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)
10151	AtCoder ABC255: G. Constrained Nim
10150	AtCoder ABC255: F. Pre-order and In-order
10149	AtCoder ABC255: E. Lucky Numbers
10148	AtCoder ABC255: D. ±1 Operation 2
10147	AtCoder ABC255: C. ±1 Operation 1
10146	AtCoder ABC255: B. Light It Up
10145	AtCoder ABC255: A. You should output ARC, though this is ABC.
10144	AtCoder ABC254: Ex. Multiply or Divide by 2
10143	AtCoder ABC254: G. Elevators
10142	AtCoder ABC254: F. Rectangle GCD
10141	AtCoder ABC254: E. Small d and k
10140	AtCoder ABC254: D. Together Square
10139	AtCoder ABC254: C. K Swap
10138	AtCoder ABC254: B. Practical Computing
10137	AtCoder ABC254: A. Last Two Digits
10136	AtCoder ABC253: Ex. We Love Forest
10135	AtCoder ABC253: G. Swap Many Times
10134	AtCoder ABC253: F. Operations on a Matrix
10133	AtCoder ABC253: E. Distance Sequence
10132	AtCoder ABC253: D. FizzBuzz Sum Hard
10131	AtCoder ABC253: C. Max - Min Query
10130	AtCoder ABC253: B. Distance Between Tokens
10129	AtCoder ABC253: A. Median?
10128	AtCoder ABC252: Ex. K-th beautiful Necklace
10127	AtCoder ABC252: G. Pre-Order
10126	AtCoder ABC252: F. Bread
10125	AtCoder ABC252: E. Road Reduction
10124	AtCoder ABC252: D. Distinct Trio
10123	AtCoder ABC252: C. Slot Strategy
10122	AtCoder ABC252: B. Takahashi's Failure
10121	AtCoder ABC252: A. ASCII code
10120	AtCoder ABC251: Ex. Fill Triangle
10119	AtCoder ABC251: G. Intersection of Polygons
10118	AtCoder ABC251: F. Two Spanning Trees
10117	AtCoder ABC251: E. Tahakashi and Animals
10116	AtCoder ABC251: D. At Most 3 (Contestant ver.)
10115	AtCoder ABC251: C. Poem Online Judge
10114	AtCoder ABC251: B. At Most 3 (Judge ver.)
10113	AtCoder ABC251: A. Six Characters
10112	AtCoder ABC250: Ex. Trespassing Takahashi
10111	AtCoder ABC250: G. Stonks
10110	AtCoder ABC250: F. One Fourth
10109	AtCoder ABC250: E. Prefix Equality
10108	AtCoder ABC250: D. 250-like Number
10107	AtCoder ABC250: C. Adjacent Swaps
10106	AtCoder ABC250: B. Enlarged Checker Board
10105	AtCoder ABC250: A. Adjacent Squares
10104	AtCoder ABC249: Ex. Dye Color
10103	AtCoder ABC249: G. Xor Cards
10102	AtCoder ABC249: F. Ignore Operations

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

10151

AtCoder ABC255: G. Constrained Nim

10150

AtCoder ABC255: F. Pre-order and In-order

10149

AtCoder ABC255: E. Lucky Numbers

10148

AtCoder ABC255: D. ±1 Operation 2

10147

AtCoder ABC255: C. ±1 Operation 1

10146