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)
6401	Codeforces 1421A: XORwice
6400	Codeforces 1420E: Battle Lemmings
6399	Codeforces 1420D: Rescue Nibel!
6398	Codeforces 1420C2: Pokémon Army (hard version)
6397	Codeforces 1420C1: Pokémon Army (easy version)
6396	Codeforces 1420B: Rock and Lever
6395	Codeforces 1420A: Cubes Sorting
6394	Codeforces 1419F: Rain of Fire
6393	Codeforces 1419E: Decryption
6392	Codeforces 1419D2: Sage's Birthday (hard version)
6391	Codeforces 1419D1: Sage's Birthday (easy version)
6390	Codeforces 1419C: Killjoy
6389	Codeforces 1419B: Stairs
6388	Codeforces 1419A: Digit Game
6387	Codeforces 1418G: Three Occurrences
6386	Codeforces 1418F: Equal Product
6385	Codeforces 1418E: Expected Damage
6384	Codeforces 1418D: Trash Problem
6383	Codeforces 1418C: Mortal Kombat Tower
6382	Codeforces 1418B: Negative Prefixes
6381	Codeforces 1418A: Buying Torches
6380	Codeforces 1417B: Two Arrays
6379	Codeforces 1417A: Copy-paste
6378	Codeforces 1416F: Showing Off
6377	Codeforces 1416E: Split
6376	Codeforces 1416D: Graph and Queries
6375	Codeforces 1416C: XOR Inverse
6374	Codeforces 1416B: Make Them Equal
6373	Codeforces 1416A: k-Amazing Numbers
6372	Codeforces 1415F: Cakes for Clones
6371	Codeforces 1415E: New Game Plus!
6370	Codeforces 1415D: XOR-gun
6369	Codeforces 1415C: Bouncing Ball
6368	Codeforces 1415B: Repainting Street
6367	Codeforces 1415A: Prison Break
6366	Codeforces 1413F: Roads and Ramen
6365	Codeforces 1413E: Solo mid Oracle
6364	Codeforces 1413D: Shurikens
6363	Codeforces 1413C: Perform Easily
6362	Codeforces 1413B: A New Technique
6361	Codeforces 1413A: Finding Sasuke
6360	Codeforces 1411G: No Game No Life
6359	Codeforces 1411F: The Thorny Path
6358	Codeforces 1411E: Poman Numbers
6357	Codeforces 1411D: Grime Zoo
6356	Codeforces 1411C: Peaceful Rooks
6355	Codeforces 1411B: Fair Numbers
6354	Codeforces 1411A: In-game Chat
6353	Codeforces 1409F: Subsequences of Length Two
6352	Codeforces 1409E: Two Platforms

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

6401

Codeforces 1421A: XORwice

6400

Codeforces 1420E: Battle Lemmings

6399

Codeforces 1420D: Rescue Nibel!

6398

Codeforces 1420C2: Pokémon Army (hard version)

6397

Codeforces 1420C1: Pokémon Army (easy version)

6396