Problems

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Total results29,461 problems

Dartboard
Medium4
Probability, Math
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Longest Common Subsequence
Medium4
Dynamic programming
No attempts yet
Time limit
0.1s
Memory limit
256 MB
Judgeable
Special Judge
Medium4
String matching, String
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Inverse Matrix
Medium4
Matrix, Number theory
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Privacy Loss
Medium4
Dynamic programming
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Let's sell Jeongjeheon!
Medium4
Number theory, Math
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Robot In A Room
Medium4
Simulation, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hoo's Afraid of the Big Bad Wolf?
Medium4
Shortest path, Graph
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Password Validation
Medium4
Implementation, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
ASCII Art Table
Medium4
Simulation, Implementation+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Flood-It
Medium4
Simulation, BFS+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Network Planning
Medium4
Greedy, Sorting+1
No attempts yet
Time limit
2s
Memory limit
64 MB
Judgeable
Digital Video Discs (DVDs)
Medium4
Segment tree
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Fence
Medium4
Shortest path, BFS+2
No attempts yet
Time limit
2s
Memory limit
64 MB
Judgeable
Casino
Medium4
String, String matching
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Big Division
Medium4
Number theory, Math
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Calculator
Medium4
String, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Rental car management trouble
Medium4
Simulation, Implementation+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Blast the Enemy!
Medium4
Geometry
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Seven Segment Counter
Medium4
Brute force, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Exact Sum of Real Numbers
Medium4
Implementation, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
A site just for programming contests
Medium4
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Happy Primes
Medium4
Number theory, Hash map+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Worst Case Scenario
Medium4
Simulation, BFS+1
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Cash Cow
Medium4
Simulation, BFS+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Stickers
Medium4
Dynamic programming, Array
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Contraband
Medium4
Math, Geometry
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cousins
Medium4
Tree, Simulation
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Enterprise Escape
Medium4
Shortest path, Matrix+1
No attempts yet
Time limit
10s
Memory limit
256 MB
Judgeable
Draughts
Medium4
Backtracking, DFS+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Handing Out Books
Medium4
Greedy, Intervals+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Lock Patterns and Spanning Trees
Medium4
Matrix, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
NASSA's Robot
Medium4
Greedy, Simulation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
First Date
Medium4
Simulation, Math
No attempts yet
Time limit
10s
Memory limit
512 MB
Judgeable
Sweeping Robot
Medium4
Simulation, Geometry+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Longest Balanced Sub-Sequence
Medium4
Prefix sum, Hash map
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Spiral Coordinates
Medium4
Math
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Repeating Decimals
Medium4
Math, Number theory
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Area Between Outer Hull and Inner Hull
Medium4
Geometry, Sorting
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Metro Manila Detour
Medium4
Shortest path, Graph
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
More Fun in Bicol
Medium4
Union-find, Graph
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Interior Lattice Points
Medium4
Geometry, Number theory
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tree Coloring
Medium4
Dynamic programming, Tree+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Vacuum World
Medium4
Shortest path, Brute force+1
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Diamond Mining Profits
Medium4
Dynamic programming, Array+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sums of Distinct Natural Numbers
Medium4
Dynamic programming, Combinatorics
No attempts yet
Time limit
7s
Memory limit
128 MB
Judgeable
Joint Venture
Medium4
Dynamic programming
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
uHunt
Medium4
Sorting, Hash map+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Magic Multiplying Machine
Medium4
Dynamic programming, Math
No attempts yet
Time limit
2s
Memory limit
64 MB
Judgeable
Pyramid volume
Medium4
Geometry, Math
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Coding of Permutations
Medium4
Combinatorics, Math
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
MODSUM
Medium4
Brute force, Math
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Pancake sorting
Medium4
BFS, Brute force
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Walking
Medium4
Dynamic programming, Sorting
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Card Shuffling
Medium4
Simulation, Queue
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Housing
Medium4
Dynamic programming, Combinatorics
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Triball Ranking
Medium4
Topological sort, Graph+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
4SUM
Medium4
Hash map
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Vacation Planning
Medium4
Shortest path, Graph
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bessie Slows Down
Medium4
Simulation, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Balanced Teams
Medium4
Brute force, Backtracking
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Claws
Medium4
Tree, DFS
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Paths
Medium4
BFS, Dynamic programming
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Lexical
Medium4
Combinatorics, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Rank
Medium4
Graph, DFS
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Coin
Medium4
Dynamic programming
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Triangles made from lines
Medium4
Hash map, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Spectrum
Medium4
BFS, Graph+1
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Word Extraction
Medium4
String, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Digit Sums
Medium4
Dynamic programming, Math
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Door Man
Medium4
Graph, DFS
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Treasure Hunters
Medium4
Backtracking, Brute force
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Auto-Complete
Medium4
Trie, Sorting
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Font
Medium4
Brute force, Bit manipulation
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Colorful Chain
Medium4
Sliding window, Hash map+1
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Lottery 2
Medium4
Greedy, Array
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Watering the Fields
Medium4
Minimum spanning tree, Union-find+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Lazy Polar Bear
Medium4
Sliding window, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Decorating the Pastures
Medium4
BFS, Graph
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tourism
Medium4
Shortest path, Math
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
JOI emblem
Medium4
Brute force, Matrix
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Tickets
Medium4
Bit manipulation, Recursion
No attempts yet
Time limit
1s
Memory limit
64 MB
Judgeable
Counting Inversions
Medium4
Divide and conquer, Sorting
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Troyangles
Medium4
Dynamic programming, Matrix
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Gates
Medium4
Shortest path, Graph
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Rummikub
Medium4
Brute force, Sorting+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Maximum Jumps for a Checkers King
Medium4
Backtracking, DFS+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
The Minions Build a Brick Wall
Medium4
Graph, BFS+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Traffic Congestion
Medium4
Tree, DFS
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Intersection Points
Medium4
Geometry, Implementation
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Hacking
Medium4
Shortest path, Graph+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Man in the Middle
Medium4
DFS, Graph
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Hiking
Medium4
Shortest path, Graph+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Turtle Elder
Medium4
Tree, Dynamic programming
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
Goldbach Partitions
Medium4
Number theory, Math
No attempts yet
Time limit
3s
Memory limit
64 MB
Judgeable
Two's Round Trips
Medium4
Backtracking, DFS+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Button Bashing
Medium4
BFS, Shortest path+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Rearranging a Bit String
Medium4
Greedy, Brute force
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Lattice Multiplication
Medium4
Simulation, Implementation
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
The Maze Makers
Medium4
Graph, DFS
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
DartboardGiven ring radii and Gaussian spread, compute the expected dart score with averaged sector values and triple and double rings.	Medium4	ProbabilityMath	No attempts yet	1s	128 MB	Judgeable
Longest Common SubsequenceCompute the length of the longest subsequence shared by two uppercase strings of length up to 1000.	Medium4	Dynamic programming	No attempts yet	0.1s	256 MB	Judgeable
Special JudgeDecide whether the given string appears as a contiguous block in both A and B.	Medium4	String matchingString	No attempts yet	1s	128 MB	Judgeable
Inverse MatrixInvert the given N by N matrix modulo 998244353 and print no inverse when the matrix is singular.	Medium4	MatrixNumber theory	No attempts yet	1s	128 MB	Judgeable
Privacy LossPick a subset of options that maximizes total security benefit without exceeding the money budget and the privacy limit.	Medium4	Dynamic programming	No attempts yet	1s	128 MB	Judgeable
Let's sell Jeongjeheon!For each input line giving 1/n, count the unordered positive integer pairs x and y with 1/x + 1/y = 1/n.	Medium4	Number theoryMath	No attempts yet	5s	128 MB	Judgeable
Robot In A RoomSimulate a vacuum robot that moves, turns right at walls, and recharges at outlets to find when it reaches the spilled drink.	Medium4	SimulationImplementation+1	No attempts yet	1s	128 MB	Judgeable
Hoo's Afraid of the Big Bad Wolf?Find the directed path from X to Y with the largest product of edge safety probabilities, printed rounded to six decimals.	Medium4	Shortest pathGraph	No attempts yet	1s	128 MB	Judgeable
Password ValidationDecide whether each password meets length, character mix, repeat, palindrome, and forbidden subsequence rules.	Medium4	ImplementationString+1	No attempts yet	1s	128 MB	Judgeable
ASCII Art TableThe program rebuilds merged cells from row and column spans and prints the ASCII table with cell coordinates.	Medium4	SimulationImplementation+1	No attempts yet	2s	128 MB	Judgeable
Flood-ItSimulate greedy flood fills from the top-left corner that pick the color giving the largest connected region and report moves and per-color counts.	Medium4	SimulationBFS+1	No attempts yet	2s	128 MB	Judgeable
Network PlanningPick M cities for new stations to maximize total supply, where each station covers 70 percent of its own demand plus 10 percent of each neighbor's.	Medium4	GreedySorting+1	No attempts yet	2s	64 MB	Judgeable
Digital Video Discs (DVDs)The program tracks disc swaps on numbered slots and reports whether slots A to B hold exactly discs A to B.	Medium4	Segment tree	No attempts yet	2s	256 MB	Judgeable
FenceFrom outside the grid, compute every empty cell's minimum fence breaks with 0-1 BFS, then report the largest value and how many cells attain it.	Medium4	Shortest pathBFS+2	No attempts yet	2s	64 MB	Judgeable
CasinoFind every longest palindromic substring of length at least 2 in each string and print them rightmost first.	Medium4	StringString matching	No attempts yet	1s	128 MB	Judgeable
Big DivisionCancel the common factors of two huge products given as factor lists and print the reduced fraction.	Medium4	Number theoryMath	No attempts yet	5s	128 MB	Judgeable
CalculatorEvaluate up to 100 polynomials given as compact strings with omitted coefficients at integer X and print each result.	Medium4	StringMath+1	No attempts yet	1s	128 MB	Judgeable
Rental car management troubleProcess each spy's rental events in order and print spies by name with the total bill or INCONSISTENT for a broken record.	Medium4	SimulationImplementation+1	No attempts yet	2s	128 MB	Judgeable
Blast the Enemy!Compute and print the centroid of each given simple polygon with six digits after the decimal point.	Medium4	Geometry	No attempts yet	1s	128 MB	Judgeable
Seven Segment CounterGiven timestamped photos with partly hidden seven-segment bars, find how many starting counter values from 0 to 999 fit every photo.	Medium4	Brute forceSimulation+1	No attempts yet	1s	128 MB	Judgeable
Exact Sum of Real NumbersAdd each group of decimal numbers with up to 30 digits exactly and print the unrounded sum with trailing zeros removed.	Medium4	ImplementationString+1	No attempts yet	1s	128 MB	Judgeable
A site just for programming contestsBuy each plot in decreasing price order, one per year, and report the total cost or Too expensive when it exceeds the budget.	Medium4	GreedySorting+1	No attempts yet	1s	128 MB	Judgeable
Happy PrimesPrint every number up to n that is both prime and happy, where repeated digit-square sums reach 1, one per line in increasing order.	Medium4	Number theoryHash map+1	No attempts yet	1s	256 MB	Judgeable
Worst Case ScenarioSimulate staged infection events on a grid where full zones erupt and chain outbreaks to four neighbors until each event settles.	Medium4	SimulationBFS+1	No attempts yet	5s	128 MB	Judgeable
Cash CowSimulate clicks that remove same-color clusters of three or more on a 12 by 10 board with downward and leftward compaction, then count the circles left.	Medium4	SimulationBFS+1	No attempts yet	1s	128 MB	Judgeable
StickersPick stickers from a 2 by n grid with no two sharing an edge to maximize the total score.	Medium4	Dynamic programmingArray	No attempts yet	1s	256 MB	Judgeable
ContrabandGiven three sight lines and confidence weights from fixed stations, compute the point that minimizes the weighted sum of squared distances to the lines.	Medium4	MathGeometry	No attempts yet	1s	128 MB	Judgeable
CousinsReconstruct the tree defined by consecutive-number groups and count the cousins of node k.	Medium4	TreeSimulation	No attempts yet	3s	128 MB	Judgeable
Enterprise EscapeStarting from E, move four-directionally across the grid paying each entered cell's class cost and escape through the cheapest border cell.	Medium4	Shortest pathMatrix+1	No attempts yet	10s	256 MB	Judgeable
DraughtsFind the most dark pieces one light piece can capture in a single chain of diagonal jumps on a 10x10 draughts board.	Medium4	BacktrackingDFS+1	No attempts yet	2s	128 MB	Judgeable
Handing Out BooksAssign each applicant at most one distinct book numbered within their requested interval to maximize the number of satisfied applicants.	Medium4	GreedyIntervals+1	No attempts yet	2s	256 MB	Judgeable
Lock Patterns and Spanning TreesCount the spanning trees of an m by m king-move grid for m up to 6 by evaluating a cofactor of its Laplacian matrix.	Medium4	MatrixMath+2	No attempts yet	1s	128 MB	Judgeable
NASSA's RobotYou get a walk of UDLR steps with ? wildcards that can stop after any prefix, and you report the smallest and largest reachable X and Y.	Medium4	GreedySimulation	No attempts yet	1s	128 MB	Judgeable
First DateFor each given last Julian calendar date, print the next day written as a Gregorian date.	Medium4	SimulationMath	No attempts yet	10s	512 MB	Judgeable
Sweeping RobotCount the distinct grid cells a robot sees sideways from each unit of its grid path inside an orthogonal polygonal museum, with walls blocking the view.	Medium4	SimulationGeometry+1	No attempts yet	1s	128 MB	Judgeable
Longest Balanced Sub-SequenceFind the length of the longest contiguous block with equal counts of positive and negative numbers.	Medium4	Prefix sumHash map	No attempts yet	1s	128 MB	Judgeable
Spiral CoordinatesFind the (row, column) of N in the clockwise integer spiral centered at 1.	Medium4	Math	No attempts yet	1s	128 MB	Judgeable
Repeating DecimalsConvert each repeating decimal with its repeating part in parentheses into a reduced fraction printed beside the input.	Medium4	MathNumber theory	No attempts yet	1s	128 MB	Judgeable
Area Between Outer Hull and Inner HullCompute the convex hull of up to 1000 points twice, removing corner vertices after the first pass, and print the difference of the two polygon areas.	Medium4	GeometrySorting	No attempts yet	5s	128 MB	Judgeable
Metro Manila DetourCompute the shortest driving distance between two intersections on concentric ring roads and radial roads with one ring and one spoke closed.	Medium4	Shortest pathGraph	No attempts yet	5s	128 MB	Judgeable
More Fun in BicolGiven unit compass offsets between named places, answer each query with the direction from one place to the other or report it as unknown.	Medium4	Union-findGraph	No attempts yet	5s	128 MB	Judgeable
Interior Lattice PointsCount the lattice points strictly inside each triangle given by three integer vertices, printing zero for collinear points.	Medium4	GeometryNumber theory	No attempts yet	1s	128 MB	Judgeable
Tree ColoringCount colorings of an N-node tree with K colors so adjacent nodes differ, modulo 93563.	Medium4	Dynamic programmingTree+1	No attempts yet	1s	128 MB	Judgeable
Vacuum WorldTwo cleaners with different power and move costs roam a row of rooms and suck dirt, and the goal is the cheapest move-and-suck sequence that cleans every room.	Medium4	Shortest pathBrute force+1	No attempts yet	5s	128 MB	Judgeable
Diamond Mining ProfitsFind the contiguous period with the largest total gain across up to 2000 test cases, breaking ties by shorter length then earlier start.	Medium4	Dynamic programmingArray+1	No attempts yet	1s	128 MB	Judgeable
Sums of Distinct Natural NumbersCount the partitions of each given N into distinct positive integers, including N itself, modulo 100999.	Medium4	Dynamic programmingCombinatorics	No attempts yet	7s	128 MB	Judgeable
Joint VentureAssign each of the M modules to company A or B so total days stay within D and both budgets hold while total cost is minimized.	Medium4	Dynamic programming	No attempts yet	1s	128 MB	Judgeable
uHuntProcess judge submissions in order and after each one report the leader's time and the submitter's rank by personal best, ignoring non-improving resubmissions.	Medium4	SortingHash map+1	No attempts yet	1s	128 MB	Judgeable
Magic Multiplying MachineChoose any subset of the given levers, including none, to maximize the product of chosen numbers modulo M.	Medium4	Dynamic programmingMath	No attempts yet	2s	64 MB	Judgeable
Pyramid volumeGiven the six edge lengths of a tetrahedron, compute its volume and print it rounded up to four decimal places.	Medium4	GeometryMath	No attempts yet	1s	128 MB	Judgeable
Coding of PermutationsThe task gives a permutation of 1 to n and asks for its 1-based rank among all permutations in lexicographic order.	Medium4	CombinatoricsMath	No attempts yet	1s	128 MB	Judgeable
MODSUMSum the given quartic function of the variable total over every tuple formed by the n integer ranges.	Medium4	Brute forceMath	No attempts yet	2s	512 MB	Judgeable
Pancake sortingSort a stack of up to 8 pancakes into descending order with the fewest suffix flips.	Medium4	BFSBrute force	No attempts yet	2s	512 MB	Judgeable
WalkingWalkers start at distinct times with fixed speeds, and a later starter who arrives earlier befriends the other; find the largest group where every pair meets.	Medium4	Dynamic programmingSorting	No attempts yet	1s	128 MB	Judgeable
Card ShufflingGiven a deck numbered from the top and a string of two shuffle moves, find the three cards at positions k-1, k and k+1 after all moves.	Medium4	SimulationQueue	No attempts yet	2s	512 MB	Judgeable
HousingCount the unordered splits of n into parts of at least 5 for n between 5 and 100.	Medium4	Dynamic programmingCombinatorics	No attempts yet	2s	512 MB	Judgeable
Triball RankingOrder all k players to satisfy every match result and return the lexicographically smallest lineup, or 0 when no lineup fits.	Medium4	Topological sortGraph+1	No attempts yet	2s	512 MB	Judgeable
4SUMPick one number from each of four sets of up to 500 integers so the four numbers sum to zero.	Medium4	Hash map	No attempts yet	2s	512 MB	Judgeable
Vacation PlanningFor each query, find the cheapest directed flight route from start to end that visits at least one hub, then report the count and total cost.	Medium4	Shortest pathGraph	No attempts yet	1s	128 MB	Judgeable
Bessie Slows DownBessie runs 1000 metres with speed 1/(k+1) after k slowdowns triggered by time or distance events, and the total time is rounded to the nearest second.	Medium4	SimulationSorting+1	No attempts yet	1s	128 MB	Judgeable
Balanced TeamsSplit twelve cows with given skill levels into four teams of three to minimize the gap between the strongest and weakest team sums.	Medium4	Brute forceBacktracking	No attempts yet	1s	128 MB	Judgeable
ClawsCompute each hinge grade from subtree and root-path bar weights and report the largest root-to-claw sum of grades over all claws.	Medium4	TreeDFS	No attempts yet	2s	512 MB	Judgeable
PathsFind the cheapest total cost among the directed paths from node 0 to node 1 that use the fewest links.	Medium4	BFSDynamic programming	No attempts yet	2s	512 MB	Judgeable
LexicalGiven n and a permutation of 0 to n-1, compute its 1-based position in lexicographic order.	Medium4	CombinatoricsMath	No attempts yet	2s	1024 MB	Judgeable
RankCount the players that lie on a directed win cycle built from the game results.	Medium4	GraphDFS	No attempts yet	2s	1024 MB	Judgeable
CoinFind the fewest coins from unlimited denominations whose values sum to V and weights sum to W.	Medium4	Dynamic programming	No attempts yet	2s	1024 MB	Judgeable
Triangles made from linesCount how many triples of the given lines form a triangle by removing triples that contain parallel lines.	Medium4	Hash mapCombinatorics+1	No attempts yet	1s	128 MB	Judgeable
SpectrumMaintain an undirected graph of named targets and answer per-query BFS hop histograms and pairwise hop distances.	Medium4	BFSGraph+1	No attempts yet	3s	128 MB	Judgeable
Word ExtractionClean each input line by lowercasing it, joining or splitting words at punctuation by neighbor rules, then print the sorted unique words per line.	Medium4	StringSorting+1	No attempts yet	1s	128 MB	Judgeable
Digit SumsCount positive integers up to A whose base-B digits add up to C for each query line.	Medium4	Dynamic programmingMath	No attempts yet	1s	128 MB	Judgeable
Door ManYou decide whether one walk from the start room closes every open door exactly once and ends in room 0.	Medium4	GraphDFS	No attempts yet	1s	128 MB	Judgeable
Treasure HuntersAssign up to 8 treasures to up to 6 hunters with differing valuations to minimize the gap between the richest and poorest hunter totals.	Medium4	BacktrackingBrute force	No attempts yet	1s	128 MB	Judgeable
Auto-CompleteThe app prints the original index of the K-th dictionary word with each query prefix in alphabetical order, or -1.	Medium4	TrieSorting	No attempts yet	1s	128 MB	Judgeable
FontCount the subsets of the given words whose letters together cover all 26 lowercase letters.	Medium4	Brute forceBit manipulation	No attempts yet	1s	256 MB	Judgeable
Colorful ChainCount the contiguous segments that hold exactly the required number of links of each listed color and no other colors.	Medium4	Sliding windowHash map+1	No attempts yet	3s	512 MB	Judgeable
Lottery 2Change as few entries as possible in a length-n sequence over 1 to k so no two adjacent entries are equal.	Medium4	GreedyArray	No attempts yet	1s	128 MB	Judgeable
Watering the FieldsConnect all fields with pipes costing at least C while minimizing total squared distance, or report -1 when impossible.	Medium4	Minimum spanning treeUnion-find+1	No attempts yet	1s	128 MB	Judgeable
Lazy Polar BearChoose a point on the line so the buckets within distance K of it hold the most ice in total.	Medium4	Sliding windowSorting+1	No attempts yet	1s	128 MB	Judgeable
Decorating the PasturesColor each connected group of pastures with two letters so neighbors differ and the count of J signs is as large as possible.	Medium4	BFSGraph	No attempts yet	1s	128 MB	Judgeable
TourismVisit the given sights in order on a grid with extra northeast diagonals and minimize the total number of road segments traveled.	Medium4	Shortest pathMath	No attempts yet	1s	128 MB	Judgeable
JOI emblemYou may change at most one cell of the letter grid, then count how many 2 by 2 blocks match the emblem, and report the largest possible count.	Medium4	Brute forceMatrix	No attempts yet	1s	256 MB	Judgeable
TicketsPrint the K-th n-bit string in reflective Gray code order for the given n and K.	Medium4	Bit manipulationRecursion	No attempts yet	1s	64 MB	Judgeable
Counting InversionsCount the pairs in a permutation of 1 to n where a larger number stands before a smaller one.	Medium4	Divide and conquerSorting	No attempts yet	1s	256 MB	Judgeable
TroyanglesCount all centered triangles of `#` cells in an N-by-N grid where row i of a height-h triangle holds 2i-1 cells.	Medium4	Dynamic programmingMatrix	No attempts yet	1s	256 MB	Judgeable
GatesFind the minimum travel time for each query pair of gates using walking and directed walkways.	Medium4	Shortest pathGraph	No attempts yet	2s	256 MB	Judgeable
RummikubFrom 14 tiles, find the highest scoring group or run, break ties by sorted tile order, and print it with its score.	Medium4	Brute forceSorting+1	No attempts yet	1s	256 MB	Judgeable
Maximum Jumps for a Checkers KingGiven up to 20 checkerboards, find for each board the red king with the longest capture chain and print its row, column, and jump count.	Medium4	BacktrackingDFS+1	No attempts yet	1s	256 MB	Judgeable
The Minions Build a Brick WallCover a grid with obstacles using dominoes to leave as few open cells bare as possible.	Medium4	GraphBFS+1	No attempts yet	1s	256 MB	Judgeable
Traffic CongestionPick the tree city that minimizes the largest number of fans traveling on any single road when all fans leave the arena city.	Medium4	TreeDFS	No attempts yet	3s	256 MB	Judgeable
Intersection PointsGiven an axis-aligned rectangle and a segment per test case, count their shared boundary points, printing 4 for infinite overlap.	Medium4	GeometryImplementation	No attempts yet	1s	256 MB	Judgeable
HackingStarting from the hacked computer, count reachable computers through dependency edges and report the longest infection time.	Medium4	Shortest pathGraph+1	No attempts yet	2s	256 MB	Judgeable
Man in the MiddleDecide whether removing some single person disconnects the connected friendship network.	Medium4	DFSGraph	No attempts yet	3s	256 MB	Judgeable
HikingFind the cheapest 8-direction path from the start to the highest cell of a height grid where flat steps cost 1 and a height change of d costs (d+1) squared.	Medium4	Shortest pathGraph+1	No attempts yet	3s	256 MB	Judgeable
Turtle ElderPick safe start and end islands in a tree so the sum of values along the path is as large as possible, staying home when the best sum is not positive.	Medium4	TreeDynamic programming	No attempts yet	5s	256 MB	Judgeable
Goldbach PartitionsCount the pairs of primes that sum to each given even number up to ten million.	Medium4	Number theoryMath	No attempts yet	3s	64 MB	Judgeable
Two's Round TripsList every route that starts at house 2, visits no house twice, returns to house 2, and print them as digit strings in numeric order.	Medium4	BacktrackingDFS+1	No attempts yet	1s	256 MB	Judgeable
Button BashingPress add and subtract buttons from 0, clamped between 0 and 3600, to reach a target time in the fewest presses or the nearest reachable longer time.	Medium4	BFSShortest path+1	No attempts yet	1s	256 MB	Judgeable
Rearranging a Bit StringFind the fewest adjacent swaps turning the start bits into one of the strings matching the run code.	Medium4	GreedyBrute force	No attempts yet	1s	256 MB	Judgeable
Lattice MultiplicationDraw the framed ASCII lattice diagram that multiplies each input pair digit by digit.	Medium4	SimulationImplementation	No attempts yet	1s	256 MB	Judgeable
The Maze MakersValidate hex-encoded grid mazes by checking that the two openings connect, every cell is reachable, and no cycles create multiple paths.	Medium4	GraphDFS	No attempts yet	1s	256 MB	Judgeable