Problems

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Total results29,461 problems

Bomberman
Medium4
Simulation, Implementation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Making Roman Numerals
Medium4
Combinatorics, Math+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Surface Area
Medium4
Implementation, Math+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Transform into a Magic Square
Medium4
Brute force, Implementation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Death Knight
Medium4
BFS, Graph+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Block Play
Medium4
Math, Implementation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Omok: Can Kyusagwa Win?
Medium4
Implementation, Simulation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Tabs vs Spaces
Medium4
Array, Simulation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Sequence and Queries 21
Medium4
Array, Prefix sum+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Cracking Eggs with Eggs
Medium4
Backtracking, Recursion
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Grass Planting
Medium4
Tree, Greedy+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Akvizna
Medium4
Greedy, Math
No attempts yet
Time limit
1.5s
Memory limit
512 MB
Judgeable
Subtitles
Medium4
String, Implementation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Jarvis
Medium4
Hash map, Array+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Terraced fields
Medium4
Math, Implementation+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Sorting
Medium4
Array, Implementation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
RPG Extreme
Medium4
Simulation, Implementation
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Baby Shark 2
Medium4
BFS, Graph+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Hide and Seek 6
Medium4
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Three Friends
Medium4
Graph, Brute force+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Goldbach Partition
Medium4
Number theory, Math+2
No attempts yet
Time limit
0.5s
Memory limit
512 MB
Judgeable
Goldbach Partition 2
Medium4
Number theory, Prefix sum+2
No attempts yet
Time limit
0.5s
Memory limit
512 MB
Judgeable
Evaluate
Medium4
String, Implementation
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Array Play
Medium4
Prefix sum, Array+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Two Arrays
Medium4
Binary search, Sorting+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Why the Williamson's Sapsucker Came Up to Information Island
Medium4
BFS, Graph+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Azulejos
Medium4
Sorting, Greedy
No attempts yet
Time limit
10s
Memory limit
512 MB
Judgeable
I'm Sick of Fibonacci~
Medium4
Dynamic programming, Recursion+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Cipher Decoder
Medium4
Hash map, Sorting+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Lining Up
Medium4
Stack, Simulation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Milk Factory
Medium4
Graph, DFS+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Jinwoo's Password
Medium4
String, Math+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Door Door Door
Medium4
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Magician Nam Jeonghun
Medium4
Implementation, String+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Making a Password
Medium4
String, Brute force+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Good Pizza, Great Pizza
Medium4
Geometry, Math+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Pineapple Advertising
Medium4
Graph, Hash map+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Taebo Taebo Punch Barrage
Medium4
String, Implementation
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Overflowing Fandom
Medium4
Intervals, Greedy+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
My Life Has Math in It
Medium4
Dynamic programming, Implementation+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Enigma
Medium4
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Badugi Poker
Medium4
Sorting, Implementation+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
But can you do it in 0.5x A presses?
Medium4
Greedy, Math+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Pattern
Medium4
Implementation, Simulation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Lawyers
Medium4
Graph, Implementation
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Road Construction
Medium4
Tree, DFS+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Who Is on First Base
Medium4
Brute force, Implementation+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
I Will Be Your Bridge!
Medium4
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Math is a Physical Education Subject 2
Medium4
Math, Brute force+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Bitberry
Medium4
Math, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Optimization is Freaky Fun
Medium4
Math, Number theory
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Bit Overflow
Medium4
Bit manipulation, Math+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Sum of Divisors 2
Medium4
Math, Number theory+2
No attempts yet
Time limit
0.5s
Memory limit
512 MB
Judgeable
Streetlights
Medium4
Hash map, Sorting+2
No attempts yet
Time limit
0.5s
Memory limit
256 MB
Judgeable
range
Medium4
Implementation, Math
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
Two Doors
Medium4
Brute force, Bit manipulation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Jung's Restaurant
Medium4
Hash map, Implementation+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Treasure Hunt
Medium4
Graph, DFS+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Sequence and Shift Queries
Medium4
Array, Implementation+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Jerry and Tom 2
Medium4
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
6789
Medium4
Implementation, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
And the Winner Is... Ourselves!
Medium4
Greedy, Sorting+2
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Architecture
Medium4
Greedy, Implementation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Inquiry I
Medium4
Prefix sum, Array+2
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
City of Lights
Medium4
Array, Implementation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Bus Logic
Medium4
Bit manipulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Last Word
Medium4
String, Simulation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
On-Screen Keyboard
Medium4
Implementation, Array+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Integral Points
Medium4
Number theory, Math+2
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Cap Size
Medium4
Implementation, Sorting+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
GPA
Medium4
Hash map, String+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Pocket Money
Medium4
Greedy, Math+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Breaking Branches
Medium4
Game theory, Math+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Dome Construction
Medium4
Binary search, Geometry+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Feeding Seals
Medium4
Greedy, Two pointers+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Rotating Disks
Medium4
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
222-Pooling
Medium4
Implementation, Simulation+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Baba is Rabbit
Medium4
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Chopping on Line
Medium4
Geometry, Brute force+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Diamonds Are for Evers
Medium4
Implementation, Matrix+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Flight Turbulence
Medium4
Array, Simulation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Hardware Sales
Medium4
Hash map, Implementation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Make America Grade Again
Medium4
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Integer Division
Medium4
Hash map, Math+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Tired Terry
Medium4
Sliding window, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Short Sell
Medium4
Array, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Cooking Water
Medium4
Intervals, Implementation+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Problem Classification
Medium4
Hash map, String+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Greedily Increasing Subsequence
Medium4
Array, Simulation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Homework Never Ends!
Medium4
Stack, Simulation+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Eeny Meeny
Medium4
Simulation, Implementation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Parliamentary Procedure
Medium4
Stack, Simulation+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Dokkaebi-bul
Medium4
String, Simulation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Minecraft
Medium4
Implementation, Brute force+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Gugu the Raccoon
Medium4
Tree, DFS+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Knight's Path
Medium4
Simulation, Implementation+1
No attempts yet
Time limit
0.5s
Memory limit
256 MB
Judgeable
ABB
Medium4
String, String matching+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Plane Division
Medium4
Math, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Umm Code
Medium4
String, Implementation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Professor, I Want a Job
Medium4
Implementation, Brute force+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
BombermanSimulate Bomberman's bomb placement and explosion cycle on a grid and print the state after N seconds.	Medium4	SimulationImplementation+2	No attempts yet	2s	512 MB	Judgeable
Making Roman NumeralsCount how many distinct sums can be formed by choosing N characters from {I, V, X, L} with repetition, where order does not matter.	Medium4	CombinatoricsMath+2	No attempts yet	2s	512 MB	Judgeable
Surface AreaGiven a grid of cube stack heights, compute the total surface area of the resulting 3D figure, including the top, bottom, and exposed side faces.	Medium4	ImplementationMath+2	No attempts yet	1s	512 MB	Judgeable
Transform into a Magic SquareGiven a 3x3 grid of the numbers 1 through 9, find the minimum total cost of changing cells so the grid becomes a magic square, where changing a cell from a to b costs \|a - b\|.	Medium4	Brute forceImplementation+2	No attempts yet	2s	512 MB	Judgeable
Death KnightFind the minimum number of moves for a knight-like piece with six fixed moves to travel between two squares on an N by N board, or -1 if unreachable.	Medium4	BFSGraph+2	No attempts yet	2s	512 MB	Judgeable
Block PlayEach tower can be changed to any height at least 1 in one minute. Find the fewest towers to change so that consecutive heights differ by K.	Medium4	MathImplementation+2	No attempts yet	2s	512 MB	Judgeable
Omok: Can Kyusagwa Win?On a 10x10 omok board, decide whether Kyusagwa, moving next with X stones, can place one stone to make five in a row.	Medium4	ImplementationSimulation+2	No attempts yet	2s	512 MB	Judgeable
Tabs vs SpacesFor each of up to 366 days, count tab and space guests from N intervals, then report occupancy days, peak headcount, fight-free days, peak headcount among those, and the longest stay length.	Medium4	ArraySimulation+2	No attempts yet	2s	512 MB	Judgeable
Sequence and Queries 21Support range-add updates and point queries on an array of up to 100,000 elements with up to 100,000 operations.	Medium4	ArrayPrefix sum+1	No attempts yet	2s	512 MB	Judgeable
Cracking Eggs with EggsEach egg in a row is lifted from the left and hits one other unbroken egg once, and the task is to find the maximum number of eggs that can break.	Medium4	BacktrackingRecursion	No attempts yet	2s	512 MB	Judgeable
Grass PlantingGiven a tree with N fields, plant grass so that no two fields at distance one or two share a type, and output the minimum number of types needed.	Medium4	TreeGreedy+1	No attempts yet	2s	512 MB	Judgeable
AkviznaGiven N opponents eliminated in exactly K rounds, find the maximum sum of each round's eliminated count divided by the remaining count.	Medium4	GreedyMath	No attempts yet	1.5s	512 MB	Judgeable
SubtitlesParse a partial SRT file, add a given number of milliseconds to every timestamp, and reprint the blocks in the same format.	Medium4	StringImplementation+2	No attempts yet	1s	512 MB	Judgeable
JarvisPick one integer X added to every factory frequency so that the count of indices with Ai + X = Bi is as large as possible.	Medium4	Hash mapArray+2	No attempts yet	1s	512 MB	Judgeable
Terraced fieldsCount how many digit characters are 6 or 8 in the decimal numbers written on steps divisible by 8 plus the final step n.	Medium4	MathImplementation+2	No attempts yet	8s	512 MB	Judgeable
SortingGiven an array, count how many single elements can be removed so that the remaining N-1 elements are in nondecreasing order.	Medium4	ArrayImplementation+2	No attempts yet	1s	512 MB	Judgeable
RPG ExtremeSimulate a hero moving through a grid dungeon according to a command string, fighting monsters and collecting items, then report the final grid and whether the boss is defeated.	Medium4	SimulationImplementation	No attempts yet	5s	1024 MB	Judgeable
Baby Shark 2Given an N by M grid with some cells holding sharks, find the empty cell whose Chebyshev distance to the nearest shark is largest.	Medium4	BFSGraph+2	No attempts yet	2s	512 MB	Judgeable
Hide and Seek 6Given Subin's position S and the positions of N siblings, find the largest step size D such that repeated moves of +D or -D from S can reach every sibling.	Medium4	MathNumber theory+2	No attempts yet	1s	512 MB	Judgeable
Three FriendsGiven a sparse undirected graph, find three mutually adjacent vertices minimizing the sum of their degrees excluding the other two chosen vertices.	Medium4	GraphBrute force+2	No attempts yet	2s	512 MB	Judgeable
Goldbach PartitionFor each even N up to one million, count the unordered pairs of primes that sum to N.	Medium4	Number theoryMath+2	No attempts yet	0.5s	512 MB	Judgeable
Goldbach Partition 2For each even N up to 1,000,000, count unordered pairs of primes that sum to N.	Medium4	Number theoryPrefix sum+2	No attempts yet	0.5s	512 MB	Judgeable
EvaluateEvaluate a math expression laid out across R lines of at most C characters each, and print its numeric value.	Medium4	StringImplementation	No attempts yet	1s	512 MB	Judgeable
Array PlayGiven an N by N grid and M rectangle-add operations, output the final sum of each row and each column.	Medium4	Prefix sumArray+2	No attempts yet	2s	512 MB	Judgeable
Two ArraysFor each element of A, find the element of B closest in value (smallest on ties) and print the sum of these chosen values.	Medium4	Binary searchSorting+2	No attempts yet	2s	512 MB	Judgeable
Why the Williamson's Sapsucker Came Up to Information IslandOn a grid with walls, find which of three food cells is nearest to the start cell 2, and print TAK with that distance, or NIE if none is reachable.	Medium4	BFSGraph+2	No attempts yet	1s	256 MB	Judgeable
AzulejosArrange two rows of tiles in non-decreasing price order so each back tile is taller than the front tile in its column, or report impossible.	Medium4	SortingGreedy	No attempts yet	10s	512 MB	Judgeable
I'm Sick of Fibonacci~Given n, count the total number of calls made by the naive recursive Fibonacci function, modulo 1,000,000,007.	Medium4	Dynamic programmingRecursion+2	No attempts yet	1s	512 MB	Judgeable
Cipher DecoderCheck whether the multiset of integers in the ciphertext matches the multiset of character codes of the given plaintext.	Medium4	Hash mapSorting+2	No attempts yet	1s	512 MB	Judgeable
Lining UpGiven N lines of 5 people each, decide whether everyone can pass through a single LIFO waiting area in increasing ticket order.	Medium4	StackSimulation+2	No attempts yet	1s	512 MB	Judgeable
Milk FactoryGiven a directed tree on N nodes, find the smallest node reachable from every other node, or output -1 if none exists.	Medium4	GraphDFS+2	No attempts yet	2s	512 MB	Judgeable
Jinwoo's PasswordGiven N and a lowercase password of length at most N, find its 1-based position among all strings of length 1 to N in lexicographic order.	Medium4	StringMath+2	No attempts yet	1s	256 MB	Judgeable
Door Door DoorAssign 0 or 1 to each door so no two consecutive doors match and all multiples of 2 agree and all multiples of 3 agree, given door 1.	Medium4	MathImplementation+2	No attempts yet	1s	256 MB	Judgeable
Magician Nam JeonghunApply a sequence of up to 10 million suit-changing and rotation commands to 26 cards, printing the arrangement whenever a show command appears.	Medium4	ImplementationString+2	No attempts yet	1s	256 MB	Judgeable
Making a PasswordGiven two uppercase strings, find the longest substring that appears in both strings; the answer is unique.	Medium4	StringBrute force+1	No attempts yet	1s	256 MB	Judgeable
Good Pizza, Great PizzaGiven N points, find the area of the smallest 45-degree tilted square (rhombus) that contains all of them.	Medium4	GeometryMath+2	No attempts yet	1s	256 MB	Judgeable
Pineapple AdvertisingAfter each of Q pizza deliveries to a house, report how many houses (the house itself plus its direct neighbors) like pineapple pizza for the first time.	Medium4	GraphHash map+2	No attempts yet	1s	256 MB	Judgeable
Taebo Taebo Punch BarrageReads an ASCII art scene of a face with fist afterimages and counts how many remain on the left and right sides.	Medium4	StringImplementation	No attempts yet	1s	256 MB	Judgeable
Overflowing FandomGiven N intervals during which fans are at school, find the minimum length of a single visit window that meets every interval.	Medium4	IntervalsGreedy+2	No attempts yet	1s	256 MB	Judgeable
My Life Has Math in ItOn an N x N grid (N odd, 3 to 5) holding numbers and operators, find the max and min results of expressions along right/down paths from (1,1) to (N,N), evaluating left to right.	Medium4	Dynamic programmingImplementation+1	No attempts yet	1s	256 MB	Judgeable
EnigmaImplement a simplified Enigma machine whose two rotors advance together after each letter, and decrypt the given uppercase ciphertext using the rotor setting CHICKENS.	Medium4	SimulationImplementation+2	No attempts yet	1s	256 MB	Judgeable
Badugi PokerGiven six distinct cards, each with a number 1 to 15 and a color, sort all 15 pairs by the ranking rules and print the winner first.	Medium4	SortingImplementation+2	No attempts yet	1s	256 MB	Judgeable
But can you do it in 0.5x A presses?Given the A-press cost of each stage as a multiple of 0.5, find the minimum total presses to clear all stages in order, since holding A carries between stages.	Medium4	GreedyMath+1	No attempts yet	1s	512 MB	Judgeable
PatternGiven a sequence of grid points, decide whether it is a valid Android unlock pattern under the no-repeat and no-skipped-point rules.	Medium4	ImplementationSimulation+2	No attempts yet	1s	512 MB	Judgeable
LawyersGiven N lawyers and M directed trust edges, decide whether every lawyer has at least one incoming edge and no two lawyers defend each other.	Medium4	GraphImplementation	No attempts yet	1s	512 MB	Judgeable
Road ConstructionGiven a tree with n countries and weighted edges, sum over all edges of weight times the absolute difference in size of the two components the edge splits the tree into.	Medium4	TreeDFS+2	No attempts yet	2s	512 MB	Judgeable
Who Is on First BaseGiven nine statements of the form 'player A is' or 'player A is not' the first baseman, and knowing exactly one statement is a lie and exactly one player holds the position, find the player forced to be the first baseman or print -1.	Medium4	Brute forceImplementation+1	No attempts yet	2s	512 MB	Judgeable
I Will Be Your Bridge!A tree lost one edge, splitting it into two components. Print any pair of islands, one from each component, that reconnects the tree.	Medium4	GraphDFS+2	No attempts yet	1s	512 MB	Judgeable
Math is a Physical Education Subject 2Given n, determine which of the five answer choices (1 to 5) of the original exam problem is correct when 1000 is replaced by n.	Medium4	MathBrute force+2	No attempts yet	1s	1024 MB	Judgeable
BitberryGiven P bits, Q berries, and exchange rates A, B, C, D, find the maximum number of bitcoins obtainable, where each bitcoin costs 1 bit and 1 coin.	Medium4	MathGreedy+1	No attempts yet	1s	1024 MB	Judgeable
Optimization is Freaky FunFor each query with N, S, and E up to 10^12, print the value that Kyojun's program outputs.	Medium4	MathNumber theory	No attempts yet	2s	256 MB	Judgeable
Bit OverflowGiven an N-digit binary number K, count how many times the operation K = K - (K & ((~K)+1)) can be applied before K becomes 0.	Medium4	Bit manipulationMath+2	No attempts yet	1s	512 MB	Judgeable
Sum of Divisors 2Given N, compute the sum over all y from 1 to N of the sum of divisors of y, by counting how often each integer divides some value up to N.	Medium4	MathNumber theory+2	No attempts yet	0.5s	512 MB	Judgeable
StreetlightsGiven N integer points, decide whether for every pair (xi,yi), (xj,yj) the two reflected points (xi,yj) and (xj,yi) are also present.	Medium4	Hash mapSorting+2	No attempts yet	0.5s	256 MB	Judgeable
rangeGiven one Python range call, print the lexicographically smallest range call that produces the same sequence of numbers.	Medium4	ImplementationMath	No attempts yet	0.5s	1024 MB	Judgeable
Two DoorsGiven n doors and m switches that flip doors, find a set of switches that makes the passage shift time by each i from -n to n years, or report that none exists.	Medium4	Brute forceBit manipulation	No attempts yet	1s	1024 MB	Judgeable
Jung's RestaurantDecide whether a customer's order satisfies the restaurant rules: special items need 20000+ in regular items, service items need 50000+ combined and at most one.	Medium4	Hash mapImplementation+2	No attempts yet	1s	256 MB	Judgeable
Treasure HuntStarting at (1, 1), follow the letters of S through adjacent grid tiles, and report the maximum number of full repetitions K and the final tile, or -1 if none exists.	Medium4	GraphDFS+1	No attempts yet	1s	256 MB	Judgeable
Sequence and Shift QueriesMaintain a sequence under point additions and cyclic rotations by s positions to the right or left, then print the final array.	Medium4	ArrayImplementation+2	No attempts yet	1s	256 MB	Judgeable
Jerry and Tom 2Given N and values a1..aN, compute 1 minus the continued fraction 1/(a1 + 1/(a2 + ... + 1/aN)) as a reduced fraction P/Q.	Medium4	MathNumber theory+2	No attempts yet	1s	256 MB	Judgeable
6789Each cell holds a card 6, 7, 8, or 9; turning a card rotates it (6 and 9 swap, 8 and 7 stay). Find the minimum number of turns so the grid stays the same after a 180-degree rotation, or -1 if impossible.	Medium4	ImplementationGreedy+1	No attempts yet	1s	1024 MB	Judgeable
And the Winner Is... Ourselves!Given 11 problems that are all solved, choose the solving order that minimizes total penalty, where each problem contributes its finish time plus 20 times its wrong submissions.	Medium4	GreedySorting+2	No attempts yet	4s	1024 MB	Judgeable
ArchitectureGiven the R row maxima and C column maxima of a grid, decide whether any grid of heights can realize both sets of maxima.	Medium4	GreedyImplementation+2	No attempts yet	1s	512 MB	Judgeable
Inquiry ISplit the array into a prefix and a suffix at some index k; maximize the sum of squares of the prefix times the sum of the suffix.	Medium4	Prefix sumArray+2	No attempts yet	3s	512 MB	Judgeable
City of LightsGiven N lights initially on and k toggles where toggle i flips every multiple of i, find the maximum number of lights that are off at any point during the sequence.	Medium4	ArrayImplementation+2	No attempts yet	1s	512 MB	Judgeable
Bus LogicGiven a starting stop and bus routes as bit strings of length s, find the maximum number of other stops reachable by choosing exactly one bus that serves the starting stop.	Medium4	Bit manipulationImplementation+2	No attempts yet	1s	512 MB	Judgeable
Last WordGiven a string and a sequence of substring(start, length) operations, output the characters that survive after all operations are applied in order.	Medium4	StringSimulation+2	No attempts yet	1s	512 MB	Judgeable
On-Screen KeyboardGiven a grid keyboard with a highlighted cell, find the total minimum button presses to type a string, where each character's cost is the Manhattan distance plus one for OK.	Medium4	ImplementationArray+2	No attempts yet	2s	512 MB	Judgeable
Integral PointsGiven n, output an integer radius r and n distinct integer points on the circle centered at the origin with radius r.	Medium4	Number theoryMath+2	No attempts yet	3s	512 MB	Judgeable
Cap SizeGiven cap sizes tried on with fit feedback, count how many untried sizes could still fit, or report inconsistent feedback.	Medium4	ImplementationSorting+2	No attempts yet	2s	512 MB	Judgeable
GPAGiven a catalog of courses with units, major requirements, and each student's grades, print each student's overall GPA and the GPA for every major whose requirements they completed.	Medium4	Hash mapString+2	No attempts yet	2s	512 MB	Judgeable
Pocket MoneyChoose banknotes from the wallet so the total is even and as large as possible, using any subset; print NIESTETY if only odd totals are reachable.	Medium4	GreedyMath+2	No attempts yet	2s	512 MB	Judgeable
Breaking BranchesTwo players alternately split pieces of a length n branch into integer parts; the last to move wins. Decide the winner and give Alice's winning first move.	Medium4	Game theoryMath+2	No attempts yet	1s	512 MB	Judgeable
Dome ConstructionGiven n points in 3D with non-negative y, find the minimum radius of a dome (hemisphere on the xz-plane) that contains at least k of them.	Medium4	Binary searchGeometry+2	No attempts yet	2s	512 MB	Judgeable
Feeding SealsEach volunteer can carry one or two buckets as long as their combined weight stays within capacity c. Find the minimum number of volunteers needed to move all buckets.	Medium4	GreedyTwo pointers+2	No attempts yet	2s	512 MB	Judgeable
Rotating DisksSimulate T rounds of rotating selected concentric disks, erasing adjacent equal numbers, or adjusting all numbers toward the average, then report the final sum.	Medium4	SimulationImplementation+2	No attempts yet	1s	512 MB	Judgeable
222-PoolingRepeatedly replace each 2x2 block of an NxN matrix with its second largest value until one number remains, and print it.	Medium4	ImplementationSimulation+2	No attempts yet	1s	256 MB	Judgeable
Baba is RabbitGiven commands of the form p is q, find all objects reachable from Baba by applying one or more commands, printed in lexicographic order.	Medium4	GraphDFS+2	No attempts yet	1s	512 MB	Judgeable
Chopping on LineA triangle is traced on a rectangular sheet; find the order of the three edge-line cuts that minimizes total cut length, with a fixed tie-break order.	Medium4	GeometryBrute force+2	No attempts yet	1s	512 MB	Judgeable
Diamonds Are for EversDecode a message written into a square grid along nested diamond diagonals, given the row-by-row concatenation of all cells.	Medium4	ImplementationMatrix+2	No attempts yet	1s	512 MB	Judgeable
Flight TurbulenceA permutation maps each seat to the passenger sitting there; count how many passengers shift when one passenger demands their assigned seat.	Medium4	ArraySimulation+2	No attempts yet	1s	512 MB	Judgeable
Hardware SalesGiven three lists of (item ID, units) purchases, count items whose total units reach 20 or more in all three stores, printing IDs in first-appearance order.	Medium4	Hash mapImplementation+2	No attempts yet	1s	512 MB	Judgeable
Make America Grade AgainGiven category weights and a list of graded assignments, sum points per category, weight each fraction, and print the truncated final grade.	Medium4	MathImplementation+2	No attempts yet	1s	512 MB	Judgeable
Integer DivisionCount pairs of indices whose values give the same quotient when both are divided by d using floor division.	Medium4	Hash mapMath+1	No attempts yet	2s	512 MB	Judgeable
Tired TerryGiven a circular sleep pattern of length n, count for how many seconds i the preceding p seconds contain fewer than d seconds of sleep.	Medium4	Sliding windowPrefix sum+2	No attempts yet	1s	512 MB	Judgeable
Short SellGiven N daily prices and a daily interest K per 100 borrowed coins, pick a borrow day and a repay day to maximize profit.	Medium4	ArrayPrefix sum+2	No attempts yet	1s	512 MB	Judgeable
Cooking WaterGiven N intervals of time Edward did not watch a pot, decide whether some single boil time is possible, meaning it lies inside every unwatched interval.	Medium4	IntervalsImplementation+1	No attempts yet	1s	512 MB	Judgeable
Problem ClassificationCount exact whole-word occurrences of each category's keywords in a statement, then print the categories with the highest total count in lexicographic order.	Medium4	Hash mapString+2	No attempts yet	1s	512 MB	Judgeable
Greedily Increasing SubsequenceGiven a permutation, repeatedly take the leftmost unused element larger than the previous pick, and report the resulting subsequence.	Medium4	ArraySimulation+2	No attempts yet	1s	512 MB	Judgeable
Homework Never Ends!Each minute either adds homework (value A, work time T) or nothing; a new task preempts the current one, and finished tasks are submitted at the minute they finish. Sum the values of tasks completed within N minutes.	Medium4	StackSimulation+2	No attempts yet	2s	256 MB	Judgeable
Eeny MeenySimulate counting around a circle of kids with a rhyme length, removing one kid per round and assigning them to alternating teams.	Medium4	SimulationImplementation+2	No attempts yet	2s	512 MB	Judgeable
Parliamentary ProcedureGiven a record of Add and Vote events for 26 parties, decide whether the events can be ordered consistently with a stack-like bill discussion rule.	Medium4	StackSimulation+1	No attempts yet	2s	512 MB	Judgeable
Dokkaebi-bulGiven a string typed in English mode on a 2-set keyboard, count how many times the Dokkaebi-bul phenomenon occurs when it is typed in Korean mode.	Medium4	StringSimulation+1	No attempts yet	1s	1024 MB	Judgeable
MinecraftGiven N by M ground heights and B starting blocks, pick a target height that minimizes flattening cost (remove 2s, place 1s, no outside blocks), breaking ties by the highest target.	Medium4	ImplementationBrute force+2	No attempts yet	1s	1024 MB	Judgeable
Gugu the RaccoonGiven a weighted tree rooted at node 1, find the maximum distance from node 1 to any other node.	Medium4	TreeDFS+2	No attempts yet	1s	1024 MB	Judgeable
Knight's PathGiven k, simulate a knight from cell 1 on a diagonally numbered grid, always taking the smallest unvisited reachable cell, and print its final cell.	Medium4	SimulationImplementation+1	No attempts yet	0.5s	256 MB	Judgeable
ABBGiven a string of colors, find how many characters must be appended at the end so the resulting string becomes a palindrome.	Medium4	StringString matching+2	No attempts yet	2s	512 MB	Judgeable
Plane DivisionGiven at most N lines with slope -1, 0, or 1, find the maximum number of regions the plane can be divided into.	Medium4	MathCombinatorics+2	No attempts yet	1s	512 MB	Judgeable
Umm CodeConcatenate u and m characters from words made only of u, m, and punctuation, then decode each 7-bit chunk as ASCII.	Medium4	StringImplementation+2	No attempts yet	2s	512 MB	Judgeable
Professor, I Want a JobGiven an N x N grid of desks, decide whether Seonggyu can escape the professor: distance at least 5 and at least three other students inside the rectangle or segment between them.	Medium4	ImplementationBrute force+1	No attempts yet	1s	256 MB	Judgeable