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.

Need help searching? Click for format/examples of problems

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)
6451	Codeforces 1428B: Belted Rooms
6450	Codeforces 1428A: Box is Pull
6449	Codeforces 1427H: Prison Break
6448	Codeforces 1427G: One Billion Shades of Grey
6447	Codeforces 1427F: Boring Card Game
6446	Codeforces 1427E: Xum
6445	Codeforces 1427D: Unshuffling a Deck
6444	Codeforces 1427C: The Hard Work of Paparazzi
6443	Codeforces 1427B: Chess Cheater
6442	Codeforces 1427A: Avoiding Zero
6441	Codeforces 1426F: Number of Subsequences
6440	Codeforces 1426E: Rock, Paper, Scissors
6439	Codeforces 1426D: Non-zero Segments
6438	Codeforces 1426C: Increase and Copy
6437	Codeforces 1426B: Symmetric Matrix
6436	Codeforces 1426A: Floor Number
6435	Codeforces 1425I: Impressive Harvesting of The Orchard
6434	Codeforces 1425H: Huge Boxes of Animal Toys
6433	Codeforces 1425F: Flamingoes of Mystery
6432	Codeforces 1425E: Excitation of Atoms
6431	Codeforces 1425D: Danger of Mad Snakes
6430	Codeforces 1425C: Captain of Knights
6429	Codeforces 1425B: Blue and Red of Our Faculty!
6428	Codeforces 1425A: Arena of Greed
6427	Codeforces 1424M: Ancient Language
6426	Codeforces 1424G: Years
6425	Codeforces 1423N: BubbleSquare Tokens
6424	Codeforces 1423M: Milutin's Plums
6423	Codeforces 1423L: Light switches
6422	Codeforces 1423K: Lonely Numbers
6421	Codeforces 1423J: Bubble Cup hypothesis
6420	Codeforces 1423I: Lookup Tables
6419	Codeforces 1423H: Virus
6418	Codeforces 1423G: Growing flowers
6417	Codeforces 1423F: Coins
6416	Codeforces 1423E: 5G Antenna Towers
6415	Codeforces 1423D: Does anyone else hate the wind?
6414	Codeforces 1423C: Dušan's Railway
6413	Codeforces 1423B: Valuable Paper
6412	Codeforces 1423A: Wakanda Forever
6411	Codeforces 1422F: Boring Queries
6410	Codeforces 1422E: Minlexes
6409	Codeforces 1422D: Returning Home
6408	Codeforces 1422C: Bargain
6407	Codeforces 1422B: Nice Matrix
6406	Codeforces 1422A: Fence
6405	Codeforces 1421E: Swedish Heroes
6404	Codeforces 1421D: Hexagons
6403	Codeforces 1421C: Palindromifier
6402	Codeforces 1421B: Putting Bricks in the Wall

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

6451

Codeforces 1428B: Belted Rooms

6450

Codeforces 1428A: Box is Pull

6449

Codeforces 1427H: Prison Break

6448

Codeforces 1427G: One Billion Shades of Grey

6447

Codeforces 1427F: Boring Card Game

6446