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)
7551	Codeforces 1638C: Inversion Graph
7550	Codeforces 1638B: Odd Swap Sort
7549	Codeforces 1638A: Reverse
7548	Codeforces 1637H: Minimize Inversions Number
7547	Codeforces 1637G: Birthday
7546	Codeforces 1637F: Towers
7545	Codeforces 1637E: Best Pair
7544	Codeforces 1637D: Yet Another Minimization Problem
7543	Codeforces 1637C: Andrew and Stones
7542	Codeforces 1637B: MEX and Array
7541	Codeforces 1637A: Sorting Parts
7540	Codeforces 1635F: Closest Pair
7539	Codeforces 1635E: Cars
7538	Codeforces 1635D: Infinite Set
7537	Codeforces 1635C: Differential Sorting
7536	Codeforces 1635B: Avoid Local Maximums
7535	Codeforces 1635A: Min Or Sum
7534	Codeforces 1634F: Fibonacci Additions
7533	Codeforces 1634E: Fair Share
7532	Codeforces 1634D: Finding Zero
7531	Codeforces 1634C: OKEA
7530	Codeforces 1634B: Fortune Telling
7529	Codeforces 1634A: Reverse and Concatenate
7528	Codeforces 1633F: Perfect Matching
7527	Codeforces 1633E: Spanning Tree Queries
7526	Codeforces 1633D: Make Them Equal
7525	Codeforces 1633C: Kill the Monster
7524	Codeforces 1633B: Minority
7523	Codeforces 1633A: Div. 7
7522	Codeforces 1632E2: Distance Tree (hard version)
7521	Codeforces 1632E1: Distance Tree (easy version)
7520	Codeforces 1632D: New Year Concert
7519	Codeforces 1632C: Strange Test
7518	Codeforces 1632B: Roof Construction
7517	Codeforces 1632A: ABC
7516	Codeforces 1631B: Fun with Even Subarrays
7515	Codeforces 1631A: Min Max Swap
7514	Codeforces 1630F: Making It Bipartite
7513	Codeforces 1630E: Expected Components
7512	Codeforces 1630D: Flipping Range
7511	Codeforces 1630C: Paint the Middle
7510	Codeforces 1630B: Range and Partition
7509	Codeforces 1630A: And Matching
7508	Codeforces 1629B: GCD Arrays
7507	Codeforces 1629A: Download More RAM
7506	Codeforces 1628F: Spaceship Crisis Management
7505	Codeforces 1628E: Groceries in Meteor Town
7504	Codeforces 1628D2: Game on Sum (Hard Version)
7503	Codeforces 1628D1: Game on Sum (Easy Version)
7502	Codeforces 1628C: Grid Xor

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

7551

Codeforces 1638C: Inversion Graph

7550

Codeforces 1638B: Odd Swap Sort

7549

Codeforces 1638A: Reverse

7548

Codeforces 1637H: Minimize Inversions Number

7547

Codeforces 1637G: Birthday

7546