Problems

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Total results29,431 problems

Ferry Schedule
Medium6
Greedy, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Maximum Vector Sum
Medium6
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Two Subsequences 2
Medium6
Dynamic programming, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
A1
Medium6
Binary search, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Closing Windows
Medium6
Simulation, Geometry+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Teams
Medium6
Union-find, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Mirko's Newspaper Time
Medium6
Dynamic programming, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
ONE
Medium6
Tree, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Restoring Sequence A from Sequence B
Medium6
Greedy, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Meadow
Medium6
Union-find, Binary search+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bar Code
Medium6
Backtracking, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Shelves
Medium6
Dynamic programming, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Arranging Cards
Medium6
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Monkey in the Labyrinth
Medium6
BFS, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Turning Off the Lamps
Medium6
Dynamic programming, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Moore Machine
Medium6
Dynamic programming, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
FATBOY
Medium6
Dynamic programming, String
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Teams
Medium6
Greedy, Sorting+1
No attempts yet
Time limit
2.5s
Memory limit
256 MB
Judgeable
Similarity
Medium6
String matching, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
An Arithmetic Rectangle
Medium6
Math, Matrix+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
A Huge Tower
Medium6
Sorting, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Messengers
Medium6
Tree, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Photographs
Medium6
Greedy, Geometry+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Ministry
Medium6
Tree, Recursion+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Roses
Medium6
Math, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Brackets
Medium6
Dynamic programming, Stack+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Melody
Medium6
Dynamic programming, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Triangulation
Medium6
Union-find, Graph+1
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Candies
Medium6
Dynamic programming, Brute force+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Rectangles
Medium6
Dynamic programming, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cards
Medium6
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Camouflaged Camp
Medium6
Prefix sum, Sliding window+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Magic Parenthesis
Medium6
Greedy, Stack+1
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Maze
Medium6
BFS, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Barrel
Medium6
Binary search, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Speed Limits
Medium6
Shortest path, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tennis Club
Medium6
Greedy, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Knight
Medium6
Graph, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Mars Map
Medium6
Segment tree, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Time Zones
Medium6
Simulation, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Stickers
Medium6
Simulation, Math+1
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Expressions
Medium6
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Stack Machine Programmer
Medium6
Simulation, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
A Strange Regulation
Medium6
Union-find, Graph+1
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Defense Line
Medium6
Array, Two pointers+1
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
A Dragon Lives
Medium6
Greedy, Heap+1
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Justice for All
Medium6
Dynamic programming, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Key Task
Medium6
BFS, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Rectilinear Polygon
Medium6
Geometry, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Robotic Sort
Medium6
Segment tree, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hang or Not to Hang
Medium6
BFS, Bit manipulation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Calendar of Maya
Medium6
Math, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Game of Master-Mind
Medium6
Brute force, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Equipment Box
Medium6
Geometry, Binary search+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Secret Code
Medium6
Math, Number theory+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Copying Books
Medium6
Binary search, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Substitution Cipher
Medium6
String, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Commedia dell'arte
Medium6
Math, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Skyscraper Floors
Medium6
Union-find, Number theory+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Glass Beads
Medium6
String, String matching+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Invitation Cards
Medium6
Shortest path, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cube Coloring
Medium6
Brute force, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Dice
Medium6
Greedy, Math+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Galaxy Interconnection
Medium6
Graph, DFS+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
John's Inversions
Medium6
Sorting, Greedy+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Evacuation Plan
Medium6
Dynamic programming, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Commuting Functions
Medium6
Graph, Greedy+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Ideal Contest
Medium6
Implementation, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Java Certification
Medium6
Brute force, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Enigmatic Device
Medium6
Segment tree, Math+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Jealous Numbers
Medium6
Math, Number theory+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Finding Liars
Medium6
Greedy, Simulation+1
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Hell on the Markets
Medium6
Greedy, Math
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Javanese Cryptanalysis
Medium6
Graph, BFS+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Billboard
Medium6
Segment tree, Greedy+2
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Fenwick Tree
Medium6
Math, Tree+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Christmas Gifts
Medium6
Graph, Math+1
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Kingdom Partitioning
Medium6
Geometry, Simulation+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Elevator
Medium6
BFS, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Exchange
Medium6
Queue, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Unit Squares Along a Diagonal
Medium6
Number theory, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Alphabet
Medium6
Linked list, Simulation+1
No attempts yet
Time limit
2s
Memory limit
64 MB
Judgeable
Set Equations
Medium6
Simulation, Implementation+1
No attempts yet
Time limit
2s
Memory limit
64 MB
Judgeable
Japanese Puzzle
Medium6
Binary search, Math+1
No attempts yet
Time limit
2s
Memory limit
64 MB
Judgeable
Kennings
Medium6
Simulation, String+1
No attempts yet
Time limit
2s
Memory limit
64 MB
Judgeable
Astronomy
Medium6
Math, Number theory+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Expectation
Medium6
Bit manipulation, Math+1
No attempts yet
Time limit
2s
Memory limit
64 MB
Judgeable
Jenny's First Exams
Medium6
Greedy, Sorting+1
No attempts yet
Time limit
2s
Memory limit
64 MB
Judgeable
Choosing a Pub
Medium6
Dynamic programming, Probability+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Idol
Medium6
Graph, DFS+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Please Go First
Medium6
Greedy, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tichu
Medium6
Dynamic programming, Bit manipulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
RFID Tracking
Medium6
Geometry, Simulation+1
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
High Score
Medium6
Greedy, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Common Subexpression Elimination
Medium6
Hash map, Tree+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Fractal
Medium6
Recursion, Geometry+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Moving to Nuremberg
Medium6
Tree, DFS+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Settlers of Catan
Medium6
Simulation, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Wormholes
Medium6
Shortest path, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Proving Equivalences
Medium6
Graph, Union-find+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Ferry ScheduleGiven ferry travel time, turnaround preparation time, and fixed departure lists for both towns, compute the minimum number of ferries required to cover every scheduled trip.	Medium6	GreedySimulation+1	No attempts yet	1s	128 MB	Judgeable
Maximum Vector SumSelect a subset of up to 30000 2D vectors so that the squared length of their sum is maximized, answer fits in 64-bit.	Medium6	GreedySorting+1	No attempts yet	1s	128 MB	Judgeable
Two Subsequences 2Given two strings A and B of length up to 2000, find the shortest string that is a subsequence of A but not a subsequence of B.	Medium6	Dynamic programmingString+1	No attempts yet	1s	128 MB	Judgeable
A1Given damaged points on a highway divided into length-M segments, find the offset K in [1,M] for segment starts that minimizes the number of segments containing damage, and list all optimal K values.	Medium6	Binary searchGreedy+1	No attempts yet	1s	128 MB	Judgeable
Closing WindowsSimulate closing overlapping windows in order to determine the minimum clicks needed to close the very first opened window whose top-right cell must become visible.	Medium6	SimulationGeometry+1	No attempts yet	1s	128 MB	Judgeable
TeamsCount ways to split N players into two equal-size teams so that no player shares a team with anyone on his exclusion list, treating the two teams as unordered.	Medium6	Union-findCombinatorics+1	No attempts yet	1s	128 MB	Judgeable
Mirko's Newspaper TimeGiven jobs with start times and durations that Mirko must greedily choose among on tie-starts while never queuing missed jobs, maximize total idle (newspaper) minutes over the shift via optimal choice, essentially a DP over time with tie-breaking.	Medium6	Dynamic programmingGreedy+1	No attempts yet	1s	128 MB	Judgeable
ONEFind the minimum fuel a plough starting at a fixed node needs to traverse every edge of a weighted tree at least once, ending anywhere.	Medium6	TreeDFS+2	No attempts yet	1s	128 MB	Judgeable
Restoring Sequence A from Sequence BReconstruct the lexicographically smallest permutation A of 1..N consistent with given prefix-set markers B and fixed positions, or report impossibility.	Medium6	GreedyImplementation+1	No attempts yet	1s	128 MB	Judgeable
MeadowPartition points into at most B groups so as to minimize the largest minimum-weight Hamiltonian-path bottleneck, essentially via binary search plus union-find on sorted distances counting connected components.	Medium6	Union-findBinary search+1	No attempts yet	1s	128 MB	Judgeable
Bar CodeReconstruct the unique binary digit sequence from a partially unreadable bar code grid of black/white/unknown squares, or report it cannot be determined.	Medium6	BacktrackingString+1	No attempts yet	1s	128 MB	Judgeable
ShelvesGiven required shelf positions in a grid, choose one ladder placement height per column to minimize the total summed climbing height covering each object from its column or adjacent columns.	Medium6	Dynamic programmingGreedy+1	No attempts yet	1s	128 MB	Judgeable
Arranging CardsGiven C≤4 colors with N cards each in a hand sequence, find the minimum number of single-card moves to reach some arrangement where colors form contiguous ascending-value blocks in any color order.	Medium6	Dynamic programmingCombinatorics+1	No attempts yet	1s	128 MB	Judgeable
Monkey in the LabyrinthFind the shortest path in a labyrinth where rooms can be locked or unlocked and up to 8 switches toggle groups of room states, using BFS over a state space that combines room and switch configuration.	Medium6	BFSBit manipulation+1	No attempts yet	1s	128 MB	Judgeable
Turning Off the LampsGiven lamp positions and power rates on a line and a starting point, find the walking order that minimizes total energy spent before all lamps are switched off.	Medium6	Dynamic programmingGreedy+1	No attempts yet	1s	128 MB	Judgeable
Moore MachineParse a series-parallel Moore machine expression and determine the unique erased output symbol that matches an observed string, or report ambiguity or impossibility.	Medium6	Dynamic programmingString+2	No attempts yet	1s	128 MB	Judgeable
FATBOYFind the longest common subsequence of three given strings, breaking ties by lexicographically smallest result.	Medium6	Dynamic programmingString	No attempts yet	1s	128 MB	Judgeable
TeamsGiven each child's minimum required team size, partition all children into the maximum number of teams and then minimize the largest team size among optimal partitions.	Medium6	GreedySorting+1	No attempts yet	2.5s	256 MB	Judgeable
SimilaritySum, over every alignment of a pattern against a text without gaps, the count of matching letter positions, for texts up to 2,000,000 characters.	Medium6	String matchingString+1	No attempts yet	1s	128 MB	Judgeable
An Arithmetic RectangleDetermine whether missing cells in a grid can be filled with rationals so every row and column becomes an arithmetic progression.	Medium6	MathMatrix+1	No attempts yet	1s	128 MB	Judgeable
A Huge TowerCount the number of orderings of N distinct blocks into a tower, respecting a size-tolerance stacking rule, modulo 1e9+9.	Medium6	SortingCombinatorics+1	No attempts yet	1s	128 MB	Judgeable
MessengersGiven a tree with per-city messenger costs, compute for every city the minimum time to relay a message to the root via edge lengths and messenger switching costs.	Medium6	TreeDynamic programming+1	No attempts yet	1s	128 MB	Judgeable
PhotographsFind the minimum number of fixed-area rectangles anchored on the x-axis needed to cover all given stars.	Medium6	GreedyGeometry+1	No attempts yet	1s	128 MB	Judgeable
MinistryParse a nested ternary-tree encoding of an organization and, using tree canonicalization/hashing, count structurally distinct subtrees grouped by depth.	Medium6	TreeRecursion+1	No attempts yet	2s	128 MB	Judgeable
RosesGiven two bundle prices for roses, find the minimum cost to buy at least N roses using any combination of bundles from either shop.	Medium6	MathGreedy+1	No attempts yet	1s	128 MB	Judgeable
BracketsCount, modulo 1e9+9, the ways to turn some matching '(' '(' pairs back into '[' ']' so the bracket string becomes valid with at least one square pair.	Medium6	Dynamic programmingStack+1	No attempts yet	1s	128 MB	Judgeable
MelodyGiven N notes with S-digit codes and a target tune of length L, choose a sequence of notes with adjacent Hamming distance at most G that minimizes total mismatch with the written tune, then output the smallest such sequence lexicographically.	Medium6	Dynamic programmingString+1	No attempts yet	1s	128 MB	Judgeable
TriangulationGiven a triangulated colored convex polygon, find the maximum number of triangulation diagonals that can be cut without separating same-colored triangles.	Medium6	Union-findGraph+1	No attempts yet	3s	128 MB	Judgeable
CandiesGiven N bags of candies, choose which bag's count to replace with a new positive value so the number of distinct subset sums is maximized, breaking ties by smallest P then smallest Q.	Medium6	Dynamic programmingBrute force+1	No attempts yet	1s	128 MB	Judgeable
RectanglesChoose an orientation (width/height swap) for each rectangle placed side by side to maximize the sum of top and internal vertical edges excluding outer sides and bottoms.	Medium6	Dynamic programmingGreedy+1	No attempts yet	1s	128 MB	Judgeable
CardsGiven N double-sided cards, choose an order, a flip for each, and assign alternating plus/minus signs to minimize the resulting alternating sum.	Medium6	GreedySorting+1	No attempts yet	1s	128 MB	Judgeable
Camouflaged CampUsing prefix sums over the grid, find the L x W camp position that satisfies the most given adjacent-area altitude comparison rules, breaking ties by smallest row then column.	Medium6	Prefix sumSliding window+1	No attempts yet	1s	128 MB	Judgeable
Magic ParenthesisGiven a bracket string with wildcard characters ']' that each consume one or more open parentheses, determine feasibility and output the lexicographically largest assignment of counts for each wildcard.	Medium6	GreedyStack+1	No attempts yet	5s	128 MB	Judgeable
MazeFind the shortest path in a triangular-grid maze where crossed edge colors (white/black) must alternate.	Medium6	BFSGraph+1	No attempts yet	1s	128 MB	Judgeable
BarrelSimulate cubes floating or sinking in a barrel of water and compute the final water level using a binary search or iterative physics-based calculation.	Medium6	Binary searchSimulation+1	No attempts yet	1s	128 MB	Judgeable
Speed LimitsFind the fastest path in a directed road network where roads without a posted speed limit inherit the previously used speed limit, requiring state-dependent shortest path search.	Medium6	Shortest pathGraph+1	No attempts yet	1s	128 MB	Judgeable
Tennis ClubGiven each player's required match count, decide if a simple graph (no self loops, no repeated edges) with that exact degree sequence exists, typically via the Erdős–Gallai theorem.	Medium6	GreedyMath+1	No attempts yet	1s	128 MB	Judgeable
KnightGiven an N×N board with M forbidden squares, find the maximum number of knights placeable so none attacks another.	Medium6	GraphGreedy+2	No attempts yet	1s	128 MB	Judgeable
Mars MapCompute the total area covered by the union of up to 10,000 axis-aligned rectangles.	Medium6	Segment treeSorting+1	No attempts yet	1s	128 MB	Judgeable
Time ZonesGiven n messages with local hhmm timestamps arriving in chronological order for a hypothetical own-zone time, deduce each message's originating time zone under a westward-offset day-wraparound rule.	Medium6	SimulationMath+1	No attempts yet	1s	128 MB	Judgeable
StickersGiven fixed digit-sticker counts per box, find how many consecutive model numbers starting from 1 can be labeled before running out of stickers, opening one box per model.	Medium6	SimulationMath+1	No attempts yet	3s	128 MB	Judgeable
ExpressionsCount balanced parenthesis strings of a given total length that have exactly a given maximum nesting depth.	Medium6	Dynamic programmingCombinatorics+1	No attempts yet	1s	128 MB	Judgeable
Stack Machine ProgrammerGenerate a stack-machine program that maps up to five given small input-output integer pairs to their exact outputs under strict operand and stack constraints.	Medium6	SimulationMath+2	No attempts yet	1s	128 MB	Judgeable
A Strange RegulationSimulate cable ownership transfers between companies while maintaining per-company degree limits of 2 per server and no cycles, using union-find like cycle detection per company.	Medium6	Union-findGraph+1	No attempts yet	5s	128 MB	Judgeable
Defense LineGiven an array, find the maximum length of a strictly increasing run achievable after deleting a single contiguous segment (possibly empty).	Medium6	ArrayTwo pointers+1	No attempts yet	3s	128 MB	Judgeable
A Dragon LivesGiven a day-by-day rain forecast on lakes and dry days when the dragon may empty one full lake, decide if overflow can always be avoided.	Medium6	GreedyHeap+1	No attempts yet	3s	128 MB	Judgeable
Justice for AllGiven a k x k 0/1 trust matrix (k up to 20), count the number of perfect matchings between knights and horses, i.e. the permanent of the matrix.	Medium6	Dynamic programmingBit manipulation+1	No attempts yet	1s	128 MB	Judgeable
Key TaskFind the shortest path from a start cell to any exit in a grid maze where doors require previously collected matching keys.	Medium6	BFSBit manipulation+1	No attempts yet	1s	128 MB	Judgeable
Rectilinear PolygonReconstruct a simple rectilinear polygon's edges from its vertices given in random order and output each edge's compass direction in clockwise order.	Medium6	GeometrySorting+1	No attempts yet	1s	128 MB	Judgeable
Robotic SortSimulate a specific selection-sort-by-reversal algorithm on samples with stable tie-breaking and report the position used in each reversal step, requiring an efficient order-statistics data structure for up to 100,000 elements.	Medium6	Segment treeSorting+2	No attempts yet	1s	128 MB	Judgeable
Hang or Not to HangGiven a tiny assembly program with 32 boolean registers, arbitrary initial state, and nondeterministic RANDOM instructions, find the minimum number of cycles over all possible executions until STOP, or report HANGS.	Medium6	BFSBit manipulation+2	No attempts yet	1s	512 MB	Judgeable
Calendar of MayaGiven a Maya Calendar Round date, verify its legality and list all matching Long Count dates within baktuns 8 and 9.	Medium6	MathSimulation+1	No attempts yet	1s	128 MB	Judgeable
The Game of Master-MindGiven past Mastermind guesses and their black/white hints, find the lexicographically smallest secret code consistent with all hints or report impossibility.	Medium6	Brute forceCombinatorics+1	No attempts yet	1s	128 MB	Judgeable
Equipment BoxDetermine whether a rectangular box of given dimensions can be rotated and placed strictly inside a rectangular tile of given dimensions without touching its border.	Medium6	GeometryBinary search+1	No attempts yet	1s	128 MB	Judgeable
Secret CodeConvert a complex number X into base-B positional digits with a Gaussian-integer complex base, or report failure if impossible.	Medium6	MathNumber theory+1	No attempts yet	1s	128 MB	Judgeable
Copying BooksSplit a sequence of book page counts into k contiguous groups minimizing the maximum group sum, breaking ties by minimizing earlier scribes' loads first.	Medium6	Binary searchGreedy+1	No attempts yet	1s	128 MB	Judgeable
Substitution CipherGiven encrypted words known to be in lexicographic plaintext order and an encrypted message, determine the substitution mapping uniquely if possible and decrypt or report failure.	Medium6	StringGreedy+1	No attempts yet	1s	128 MB	Judgeable
Commedia dell'arteDetermine whether a 3D M^3 sliding puzzle can be restored to its solved state given its parity/permutation solvability rules.	Medium6	MathCombinatorics+1	No attempts yet	1s	128 MB	Judgeable
Skyscraper FloorsGiven elevators each stopping on an arithmetic progression of floors starting at Y with step X, determine whether furniture can travel from floor A to floor B by switching elevators only on shared stop floors.	Medium6	Union-findNumber theory+1	No attempts yet	1s	128 MB	Judgeable
Glass BeadsFind the starting index that produces the lexicographically smallest rotation of a circular string of beads, using an efficient least-rotation algorithm.	Medium6	StringString matching+1	No attempts yet	1s	128 MB	Judgeable
Invitation CardsGiven a directed weighted graph with up to a million nodes and edges, compute the sum of shortest paths from the CCS to all stops plus shortest paths from all stops back to the CCS.	Medium6	Shortest pathGraph+1	No attempts yet	1s	128 MB	Judgeable
Cube ColoringGiven six unordered face-vision descriptions of a cube, reconstruct the lexicographically smallest assignment of colors to the six numbered faces that reproduces the vision multiset, or report impossibility.	Medium6	Brute forceCombinatorics+1	No attempts yet	2s	512 MB	Judgeable
DiceAssign numbers 1 to m to n dice faces to maximize the expected sum, output the answer as an irreducible fraction.	Medium6	GreedyMath+1	No attempts yet	2s	512 MB	Judgeable
Galaxy InterconnectionGiven a low-degree graph with a proper k-coloring, output -1 if any edge shares a color, otherwise count vertices that start a simple path of k vertices visiting all k colors.	Medium6	GraphDFS+1	No attempts yet	3s	256 MB	Judgeable
John's InversionsOrder cards with two attached numbers to minimize the total count of same-color inversions summed over red and blue sequences.	Medium6	SortingGreedy+1	No attempts yet	3s	256 MB	Judgeable
Evacuation PlanGiven n team positions and m shelter positions on a line, find the minimum total distance assignment where every shelter gets at least one team.	Medium6	Dynamic programmingSorting+1	No attempts yet	1s	128 MB	Judgeable
Commuting FunctionsGiven a permutation f on {1..n}, construct the lexicographically smallest permutation g that commutes with f under composition.	Medium6	GraphGreedy+1	No attempts yet	3s	256 MB	Judgeable
Ideal ContestParse an ASCII contest scoreboard and compute several weighted penalty metrics (vainness, oversimplification, evenness, unsolvability, instability per problem) into a total negidealness score.	Medium6	ImplementationSimulation+1	No attempts yet	1s	128 MB	Judgeable
Java CertificationGiven rounded per-category percentages and totals, find n_i and w_i values reproducing them while minimizing the spread between the largest and smallest category size.	Medium6	Brute forceMath+1	No attempts yet	1s	128 MB	Judgeable
Enigmatic DeviceGiven an array, support range squaring modulo 2010 and range sum queries, using the fact that values cycle quickly under repeated squaring.	Medium6	Segment treeMath+1	No attempts yet	3s	256 MB	Judgeable
Jealous NumbersCount integers in a huge range [a, b] whose exponent of prime p in factorization exceeds that of prime q.	Medium6	MathNumber theory+1	No attempts yet	3s	256 MB	Judgeable
Finding LiarsGiven a circular chain of accusations among truth-tellers and liars with at most t liars, identify people who must be liars in every consistent assignment.	Medium6	GreedySimulation+1	No attempts yet	3s	128 MB	Judgeable
Hell on the MarketsDecide if signs (+1/-1) can be assigned to a given sequence with 1<=a_i<=i so the signed sum is zero.	Medium6	GreedyMath	No attempts yet	2s	128 MB	Judgeable
Javanese CryptanalysisGiven a ciphered text, determine a 2-coloring of the 26 letters into vowels and consonants consistent with alternation constraints from adjacent letters in every word, and output the lexicographically smallest valid decoding using graph bipartition and greedy label assignment.	Medium6	GraphBFS+1	No attempts yet	1s	128 MB	Judgeable
BillboardSimulate posting strips onto rows of a billboard using a multiset keyed by remaining width, tracking the topmost-leftmost valid row for each strip efficiently.	Medium6	Segment treeGreedy+2	No attempts yet	3s	256 MB	Judgeable
Fenwick TreeGiven an array, find the minimum number of element changes so that the array equals its own Fenwick (BIT) prefix-sum tree.	Medium6	MathTree+1	No attempts yet	3s	256 MB	Judgeable
Christmas GiftsCompute the smallest mutually consistent gift sets for children whose conditions form monotone equations with union, intersection, and set-difference operators over sibling references.	Medium6	GraphMath+1	No attempts yet	3s	128 MB	Judgeable
Kingdom PartitioningSimulate a sweep of vertical lines where each remaining kingdom's threshold crossing position is found via circle-area integration and the smallest threshold is served each round.	Medium6	GeometrySimulation+1	No attempts yet	2s	128 MB	Judgeable
ElevatorGiven three step sizes and a reset-to-1 button, count how many floors from 1 to h an elevator starting at floor 1 can reach.	Medium6	BFSMath+1	No attempts yet	1s	128 MB	Judgeable
ExchangeImplement a limit order book that matches buy/sell orders FIFO by price-time priority, supports cancellation, and emits trades and quotes for each message.	Medium6	QueueSimulation+1	No attempts yet	1s	128 MB	Judgeable
Unit Squares Along a DiagonalGiven N, count unordered integer side pairs (a,b) such that a+b-gcd(a,b) equals N, using the diagonal-crossing formula for a grid rectangle.	Medium6	Number theoryMath+1	No attempts yet	1s	128 MB	Judgeable
AlphabetSimulate inserting tokens into a growing circular list by repeatedly stepping k tokens forward and inserting the next alphabet letter, then report the letter inserted on turn m (up to 1e9), requiring an efficient data structure rather than brute simulation.	Medium6	Linked listSimulation+1	No attempts yet	2s	64 MB	Judgeable
Set EquationsParse a set-theory equation with union, intersection, difference, and symmetric difference, then determine per-element membership assignments for undefined variables that satisfy it, printing the canonical lexicographically smallest solution or reporting impossibility.	Medium6	SimulationImplementation+1	No attempts yet	2s	64 MB	Judgeable
Japanese PuzzleGiven counts of k picture types filling an n by n grid, find the maximum number of rows that can be rearranged to be identical, using each picture's total count as a constraint.	Medium6	Binary searchMath+1	No attempts yet	2s	64 MB	Judgeable
KenningsExpand a text plan by repeatedly substituting kenning referents with their bodies until reaching a length threshold, then reflow the text to a given line width.	Medium6	SimulationString+1	No attempts yet	2s	64 MB	Judgeable
AstronomyGiven orbital periods of n planets moving on circular orbits, compute the exact fractional time interval between consecutive moments all planets and the star are collinear.	Medium6	MathNumber theory+1	No attempts yet	2s	128 MB	Judgeable
ExpectationCompute the exact expected value (as a reduced fraction) of the XOR of two independent uniform random integers in [0, n-1), for up to 1000 values of n up to 1e9.	Medium6	Bit manipulationMath+1	No attempts yet	2s	64 MB	Judgeable
Jenny's First ExamsGiven exam dates and earliest-start offsets, find the latest possible start day for a schedule where Jenny studies one exam per day, one at a time, without conflicts, or report impossibility.	Medium6	GreedySorting+1	No attempts yet	2s	64 MB	Judgeable
Choosing a PubSimulate probabilistic vote-following among n pubs (Pólya urn style) to compute exact final probability each pub wins, handling ties uniformly.	Medium6	Dynamic programmingProbability+1	No attempts yet	1s	128 MB	Judgeable
IdolGiven judges' two-literal votes as a 2-SAT instance, decide if there's a valid advance/eliminate assignment where contestant 1 advances and no judge's clause is fully violated.	Medium6	GraphDFS+1	No attempts yet	1s	128 MB	Judgeable
Please Go FirstGiven a queue string where equal characters denote groups, compute total seconds saved when people yield positions so each group can board together as early as possible.	Medium6	GreedySimulation+1	No attempts yet	1s	128 MB	Judgeable
TichuGiven a 13-card Tichu hand, compute the minimum number of legal combinations (singles, pairs, triples, quads, full houses, straights) that partition the hand.	Medium6	Dynamic programmingBit manipulation+2	No attempts yet	1s	128 MB	Judgeable
RFID TrackingGiven sensors, walls, and items on a plane, find for each item all sensors whose distance minus the number of walls crossed is within range r, then print them sorted by coordinates.	Medium6	GeometrySimulation+1	No attempts yet	3s	128 MB	Judgeable
High ScoreCompute the minimum joystick moves (up/down letter changes and left/right cursor moves, with wraparound) needed to type a target uppercase string starting from all 'A's.	Medium6	GreedyString+1	No attempts yet	1s	128 MB	Judgeable
Common Subexpression EliminationCompress a labeled binary expression tree into a minimal DAG by merging identical subexpressions and print it with backreference numbers to earlier nodes.	Medium6	Hash mapTree+2	No attempts yet	1s	128 MB	Judgeable
FractalGiven a recursively self-similar fractal built from a base polyline, find the point at a given fraction of its total arc length after d recursive refinements.	Medium6	RecursionGeometry+1	No attempts yet	1s	128 MB	Judgeable
Moving to NurembergGiven a weighted tree and visit frequencies at some nodes, find the node minimizing total weighted round-trip distance and list all optimal nodes.	Medium6	TreeDFS+1	No attempts yet	1s	128 MB	Judgeable
Settlers of CatanSimulate filling hexagonal tiles in an outward spiral with resource-choice rules and report the resource of the n-th tile.	Medium6	SimulationImplementation+1	No attempts yet	1s	128 MB	Judgeable
WormholesGiven start, destination, and wormholes with entry-time constraints and time shifts, compute the earliest arrival time using a shortest-path style relaxation over travel distances and wormhole jumps.	Medium6	Shortest pathGraph+1	No attempts yet	1s	128 MB	Judgeable
Proving EquivalencesGiven a directed graph of proven implications, find the minimum number of edges to add so every node becomes mutually reachable (classic SCC condensation + max(sources, sinks) technique).	Medium6	GraphUnion-find+1	No attempts yet	2s	128 MB	Judgeable