Problems

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Total results29,466 problems

Seat Reservation
Easy3
Sorting, Simulation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Delicious Apples
Easy3
Sorting, Binary search
No attempts yet
Time limit
2s
Memory limit
2048 MB
Judgeable
Bus
Easy3
Brute force, Implementation
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
E-Circuit Is Now on Sale!
Easy3
Tree, DFS+1
No attempts yet
Time limit
2s
Memory limit
2048 MB
Judgeable
Anomaly Mahjong 9
Easy3
Hash map, Array
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
The Hardest Part of Mahjong
Easy3
Math, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Observing Objects
Easy3
Matrix, DFS+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Golden Tickets
Easy3
Hash map, Simulation
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Road Network
Easy3
Union-find, Graph
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Latin Squares
Easy3
Array, Simulation+1
No attempts yet
Time limit
0.5s
Memory limit
2048 MB
Judgeable
Billiards
Easy3
Tree, Prefix sum
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Ducks and Sharks
Easy3
Hash map, Sorting+2
No attempts yet
Time limit
2s
Memory limit
2048 MB
Judgeable
Group Activities
Easy3
Math, Number theory
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Halt and Catch Fire
Easy3
Simulation, Hash map
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Integrity Overflow
Easy3
String, Implementation
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Forest Run
Easy3
Tree, DFS
No attempts yet
Time limit
6s
Memory limit
2048 MB
Judgeable
Hurry the Hedgehog
Easy3
BFS, Graph
No attempts yet
Time limit
5s
Memory limit
2048 MB
Judgeable
Scoreboard Screenshots
Easy3
Sorting, Array+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Sanghyeon's Physics and Experiment 1 Operation
Easy3
Sorting, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Minimal Coprime
Easy3
Number theory, Math
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Potion
Medium4
Graph, Dynamic programming+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Endless String
Medium4
String, Recursion+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Good Intervals
Medium4
Math, Array+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Parallelogram
Medium4
Geometry, Math+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Raising the Win Rate
Medium4
Math, Binary search+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Room Number
Medium4
Greedy, String+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Stick
Medium4
Bit manipulation, Simulation+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Remote Control
Medium4
Brute force, String+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Base Conversion
Medium4
Math, Implementation+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Digit-Power Sequence
Medium4
Simulation, Math+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Line Up
Medium4
Array, Greedy+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Gifts
Medium4
Binary search, Math
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Josephus Permutation 2
Medium4
Queue, Simulation+1
No attempts yet
Time limit
0.15s
Memory limit
128 MB
Judgeable
Sum of Subsequences
Medium4
Backtracking, Brute force+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Appointments
Medium4
Sorting, Math+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Find the Fraction
Medium4
Math, Simulation
No attempts yet
Time limit
0.5s
Memory limit
256 MB
Judgeable
Kickdown
Medium4
String, Brute force+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Minimum Spanning Tree
Medium4
Minimum spanning tree, Union-find+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Make a Palindrome
Medium4
String, Greedy+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Pie Chart
Medium4
Brute force, Combinatorics+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Distance Between Tree Nodes
Medium4
Tree, BFS+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Online Egg Sales
Medium4
Sorting, Greedy+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Time Management
Medium4
Greedy, Sorting+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Temporary Class President
Medium4
Array, Brute force+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Enormous Wealth 2
Medium4
Math, String+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Coffee Shop 1
Medium4
Simulation, Math+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Coffee Shop Game 2
Medium4
Segment tree, Prefix sum+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Platform Support Pillars
Medium4
Simulation, Sorting+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
War - Battle
Medium4
BFS, Graph+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Zoo
Medium4
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Efficient Hacking
Medium4
Graph, BFS+1
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
Valid Array
Medium4
Array, Brute force+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Unknown Number
Medium4
Math, Implementation+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Word Math
Medium4
Greedy, Math+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Lucky Strings
Medium4
Backtracking, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Polyomino
Medium4
Greedy, String+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Soccer
Medium4
Probability, Math+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Infinite Sequence
Medium4
Recursion, Dynamic programming+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Lecture Rooms
Medium4
Greedy, Sorting+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Age Relations
Medium4
Graph, DFS+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Flammable Railway 997
Medium4
Prefix sum, Simulation+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Tournament Winner
Medium4
Probability, Dynamic programming+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Text Editor
Medium4
Stack, Simulation+2
No attempts yet
Time limit
0.3s
Memory limit
512 MB
Judgeable
Similar Words
Medium4
String, Hash map+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Cable Donation
Medium4
Minimum spanning tree, Graph+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Tower Attack
Medium4
BFS, Graph+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Number Decomposition
Medium4
Math, Greedy+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Flipping
Medium4
String, Greedy+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Highway Shortcuts
Medium4
Shortest path, Graph+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Triangle Builder
Medium4
Sorting, Greedy+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Candy Rotation
Medium4
Simulation, Brute force+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Building Rest Stops
Medium4
Binary search, Greedy+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Square
Medium4
Geometry, Math+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Selling Goods
Medium4
Brute force, Sorting+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Guitarist
Medium4
Dynamic programming, Array
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
English Reading
Medium4
Hash map, String+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Choosing Three Numbers
Medium4
Brute force, Math+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Police Stations
Medium4
Graph, DFS+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Building Completion Times
Medium4
Topological sort, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Bubble Sort Swap Count
Medium4
Sorting, Divide and conquer+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Downhill Paths
Medium4
Dynamic programming, DFS+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Sliding Puzzle
Medium4
BFS, Implementation+1
No attempts yet
Time limit
1s
Memory limit
32 MB
Judgeable
Document Search
Medium4
String matching, Greedy+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Dominoes
Medium4
Brute force, Backtracking+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Bishop
Medium4
Math, String+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Perfect Attendance Award
Medium4
Dynamic programming, String+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Numbers Between Multiples and Divisors
Medium4
Number theory, Math
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Number of Roads
Medium4
Dynamic programming, Matrix+1
No attempts yet
Time limit
2s
Memory limit
16 MB
Judgeable
Lee Dongho's Truck
Medium4
Sorting, Geometry+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Glyph Decoding
Medium4
Sliding window, String+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Minsik Language Word Sorting
Medium4
String, Sorting+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Length of a Repunit Multiple
Medium4
Math, Number theory+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Coupons
Medium4
Probability, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Consecutive Prime Sum
Medium4
Sliding window, Two pointers+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Cable Cutting
Medium4
Binary search, Greedy+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Decompressed String Length
Medium4
Stack, String+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Magic Square Rotations
Medium4
BFS, Simulation+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Same Remainder
Medium4
Number theory, Math+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Overlapping Segments
Medium4
Intervals, Sorting+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Sum of Squares
Medium4
Dynamic programming, Math
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Seat ReservationReplay the seat applications in time order, granting a seat only when it is unreserved, and report each student's final seat by student number.	Easy3	SortingSimulation	No attempts yet	1s	1024 MB	Judgeable
Delicious ApplesFor each query p, count the apples with taste at least p that have the largest size among those apples.	Easy3	SortingBinary search	No attempts yet	2s	2048 MB	Judgeable
BusFind the shortest travel time from Zagreb to Wroclaw by taking a Zagreb-Graz bus, then a Graz-Wroclaw bus, or report NEMOGUCE if no connection works.	Easy3	Brute forceImplementation	No attempts yet	1s	2048 MB	Judgeable
E-Circuit Is Now on Sale!Given a grid of units that form a formula tree, compute the integer value that the printer unit displays.	Easy3	TreeDFS+1	No attempts yet	2s	2048 MB	Judgeable
Anomaly Mahjong 9Given up to 100000 tiles from 34 kinds, find the shortest contiguous span that contains 5 tiles of the same kind, or -1 if no span does.	Easy3	Hash mapArray	No attempts yet	2s	1024 MB	Judgeable
The Hardest Part of MahjongSplit people who want 3-player, 4-player, or either game into 3-person and 4-person tables so everyone plays their preferred game, minimizing 3-player tables.	Easy3	MathImplementation	No attempts yet	1s	1024 MB	Judgeable
Observing ObjectsCount connected groups of same-colored pixels on an N by M grid, where pixels connect in 8 directions and must share identical RGB values.	Easy3	MatrixDFS+1	No attempts yet	2s	1024 MB	Judgeable
Golden TicketsGiven ranked teams and their institutions, pick the top M teams plus up to K more teams from new institutions, then print them in rank order.	Easy3	Hash mapSimulation	No attempts yet	1s	2048 MB	Judgeable
Road NetworkGiven N cities where road i joins city i and city (3i+7) mod N, decide whether all cities are connected, and if not, output two cities that cannot reach each other.	Easy3	Union-findGraph	No attempts yet	1s	2048 MB	Judgeable
Latin SquaresGiven T row and column swaps applied in order, output any Latin square of size N that would produce the final matrix, or print * if none exists.	Easy3	ArraySimulation+1	No attempts yet	0.5s	2048 MB	Judgeable
BilliardsEach ball needs its prerequisite chain dropped first, so find the largest ball whose chain, including itself, has total A at most X.	Easy3	TreePrefix sum	No attempts yet	1s	2048 MB	Judgeable
Ducks and SharksGiven every match result in a round-robin tournament, print the five teams with the most points, with ties broken alphabetically.	Easy3	Hash mapSorting+2	No attempts yet	2s	2048 MB	Judgeable
Group ActivitiesGiven n integers up to 10^18, find their least common multiple, the smallest positive number that every given value divides evenly.	Easy3	MathNumber theory	No attempts yet	1s	2048 MB	Judgeable
Halt and Catch FireSimulate a small assembly-like program with mov, add, sub, jeq, and hcf, then print $out or the machine state at the hcf instruction.	Easy3	SimulationHash map	No attempts yet	1s	2048 MB	Judgeable
Integrity OverflowGiven an audit log of password attempts, decide whether the safe ever opened for a password that is neither correct nor one character off from the correct one.	Easy3	StringImplementation	No attempts yet	1s	2048 MB	Judgeable
Forest RunGiven trees of trails rooted at entrances, find the total kilometers of a walk from each entrance that reaches every trail end and returns.	Easy3	TreeDFS	No attempts yet	6s	2048 MB	Judgeable
Hurry the HedgehogFind the shortest path from intersection 1 to n that uses only intersections with a Super Mushroom, and print its number of intersections.	Easy3	BFSGraph	No attempts yet	5s	2048 MB	Judgeable
Scoreboard ScreenshotsGiven N scoreboard screenshots of K teams, find an order in which every team's score never decreases, or report NO if none exists.	Easy3	SortingArray+1	No attempts yet	2s	256 MB	Judgeable
Sanghyeon's Physics and Experiment 1 OperationGiven N densities and an error range E, count the groups of weights that link together when sorted neighbors differ by less than E.	Easy3	SortingArray	No attempts yet	1s	1024 MB	Judgeable
Minimal CoprimeFor each test case, count the minimal coprime segments inside [l, r], where a coprime segment is minimal if it contains no other coprime segment.	Easy3	Number theoryMath	No attempts yet	1s	2048 MB	Judgeable
PotionGiven market prices and mixture recipes, compute the cheapest cost to produce one unit of the potion named LOVE.	Medium4	GraphDynamic programming+2	No attempts yet	2s	128 MB	Judgeable
Endless StringStarting from a string A, repeatedly replace every $ in S with the previous result, then print characters from position min to max after N runs.	Medium4	StringRecursion+2	No attempts yet	2s	128 MB	Judgeable
Good IntervalsGiven a set S of integers and a target n, count the number of intervals [A,B] with A<B that avoid all elements of S and contain n.	Medium4	MathArray+1	No attempts yet	2s	128 MB	Judgeable
ParallelogramGiven three points, find the difference between the largest and smallest perimeter among all parallelograms that use the three points and one extra point D.	Medium4	GeometryMath+1	No attempts yet	2s	128 MB	Judgeable
Raising the Win RateGiven total games X and wins Y, find the minimum extra consecutive wins needed to raise the floor(100*Y/X) displayed win rate, or report -1 if impossible.	Medium4	MathBinary search+1	No attempts yet	2s	128 MB	Judgeable
Room NumberGiven digit prices and a budget, find the largest possible room number (no leading zero unless it's just 0) that can be bought within the budget.	Medium4	GreedyString+1	No attempts yet	2s	128 MB	Judgeable
StickSimulate repeatedly halving and discarding pieces of a 64 cm stick until the remaining pieces sum to X, then count how many pieces are glued together.	Medium4	Bit manipulationSimulation+1	No attempts yet	2s	128 MB	Judgeable
Remote ControlGiven a target channel and a set of broken digit buttons, compute the minimum button presses to reach the channel from 100 using digits, plus and minus.	Medium4	Brute forceString+2	No attempts yet	2s	256 MB	Judgeable
Base ConversionConvert a decimal integer to its digit representation in a given base, which may be negative, without using a minus sign.	Medium4	MathImplementation+1	No attempts yet	2s	128 MB	Judgeable
Digit-Power SequenceFor each N from A to B, repeatedly sum the K-th powers of its digits, detect the eventual cycle, and sum the minimum value reached over all sequences.	Medium4	SimulationMath+1	No attempts yet	2s	128 MB	Judgeable
Line UpReconstruct a line of N people (heights 1..N) given for each height how many taller people stand to its left, using reverse insertion.	Medium4	ArrayGreedy+1	No attempts yet	2s	128 MB	Judgeable
GiftsFind the maximum cube side length A so that N cubes of size A can fit inside an L×W×H box, using binary search on A.	Medium4	Binary searchMath	No attempts yet	2s	128 MB	Judgeable
Josephus Permutation 2Given N people in a circle and a step size K, output the full removal order produced by repeatedly eliminating every K-th remaining person.	Medium4	QueueSimulation+1	No attempts yet	0.15s	128 MB	Judgeable
Sum of SubsequencesCount how many non-empty subsequences of up to 20 integers sum exactly to a given target S.	Medium4	BacktrackingBrute force+1	No attempts yet	2s	256 MB	Judgeable
AppointmentsGiven N pairs of appointment and arrival times, find how many integer shifts T minimize the total waiting time, which reduces to counting optimal medians of the differences.	Medium4	SortingMath+1	No attempts yet	2s	128 MB	Judgeable
Find the FractionGiven an index X, determine which fraction r/c appears at that position when all fractions r/c are enumerated in a zigzag diagonal order.	Medium4	MathSimulation	No attempts yet	0.5s	256 MB	Judgeable
KickdownGiven two gear strings of 1s and 2s, slide one horizontally to minimize the combined width without any overlapping position having a tooth (2) on both.	Medium4	StringBrute force+1	No attempts yet	2s	128 MB	Judgeable
Minimum Spanning TreeCompute the total edge weight of a minimum spanning tree for a weighted undirected graph with up to 10,000 vertices and 100,000 edges, allowing negative weights.	Medium4	Minimum spanning treeUnion-find+1	No attempts yet	1s	128 MB	Judgeable
Make a PalindromeRearrange the letters of a given uppercase string into the lexicographically smallest palindrome, or report it is impossible.	Medium4	StringGreedy+1	No attempts yet	2s	128 MB	Judgeable
Pie ChartOrder class percentages around a pie chart to maximize the count of sector boundaries exactly 50% apart, forming diameter lines through the center.	Medium4	Brute forceCombinatorics+2	No attempts yet	2s	128 MB	Judgeable
Distance Between Tree NodesGiven a weighted tree and multiple node pairs, compute the path distance between each pair using tree traversal.	Medium4	TreeBFS+1	No attempts yet	2s	128 MB	Judgeable
Online Egg SalesGiven N eggs and M customers' maximum bid prices, pick the selling price (lowest if tied) that maximizes total revenue when all customers bidding at least that price buy an egg, capped at N sales.	Medium4	SortingGreedy+1	No attempts yet	2s	128 MB	Judgeable
Time ManagementGiven tasks with durations and deadlines, find the latest single start time so that all tasks scheduled back to back meet their deadlines, or report -1 if impossible.	Medium4	GreedySorting+1	No attempts yet	2s	128 MB	Judgeable
Temporary Class PresidentGiven each student's class per grade for 5 grades, find the student who shared a class with the most distinct other students, choosing the smallest index on ties.	Medium4	ArrayBrute force+1	No attempts yet	2s	128 MB	Judgeable
Enormous Wealth 2Given two huge decimal integers n and m (up to 10^1000), compute the quotient and remainder of dividing n by m using big-integer division.	Medium4	MathString+1	No attempts yet	2s	128 MB	Judgeable
Coffee Shop 1Simulate coffee being poured between two jars each cycle and count how many cups Dongho can still taste, printing gg if the count is 0 or over 50.	Medium4	SimulationMath+1	No attempts yet	2s	128 MB	Judgeable
Coffee Shop Game 2Given an array, answer Q online queries each asking a range sum (with swapped bounds allowed) followed by a point update.	Medium4	Segment treePrefix sum+1	No attempts yet	2s	256 MB	Judgeable
Platform Support PillarsGiven platforms with heights and horizontal spans, compute the total length of vertical support pillars placed slightly inside each platform's ends resting on the floor or a lower platform.	Medium4	SimulationSorting+2	No attempts yet	2s	128 MB	Judgeable
War - BattleFind connected groups of same-colored soldiers on a grid (4-directional) and output the sum of squared group sizes for each of the two colors.	Medium4	BFSGraph+1	No attempts yet	2s	128 MB	Judgeable
ZooCount the ways to place non-attacking lions in a 2 by N grid so that no two lions sit in adjacent cells, modulo 9901.	Medium4	Dynamic programmingCombinatorics+1	No attempts yet	2s	128 MB	Judgeable
Efficient HackingGiven directed trust edges between N computers, find all computers that, if hacked first, let the hacker reach the maximum possible number of computers.	Medium4	GraphBFS+1	No attempts yet	5s	256 MB	Judgeable
Valid ArrayGiven a distinct integer array, find the minimum number of elements to add so it contains five consecutive integers.	Medium4	ArrayBrute force+1	No attempts yet	2s	128 MB	Judgeable
Unknown NumberGiven an interval's two endpoints and a divisor-remainder pair, determine whether exactly one integer in that range satisfies the modular condition and print it, or report the number as unknown.	Medium4	MathImplementation+1	No attempts yet	2s	128 MB	Judgeable
Word MathAssign distinct digits 0-9 to letters so that the sum of several words, read as base-10 numbers, is as large as possible.	Medium4	GreedyMath+1	No attempts yet	2s	256 MB	Judgeable
Lucky StringsCount the distinct rearrangements of a short string (length up to 10) that have no two adjacent equal characters.	Medium4	BacktrackingCombinatorics+1	No attempts yet	2s	256 MB	Judgeable
PolyominoCover every run of X cells with 2-cell (BB) and 4-cell (AAAA) blocks and print the lexicographically smallest resulting board, or -1 if some run has odd length.	Medium4	GreedyString+2	No attempts yet	2s	128 MB	Judgeable
SoccerGiven per-interval scoring probabilities for two teams over 18 intervals, compute the probability that at least one team ends with a prime number of goals.	Medium4	ProbabilityMath+1	No attempts yet	2s	128 MB	Judgeable
Infinite SequenceCompute the N-th term of a sequence where A_i equals A at floor(i/P) plus A at floor(i/Q), using memoized recursion for huge N.	Medium4	RecursionDynamic programming+2	No attempts yet	2s	128 MB	Judgeable
Lecture RoomsGiven N lecture intervals, compute the minimum number of rooms needed so no room hosts overlapping lectures, treating touching endpoints as non-overlapping.	Medium4	GreedySorting+1	No attempts yet	2s	128 MB	Judgeable
Age RelationsBuild a directed graph from age comparisons and answer queries about who is older using reachability through transitive relations.	Medium4	GraphDFS+1	No attempts yet	2s	128 MB	Judgeable
Flammable Railway 997Given fireproof material amounts between train cars and a starting fire location, compute the time step when a target car explodes, or report it never does.	Medium4	Prefix sumSimulation+2	No attempts yet	2s	128 MB	Judgeable
Tournament WinnerGiven all pairwise win probabilities among 8 players in a fixed single-elimination bracket, compute each player's probability of winning the whole tournament.	Medium4	ProbabilityDynamic programming+2	No attempts yet	2s	128 MB	Judgeable
Text EditorSimulate a line editor with cursor movement, character deletion, and insertion commands, printing the final string.	Medium4	StackSimulation+2	No attempts yet	0.3s	512 MB	Judgeable
Similar WordsCount unordered pairs of equal-length words that are related by some bijection between letters, similar to the isomorphic-strings check.	Medium4	StringHash map+1	No attempts yet	2s	128 MB	Judgeable
Cable DonationGiven an adjacency matrix of cable lengths between rooms encoded as letters, find a minimum spanning tree and output the maximum total cable length that can be donated, or -1 if the rooms cannot all be connected.	Medium4	Minimum spanning treeGraph+2	No attempts yet	2s	128 MB	Judgeable
Tower AttackGiven towers that can relay energy over short hops with 50% loss per hop, compute the maximum damage reachable towers can deal to an enemy using multi-source BFS.	Medium4	BFSGraph+2	No attempts yet	2s	128 MB	Judgeable
Number DecompositionGiven N up to 1,000,000, decompose it into nonnegative integers whose sum is N to maximize the product, then output that product mod 10007.	Medium4	MathGreedy+1	No attempts yet	2s	128 MB	Judgeable
FlippingGiven a binary string, find the minimum number of contiguous-segment flips needed to make all characters equal.	Medium4	StringGreedy+1	No attempts yet	2s	128 MB	Judgeable
Highway ShortcutsCompute the minimum driving distance from position 0 to D on a highway with up to 12 one-way shortcuts that skip forward sections.	Medium4	Shortest pathGraph+2	No attempts yet	2s	128 MB	Judgeable
Triangle BuilderGiven N straw lengths, pick three that form a triangle with the largest possible perimeter, or report -1 if none exist.	Medium4	SortingGreedy+1	No attempts yet	2s	128 MB	Judgeable
Candy RotationGiven N cells in a circle, simulate digit-sum-based clockwise moves from every starting cell and find the maximum count of distinct cells visited before a repeat.	Medium4	SimulationBrute force+1	No attempts yet	2s	128 MB	Judgeable
Building Rest StopsGiven existing rest stops on a highway, place M new integer-position stops to minimize the longest gap between consecutive stops, found via binary search.	Medium4	Binary searchGreedy+1	No attempts yet	2s	128 MB	Judgeable
SquareGiven four points per test case, decide whether they can form the vertices of a square using pairwise distance checks.	Medium4	GeometryMath+1	No attempts yet	1s	512 MB	Judgeable
Selling GoodsGiven each buyer's max price and delivery cost, choose a sale price (ties broken by lowest) that maximizes total profit summed over buyers who purchase profitably.	Medium4	Brute forceSorting+2	No attempts yet	2s	128 MB	Judgeable
GuitaristGiven a starting volume and a sequence of forced up/down changes bounded by [0, M], find the maximum achievable volume for the last song using reachability DP.	Medium4	Dynamic programmingArray	No attempts yet	2s	128 MB	Judgeable
English ReadingCount how many dictionary-word combinations match each scrambled sentence when each word's middle letters can be permuted freely.	Medium4	Hash mapString+2	No attempts yet	2s	128 MB	Judgeable
Choosing Three NumbersGiven N and a forbidden set S, find positive integers x, y, z not in S that minimize \|N - xyz\|.	Medium4	Brute forceMath+1	No attempts yet	2s	128 MB	Judgeable
Police StationsGiven a directed graph and per-city build costs, find strongly connected components and sum the minimum cost city in each component.	Medium4	GraphDFS+1	No attempts yet	2s	128 MB	Judgeable
Building Completion TimesGiven N buildings with construction times and prerequisite dependencies, compute for each building the earliest possible completion time assuming unlimited parallel construction.	Medium4	Topological sortDynamic programming+1	No attempts yet	2s	128 MB	Judgeable
Bubble Sort Swap CountCount the number of adjacent swaps bubble sort performs to sort an array, equivalent to counting inversions efficiently.	Medium4	SortingDivide and conquer+1	No attempts yet	1s	512 MB	Judgeable
Downhill PathsCount the number of strictly decreasing height paths from the top-left to the bottom-right cell of a grid, moving only to adjacent cells, using memoized DFS.	Medium4	Dynamic programmingDFS+1	No attempts yet	2s	128 MB	Judgeable
Sliding PuzzleFind the minimum number of moves to solve a 3x3 sliding puzzle into a fixed goal state, or report -1 if unsolvable.	Medium4	BFSImplementation+1	No attempts yet	1s	32 MB	Judgeable
Document SearchGiven a document and a word, find the maximum number of non-overlapping occurrences of the word within the document.	Medium4	String matchingGreedy+1	No attempts yet	2s	128 MB	Judgeable
DominoesGiven an N x N grid of domino values (N up to 6), find the minimum and maximum of the cycle-sign-adjusted product over all row-column permutations.	Medium4	Brute forceBacktracking+2	No attempts yet	2s	128 MB	Judgeable
BishopGiven board size N as a big number up to 70 digits, compute the maximum bishops placeable on an N by N board without mutual attacks, which is 2N-2 (or 1 if N=1).	Medium4	MathString+1	No attempts yet	2s	128 MB	Judgeable
Perfect Attendance AwardCount length-N attendance strings over O, L, A that have at most one L and no three consecutive A's, modulo 1,000,000.	Medium4	Dynamic programmingString+1	No attempts yet	2s	128 MB	Judgeable
Numbers Between Multiples and DivisorsFind how many positive integers are simultaneously a common multiple of array D and a common divisor of array M by combining LCM and GCD with divisor counting.	Medium4	Number theoryMath	No attempts yet	2s	128 MB	Judgeable
Number of RoadsCount right/up lattice paths from (0,0) to (N,M) on a grid where certain unit edges are blocked by construction.	Medium4	Dynamic programmingMatrix+1	No attempts yet	2s	16 MB	Judgeable
Lee Dongho's TruckGiven pillar coordinates in a square warehouse, find the widest integer-width straight lane from west to east that touches no pillar or wall.	Medium4	SortingGeometry+2	No attempts yet	2s	128 MB	Judgeable
Glyph DecodingCount how many length-g substrings of S are letter-for-letter rearrangements of a given word W.	Medium4	Sliding windowString+1	No attempts yet	2s	128 MB	Judgeable
Minsik Language Word SortingSort Minsik language words using a custom 20-letter alphabet where the digraph 'ng' counts as a single letter between 'n' and 'o'.	Medium4	StringSorting+1	No attempts yet	2s	128 MB	Judgeable
Length of a Repunit MultipleFind the minimum number of digits in a repunit (a number made only of 1s) that is divisible by a given N, or report -1 if none exists.	Medium4	MathNumber theory+2	No attempts yet	2s	128 MB	Judgeable
CouponsCompute the expected number of purchases needed to collect all N coupon numbers, printing the result as an integer or reduced mixed fraction.	Medium4	ProbabilityMath+1	No attempts yet	1s	128 MB	Judgeable
Consecutive Prime SumCount how many ways a given N up to 4,000,000 can be written as a sum of one or more consecutive prime numbers.	Medium4	Sliding windowTwo pointers+2	No attempts yet	2s	128 MB	Judgeable
Cable CuttingGiven K cable lengths, binary search the maximum integer cut length so that summing floor(length/cut) over all cables reaches at least N pieces.	Medium4	Binary searchGreedy+1	No attempts yet	2s	128 MB	Judgeable
Decompressed String LengthCompute the total length of a string after fully expanding nested K(Q) compression patterns, where K is a single digit repeat count.	Medium4	StackString+1	No attempts yet	2s	128 MB	Judgeable
Magic Square RotationsGiven four fixed permutations that can be applied to an 8-number arrangement, find the minimum number of operations to reach a target arrangement from the initial one via BFS.	Medium4	BFSSimulation+1	No attempts yet	2s	128 MB	Judgeable
Same RemainderGiven a sequence, find the largest divisor D so that all numbers leave the same remainder when divided by D.	Medium4	Number theoryMath+1	No attempts yet	2s	128 MB	Judgeable
Overlapping SegmentsGiven N line segments on a number line, compute the maximum number of segments that overlap at any single point, not counting endpoint-only contacts.	Medium4	IntervalsSorting+2	No attempts yet	2s	256 MB	Judgeable
Sum of SquaresGiven N up to 100,000, find the minimum number of perfect squares that sum to N.	Medium4	Dynamic programmingMath	No attempts yet	2s	128 MB	Judgeable