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)
10451	AtCoder ABC293: C. Make Takahashi Happy
10450	AtCoder ABC293: B. Call the ID Number
10449	AtCoder ABC293: A. Swap Odd and Even
10448	AtCoder ABC292: Ex. Rating Estimator
10447	AtCoder ABC292: G. Count Strictly Increasing Sequences
10446	AtCoder ABC292: F. Regular Triangle Inside a Rectangle
10445	AtCoder ABC292: E. Transitivity
10444	AtCoder ABC292: D. Unicyclic Components
10443	AtCoder ABC292: C. Four Variables
10442	AtCoder ABC292: B. Yellow and Red Card
10441	AtCoder ABC292: A. CAPS LOCK
10440	AtCoder ABC291: Ex. Balanced Tree
10439	AtCoder ABC291: G. OR Sum
10438	AtCoder ABC291: F. Teleporter and Closed off
10437	AtCoder ABC291: E. Find Permutation
10436	AtCoder ABC291: D. Flip Cards
10435	AtCoder ABC291: C. LRUD Instructions 2
10434	AtCoder ABC291: B. Trimmed Mean
10433	AtCoder ABC291: A. camel Case
10432	AtCoder ABC290: Ex. Bow Meow Optimization
10431	AtCoder ABC290: G. Edge Elimination
10430	AtCoder ABC290: F. Maximum Diameter
10429	AtCoder ABC290: E. Make it Palindrome
10428	AtCoder ABC290: D. Marking
10427	AtCoder ABC290: C. Max MEX
10426	AtCoder ABC290: B. Qual B
10425	AtCoder ABC290: A. Contest Result
10424	AtCoder ABC289: Ex. Trio
10423	AtCoder ABC289: G. Shopping in AtCoder store
10422	AtCoder ABC289: F. Teleporter Takahashi
10421	AtCoder ABC289: E. Swap Places
10420	AtCoder ABC289: D. Step Up Robot
10419	AtCoder ABC289: C. Coverage
10418	AtCoder ABC289: B. V
10417	AtCoder ABC289: A. flip
10416	AtCoder ABC288: Ex. A Nameless Counting Problem
10415	AtCoder ABC288: G. 3^N Minesweeper
10414	AtCoder ABC288: F. Integer Division
10413	AtCoder ABC288: E. Wish List
10412	AtCoder ABC288: D. Range Add Query
10411	AtCoder ABC288: C. Don’t be cycle
10410	AtCoder ABC288: B. Qualification Contest
10409	AtCoder ABC288: A. Many A+B Problems
10408	AtCoder ABC287: Ex. Directed Graph and Query
10407	AtCoder ABC287: G. Balance Update Query
10406	AtCoder ABC287: F. Components
10405	AtCoder ABC287: E. Karuta
10404	AtCoder ABC287: D. Match or Not
10403	AtCoder ABC287: C. Path Graph?
10402	AtCoder ABC287: B. Postal Card

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

10451

AtCoder ABC293: C. Make Takahashi Happy

10450

AtCoder ABC293: B. Call the ID Number

10449

AtCoder ABC293: A. Swap Odd and Even

10448

AtCoder ABC292: Ex. Rating Estimator

10447

AtCoder ABC292: G. Count Strictly Increasing Sequences

10446