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)
1451	Codeforces 327C: Magic Five
1450	Codeforces 327B: Hungry Sequence
1449	Codeforces 327A: Flipping Game
1448	Codeforces 325E: The Red Button
1447	Codeforces 325D: Reclamation
1446	Codeforces 325C: Monsters and Diamonds
1445	Codeforces 325B: Stadium and Games
1444	Codeforces 325A: Square and Rectangles
1443	Codeforces 323C: Two permutations
1442	Codeforces 323B: Tournament-graph
1441	Codeforces 323A: Black-and-White Cube
1440	Codeforces 322B: Ciel and Flowers
1439	Codeforces 322A: Ciel and Dancing
1438	Codeforces 321E: Ciel and Gondolas
1437	Codeforces 321D: Ciel and Flipboard
1436	Codeforces 321C: Ciel the Commander
1435	Codeforces 321B: Ciel and Duel
1434	Codeforces 321A: Ciel and Robot
1433	Codeforces 320B: Ping-Pong (Easy Version)
1432	Codeforces 320A: Magic Numbers
1431	Codeforces 319E: Ping-Pong
1430	Codeforces 319D: Have You Ever Heard About the Word?
1429	Codeforces 319C: Kalila and Dimna in the Logging Industry
1428	Codeforces 319B: Psychos in a Line
1427	Codeforces 319A: Malek Dance Club
1426	Codeforces 318B: Strings of Power
1425	Codeforces 318A: Even Odds
1424	Codeforces 317E: Princess and Her Shadow
1423	Codeforces 317D: Game with Powers
1422	Codeforces 317C: Balance
1421	Codeforces 317B: Ants
1420	Codeforces 317A: Perfect Pair
1419	Codeforces 316G3: Good Substrings
1418	Codeforces 316G2: Good Substrings
1417	Codeforces 316G1: Good Substrings
1416	Codeforces 316F3: Suns and Rays
1415	Codeforces 316F2: Suns and Rays
1414	Codeforces 316F1: Suns and Rays
1413	Codeforces 316E3: Summer Homework
1412	Codeforces 316E2: Summer Homework
1411	Codeforces 316E1: Summer Homework
1410	Codeforces 316D3: PE Lesson
1409	Codeforces 316D2: PE Lesson
1408	Codeforces 316D1: PE Lesson
1407	Codeforces 316C2: Tidying Up
1406	Codeforces 316C1: Tidying Up
1405	Codeforces 316B2: EKG
1404	Codeforces 316B1: EKG
1403	Codeforces 316A2: Special Task
1402	Codeforces 316A1: Special Task

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

1451

Codeforces 327C: Magic Five

1450

Codeforces 327B: Hungry Sequence

1449

Codeforces 327A: Flipping Game

1448

Codeforces 325E: The Red Button

1447

Codeforces 325D: Reclamation

1446