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)
23651	USACO 2020 February Contest, Silver: Clock Tree
23650	USACO 2020 February Contest, Silver: Triangles
23649	USACO 2020 February Contest, Silver: Swapity Swapity Swap
23648	USACO 2020 February Contest, Gold: Delegation
23647	USACO 2020 February Contest, Gold: Help Yourself
23646	USACO 2020 February Contest, Gold: Timeline
23645	USACO 2020 February Contest, Platinum: Help Yourself
23644	USACO 2020 February Contest, Platinum: Equilateral Triangles
23643	USACO 2020 February Contest, Platinum: Delegation
23642	USACO 2020 January Contest, Bronze: Race
23641	USACO 2020 January Contest, Bronze: Photoshoot
23640	USACO 2020 January Contest, Bronze: Word Processor
23639	USACO 2020 January Contest, Silver: Wormhole Sort
23638	USACO 2020 January Contest, Silver: Loan Repayment
23637	USACO 2020 January Contest, Silver: Berry Picking
23636	USACO 2020 January Contest, Gold: Springboards
23635	USACO 2020 January Contest, Gold: Farmer John Solves 3SUM
23634	USACO 2020 January Contest, Gold: Time is Mooney
23633	USACO 2020 January Contest, Platinum: Falling Portals
23632	USACO 2020 January Contest, Platinum: Non-Decreasing Subsequences
23631	USACO 2020 January Contest, Platinum: Cave Paintings
23630	USACO 2020 December Contest, Bronze: Stuck in a Rut
23629	USACO 2020 December Contest, Bronze: Daisy Chains
23628	USACO 2020 December Contest, Bronze: Do You Know Your ABCs?
23627	USACO 2020 December Contest, Silver: Stuck in a Rut
23626	USACO 2020 December Contest, Silver: Rectangular Pasture
23625	USACO 2020 December Contest, Silver: Cowntagion
23624	USACO 2020 December Contest, Gold: Square Pasture
23623	USACO 2020 December Contest, Gold: Bovine Genetics
23622	USACO 2020 December Contest, Gold: Replication
23621	USACO 2020 December Contest, Platinum: Cowmistry
23620	USACO 2020 December Contest, Platinum: Spaceship
23619	USACO 2020 December Contest, Platinum: Sleeping Cows
23618	USACO 2019 US Open Contest, Bronze: Cow Evolution
23617	USACO 2019 US Open Contest, Bronze: Milk Factory
23616	USACO 2019 US Open Contest, Bronze: Bucket Brigade
23615	USACO 2019 US Open Contest, Silver: Fence Planning
23614	USACO 2019 US Open Contest, Silver: Cow Steeplechase II
23613	USACO 2019 US Open Contest, Silver: Left Out
23612	USACO 2019 US Open Contest, Gold: Balancing Inversions
23611	USACO 2019 US Open Contest, Gold: I Would Walk 500 Miles
23610	USACO 2019 US Open Contest, Gold: Snakes
23609	USACO 2019 US Open Contest, Platinum: Valleys
23608	USACO 2019 US Open Contest, Platinum: Compound Escape
23607	USACO 2019 US Open Contest, Platinum: Tree Boxes
23606	USACO 2019 February Contest, Bronze: Measuring Traffic
23605	USACO 2019 February Contest, Bronze: The Great Revegetation
23604	USACO 2019 February Contest, Bronze: Sleepy Cow Herding
23603	USACO 2019 February Contest, Silver: The Great Revegetation
23602	USACO 2019 February Contest, Silver: Painting the Barn

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

23651

USACO 2020 February Contest, Silver: Clock Tree

23650

USACO 2020 February Contest, Silver: Triangles

23649

USACO 2020 February Contest, Silver: Swapity Swapity Swap

23648

USACO 2020 February Contest, Gold: Delegation

23647

USACO 2020 February Contest, Gold: Help Yourself

23646