures
5638	Codeforces 1270H: Number of Components
5637	Codeforces 1270G: Subset with Zero Sum
5636	Codeforces 1270F: Awesome Substrings
5635	Codeforces 1270E: Divide Points
5634	Codeforces 1270D: Strange Device
5633	Codeforces 1270C: Make Good
5632	Codeforces 1270B: Interesting Subarray
5631	Codeforces 1270A: Card Game
5630	Codeforces 1269B: Modulo Equality
5629	Codeforces 1269A: Equation
5628	Codeforces 1268E: Happy Cactus
5627	Codeforces 1268D: Invertation in Tournament
5626	Codeforces 1268C: K Integers
5625	Codeforces 1268B: Domino for Young
5624	Codeforces 1268A: Long Beautiful Integer
5623	Codeforces 1267L: Lexicography
5622	Codeforces 1267K: Key Storage
5621	Codeforces 1267J: Just Arrange the Icons
5620	Codeforces 1267I: Intriguing Selection
5619	Codeforces 1267H: Help BerLine
5618	Codeforces 1267G: Game Relics
5617	Codeforces 1267F: Foolprüf Security
5616	Codeforces 1267E: Elections
5615	Codeforces 1267D: DevOps Best Practices
5614	Codeforces 1267C: Cactus Revenge
5613	Codeforces 1267B: Balls of Buma
5612	Codeforces 1267A: Apprentice Learning Trajectory
5611	Codeforces 1266H: Red-Blue Graph
5610	Codeforces 1266G: Permutation Concatenation
5609	Codeforces 1266F: Almost Same Distance
5608	Codeforces 1266E: Spaceship Solitaire
5607	Codeforces 1266D: Decreasing Debts
5606	Codeforces 1266C: Diverse Matrix
5605	Codeforces 1266B: Dice Tower
5604	Codeforces 1266A: Competitive Programmer
5603	Codeforces 1265E: Beautiful Mirrors
5602	Codeforces 1265B: Beautiful Numbers

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

5651

Codeforces 1272F: Two Bracket Sequences

5650

Codeforces 1272E: Nearest Opposite Parity

5649

Codeforces 1272D: Remove One Element

5648

Codeforces 1272C: Yet Another Broken Keyboard

5647

Codeforces 1272B: Snow Walking Robot

5646