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)
23801	DMOJ NOIP '07 P2 - Expanding Strings
23800	DMOJ NOIP '07 P1 - Counting Numbers
23799	DMOJ IOI '04 P3 - Polygon
23798	USACO 2023 US Open Contest, Bronze: Rotate and Shift
23797	USACO 2023 US Open Contest, Bronze: Moo Language
23796	USACO 2023 US Open Contest, Bronze: FEB
23795	USACO 2023 US Open Contest, Silver: Pareidolia
23794	USACO 2023 US Open Contest, Silver: Field Day
23793	USACO 2023 US Open Contest, Silver: Milk Sum
23792	USACO 2023 US Open Contest, Gold: Tree Merging
23791	USACO 2023 US Open Contest, Gold: Pareidolia
23790	USACO 2023 US Open Contest, Gold: Custodial Cleanup
23789	USACO 2023 US Open Contest, Platinum: Triples of Cows
23788	USACO 2023 US Open Contest, Platinum: Good Bitstrings
23787	USACO 2023 US Open Contest, Platinum: Pareidolia
23786	USACO 2023 February Contest, Bronze: Watching Mooloo
23785	USACO 2023 February Contest, Bronze: Stamp Grid
23784	USACO 2023 February Contest, Bronze: Hungry Cow
23783	USACO 2023 February Contest, Silver: Moo Route II
23782	USACO 2023 February Contest, Silver: Cow-libi
23781	USACO 2023 February Contest, Silver: Bakery
23780	USACO 2023 February Contest, Gold: Piling Papers
23779	USACO 2023 February Contest, Gold: Fertilizing Pastures
23778	USACO 2023 February Contest, Gold: Equal Sum Subarrays
23777	USACO 2023 February Contest, Platinum: Watching Cowflix
23776	USACO 2023 February Contest, Platinum: Problem Setting
23775	USACO 2023 February Contest, Platinum: Hungry Cow
23774	USACO 2023 January Contest, Bronze: Moo Operations
23773	USACO 2023 January Contest, Bronze: Air Cownditioning II
23772	USACO 2023 January Contest, Bronze: Leaders
23771	USACO 2023 January Contest, Silver: Moo Route
23770	USACO 2023 January Contest, Silver: Following Directions
23769	USACO 2023 January Contest, Silver: Find and Replace
23768	USACO 2023 January Contest, Gold: Moo Route
23767	USACO 2023 January Contest, Gold: Lights Off
23766	USACO 2023 January Contest, Gold: Find and Replace
23765	USACO 2023 January Contest, Platinum: Subtree Activation
23764	USACO 2023 January Contest, Platinum: Mana Collection
23763	USACO 2023 January Contest, Platinum: Tractor Paths
23762	USACO 2022 US Open Contest, Bronze: Alchemy
23761	USACO 2022 US Open Contest, Bronze: Counting Liars
23760	USACO 2022 US Open Contest, Bronze: Photoshoot
23759	USACO 2022 US Open Contest, Silver: COW Operations
23758	USACO 2022 US Open Contest, Silver: Subset Equality
23757	USACO 2022 US Open Contest, Silver: Visits
23756	USACO 2022 US Open Contest, Gold: Balancing a Tree
23755	USACO 2022 US Open Contest, Gold: Pair Programming
23754	USACO 2022 US Open Contest, Gold: Apple Catching
23753	USACO 2022 US Open Contest, Platinum: Up Down Subsequence
23752	USACO 2022 US Open Contest, Platinum: Hoof and Brain

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

23801

DMOJ NOIP '07 P2 - Expanding Strings

23800

DMOJ NOIP '07 P1 - Counting Numbers

23799

DMOJ IOI '04 P3 - Polygon

23798

USACO 2023 US Open Contest, Bronze: Rotate and Shift

23797

USACO 2023 US Open Contest, Bronze: Moo Language

23796