Problems

Pick a problem, code in the editor, and watch the judge run real test cases. The archive is open to browse

Under construction

Still being built. Things may change

Total results29,068 problems

Calvinball minimum teams
Medium7
Backtracking, Graph+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Calvinball team assignment
Medium7
Backtracking, Graph+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Calvinball championship team split
Medium7
Backtracking, Graph+1
No attempts yet
Time limit
7s
Memory limit
512 MB
Judgeable
Evacuation
Medium7
Graph
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Kimchi
Medium7
Dynamic programming, Sliding window+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Forged Answers
Medium7
Greedy, Binary search
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Cheating 2
Medium7
Graph, DFS
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Summer on the Beach
Medium7
Geometry, Math
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Pair Transformation
Medium7
Number theory, BFS+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Unique right triangle
Medium7
Number theory, Array+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Dragon curve
Medium7
Recursion, Divide and conquer+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Rectangle update and rectangle sum
Medium7
Segment tree, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
500-Yen Saving
Medium7
Dynamic programming, Simulation+1
No attempts yet
Time limit
8s
Memory limit
256 MB
Judgeable
Deadlock Detection
Medium7
Graph, DFS
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Bridge Construction Planning
Medium7
Minimum spanning tree, Binary search
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Awkward Group
Medium7
Minimum spanning tree, Union-find+1
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
Consecutive Ordering
Medium7
Intervals, Two pointers+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Grid Aliens
Medium7
Graph
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Monotone Walkway
Medium7
Sorting, Geometry+1
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
Particle
Medium7
Number theory, Geometry
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Shelob's Lair
Medium7
Graph, Geometry+1
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
Resistance Is (Not) Futile!
Medium7
Backtracking, Greedy+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Cutting Brownies
Medium7
Game theory, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Virus Bomb
Medium7
Matrix, Binary search+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Party
Medium7
Graph, Binary search
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Tofu Seller Jang Hongjun 2
Medium7
Graph, Shortest path
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Shortest Boolean Expression
Medium7
Dynamic programming, Brute force+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
The Still Embarrassed Cryptographer
Medium7
Graph, Number theory+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Bicycle picture puzzle
Medium7
Combinatorics, Probability+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Train Ticket Allocation
Medium7
Graph, Shortest path+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Solving a 2×2×2 cube
Medium7
BFS, Simulation+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Beehive Epidemic
Medium7
Graph, Geometry
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Ambulance Antics
Medium7
Dynamic programming, Shortest path+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Typing monkey
Medium7
Probability, String matching+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Counting Soundex Strings
Medium7
Dynamic programming, String+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Sheep Frenzy
Medium7
Dynamic programming, BFS+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Treasure Hunt
Medium7
Geometry, Brute force
No attempts yet
Time limit
10s
Memory limit
256 MB
Judgeable
Inverse Divisor Sums
Medium7
Backtracking, Number theory+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Longest Common Path
Medium7
Shortest path, Graph+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Holey Road
Medium7
Geometry, Shortest path+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Kings on a Chessboard
Medium7
Dynamic programming, Bit manipulation+1
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
Worm Tube Space Travel
Medium7
Shortest path, Geometry+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Icons in the Toolbar
Medium7
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Spam Filter
Medium7
Binary search, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Xor Maximization
Medium7
Bit manipulation, Greedy
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Intercept
Medium7
Shortest path, Graph+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Radar
Medium7
Number theory, Brute force
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Count von Walken's Fence
Medium7
Intervals, Math
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Counting Odd Binomial Coefficients
Medium7
Number theory, Bit manipulation+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
The Addition Game
Medium7
Math, Combinatorics
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
String Stretching
Medium7
Dynamic programming, String+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Rainbow Zamboni
Medium7
Math, Simulation+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Word Ladder
Medium7
BFS, Graph+2
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Shuffles
Medium7
Math, Array
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Stained Carpet
Medium7
Geometry, Math
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Song
Medium7
Dynamic programming, Matrix+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Bond Tour
Medium7
Segment tree, Tree
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
Design a Tree
Medium7
Combinatorics, Dynamic programming+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
K closest planet pairs
Medium7
Divide and conquer, Geometry+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Hero Power
Medium7
Dynamic programming, Greedy+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
2-SAT Satisfiability
Medium7
Graph, DFS
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Alicia's Afternoon Amble
Medium7
Dynamic programming, Geometry+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
String Game
Medium7
Game theory, String matching+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
One-Way Roads
Medium7
DFS, Graph
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Power Eggs
Medium7
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Batman Begins
Medium7
Shortest path, Graph+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Solitaire
Medium7
Simulation, Greedy+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
XOR Sum
Medium7
Trie, Bit manipulation
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Tools of the Trade
Medium7
Graph, Shortest path
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Avoider
Medium7
Backtracking, DFS+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Sequences
Medium7
Shortest path, Number theory
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Think Small
Medium7
Divide and conquer, Math
No attempts yet
Time limit
10s
Memory limit
512 MB
Judgeable
The Running Game
Medium7
Dynamic programming, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Optimal ability loadout
Medium7
Dynamic programming, Probability
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Buying Books
Medium7
Graph, Shortest path
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Assigning Jobs 5
Medium7
Graph, Shortest path
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Job Assignment at Kangho's Company
Medium7
Graph, Shortest path
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Choo Choo
Medium7
Graph, Shortest path+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Tree of Almost Clean Money
Medium7
Tree, Segment tree
No attempts yet
Time limit
4s
Memory limit
256 MB
Judgeable
Taxi sharing
Medium7
Dynamic programming, Shortest path+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Word by mouth
Medium7
Simulation, Dynamic programming+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Bitris
Medium7
Intervals, Sorting+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Softville Initiation Program
Medium7
Number theory, Math
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Van Dinsky's Color Mixing
Medium7
Shortest path, Graph+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Binomial Coefficient 5
Medium7
Number theory, Combinatorics
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Chess Tournament
Medium7
Graph, Union-find+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Pac-Man
Medium7
BFS, Graph+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Risk
Medium7
Dynamic programming, Probability+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Tanks
Medium7
Geometry, Simulation
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
The Fox and the Owl
Medium7
Greedy, String+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Hacking the Screen
Medium7
Implementation, Recursion+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Fygon
Medium7
Math, Combinatorics+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Journey to "The World's Start"
Medium7
Dynamic programming, Binary search+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Number of distinct substrings 2
Medium7
String matching, Sorting+1
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
Aqueduct Construction
Medium7
Shortest path, Graph+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Slant Drilling
Medium7
Geometry, Tree+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Rainfall
Medium7
Math, Prefix sum+1
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
Sunlight
Medium7
Stack, Geometry+1
No attempts yet
Time limit
4s
Memory limit
256 MB
Judgeable
Jelly Raid
Medium7
BFS, Simulation+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Telescope
Medium7
Greedy, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Calvinball minimum teamsSplit up to 20 players into the fewest teams with no disliking pair together, breaking ties lexicographically.	Medium7	BacktrackingGraph+1	No attempts yet	1s	256 MB	Judgeable
Calvinball team assignmentColor up to 15 players with the fewest teams so no disliking pair shares a team, breaking ties by lexicographic order.	Medium7	BacktrackingGraph+1	No attempts yet	1s	256 MB	Judgeable
Calvinball championship team splitColor up to 16 players with the fewest teams so no disliking pair shares a team, and print the lexicographically smallest optimal assignment.	Medium7	BacktrackingGraph+1	No attempts yet	7s	512 MB	Judgeable
EvacuationFind the maximum number of queens that can travel from checkpoint 1 to checkpoint N when only roads touching either end carry at most one ant.	Medium7	Graph	No attempts yet	1s	128 MB	Judgeable
KimchiPick bury and take-out days at most D apart to maximize aging days times take-out temperature plus crock value while temperatures fall.	Medium7	Dynamic programmingSliding window+1	No attempts yet	1s	256 MB	Judgeable
Forged AnswersGiven three answer strings over A to D, choose one answer per question to maximize the lowest of the three scores.	Medium7	GreedyBinary search	No attempts yet	3s	256 MB	Judgeable
Cheating 2Place the most students on an N by M grid with broken seats so no two sit side by side or diagonally adjacent.	Medium7	GraphDFS	No attempts yet	2s	256 MB	Judgeable
Summer on the BeachCompute the share of a body rectangle that falls outside the moving elliptical shadow of a circular parasol at some sun angle in the given interval.	Medium7	GeometryMath	No attempts yet	1s	256 MB	Judgeable
Pair TransformationFrom (1,1), add one component to the other or swap them, and report the fewest steps that put N in the pair for each query.	Medium7	Number theoryBFS+1	No attempts yet	1s	256 MB	Judgeable
Unique right triangleCount the perimeters up to N that form exactly one integer-sided right triangle.	Medium7	Number theoryArray+1	No attempts yet	1s	256 MB	Judgeable
Dragon curveReport the cursor position after the Xth drawn segment of the order N dragon curve generated by the given rewriting rules.	Medium7	RecursionDivide and conquer+2	No attempts yet	1s	256 MB	Judgeable
Rectangle update and rectangle sumYou add w to all cells in one rectangle per update and print the cell sum of one rectangle per query in order.	Medium7	Segment treePrefix sum+1	No attempts yet	1s	256 MB	Judgeable
500-Yen SavingVisit shops in order, paying with held coins and bills, to collect the most 500-yen coins in change and spend the least for them.	Medium7	Dynamic programmingSimulation+1	No attempts yet	8s	256 MB	Judgeable
Deadlock DetectionGiven an instruction string of lock acquisitions and releases, decide whether any interleaving of ten threads running it can deadlock.	Medium7	GraphDFS	No attempts yet	3s	256 MB	Judgeable
Bridge Construction PlanningFind the cheapest spanning tree that uses exactly k edges from company A and the rest from company B, or report that none exists.	Medium7	Minimum spanning treeBinary search	No attempts yet	1s	256 MB	Judgeable
Awkward GroupCount the subsets whose largest inner closeness is smaller than every closeness to the outside.	Medium7	Minimum spanning treeUnion-find+1	No attempts yet	5s	256 MB	Judgeable
Consecutive OrderingDecide whether every vertex's closed neighbourhood forms one unbroken block in the given vertex ordering.	Medium7	IntervalsTwo pointers+1	No attempts yet	1s	256 MB	Judgeable
Grid AliensAssign each cell of an N by N grid to one of two regions to maximize node rewards minus the cut edge costs.	Medium7	Graph	No attempts yet	1s	256 MB	Judgeable
Monotone WalkwayGiven unordered cafe coordinates on an x-monotone orthogonal path from the origin, recover the visit order and report the coordinates of the queried positions.	Medium7	SortingGeometry+1	No attempts yet	5s	256 MB	Judgeable
ParticleDecide whether a point bouncing off rectangle walls with fixed velocity reaches target A before target B or neither.	Medium7	Number theoryGeometry	No attempts yet	1s	256 MB	Judgeable
Shelob's LairDecide if a path from the south wall to the north wall can avoid all web segments except possibly one shared cut point.	Medium7	GraphGeometry+1	No attempts yet	5s	256 MB	Judgeable
Resistance Is (Not) Futile!Pick the fewest E-12 resistors whose sum is within 1 percent of the voltage over current, breaking ties by closeness.	Medium7	BacktrackingGreedy+1	No attempts yet	2s	256 MB	Judgeable
Cutting BrowniesGiven a B by D brownie sheet where Harry cuts depth and Vicky cuts breadth, decide if the named starting player has a forced win.	Medium7	Game theoryDynamic programming+1	No attempts yet	2s	256 MB	Judgeable
Virus BombStarting from one virus of the first form, find the seconds until cumulative tritium atoms reach L, or report lucky when the total never does.	Medium7	MatrixBinary search+1	No attempts yet	2s	256 MB	Judgeable
PartyFind the smallest number of parties so each student pairs with a willing volunteer and no volunteer takes two students at one party.	Medium7	GraphBinary search	No attempts yet	1s	256 MB	Judgeable
Tofu Seller Jang Hongjun 2Pair orthogonally adjacent cells into dominoes priced by the grade table, leaving cells unused for zero, to maximize the total price.	Medium7	GraphShortest path	No attempts yet	1s	256 MB	Judgeable
Shortest Boolean ExpressionGiven a fully parenthesized boolean expression over x, y, and z with &, \|, and !, print the length of the shortest equivalent expression, ignoring spaces.	Medium7	Dynamic programmingBrute force+1	No attempts yet	1s	256 MB	Judgeable
The Still Embarrassed CryptographerGiven a plaintext and its ciphertext under an unknown substitution cipher, find the re-encryption count that restores it or report that the count is ambiguous.	Medium7	GraphNumber theory+1	No attempts yet	1s	256 MB	Judgeable
Bicycle picture puzzleThe program reads W, H, and S and prints the probability that a random scramble needs fewer optimal swaps than S.	Medium7	CombinatoricsProbability+2	No attempts yet	1s	256 MB	Judgeable
Train Ticket AllocationDecide how many tickets to sell for each station pair so paid and free riders fit capacity P on every segment and total income is maximal.	Medium7	GraphShortest path+1	No attempts yet	1s	256 MB	Judgeable
Solving a 2×2×2 cubeGiven an unfolded 2x2x2 cube net, compute the fewest quarter turns that make each face a single color.	Medium7	BFSSimulation+1	No attempts yet	1s	256 MB	Judgeable
Beehive EpidemicOn a hexagonal grid, assign bees to distinct safe zones they reach before the spreading bacteria to save as many as possible.	Medium7	GraphGeometry	No attempts yet	2s	256 MB	Judgeable
Ambulance AnticsPlan tours from the hospital that carry up to three patients each to bring every patient back in the least total driving time.	Medium7	Dynamic programmingShortest path+1	No attempts yet	2s	256 MB	Judgeable
Typing monkeyGiven per-letter probabilities and two words P and Q, compute the probability that P appears as a substring before Q does.	Medium7	ProbabilityString matching+1	No attempts yet	1s	256 MB	Judgeable
Counting Soundex StringsCount case-insensitive strings up to length L whose Soundex code equals the given code, modulo 1000000007.	Medium7	Dynamic programmingString+1	No attempts yet	1s	256 MB	Judgeable
Sheep FrenzyMove across a grid with mountains to reach every sheep and spend one second eating each, using the fewest seconds, or report impossible.	Medium7	Dynamic programmingBFS+1	No attempts yet	1s	256 MB	Judgeable
Treasure HuntFind the most treasures a single straight line can place on the opposite side from all mines.	Medium7	GeometryBrute force	No attempts yet	10s	256 MB	Judgeable
Inverse Divisor SumsPrint every integer M whose divisor sum equals the given N in increasing order, or none when no such number exists.	Medium7	BacktrackingNumber theory+1	No attempts yet	3s	256 MB	Judgeable
Longest Common PathTwo friends each walk a shortest route from school to their own home, and the goal is to maximize the shared consecutive stretch of both routes.	Medium7	Shortest pathGraph+1	No attempts yet	1s	256 MB	Judgeable
Holey RoadFind the shortest route from the bottom center to the top center of a rectangular road while avoiding circular holes.	Medium7	GeometryShortest path+1	No attempts yet	2s	256 MB	Judgeable
Kings on a ChessboardCount the ways to place k non-attacking kings on an x by y board and print each answer modulo 1,000,000,007.	Medium7	Dynamic programmingBit manipulation+1	No attempts yet	5s	256 MB	Judgeable
Worm Tube Space TravelTravel between two points in 3D where movement along given segments is free and all other movement costs its Euclidean length, minimizing the paid distance.	Medium7	Shortest pathGeometry+1	No attempts yet	1s	256 MB	Judgeable
Icons in the ToolbarPlace 2N squares with given side lengths into a 2 by N grid so the product of the summed row heights and summed column widths is minimal.	Medium7	GreedySorting+1	No attempts yet	1s	256 MB	Judgeable
Spam FilterFind the contiguous block of at least k binary results with the highest share of ones, breaking ties by earliest start then shortest length.	Medium7	Binary searchPrefix sum+1	No attempts yet	1s	256 MB	Judgeable
Xor MaximizationPick a nonempty subset of the given integers so the xor of the chosen numbers is as large as possible.	Medium7	Bit manipulationGreedy	No attempts yet	1s	256 MB	Judgeable
InterceptFind every station that lies on all shortest routes from s to t in a directed weighted graph.	Medium7	Shortest pathGraph+1	No attempts yet	1s	256 MB	Judgeable
RadarFind the smallest nonnegative integer whose remainders modulo three distinct primes each fall within given tolerances of the measured values.	Medium7	Number theoryBrute force	No attempts yet	2s	256 MB	Judgeable
Count von Walken's FenceGiven a spacing D and the footstep counts between consecutive poles, decide whether unit steps can yield those counts without landing on a pole.	Medium7	IntervalsMath	No attempts yet	1s	256 MB	Judgeable
Counting Odd Binomial CoefficientsCount the pairs (m, k) with m below n whose binomial coefficient is odd.	Medium7	Number theoryBit manipulation+2	No attempts yet	1s	256 MB	Judgeable
The Addition GameDecide whether two permutations of 1 to n add up to the given sequence modulo n.	Medium7	MathCombinatorics	No attempts yet	1s	256 MB	Judgeable
String StretchingGiven a lowercase string up to length 200, find the shortest base string that builds it by repeated insertions anywhere, breaking ties alphabetically.	Medium7	Dynamic programmingString+1	No attempts yet	1s	256 MB	Judgeable
Rainbow ZamboniA zamboni paints cells on a wrapping grid while walking ever-longer legs that turn clockwise, and you print the final colors and resting cell.	Medium7	MathSimulation+1	No attempts yet	1s	256 MB	Judgeable
Word LadderPick one new word to add to the dictionary so the single-letter ladder from the first word to the second is as short as possible.	Medium7	BFSGraph+2	No attempts yet	3s	256 MB	Judgeable
ShufflesGiven a permutation of 1 to n, find the fewest riffle shuffles that can turn the sorted deck into it.	Medium7	MathArray	No attempts yet	2s	256 MB	Judgeable
Stained CarpetGiven three distances from a point to the vertices of an equilateral triangle, find the largest possible triangle area or report -1.	Medium7	GeometryMath	No attempts yet	1s	256 MB	Judgeable
SongGiven a 26 by 26 pair score table, pick an L-note song starting from C that maximizes the sum of adjacent pair scores.	Medium7	Dynamic programmingMatrix+1	No attempts yet	1s	256 MB	Judgeable
Bond TourEach parade route is the tree path between two towns, and you report the best contiguous stretch of road weights on it, or zero.	Medium7	Segment treeTree	No attempts yet	5s	256 MB	Judgeable
Design a TreeCount binary tree shapes with exactly N left edges and M right edges modulo 9999991 for up to 10000 queries.	Medium7	CombinatoricsDynamic programming+1	No attempts yet	3s	256 MB	Judgeable
K closest planet pairsPrint the K smallest squared distances among all pairs of up to 50000 planar points per query.	Medium7	Divide and conquerGeometry+1	No attempts yet	2s	256 MB	Judgeable
Hero PowerEarn charge during star phrases and spend it on activations that double note points without wiping future phrases to maximize the score.	Medium7	Dynamic programmingGreedy+1	No attempts yet	1s	256 MB	Judgeable
2-SAT SatisfiabilityDecide whether N boolean variables admit values that satisfy all M two-literal clauses.	Medium7	GraphDFS	No attempts yet	1s	256 MB	Judgeable
Alicia's Afternoon AmbleVisit all points on a bitonic tour from the leftmost hotel to the rightmost parlour and back, minimizing total Euclidean length.	Medium7	Dynamic programmingGeometry+1	No attempts yet	1s	256 MB	Judgeable
String GameFor each game, decide if Alice wins when both players alternately delete the first or last letter until the string matches the target length.	Medium7	Game theoryString matching+1	No attempts yet	1s	256 MB	Judgeable
One-Way RoadsDecide whether undirected roads can be oriented into a strongly connected digraph and output the DFS-based orientation when possible.	Medium7	DFSGraph	No attempts yet	1s	256 MB	Judgeable
Power EggsFind the fewest egg drops in the worst case that pin down the highest safe floor for N floors and K eggs, or report Impossible past 32.	Medium7	Dynamic programmingCombinatorics+1	No attempts yet	1s	256 MB	Judgeable
Batman BeginsFind the fastest drive from start to target on a blocked grid where the car speeds up and brakes at a fixed rate and must stop before each turn and at the goal.	Medium7	Shortest pathGraph+1	No attempts yet	2s	256 MB	Judgeable
SolitaireGiven the starting deck order, compute the fewest redeals needed to move every card to the goal pile using the helper as ordered storage.	Medium7	SimulationGreedy+1	No attempts yet	2s	256 MB	Judgeable
XOR SumYou insert numbers into a list and each print query asks for the XOR of the K largest values.	Medium7	TrieBit manipulation	No attempts yet	2s	256 MB	Judgeable
Tools of the TradeAssign each soldier one stocked weapon to minimize the sum of rank positions in their preference lists.	Medium7	GraphShortest path	No attempts yet	1s	256 MB	Judgeable
AvoiderCount self-avoiding walks of each length from a to b in the first quadrant starting east from the origin and print the sum.	Medium7	BacktrackingDFS+1	No attempts yet	1s	256 MB	Judgeable
SequencesFind the largest integer that cannot be written as a nonnegative combination of the given generators.	Medium7	Shortest pathNumber theory	No attempts yet	1s	256 MB	Judgeable
Think SmallMultiply two polynomials of degree up to one million and print the xor of all coefficients of the product.	Medium7	Divide and conquerMath	No attempts yet	10s	512 MB	Judgeable
The Running GamePick disjoint segments of the given sequence so the sum of each segment weighted by its position inside the segment is as large as possible.	Medium7	Dynamic programmingPrefix sum+1	No attempts yet	1s	512 MB	Judgeable
Optimal ability loadoutChoose a subset of abilities with given trigger chances and damage values to maximize the expected damage of one attack under a random trigger order.	Medium7	Dynamic programmingProbability	No attempts yet	1s	512 MB	Judgeable
Buying BooksShip book copies from M stores to N buyers with per-route costs to minimize the total shipping fee.	Medium7	GraphShortest path	No attempts yet	1s	256 MB	Judgeable
Assigning Jobs 5Assign each employee at most one job they can do so the number of finished jobs is largest and the total salary is smallest.	Medium7	GraphShortest path	No attempts yet	2s	256 MB	Judgeable
Job Assignment at Kangho's CompanyAssign each employee at most one job they can do so the number of finished jobs is largest, then maximize the total salary over those assignments.	Medium7	GraphShortest path	No attempts yet	2s	256 MB	Judgeable
Choo ChooPassengers request trips between numbered cities with per-person fares, and the train picks whom to board within its capacity to maximize total fare revenue.	Medium7	GraphShortest path+1	No attempts yet	1s	256 MB	Judgeable
Tree of Almost Clean MoneyEach operation adds generated values to up to 1000 vertices and asks for the sum on the path between two vertices.	Medium7	TreeSegment tree	No attempts yet	4s	256 MB	Judgeable
Taxi sharingSplit up to 15 employees into taxis of four or fewer and order each drop-off route to minimize total distance fares plus boarding fees.	Medium7	Dynamic programmingShortest path+1	No attempts yet	1s	256 MB	Judgeable
Word by mouthSimulate the recursive WBM(m) vote, where faulty friends always forward cat, and report each loyal friend's majority word.	Medium7	SimulationDynamic programming+1	No attempts yet	3s	256 MB	Judgeable
BitrisFind the fewest adjacent swaps that let all paired cubes cancel by repeatedly deleting equal neighbors.	Medium7	IntervalsSorting+1	No attempts yet	1s	256 MB	Judgeable
Softville Initiation ProgramFind the smallest program length that each given day count can produce under the rule of writing one more line each day.	Medium7	Number theoryMath	No attempts yet	1s	256 MB	Judgeable
Van Dinsky's Color MixingCompute the fewest mixing steps to derive each requested color from the palette using the listed two-ingredient rules.	Medium7	Shortest pathGraph+1	No attempts yet	1s	256 MB	Judgeable
Binomial Coefficient 5Compute the remainder of the binomial coefficient C(N, K) divided by M, where M is not necessarily prime.	Medium7	Number theoryCombinatorics	No attempts yet	1s	256 MB	Judgeable
Chess TournamentCount the equal two-team splits in which every pair across the teams played at least once, and print the lexicographically smallest team containing player 1.	Medium7	GraphUnion-find+1	No attempts yet	3s	256 MB	Judgeable
Pac-ManMerge two Pac-Men that move in lockstep on a wrapping maze with walls and ghosts using the fewest joystick pushes.	Medium7	BFSGraph+1	No attempts yet	1s	256 MB	Judgeable
RiskCompute the attacker win probability in a Risk battle with D-sided dice where the defender picks one or two dice after seeing the attack roll.	Medium7	Dynamic programmingProbability+2	No attempts yet	2s	256 MB	Judgeable
TanksTrace a shot through a convex hull and inner boxes, applying face resistance and ricochets, and report pierced components and where it stops.	Medium7	GeometrySimulation	No attempts yet	1s	256 MB	Judgeable
The Fox and the OwlGiven a huge integer N, print the largest integer below N whose digit sum is exactly one more than that of N.	Medium7	GreedyString+1	No attempts yet	1s	256 MB	Judgeable
Hacking the ScreenParse an arithmetic formula with square roots and fractions drawn as ASCII art up to three lines high and print its integer value.	Medium7	ImplementationRecursion+1	No attempts yet	1s	256 MB	Judgeable
FygonGiven a short program of nested loops bounded by n, outer loop variables, or small constants, output the exact count of lag executions as a polynomial in n.	Medium7	MathCombinatorics+2	No attempts yet	2s	256 MB	Judgeable
Journey to "The World's Start"Pick the cheapest travel card whose range lets you ride from stop 1 to stop n with transfer delays within t minutes.	Medium7	Dynamic programmingBinary search+1	No attempts yet	2s	256 MB	Judgeable
Number of distinct substrings 2Count how many different contiguous substrings appear in the given lowercase string of length up to 1,000,000.	Medium7	String matchingSorting+1	No attempts yet	5s	256 MB	Judgeable
Aqueduct ConstructionEach town must connect to a distinct spring through downhill hops of limited length so the combined aqueduct length is minimal.	Medium7	Shortest pathGraph+1	No attempts yet	3s	256 MB	Judgeable
Slant DrillingChoose a ground point over nested contour polygons so the straight-line distance from the surface to the pocket at the origin is shortest.	Medium7	GeometryTree+1	No attempts yet	1s	256 MB	Judgeable
RainfallChoose when to leave and how fast to ride within T minutes to minimize trip rain plus sweat that grows with the square of speed.	Medium7	MathPrefix sum+1	No attempts yet	5s	256 MB	Judgeable
SunlightCompute sunlight hours for each rooftop from the sky angles blocked by taller buildings on both sides.	Medium7	StackGeometry+1	No attempts yet	4s	256 MB	Judgeable
Jelly RaidGuide the child from the bed to the fridge in the fewest turns while dodging patrols that catch anything sharing a clear row or column.	Medium7	BFSSimulation+2	No attempts yet	1s	256 MB	Judgeable
TelescopeCount the 4-connected white regions of a binary sky given only its N by N averaged and rounded-down picture.	Medium7	GreedyPrefix sum+1	No attempts yet	1s	256 MB	Judgeable