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)
11451	AtCoder ARC098: F. Donation
11450	AtCoder ARC098: E. Range Minimum Queries
11449	AtCoder ABC098: D. Xor Sum 2
11448	AtCoder ABC098: C. Attention
11447	AtCoder ARC097: F. Monochrome Cat
11446	AtCoder ARC097: E. Sorted and Sorted
11445	AtCoder ABC097: D. Equals
11444	AtCoder ABC097: C. K-th Substring
11443	AtCoder ARC096: F. Sweet Alchemy
11442	AtCoder ARC096: E. Everything on It
11441	AtCoder ABC095: D. Static Sushi
11440	AtCoder ABC095: C. Half and Half
11439	AtCoder ARC095: F. Permutation Tree
11438	AtCoder ARC095: E. Symmetric Grid
11437	AtCoder ABC094: D. Binomial Coefficients
11436	AtCoder ABC094: C. Many Medians
11435	AtCoder ARC094: F. Normalization
11434	AtCoder ARC094: E. Tozan and Gezan
11433	AtCoder ABC093: D. Worst Case
11432	AtCoder ABC093: C. Same Integers
11431	AtCoder ARC093: F. Dark Horse
11430	AtCoder ARC093: E. Bichrome Spanning Tree
11429	AtCoder ABC092: D. Grid Components
11428	AtCoder ABC092: C. Traveling Plan
11427	AtCoder ARC092: F. Two Faced Edges
11426	AtCoder ARC092: E. Both Sides Merger
11425	AtCoder ABC091: D. Two Sequences
11424	AtCoder ABC091: C. 2D Plane 2N Points
11423	AtCoder ARC091: F. Strange Nim
11422	AtCoder ARC091: E. LISDL
11421	AtCoder ABC090: D. Remainder Reminder
11420	AtCoder ABC090: C. Flip,Flip, and Flip......
11419	AtCoder ARC090: F. Number of Digits
11418	AtCoder ARC090: E. Avoiding Collision
11417	AtCoder ABC087: D. People on a Line
11416	AtCoder ABC087: C. Candies
11415	AtCoder ARC089: F. ColoringBalls
11414	AtCoder ARC089: E. GraphXY
11413	AtCoder ABC086: D. Checker
11412	AtCoder ABC086: C. Traveling
11411	AtCoder ARC088: F. Christmas Tree
11410	AtCoder ARC088: E. Papple Sort
11409	AtCoder ABC083: D. Wide Flip
11408	AtCoder ABC083: C. Multiple Gift
11407	AtCoder ARC087: F. Squirrel Migration
11406	AtCoder ARC087: E. Prefix-free Game
11405	AtCoder ABC082: D. FT Robot
11404	AtCoder ABC082: C. Good Sequence
11403	AtCoder ARC086: F. Shift and Decrement
11402	AtCoder ARC086: E. Smuggling Marbles

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

11451

AtCoder ARC098: F. Donation

11450

AtCoder ARC098: E. Range Minimum Queries

11449

AtCoder ABC098: D. Xor Sum 2

11448

AtCoder ABC098: C. Attention

11447

AtCoder ARC097: F. Monochrome Cat

11446