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)
1851	Codeforces 425E: Sereja and Sets
1850	Codeforces 425D: Sereja and Squares
1849	Codeforces 425C: Sereja and Two Sequences
1848	Codeforces 425B: Sereja and Table
1847	Codeforces 425A: Sereja and Swaps
1846	Codeforces 424E: Colored Jenga
1845	Codeforces 424D: Biathlon Track
1844	Codeforces 424C: Magic Formulas
1843	Codeforces 424B: Megacity
1842	Codeforces 424A: Squats
1841	Codeforces 421D: Bug in Code
1840	Codeforces 421A: Pasha and Hamsters
1839	Codeforces 420E: Playing the ball
1838	Codeforces 420D: Cup Trick
1837	Codeforces 420C: Bug in Code
1836	Codeforces 420B: Online Meeting
1835	Codeforces 420A: Start Up
1834	Codeforces 418E: Tricky Password
1833	Codeforces 418D: Big Problems for Organizers
1832	Codeforces 417E: Square Table
1831	Codeforces 417D: Cunning Gena
1830	Codeforces 417C: Football
1829	Codeforces 417B: Crash
1828	Codeforces 417A: Elimination
1827	Codeforces 416E: President's Path
1826	Codeforces 416D: Population Size
1825	Codeforces 416C: Booking System
1824	Codeforces 416B: Art Union
1823	Codeforces 416A: Guess a number!
1822	Codeforces 415B: Mashmokh and Tokens
1821	Codeforces 415A: Mashmokh and Lights
1820	Codeforces 414E: Mashmokh's Designed Problem
1819	Codeforces 414D: Mashmokh and Water Tanks
1818	Codeforces 414C: Mashmokh and Reverse Operation
1817	Codeforces 414B: Mashmokh and ACM
1816	Codeforces 414A: Mashmokh and Numbers
1815	Codeforces 413E: Maze 2D
1814	Codeforces 413D: 2048
1813	Codeforces 413C: Jeopardy!
1812	Codeforces 413B: Spyke Chatting
1811	Codeforces 413A: Data Recovery
1810	Codeforces 412E: E-mail Addresses
1809	Codeforces 412D: Giving Awards
1808	Codeforces 412C: Pattern
1807	Codeforces 412B: Network Configuration
1806	Codeforces 412A: Poster
1805	Codeforces 411C: Kicker
1804	Codeforces 411B: Multi-core Processor
1803	Codeforces 411A: Password Check
1802	Codeforces 409I: Feed the Golorp

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

1851

Codeforces 425E: Sereja and Sets

1850

Codeforces 425D: Sereja and Squares

1849

Codeforces 425C: Sereja and Two Sequences

1848

Codeforces 425B: Sereja and Table

1847

Codeforces 425A: Sereja and Swaps

1846