Problems

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Total results29,429 problems

Cats and Dogs
Medium6
Graph
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Recovering a Linear Congruential Sequence
Medium6
Math, Number theory+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Kim Kangsan
Medium6
Dynamic programming, Array+1
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Shuffle
Medium6
Sliding window, Array+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Video Poker
Medium6
Brute force, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Assembling a Computer
Medium6
Binary search, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Youth Hostel Dorm
Medium6
Combinatorics, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sudoku Transformation
Medium6
Brute force, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The SetStack Computer
Medium6
Hash map, Stack+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Lineland's Airport
Medium6
Geometry, Binary search+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Declaration of Content
Medium6
Greedy, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Safety Grade
Medium6
Graph, Math
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Palindrome Date
Medium6
String, Math+1
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Gamers
Medium6
Matrix, Math+1
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Row and Column Deletion Game
Medium6
Game theory, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hard-working Student
Medium6
Graph, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
System Engineer
Medium6
Graph, BFS+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cycles of Lanes
Medium6
Graph, DFS+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Lucky Numbers
Medium6
Combinatorics, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Robbery
Medium6
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
The Computer Game
Medium6
Brute force, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Bad Number
Medium6
Math, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sky Code
Medium6
Number theory, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Perfect Election!
Medium6
Graph, DFS+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Quick Answer
Medium6
Union-find, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Lucky Numbers
Medium6
Math, Number theory+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Determinant of the GCD Matrix
Medium6
Number theory, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Loan Scheduling
Medium6
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
16x16 Sudoku
Medium6
Backtracking, Matrix+1
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Sherlock Holmes
Medium6
Sorting, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Stargates
Medium6
Union-find, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Computer Transformation
Medium6
Math, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
City Game
Medium6
Stack, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cable TV Network
Medium6
Graph, Brute force+1
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Delta Encoding and Decoding
Medium6
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hidden Password
Medium6
String, String matching+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Crazy Tea Party
Medium6
Math, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Power Network
Medium6
Graph, Math
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Firefighters
Medium6
Brute force, Recursion+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Binary Polynomials
Medium6
Bit manipulation, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
BOAT
Medium6
Dynamic programming, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Winning the Match
Medium6
Dynamic programming, Probability+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sly Number
Medium6
Math, Brute force+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Turn S into T
Medium6
Greedy, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Reseller's Eye
Medium6
Dynamic programming, Greedy+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Countdown
Medium6
Brute force, Recursion+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bank Numbers
Medium6
Number theory, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
One-Dimensional Cellular Automaton
Medium6
Matrix, Math+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Wrong Calculation
Medium6
Math, Brute force+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Professor Does Not Wait
Medium6
Union-find, Graph
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Convex Regular Polygon
Medium6
Geometry, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Fake Scoreboard
Medium6
Greedy, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Sensor Network
Medium6
Union-find, Sorting+1
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Production Process
Medium6
Dynamic programming, String+1
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Halloween Graveyard
Medium6
Shortest path, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Slalom
Medium6
Geometry, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Where's Wally
Medium6
Matrix, String matching+2
No attempts yet
Time limit
4s
Memory limit
128 MB
Judgeable
Cubist Artwork
Medium6
Greedy, Matrix+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Point Separation
Medium6
Geometry, Math
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Chemist's Mathematics
Medium6
Math, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Malfatti Circles
Medium6
Math, Geometry+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Spherical Mirrors
Medium6
Geometry, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Morning after Halloween
Medium6
BFS, Graph+1
No attempts yet
Time limit
9s
Memory limit
128 MB
Judgeable
Enjoyable Communication
Medium6
Shortest path, Graph+1
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Book Replacement
Medium6
Simulation, Queue+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Colored Cubes
Medium6
Brute force, Simulation+1
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Atomic Car Race
Medium6
Dynamic programming, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Balance Scale
Medium6
Number theory, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Make a Sequence
Medium6
Simulation, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Finding the Weakness in the Encryption
Medium6
Bit manipulation, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Confusing Login Names
Medium6
Dynamic programming, String+1
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Color the Map
Medium6
Geometry, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
God of Wind
Medium6
BFS, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Gap
Medium6
BFS, Simulation+1
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Monster Trap
Medium6
Geometry, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Random Walk
Medium6
Dynamic programming, Probability+1
No attempts yet
Time limit
10s
Memory limit
128 MB
Judgeable
Hongjun's Royal Guard
Medium6
Dynamic programming, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Ski Jump
Medium6
Binary search, Math+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Suffix Array Re-construction
Medium6
String, Implementation+2
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Genetic Fraud
Medium6
String, Two pointers+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Safe Zone
Medium6
Geometry, Divide and conquer
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sightseeing
Medium6
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Suiting Weavers
Medium6
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Absurd Prices
Medium6
Math, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Soccer Tactics
Medium6
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Hacking
Medium6
String, Binary search+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Starting Lineup
Medium6
Backtracking, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Screen Saver
Medium6
Geometry, Segment tree+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Telejump
Medium6
Greedy, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Convention Center
Medium6
Greedy, Sorting+2
No attempts yet
Time limit
2s
Memory limit
64 MB
Judgeable
Road Series
Medium6
Simulation, Hash map+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Show Me the Money
Medium6
Graph, DFS+2
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Town Square
Medium6
Geometry, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Agency
Medium6
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Mobile
Medium6
Tree, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Flip It!
Medium6
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
3D Rod Maze
Medium6
BFS, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Photo Shoot
Medium6
Sorting, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Polar Bear
Medium6
Simulation, Array+1
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Vampires!
Medium6
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Cats and Dogsplaceholder	Medium6	Graph	No attempts yet	1s	128 MB	Judgeable
Recovering a Linear Congruential SequenceGiven odd-indexed terms of a hidden linear congruential generator mod 10001, find (a,b) and output the even-indexed terms forming the lexicographically smallest valid sequence.	Medium6	MathNumber theory+1	No attempts yet	2s	128 MB	Judgeable
Kim KangsanGiven fixed first and last pile heights, find the minimum total bricks added or removed to any middle pile so adjacent height differences stay within d.	Medium6	Dynamic programmingArray+1	No attempts yet	3s	128 MB	Judgeable
ShuffleGiven a song-play log and playlist size s, count starting offsets that split the log into blocks of length s (first/last possibly shorter) with no repeated song inside any block.	Medium6	Sliding windowArray+1	No attempts yet	1s	128 MB	Judgeable
Video PokerGiven a poker payout table and a five-card hand, compute the exact fraction expected value of the best discard strategy over all 32 subsets of held cards.	Medium6	Brute forceCombinatorics+2	No attempts yet	1s	128 MB	Judgeable
Assembling a ComputerChoose one part per category within a budget to maximize the minimum quality among chosen parts, typically via binary search plus greedy cheapest-part selection.	Medium6	Binary searchGreedy+1	No attempts yet	1s	128 MB	Judgeable
Youth Hostel DormFind the maximum number of beds that can be placed in an l by w grid so every bed stays reachable from a single boundary entrance via floor tiles.	Medium6	CombinatoricsGreedy+1	No attempts yet	1s	128 MB	Judgeable
Sudoku TransformationDetermine whether a completed sudoku board can be turned into another via rotations, band/stack swaps, row/column swaps, and digit relabeling.	Medium6	Brute forceSimulation+1	No attempts yet	1s	128 MB	Judgeable
The SetStack ComputerSimulate a stack machine whose elements are hereditarily finite sets, printing top-of-stack cardinality after each of five set operations.	Medium6	Hash mapStack+2	No attempts yet	1s	128 MB	Judgeable
Lineland's AirportFind the position of a length-L window along a piecewise-linear terrain profile that minimizes the area above the flat strip that must be excavated.	Medium6	GeometryBinary search+1	No attempts yet	2s	128 MB	Judgeable
Declaration of ContentFor each product, derive tight lower and upper percentage bounds for every listed ingredient from its ordering and optional exact percentages, then answer queries asking which products maximize or minimize a given ingredient's possible amount.	Medium6	GreedyMath+1	No attempts yet	1s	128 MB	Judgeable
Safety GradeGiven multigraphs with repeated edges, compute the global minimum edge cut (edge connectivity) or 0 if disconnected or trivial.	Medium6	GraphMath	No attempts yet	1s	128 MB	Judgeable
Palindrome DateGiven a date, find the next date whose YearMMDD string is a palindrome, handling huge years and leap years correctly.	Medium6	StringMath+1	No attempts yet	5s	128 MB	Judgeable
GamersFor a grid where each cell must visit every other cell offering a different game via round trips through its own home, compute the total travel cost summed over all cells.	Medium6	MatrixMath+1	No attempts yet	5s	128 MB	Judgeable
Row and Column Deletion GameGiven an n x n matrix where players alternately remove the last row or column if its sum is even, determine which player wins with optimal play across possibly many test cases up to n=1000.	Medium6	Game theoryDynamic programming+1	No attempts yet	1s	128 MB	Judgeable
Hard-working StudentSimulate a growing graph with forward and backward edges, processing commands whose action strings execute right to left, printing results of 'k' and '=' actions.	Medium6	GraphSimulation+1	No attempts yet	1s	128 MB	Judgeable
System EngineerGiven jobs each with a set of eligible servers, compute the maximum bipartite matching size assigning jobs to distinct servers.	Medium6	GraphBFS+1	No attempts yet	1s	128 MB	Judgeable
Cycles of LanesGiven a connected graph where every edge lies in at most one simple cycle, find the length of the longest simple cycle across all test cases.	Medium6	GraphDFS+1	No attempts yet	1s	128 MB	Judgeable
The Lucky NumbersCount lucky numbers (digits 4 and 7 only) in [A,B], plus lucky numbers outside the range whose digit-reversal lands inside it, for B up to 10^47.	Medium6	CombinatoricsMath+1	No attempts yet	1s	128 MB	Judgeable
The RobberyGiven N item types where type k has exactly k identical copies, pick copies within a weight budget M to maximize total value (bounded knapsack with huge M and small N).	Medium6	Dynamic programmingCombinatorics+1	No attempts yet	3s	128 MB	Judgeable
The Computer GameGiven a diamond-shaped lattice grid with some cells blocked, count all nonempty subsets of free cells that form a single connected (4-adjacency) region.	Medium6	Brute forceGraph+2	No attempts yet	1s	128 MB	Judgeable
The Bad NumberFind the minimum number of terms summing to M, each term at most K and not a multiple of N, where the term count itself is also not a multiple of N.	Medium6	MathGreedy+1	No attempts yet	1s	128 MB	Judgeable
Sky CodeGiven up to 10000 star IDs, count the 4-element subsets whose greatest common divisor equals 1, using Mobius inversion over divisor counts.	Medium6	Number theoryCombinatorics+1	No attempts yet	1s	128 MB	Judgeable
Perfect Election!Given boolean 2-SAT style clauses over candidates being elected or not, determine if a satisfying election outcome exists.	Medium6	GraphDFS+1	No attempts yet	3s	256 MB	Judgeable
Quick AnswerSimulate union-find with a special disconnect operation that isolates a node while keeping the rest of its group connected, then answer connectivity queries.	Medium6	Union-findImplementation+1	No attempts yet	1s	128 MB	Judgeable
Lucky NumbersCount numbers in [A,B] up to 10^12 expressible as products of one or more lucky numbers made only of digits 4 and 7, across many queries.	Medium6	MathNumber theory+1	No attempts yet	1s	128 MB	Judgeable
Determinant of the GCD MatrixGiven a divisor-closed set of numbers, compute the determinant of the pairwise-gcd matrix modulo 1e9+7 using Smith's theorem via Euler's totient function.	Medium6	Number theoryMath+1	No attempts yet	1s	128 MB	Judgeable
Loan SchedulingGiven jobs with deadlines and profits and a per-slot capacity, select a maximum-profit subset schedulable within slot capacity limits by each deadline.	Medium6	GreedySorting+1	No attempts yet	1s	128 MB	Judgeable
16x16 SudokuSolve a given 16x16 Sudoku puzzle so each row, column, and 4x4 box contains letters A to P exactly once, given a unique solution exists.	Medium6	BacktrackingMatrix+1	No attempts yet	3s	128 MB	Judgeable
Sherlock HolmesSplit n boxes into two equal groups so that one ball color is a strict majority in both groups, and output that color with the maximum of the smaller group's majority percentage, or report no solution.	Medium6	SortingGreedy+1	No attempts yet	1s	128 MB	Judgeable
StargatesImplement a union-find structure over up to 6,000,000 nodes supporting batched connect and query commands defined by arithmetic sequences of pairs.	Medium6	Union-findImplementation+1	No attempts yet	1s	128 MB	Judgeable
Computer TransformationGiven n up to 1000, compute the count of adjacent	Medium6	MathString+1	No attempts yet	1s	128 MB	Judgeable
City GameGiven several grid maps of free and reserved cells, find the largest all-free rectangle in each grid and print its area times three.	Medium6	StackDynamic programming+1	No attempts yet	1s	128 MB	Judgeable
Cable TV NetworkGiven an undirected graph, compute its vertex connectivity, the minimum number of vertices whose removal disconnects it (or n if never possible).	Medium6	GraphBrute force+1	No attempts yet	5s	128 MB	Judgeable
Delta Encoding and DecodingImplement a stateful command interpreter that encrypts, decrypts, or redefines a letter-substitution cipher based on positional value differences, with exact output formatting.	Medium6	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
Hidden PasswordFind the starting index of the lexicographically smallest rotation of a string, choosing the smallest index in case of ties (Booth's algorithm).	Medium6	StringString matching+1	No attempts yet	2s	128 MB	Judgeable
Crazy Tea PartyGiven n people seated around a circular table, compute the minimum number of adjacent swaps needed to reverse the circular seating order, for many test cases.	Medium6	MathCombinatorics+1	No attempts yet	1s	128 MB	Judgeable
Power NetworkGiven a network of power stations, consumers, and dispatchers with capacity limits on production, consumption, and edges, compute the maximum feasible total consumption via a max-flow reduction.	Medium6	GraphMath	No attempts yet	1s	128 MB	Judgeable
FirefightersDetermine if question-mark operators in an arithmetic expression with brackets can be replaced by +,-,*,/ to reach a given target value under integer truncating division.	Medium6	Brute forceRecursion+1	No attempts yet	1s	128 MB	Judgeable
Binary PolynomialsGiven a Boolean function's polynomial coefficients over n variables, count vectors with exactly k ones that make the function evaluate to 1.	Medium6	Bit manipulationCombinatorics+2	No attempts yet	1s	128 MB	Judgeable
BOATGiven clients in fixed order, each with rental durations and deadline-based payment options, schedule non-overlapping rentals to maximize total earned money.	Medium6	Dynamic programmingGreedy+1	No attempts yet	1s	128 MB	Judgeable
Winning the MatchCompute the probability that team A wins a best-of-K volleyball match given per-serve win probabilities and a serve-switching rule between rounds and games.	Medium6	Dynamic programmingProbability+1	No attempts yet	1s	128 MB	Judgeable
Sly NumberDetermine whether a cyclic-convolution-based inverse (with entries restricted to {0,1,2}) exists for a given array modulo Q, essentially a search over polynomial ring inverses.	Medium6	MathBrute force+1	No attempts yet	1s	128 MB	Judgeable
Turn S into TGiven strings S (with 0,1,?) and T (0,1), compute the minimum number of change/swap operations to transform S into T, or -1 if impossible.	Medium6	GreedyString+1	No attempts yet	1s	128 MB	Judgeable
Reseller's EyeGiven a budget and multiple sellers each offering a fixed bundle of items (buy all or none), choose a subset of sellers within budget to maximize resale profit, a bundled knapsack problem.	Medium6	Dynamic programmingGreedy+1	No attempts yet	2s	128 MB	Judgeable
CountdownFind the closest achievable value to a target by combining six given numbers with the four operations, keeping intermediate results positive integers.	Medium6	Brute forceRecursion+1	No attempts yet	1s	128 MB	Judgeable
Bank NumbersDetermine whether a given Gaussian-integer-like pair (m,n) is a Gaussian prime by checking divisors of m^2+n^2.	Medium6	Number theoryMath+1	No attempts yet	1s	128 MB	Judgeable
One-Dimensional Cellular AutomatonSimulate a linear recurrence over N cells modulo M for up to 1e9 steps using fast matrix exponentiation.	Medium6	MatrixMath+1	No attempts yet	2s	128 MB	Judgeable
Wrong CalculationGiven d+3 noisy samples of a degree-d polynomial with exactly one value corrupted by a large error, identify the index of the corrupted sample.	Medium6	MathBrute force+1	No attempts yet	1s	128 MB	Judgeable
The Professor Does Not WaitProcess weight-difference measurements and queries between samples, answering with weighted union-find or output UNKNOWN if not determinable.	Medium6	Union-findGraph	No attempts yet	2s	256 MB	Judgeable
Convex Regular PolygonGiven three vertices of some convex regular polygon, compute the minimum number of sides that polygon could have.	Medium6	GeometryMath+1	No attempts yet	1s	128 MB	Judgeable
Fake ScoreboardReconstruct a binary team-by-problem matrix matching given row and column sums, outputting the lexicographically smallest valid matrix or reporting impossibility (Gale-Ryser style bipartite degree sequence problem).	Medium6	GreedyCombinatorics+1	No attempts yet	2s	128 MB	Judgeable
Sensor NetworkGiven a weighted simple graph, find the minimum weight-range window such that the edges within that voltage range form a connected spanning subgraph covering all vertices.	Medium6	Union-findSorting+1	No attempts yet	3s	128 MB	Judgeable
Production ProcessGiven a matrix chain-like joining table for pieces, find the minimum-time parenthesization to assemble a given string, breaking ties by piece order.	Medium6	Dynamic programmingString+1	No attempts yet	5s	128 MB	Judgeable
Halloween GraveyardFind the fastest time to travel from entrance to exit on a grid with walls and time-warping portals, detecting negative cycles and unreachability.	Medium6	Shortest pathGraph+1	No attempts yet	1s	128 MB	Judgeable
SlalomGiven a start point and a sequence of horizontal gates at decreasing heights, find the minimum-length path from the start that passes through each gate segment in order.	Medium6	GeometryGreedy+1	No attempts yet	1s	128 MB	Judgeable
Where's WallyDecode base64-like bit matrices for an image and a square pattern, then count all image squares matching the pattern under any rotation or mirror flip.	Medium6	MatrixString matching+2	No attempts yet	4s	128 MB	Judgeable
Cubist ArtworkGiven front and side view maximum heights for a grid of cube piles, find the minimum total number of cubes consistent with both views.	Medium6	GreedyMatrix+1	No attempts yet	1s	128 MB	Judgeable
Point SeparationDecide if two colored point sets on a plane can be separated by a straight line, essentially checking convex hull separation.	Medium6	GeometryMath	No attempts yet	1s	128 MB	Judgeable
The Chemist's MathematicsParse chemical equations with nested parentheses and molecule counts, then solve the resulting linear system to find the minimal positive integer coefficients balancing each element.	Medium6	MathString+1	No attempts yet	1s	128 MB	Judgeable
Malfatti CirclesGiven triangle vertices, compute the radii of the three classical Malfatti circles using the known closed-form formula.	Medium6	MathGeometry+1	No attempts yet	1s	128 MB	Judgeable
Spherical MirrorsSimulate a laser reflecting off multiple spheres in 3D using mirror-reflection geometry and report the final reflection point.	Medium6	GeometrySimulation+1	No attempts yet	1s	128 MB	Judgeable
The Morning after HalloweenGiven a maze with up to 3 ghosts, find the minimum number of simultaneous synchronized moves to bring every ghost to its target cell without collisions or swaps.	Medium6	BFSGraph+1	No attempts yet	9s	128 MB	Judgeable
Enjoyable CommunicationFind the k-th shortest simple path (by length then lexicographic node order) between two nodes in a directed graph with up to 50 nodes and k up to 200.	Medium6	Shortest pathGraph+1	No attempts yet	3s	128 MB	Judgeable
Book ReplacementSimulate a library queue where a librarian relocates books between capacity-limited desks and a shelf using an LRU-like eviction rule, and compute total access cost.	Medium6	SimulationQueue+1	No attempts yet	1s	128 MB	Judgeable
Colored CubesGiven up to four cubes with colored faces, find the minimum number of face repaints so all cubes become identical under rotation.	Medium6	Brute forceSimulation+1	No attempts yet	3s	128 MB	Judgeable
Atomic Car RaceGiven checkpoints and a per-kilometer speed model that depends on distance since last tire change, find the tire-change strategy at checkpoints that minimizes total race time.	Medium6	Dynamic programmingMath+1	No attempts yet	1s	128 MB	Judgeable
Balance ScaleGiven two weight denominations and a target amount, find the minimum-count (then minimum-weight) combination of weights placed on either pan to balance the given amount of medicine.	Medium6	Number theoryMath+1	No attempts yet	1s	128 MB	Judgeable
Make a SequenceSimulate a 3D tic-tac-toe game with gravity-dropped balls and report the first move that completes an m-in-a-row across 13 directions, or a draw.	Medium6	SimulationImplementation+1	No attempts yet	1s	128 MB	Judgeable
Finding the Weakness in the EncryptionGiven nine XOR-encrypted 32-bit values where the last is a checksum of the others, recover the XOR key bit by bit using carry propagation.	Medium6	Bit manipulationMath+1	No attempts yet	1s	128 MB	Judgeable
Confusing Login NamesCompute an extended edit distance (insert, delete, replace, adjacent swap) between all pairs of given login names and output pairs within a given threshold, sorted alphabetically.	Medium6	Dynamic programmingString+1	No attempts yet	3s	128 MB	Judgeable
Color the MapGiven polygons grouped into named countries, determine the minimum colors needed so adjacent countries (sharing a border segment of positive length) differ, using geometric segment overlap detection to build the adjacency graph then graph coloring.	Medium6	GeometryGraph+1	No attempts yet	1s	128 MB	Judgeable
God of WindDecide if a 2x2 cloud can move on a 4x4 grid, one to two cells per step in a straight line, so every village avoids rain-free streaks over 6 days while never raining on a marked village on its festival day.	Medium6	BFSBit manipulation+1	No attempts yet	1s	128 MB	Judgeable
GapGiven a shuffled layout of the card game Gap, compute the minimum number of moves (via BFS/IDA* style search over legal gap-fill moves) to sort each suit row into ascending order, or report -1 if impossible.	Medium6	BFSSimulation+1	No attempts yet	3s	128 MB	Judgeable
Monster TrapGiven up to 100 line segments around the origin, decide whether they form a closed barrier that completely encloses the origin with no gap for the monster to escape through.	Medium6	GeometryGraph+1	No attempts yet	1s	128 MB	Judgeable
Random WalkGiven n steps with probabilities of moving left, right, or staying, compute the expected value of the maximum position reached.	Medium6	Dynamic programmingProbability+1	No attempts yet	10s	128 MB	Judgeable
Hongjun's Royal GuardCount permutations of N distinct elements where every interior element is a local extremum (both neighbors larger or both smaller); N is at most 20.	Medium6	Dynamic programmingCombinatorics+2	No attempts yet	1s	128 MB	Judgeable
Ski JumpGiven a piecewise hill profile and a take-off parabola, find where the jump lands and report the landing distance, speed, and angle from the hill tangent.	Medium6	Binary searchMath+2	No attempts yet	2s	128 MB	Judgeable
Suffix Array Re-constructionReconstruct a base string from partial suffix descriptions, where each suffix may contain one wildcard block, and decide when that is impossible.	Medium6	StringImplementation+2	No attempts yet	3s	128 MB	Judgeable
Genetic FraudDecide whether two equal-length strings share an aligned substring of length at least ceil(N/2) where every pair of aligned letters differs by at most 1.	Medium6	StringTwo pointers+2	No attempts yet	1s	128 MB	Judgeable
Safe ZoneGiven disjoint circles, find the shortest closed fence enclosing all of them, which equals the convex hull perimeter plus the circumference of one circle.	Medium6	GeometryDivide and conquer	No attempts yet	1s	128 MB	Judgeable
SightseeingChoose a direction for each track on a circular tour so the total hiking plus transfer time is minimized, and check it against a limit T.	Medium6	Dynamic programmingGreedy+2	No attempts yet	1s	128 MB	Judgeable
Suiting WeaversGiven each weaver's circular territory and each fiber pile, decide whether Willy can end up with at least as many fibers as every rival under any assignment of piles to reachable weavers.	Medium6	GreedySorting+2	No attempts yet	1s	128 MB	Judgeable
Absurd PricesGiven a price in cents, decide whether some integer within 5 percent (rounded to a closed interval) has strictly smaller digit-based absurdity, where absurdity is twice the digit count minus one if the last nonzero digit is 5.	Medium6	MathBrute force+2	No attempts yet	1s	128 MB	Judgeable
Soccer TacticsGiven a directed graph, find every vertex from which all other vertices are reachable, or report that none exists.	Medium6	GraphDFS+2	No attempts yet	1s	256 MB	Judgeable
HackingFind the shortest lexicographically smallest string over the first k letters that appears nowhere as a substring of a given text, with length capped at m.	Medium6	StringBinary search+2	No attempts yet	1s	512 MB	Judgeable
Starting LineupAssign 11 players to 11 positions, each with ability 0 to 100, maximizing total ability while avoiding zero-ability slots; every player suits at most 5 positions.	Medium6	BacktrackingBrute force+2	No attempts yet	1s	128 MB	Judgeable
Screen SaverGiven a piecewise linear floor and a water level, update floor heights or the level and report the submerged area to three decimals.	Medium6	GeometrySegment tree+1	No attempts yet	2s	128 MB	Judgeable
TelejumpGiven a type-1 jumps, b type-2 jumps, and c type-3 jumps with n = a+b+c+1, output a route visiting planets 0 through n-1 exactly once using every ticket exactly once.	Medium6	GreedyImplementation+1	No attempts yet	1s	128 MB	Judgeable
Convention CenterChoose the largest set of non-overlapping day intervals, breaking ties by picking the set of group indices that is lexicographically smallest.	Medium6	GreedySorting+2	No attempts yet	2s	64 MB	Judgeable
Road SeriesGiven signs of text processed in order, track how far the consecutive count from 1 reaches while remembering seen numbers only within a sliding window.	Medium6	SimulationHash map+2	No attempts yet	1s	128 MB	Judgeable
Show Me the MoneyGiven consistent exchange rates among at most 8 currencies and a requested amount, find the substitute currency giving the smallest value that is at least the request, using at most 100000 units.	Medium6	GraphDFS+2	No attempts yet	3s	128 MB	Judgeable
Town SquareGiven four statue points, find the side length of the largest square whose four sides each sit exactly 5 feet from one distinct statue.	Medium6	GeometryBrute force+2	No attempts yet	1s	128 MB	Judgeable
The AgencyFind the minimum landing-tax cost to travel from one N-bit planet to another, where flights flip exactly one bit.	Medium6	GraphShortest path+2	No attempts yet	1s	128 MB	Judgeable
MobileGiven a mobile's arm structure and pivot distances, find the smallest integer weights, with a named weight at least w, that keep every arm balanced.	Medium6	TreeMath+2	No attempts yet	1s	128 MB	Judgeable
Flip It!Simulate a sequence of row and column flips that collapse a grid of cards into one pile, then list the face-up cards from the bottom.	Medium6	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
3D Rod MazeMarkers move through a cube whose six faces are 2D mazes; find the lexicographically smallest shortest move sequence to the opposite interior corner.	Medium6	BFSGraph+2	No attempts yet	1s	128 MB	Judgeable
Photo ShootGiven Adam's position, each person's angle around him, and a fixed camera width, find the fewest photos that cover every person.	Medium6	SortingGreedy+2	No attempts yet	1s	128 MB	Judgeable
Polar BearSimulate Conway's Game of Life on concentric rings with special opposite-cell neighbors, then report the live count and lexicographic first and last live cells after g steps.	Medium6	SimulationArray+1	No attempts yet	5s	128 MB	Judgeable
Vampires!For each vampire, find the directions along which a mirror's reflecting side sees it with no mortal or mirror blocking the line.	Medium6	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable