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)
2801	Codeforces 661C: Array Sum
2800	Codeforces 661B: Seasons
2799	Codeforces 661A: Lazy Caterer Sequence
2798	Codeforces 660F: Bear and Bowling 4
2797	Codeforces 660E: Different Subsets For All Tuples
2796	Codeforces 660D: Number of Parallelograms
2795	Codeforces 660C: Hard Process
2794	Codeforces 660B: Seating On Bus
2793	Codeforces 660A: Co-prime Array
2792	Codeforces 659G: Fence Divercity
2791	Codeforces 659F: Polycarp and Hay
2790	Codeforces 659E: New Reform
2789	Codeforces 659D: Bicycle Race
2788	Codeforces 659C: Tanya and Toys
2787	Codeforces 659B: Qualifying Contest
2786	Codeforces 659A: Round House
2785	Codeforces 658A: Bear and Reverse Radewoosh
2784	Codeforces 656G: You're a Professional
2783	Codeforces 656F: Ace It!
2782	Codeforces 656E: Out of Controls
2781	Codeforces 656D: Rosetta Problem
2780	Codeforces 656C: Without Text
2779	Codeforces 656B: Scrambled
2778	Codeforces 656A: Da Vinci Powers
2777	Codeforces 653G: Move by Prime
2776	Codeforces 653F: Paper task
2775	Codeforces 653E: Bear and Forgotten Tree 2
2774	Codeforces 653D: Delivery Bears
2773	Codeforces 653C: Bear and Up-Down
2772	Codeforces 653B: Bear and Compressing
2771	Codeforces 653A: Bear and Three Balls
2770	Codeforces 652F: Ants on a Circle
2769	Codeforces 652E: Pursuit For Artifacts
2768	Codeforces 652D: Nested Segments
2767	Codeforces 652C: Foe Pairs
2766	Codeforces 652B: z-sort
2765	Codeforces 652A: Gabriel and Caterpillar
2764	Codeforces 651B: Beautiful Paintings
2763	Codeforces 651A: Joysticks
2762	Codeforces 650E: Clockwork Bomb
2761	Codeforces 650D: Zip-line
2760	Codeforces 650C: Table Compression
2759	Codeforces 650B: Image Preview
2758	Codeforces 650A: Watchmen
2757	Codeforces 645G: Armistice Area Apportionment
2756	Codeforces 645F: Cowslip Collections
2755	Codeforces 645E: Intellectual Inquiry
2754	Codeforces 645D: Robot Rapping Results Report
2753	Codeforces 645C: Enduring Exodus
2752	Codeforces 645B: Mischievous Mess Makers

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

2801

Codeforces 661C: Array Sum

2800

Codeforces 661B: Seasons

2799

Codeforces 661A: Lazy Caterer Sequence

2798

Codeforces 660F: Bear and Bowling 4

2797

Codeforces 660E: Different Subsets For All Tuples

2796