Problems

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Total results21,446 problems

SubstringHard8
String, Sorting +2No attempts yetTime limit2sMemory limit512 MB
Judgeable
EnumerationHard8
Probability, Combinatorics +2No attempts yetTime limit5sMemory limit512 MB
Judgeable
UsoperantoHard8
Greedy, Tree +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Common PalindromesHard8
String, String matching +2No attempts yetTime limit2sMemory limit512 MB
Judgeable
On or OffHard8
Tree, Dynamic programming +2No attempts yetTime limit7sMemory limit512 MB
Judgeable
Marathon MatchHard8
Probability, Dynamic programming +2No attempts yetTime limit5sMemory limit512 MB
Judgeable
Beautiful CurrencyHard8
Binary search, Greedy +2No attempts yetTime limit5sMemory limit512 MB
Judgeable
Vector CompressionHard8
Greedy, Geometry +2No attempts yetTime limit5sMemory limit512 MB
Judgeable
Set-constructing WitchHard8
Dynamic programming, Greedy +2No attempts yetTime limit2sMemory limit512 MB
Judgeable
6÷2(1+2)Hard8
Dynamic programming, Brute force +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Divide the CakeHard8
Geometry, Probability +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Sakura PoetryHard8
Dynamic programming, String matching +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Light RoadHard8
BFS, Graph +2No attempts yetTime limit2sMemory limit512 MB
Judgeable
Network ReliabilityHard8
Dynamic programming, Bit manipulation +2No attempts yetTime limit3sMemory limit512 MB
Judgeable
Mr. Rito's Post OfficeHard8
Dynamic programming, Shortest path +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Immortal JewelsHard8
Geometry, Brute force +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
My Friends Are SmallHard8
Dynamic programming, Sorting +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Ten-Year-Old Dynamic ProgrammingHard8
Combinatorics, Dynamic programming +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Carrot TourHard8
Dynamic programming, Graph +2No attempts yetTime limit1sMemory limit512 MB
Judgeable
UsagitobiHard8
Graph, DFS +2No attempts yetTime limit1sMemory limit512 MB
Judgeable
Dungeon WallHard8
BFS, Graph +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
How to Create a Good GameHard8
Graph, Dynamic programming +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Cruel BingoHard8
Combinatorics, Dynamic programming +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Ika NumberHard8
Combinatorics, Dynamic programming +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Bubble PuzzleHard8
BFS, Simulation +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
ShelterHard8
Geometry, Divide and conquer +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Magic SlayerHard8
Dynamic programming, Greedy +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Voronoi IslandHard8
Geometry, Divide and conquer +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Revenge of the Round TableHard8
Combinatorics, Math +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Luigi's TavernHard8
Graph, Dynamic programming +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Colored OctahedraHard8
Combinatorics, Math +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Adhoc TranslationHard8
Dynamic programming, String +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Cover TimeHard8
Dynamic programming, Probability +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
CraftsmanHard8
Dynamic programming, Bit manipulation +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Divide the WaterHard8
Tree, Greedy +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Mickle's BeamHard8
Geometry, Greedy +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Poor ComputerHard8
Brute force, Dynamic programming +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Trading ShipHard8
Binary search, Graph +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Princess' MarriageHard8
Greedy, Sorting +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Princess, a CryptanalystHard8
Dynamic programming, Bit manipulation +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Time TrialHard8
BFS, Graph +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Memory MatchHard8
Probability, Dynamic programming +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Girls' PartyHard8
Simulation, Brute force +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Do ItHard8
Math, Divide and conquer +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Robot CommunicationHard8
Minimum spanning tree, Geometry +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Compress FilesHard8
Dynamic programming, Bit manipulation +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Save the EnergyHard8
Geometry, Graph +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
!Hard8
Number theory, Math +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
SpirographHard8
Math, Geometry +1No attempts yetTime limit8sMemory limit512 MB
Judgeable
PetorisHard8
Brute force, Implementation +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Nagashi SoumenHard8
Dynamic programming, Geometry +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Median FilterHard8
Brute force, Backtracking +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Connect Line SegmentsHard8
Dynamic programming, Bit manipulation +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Divisor FunctionHard8
Number theory, Math +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Two RingsHard8
Geometry, Math +1No attempts yetTime limit8sMemory limit512 MB
Judgeable
Billion Million ThousandHard8
Dynamic programming, String +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
The Closest CircleHard8
Divide and conquer, Geometry +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
RakunarokHard8
Shortest path, Dynamic programming +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Flame of NucleusHard8
Graph, Shortest path +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Poor Mail ForwardingHard8
Simulation, Shortest path +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Ellipse IntersectionHard8
Math, Geometry +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
ColorsHard8
Graph, DFS +2No attempts yetTime limit2sMemory limit512 MB
Judgeable
A Treasure Or A BombHard8
Dynamic programming, Math +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Up and DownHard8
Dynamic programming, Backtracking +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Help the MuseumHard8
BFS, Graph +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Enclosing CirclesHard8
Geometry, Graph +2No attempts yetTime limit2sMemory limit512 MB
Judgeable
Jigsaw Puzzles for ComputersHard8
Backtracking, Brute force +2No attempts yetTime limit2sMemory limit512 MB
Judgeable
PatienceHard8
Dynamic programming, Bit manipulation +2No attempts yetTime limit2sMemory limit512 MB
Judgeable
NumoebaHard8
Simulation, Tree +2No attempts yetTime limit2sMemory limit512 MB
Judgeable
TrapezoidsHard8
Implementation, Simulation +2No attempts yetTime limit2sMemory limit512 MB
Judgeable
Tsubame GaeshiHard8
Brute force, Sorting +2No attempts yetTime limit4sMemory limit1024 MB
Judgeable
A Simple ProblemHard8
Sorting, Divide and conquer +2No attempts yetTime limit4sMemory limit1024 MB
Judgeable
Beacon Fire TowersHard8
Dynamic programming, Divide and conquer +2No attempts yetTime limit1sMemory limit1024 MB
Judgeable
Prime TimeHard8
Dynamic programming, Math +2No attempts yetTime limit45sMemory limit1024 MB
Judgeable
Setting Problems for the Orange CupHard8
Greedy, Sorting +2No attempts yetTime limit1sMemory limit1024 MB
Judgeable
Orange NumberHard8
Math, Number theory +2No attempts yetTime limit1sMemory limit1024 MB
Judgeable
Contest ConstructionHard8
Sorting, Dynamic programming +2No attempts yetTime limit1sMemory limit2048 MB
Judgeable
TraveLogHard8
Graph, Shortest path +2No attempts yetTime limit4sMemory limit2048 MB
Judgeable
Weekly CalendarHard8
Sliding window, Prefix sum +2No attempts yetTime limit1sMemory limit512 MB
Judgeable
Graph Tree PartitionHard8
Graph, DFS +2No attempts yetTime limit2sMemory limit1024 MB
Judgeable
ShowerHard8
Union-find, Simulation +2No attempts yetTime limit2sMemory limit1024 MB
Judgeable
k SubarraysHard8
Array, Sorting +2No attempts yetTime limit1sMemory limit1024 MB
Judgeable
TerrorHard8
Backtracking, Recursion +2No attempts yetTime limit2.5sMemory limit1024 MB
Judgeable
Calculator OptimizationHard8
Segment tree, Matrix +2No attempts yetTime limit2sMemory limit512 MB
Judgeable
The Snail Wants to Rest in the ShadeHard8
Geometry, Sorting +1No attempts yetTime limit1sMemory limit512 MB
Judgeable
Dakku (Diary Decorating)Hard8
Segment tree, Matrix +1No attempts yetTime limit3sMemory limit1024 MB
Judgeable
Number of Increasing Subsequences KHard8
Combinatorics, Dynamic programming +2No attempts yetTime limit2sMemory limit1024 MB
Judgeable
Truck DeliveryHard8
Tree, DFS +2No attempts yetTime limitNot setMemory limit1024 MB
Judgeable
Primes and QueriesHard8
Number theory, Segment tree +2No attempts yetTime limit90sMemory limit1024 MB
Judgeable
Hiking TrailsHard8
Dynamic programming, Bit manipulation +2No attempts yetTime limit1sMemory limit512 MB
Judgeable
HomeworkHard8
Greedy, Sorting +1No attempts yetTime limit1.5sMemory limit512 MB
Judgeable
Stop the Group Project!Hard8
Minimum spanning tree, Graph +2No attempts yetTime limit2sMemory limit512 MB
Judgeable
Leaping PiecesHard8
Math, Number theory +2No attempts yetTime limit0.5sMemory limit1024 MB
Judgeable
Sculpting a TreeHard8
Tree, Binary search +2No attempts yetTime limit2sMemory limit1024 MB
Judgeable
Kyojun StargazingHard8
Geometry, Combinatorics +2No attempts yetTime limit1.5sMemory limit1024 MB
Judgeable
Nutella TreeHard8
Tree, Segment treeNo attempts yetTime limit7sMemory limit1024 MB
Judgeable
NewspapersHard8
Graph, ImplementationNo attempts yetTime limit2sMemory limit1024 MB
Judgeable
StonesHard8
Game theory, Greedy +2No attempts yetTime limit3sMemory limit512 MB
Judgeable
UuuHard8
Union-find, Graph +2No attempts yetTime limit2sMemory limit1024 MB
Judgeable
Graph TravelHard8
Graph, Dynamic programming +2No attempts yetTime limitNot setMemory limit1024 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
SubstringA window [l, r] over a string moves by changing one endpoint at a time, and after each of m queries you must count how many distinct substring values have appeared across all windows visited.	Hard8	StringSorting+2	No attempts yet	2s	512 MB	Judgeable
EnumerationEach integer a_k is chosen independently with probability p_k%, and we need the expected count of numbers in [1,m] divisible by at least one chosen integer.	Hard8	ProbabilityCombinatorics+2	No attempts yet	5s	512 MB	Judgeable
UsoperantoGiven words where each word modifies at most one other word, order all words to minimize the total letter distance between each modifier and its modifiee, then report that minimum cost.	Hard8	GreedyTree+2	No attempts yet	8s	512 MB	Judgeable
Common PalindromesCount pairs of intervals, one in S and one in T, whose substrings are equal and palindromic; lengths up to 50,000.	Hard8	StringString matching+2	No attempts yet	2s	512 MB	Judgeable
On or OffIn a tree-shaped grid of rooms, visit M target rooms in order, choosing when to leave lights on or off so the total power plus switching cost is minimal.	Hard8	TreeDynamic programming+2	No attempts yet	7s	512 MB	Judgeable
Marathon MatchFor each of N runners who may rest at each of M stops with given probabilities, compute the probability that the runner finishes in strictly least time.	Hard8	ProbabilityDynamic programming+2	No attempts yet	5s	512 MB	Judgeable
Beautiful CurrencyGiven N increasing coin values, assign new positive integers so each value divides the next, minimizing the maximum relative change \|a_i - b_i\| / a_i.	Hard8	Binary searchGreedy+2	No attempts yet	5s	512 MB	Judgeable
Vector CompressionGiven M vectors in N dimensions and a free ordering, minimize the total squared length when each vector is stored either as is or as the residual after subtracting a real multiple of an earlier vector.	Hard8	GreedyGeometry+2	No attempts yet	5s	512 MB	Judgeable
Set-constructing WitchEach synthesis rule combines several distinct witches into one new witch; find the minimum number of special Grief Seeds (at most one copy of each witch kind at a time) needed to produce witch T from easily obtainable witches.	Hard8	Dynamic programmingGreedy+2	No attempts yet	2s	512 MB	Judgeable
6÷2(1+2)Count the distinct integer results obtainable by parenthesizing an expression in any order, with integer division truncated toward zero and division by zero treated as invalid.	Hard8	Dynamic programmingBrute force+2	No attempts yet	8s	512 MB	Judgeable
Divide the CakeGiven 2N strawberry points on a W by H cake, find the probability that two uniformly random points, one on each vertical side, define a line splitting the strawberries into N and N.	Hard8	GeometryProbability+2	No attempts yet	8s	512 MB	Judgeable
Sakura PoetryCount word sequences of total length M following a directed word-connection graph, such that the concatenated string contains exactly one season word exactly once, modulo 1e9+7.	Hard8	Dynamic programmingString matching+2	No attempts yet	8s	512 MB	Judgeable
Light RoadPlace up to A P-mirrors and A Q-mirrors on a grid with obstacles so the southward laser beam reaches the creature, minimizing mirrors used.	Hard8	BFSGraph+2	No attempts yet	2s	512 MB	Judgeable
Network ReliabilityEach edge of an undirected graph vanishes independently with the same probability; find the probability that what remains is connected.	Hard8	Dynamic programmingBit manipulation+2	No attempts yet	3s	512 MB	Judgeable
Mr. Rito's Post OfficeGiven a graph with land and sea edges and a fixed delivery order, find the shortest time to deliver in order while tracking the boat's location, since sea travel requires the boat.	Hard8	Dynamic programmingShortest path+2	No attempts yet	8s	512 MB	Judgeable
Immortal JewelsPlace an infinite line so it touches as many disjoint circles as possible without crossing any, where circle i is usable only if the line's distance to its surface is at most m_i.	Hard8	GeometryBrute force+2	No attempts yet	8s	512 MB	Judgeable
My Friends Are SmallCount subsets of friend weights that can be the final backpack load when items are added one by one in any order until no further friend fits under weight limit W.	Hard8	Dynamic programmingSorting+2	No attempts yet	8s	512 MB	Judgeable
Ten-Year-Old Dynamic ProgrammingCount monotone grid paths from (0,0) to (N,M) that contain exactly K backward steps (left or down), allowing the walk to overshoot the target and never step to a negative coordinate, modulo 1e9+7.	Hard8	CombinatoricsDynamic programming+2	No attempts yet	8s	512 MB	Judgeable
Carrot TourA rabbit walks a polyline of total length at most r, turning at most theta at each corner, earning one carrot per visited city; maximize carrots.	Hard8	Dynamic programmingGraph+2	No attempts yet	1s	512 MB	Judgeable
UsagitobiA rabbit on an m by n torus jumps by two fixed offset vectors; find the maximum number of jumps without revisiting a cell.	Hard8	GraphDFS+2	No attempts yet	1s	512 MB	Judgeable
Dungeon WallGiven a grid with internal walls, add one unit-length wall to maximize the increase in the shortest entrance-to-exit path length, keeping the path connected.	Hard8	BFSGraph+2	No attempts yet	8s	512 MB	Judgeable
How to Create a Good GameA DAG with weighted edges has each edge weight increased as much as possible without raising the longest path from node 0 to node N-1. Output the total added weight.	Hard8	GraphDynamic programming+2	No attempts yet	8s	512 MB	Judgeable
Cruel BingoGiven up to 8 pre-marked cells on an N by N bingo card, count the ways to reach exactly N unmarked cells while avoiding any full row, column, or diagonal, modulo 10007.	Hard8	CombinatoricsDynamic programming+2	No attempts yet	8s	512 MB	Judgeable
Ika NumberFind the K-th smallest positive integer that counts squid paths from one point to another (jumps of 1 or 2) while avoiding a forbidden integer coordinate.	Hard8	CombinatoricsDynamic programming+2	No attempts yet	8s	512 MB	Judgeable
Bubble PuzzleGiven a 4x4 grid of bubble states, find the minimum clicks to clear every bubble, with chain reactions from flying waterdrops, or -1 if more than 5.	Hard8	BFSSimulation+2	No attempts yet	8s	512 MB	Judgeable
ShelterGiven a convex polygon town and N interior shelters, compute the expected squared distance from a uniformly random point in the town to its nearest shelter.	Hard8	GeometryDivide and conquer+2	No attempts yet	8s	512 MB	Judgeable
Magic SlayerGiven N monsters with hit points and M spells that damage one or all monsters at some power cost, find the minimum total power to defeat every monster.	Hard8	Dynamic programmingGreedy+2	No attempts yet	8s	512 MB	Judgeable
Voronoi IslandFor each dataset, divide a convex island polygon among M castles by nearest-castle rule and print each lord's resulting area within 1e-4.	Hard8	GeometryDivide and conquer+2	No attempts yet	8s	512 MB	Judgeable
Revenge of the Round TableCount circular binary sequences of length n with no run of more than k equal symbols, modulo 1000003, up to rotation.	Hard8	CombinatoricsMath+2	No attempts yet	8s	512 MB	Judgeable
Luigi's TavernGiven counts of heroes, warriors, clerics, and mages plus pairwise compatibility lists along a hero-warrior-cleric-mage chain, find the maximum number of valid parties under limits on how many may skip a role.	Hard8	GraphDynamic programming+2	No attempts yet	8s	512 MB	Judgeable
Colored OctahedraCount how many distinct octahedra can be formed from eight colored triangular panels, treating two octahedra as identical when a rotation maps one to the other.	Hard8	CombinatoricsMath+2	No attempts yet	8s	512 MB	Judgeable
Adhoc TranslationGiven text words and dictionary words, assign each distinct text word a unique dictionary word, minimizing the total edit distance summed over all occurrences.	Hard8	Dynamic programmingString+2	No attempts yet	8s	512 MB	Judgeable
Cover TimeCompute the expected number of steps for a random walk starting at vertex 1 to visit every vertex of a connected undirected graph with N at most 10.	Hard8	Dynamic programmingProbability+2	No attempts yet	8s	512 MB	Judgeable
CraftsmanChoose which orders to accept and which tools to buy, where discounted tool pairs bought together change the cost, to maximize income minus tool cost.	Hard8	Dynamic programmingBit manipulation+2	No attempts yet	8s	512 MB	Judgeable
Divide the WaterGiven the target integer proportions of N ordered columns, find the minimum number of faucets (each splitting into halves via binary tubes) whose flow, laid out without crossing, realizes those proportions.	Hard8	TreeGreedy+2	No attempts yet	8s	512 MB	Judgeable
Mickle's BeamGiven up to 2000 disjoint axis-aligned rectangles that avoid the origin, find the minimum number of rays from the origin needed to hit every rectangle.	Hard8	GeometryGreedy+2	No attempts yet	8s	512 MB	Judgeable
Poor ComputerGiven distinct multipliers between 2 and 42, find the shortest sequence of additions, subtractions, and left shifts that builds all values a_i*x from x without exceeding 42x.	Hard8	Brute forceDynamic programming+2	No attempts yet	8s	512 MB	Judgeable
Trading ShipFind a path from the bottom edge y=0 to the top edge y=H inside a rectangle that maximizes the minimum distance to any of N given points.	Hard8	Binary searchGraph+2	No attempts yet	8s	512 MB	Judgeable
Princess' MarriageWith budget M, choose how much of each road segment to guard (cost 1 per unit, reducing attacks proportionally) to minimize the total expected number of attacks along the route.	Hard8	GreedySorting+2	No attempts yet	8s	512 MB	Judgeable
Princess, a CryptanalystGiven up to 10 short words, find the shortest string that contains every word as a substring, breaking ties by lexicographic order.	Hard8	Dynamic programmingBit manipulation+2	No attempts yet	8s	512 MB	Judgeable
Time TrialGiven a grid with a hero, three rocks, and three marked squares, find the minimum number of steps to push all rocks onto the marks, where the hero can only push one rock at a time.	Hard8	BFSGraph+2	No attempts yet	8s	512 MB	Judgeable
Memory MatchWith perfect memory of every card seen, compute the expected number of mismatches when playing memory match optimally on 2M cards.	Hard8	ProbabilityDynamic programming+2	No attempts yet	8s	512 MB	Judgeable
Girls' PartyIn a Josephus-style elimination game on a circular string of B and G girls, Bella may switch the count start from 1 to 0 at most once; find the maximum number of B girls that can survive at the end.	Hard8	SimulationBrute force+2	No attempts yet	8s	512 MB	Judgeable
Do ItIntegrate a product of N sine functions over [0, R], with N up to 16, to absolute or relative error 1e-8.	Hard8	MathDivide and conquer+2	No attempts yet	8s	512 MB	Judgeable
Robot CommunicationRobots move linearly on a plane over time; choose a single moment and a connected communication graph to minimize the total distance of its edges.	Hard8	Minimum spanning treeGeometry+2	No attempts yet	8s	512 MB	Judgeable
Compress FilesGiven n files with uncompressed and compressed sizes and a disk with m free space, find the minimum number of archives reachable through repeated group-compress-delete steps.	Hard8	Dynamic programmingBit manipulation+2	No attempts yet	8s	512 MB	Judgeable
Save the EnergyGiven N infinite straight lines in 3D, find the minimum off-line distance needed to travel from a source point on some line to a destination point on some line, where travel along lines is free.	Hard8	GeometryGraph+2	No attempts yet	8s	512 MB	Judgeable
!For each pair of a base N (8 to 36) and a number M written in base N, output how many trailing zeros M! has when written in base N.	Hard8	Number theoryMath+2	No attempts yet	8s	512 MB	Judgeable
SpirographFor each test case, compute the total arc length of a hypotrochoid traced by a pinhole in a circle of radius Q rolling inside a fixed circle of radius P, with pinhole offset R.	Hard8	MathGeometry+1	No attempts yet	8s	512 MB	Judgeable
PetorisPlace a rotatable, non-flippable polyomino block on a board without overlap, maximizing fully filled horizontal lines, or discard it for -1.	Hard8	Brute forceImplementation+2	No attempts yet	8s	512 MB	Judgeable
Nagashi SoumenGiven N points in space and at most K strictly descending flumes (paths whose z-coordinate decreases), find the minimum total length of flumes that cover every point.	Hard8	Dynamic programmingGeometry+2	No attempts yet	8s	512 MB	Judgeable
Median FilterGiven a 3x3 median-filtered black-and-white image, find the maximum and minimum possible counts of black pixels in any original image and report their difference, or Impossible.	Hard8	Brute forceBacktracking+2	No attempts yet	8s	512 MB	Judgeable
Connect Line SegmentsGiven up to 14 line segments, add connecting segments between endpoints to join all of them into one polyline of minimum total length.	Hard8	Dynamic programmingBit manipulation+2	No attempts yet	8s	512 MB	Judgeable
Divisor FunctionFor each k up to 10^15, find the maximum value of sigma(n)/n over all n from 1 to k, printed to six decimals.	Hard8	Number theoryMath+2	No attempts yet	8s	512 MB	Judgeable
Two RingsGiven two circles on the unit sphere, each defined by two latitude/longitude endpoints, find and print their intersection points or report that none exist.	Hard8	GeometryMath+1	No attempts yet	8s	512 MB	Judgeable
Billion Million ThousandGiven dictionary words for powers of ten, parse an unseparated Usoperant numeral as the largest possible number and find the shortest separated expression with the same value.	Hard8	Dynamic programmingString+2	No attempts yet	8s	512 MB	Judgeable
The Closest CircleGiven up to 100000 non-overlapping circles whose radii differ by at most a factor of two, find the pair of circles with the smallest gap between them and print that distance.	Hard8	Divide and conquerGeometry+2	No attempts yet	8s	512 MB	Judgeable
RakunarokGiven a weighted undirected graph with experience and time on each road, find a path from s to t whose towns strictly decrease in shortest-time distance to t and whose total experience divided by total time is maximal.	Hard8	Shortest pathDynamic programming+2	No attempts yet	8s	512 MB	Judgeable
Flame of NucleusGiven a weighted undirected graph with citizens and shelter capacities at each node, find the maximum number who can reach a shelter in fewer than L days.	Hard8	GraphShortest path+2	No attempts yet	8s	512 MB	Judgeable
Poor Mail ForwardingSimulate mail moving through a post office network where each office has one courier; find each piece's arrival time at its destination.	Hard8	SimulationShortest path+2	No attempts yet	8s	512 MB	Judgeable
Ellipse IntersectionGiven two concentric axis-aligned ellipses with perpendicular major axes, compute the area of their intersection to within 0.001.	Hard8	MathGeometry+2	No attempts yet	8s	512 MB	Judgeable
ColorsGiven a robot blueprint that builds a graph by adding nodes on tracks, linking active components, and merging modules, decide whether the resulting toy graph is 3-colorable.	Hard8	GraphDFS+2	No attempts yet	2s	512 MB	Judgeable
A Treasure Or A BombAssign each key to a distinct keyhole to maximize the product of (1 - p_ij), printing the chosen key per keyhole; N up to 100, multiple test cases.	Hard8	Dynamic programmingMath+2	No attempts yet	8s	512 MB	Judgeable
Up and DownCount permutations of 1..N whose up-sequence and down-sequence (nearest larger/smaller distance to the right) match the given arrays; N is at most 17.	Hard8	Dynamic programmingBacktracking+2	No attempts yet	8s	512 MB	Judgeable
Help the MuseumGiven a grid of artist letters, find the shortest left-to-right path using cells of one chosen artist, optionally swapping two cells first, and print the path coordinates.	Hard8	BFSGraph+2	No attempts yet	8s	512 MB	Judgeable
Enclosing CirclesGiven up to 100 circles that may overlap or nest, find the shortest rope that encloses them all, allowing straight segments and arcs along circle boundaries.	Hard8	GeometryGraph+2	No attempts yet	2s	512 MB	Judgeable
Jigsaw Puzzles for ComputersCount the ways to arrange nine given square pieces in a 3x3 grid, rotating each freely, so that every touching pair of edges matches as an uppercase and lowercase pair.	Hard8	BacktrackingBrute force+2	No attempts yet	2s	512 MB	Judgeable
PatienceGiven twenty cards in a 5 by 4 grid, repeatedly remove an adjacent equal pair and compact the survivors, choosing pairs to minimize the cards left.	Hard8	Dynamic programmingBit manipulation+2	No attempts yet	2s	512 MB	Judgeable
NumoebaSimulate a tree of cells whose odd values evolve under a 3n+1 rule, with deaths, bonus spawns, and leader changes, then report lifetime and peak population.	Hard8	SimulationTree+2	No attempts yet	2s	512 MB	Judgeable
TrapezoidsGiven an ASCII picture made of asterisks, find all trapezoids whose sides are horizontal and vertical or 45-degree lines, and report counts of trapezoids grouped by area.	Hard8	ImplementationSimulation+2	No attempts yet	2s	512 MB	Judgeable
Tsubame GaeshiGiven N weighted points, choose exactly three axis-parallel lines to maximize the total weight of points they cover, counting overlaps once.	Hard8	Brute forceSorting+2	No attempts yet	4s	1024 MB	Judgeable
A Simple ProblemGiven two length-N sequences p and q, compute the sum over all ordered pairs of the smaller of the p-distance and the q-distance. N can reach one million.	Hard8	SortingDivide and conquer+2	No attempts yet	4s	1024 MB	Judgeable
Beacon Fire TowersGiven a permutation of heights 1..N, count the ways to cut the line into consecutive segments so that the segment maxima strictly increase left to right, modulo 1e9+7.	Hard8	Dynamic programmingDivide and conquer+2	No attempts yet	1s	1024 MB	Judgeable
Prime TimeSplit a multiset of prime cards into two nonempty groups so the first group's sum equals the second group's product, maximizing that common value.	Hard8	Dynamic programmingMath+2	No attempts yet	45s	1024 MB	Judgeable
Setting Problems for the Orange CupFor each cap L from 1 to N, choose exactly K problems so that no setter appears more than L times, minimizing total preparation time, or report -1.	Hard8	GreedySorting+2	No attempts yet	1s	1024 MB	Judgeable
Orange NumberGiven K between 1000 and 10000, output three distinct natural numbers N under 100000 digits, not divisible by 10, such that the digit sum of N and of N squared both equal K, or -1 if impossible.	Hard8	MathNumber theory+2	No attempts yet	1s	1024 MB	Judgeable
Contest ConstructionCount k-element subsets of n given difficulties such that, sorted ascending, each element from the third onward is at most the sum of the two before it.	Hard8	SortingDynamic programming+2	No attempts yet	1s	2048 MB	Judgeable
TraveLogGiven a weighted digraph and a shuffled set of arrival times from a shortest 1-to-n path, decide whether the path is unique and print it if so.	Hard8	GraphShortest path+2	No attempts yet	4s	2048 MB	Judgeable
Weekly CalendarPlace N consecutive 7-day weeks over a timeline, maximize total covered schedule area, and among ties minimize start date and report the number of tape cuts.	Hard8	Sliding windowPrefix sum+2	No attempts yet	1s	512 MB	Judgeable
Graph Tree PartitionSplit a graph into two vertex-disjoint trees of different sizes by deleting edges, or report that no such split exists.	Hard8	GraphDFS+2	No attempts yet	2s	1024 MB	Judgeable
ShowerRain lowers cell heights over Q days; after each shower, report the lowest cell in the water-connected region containing the shower cell, breaking ties by the earliest rain time.	Hard8	Union-findSimulation+2	No attempts yet	2s	1024 MB	Judgeable
k SubarraysGiven a permutation of distinct integers, find the smallest k such that repeatedly cutting the array into k contiguous pieces and reordering them can sort it.	Hard8	ArraySorting+2	No attempts yet	1s	1024 MB	Judgeable
TerrorGiven the sorted list of all pairwise distances among N houses on a line, reconstruct the actual positions with the first house fixed at 0.	Hard8	BacktrackingRecursion+2	No attempts yet	2.5s	1024 MB	Judgeable
Calculator OptimizationGiven a sequence of add and multiply operations modulo 1e9+7, process up to 5e5 point updates and after each one output the result of evaluating the whole sequence.	Hard8	Segment treeMatrix+2	No attempts yet	2s	512 MB	Judgeable
The Snail Wants to Rest in the ShadeGiven a rectilinear polygon lit by 45-degree sunlight from the upper right, find the total length of shaded surface where a snail can avoid the sun.	Hard8	GeometrySorting+1	No attempts yet	1s	512 MB	Judgeable
Dakku (Diary Decorating)Given a grid with point updates, each query asks for the largest sum of one contiguous piece of a rectangle's one-cell-thick border.	Hard8	Segment treeMatrix+1	No attempts yet	3s	1024 MB	Judgeable
Number of Increasing Subsequences KGiven K, construct a sequence of at most 34 positive integers that has exactly K increasing subsequences.	Hard8	CombinatoricsDynamic programming+2	No attempts yet	2s	1024 MB	Judgeable
Truck DeliveryFor each query (city C, weight W) on a tree, find the gcd of toll charges on edges from C to the root whose load-limit is at most W, or 0 if none apply.	Hard8	TreeDFS+2	No attempts yet	Not set	1024 MB	Judgeable
Primes and QueriesGiven a prime P, an array A, and point updates, answer range queries summing V(A_i^S - (A_i mod P)^S), where V counts the exponent of P.	Hard8	Number theorySegment tree+2	No attempts yet	90s	1024 MB	Judgeable
Hiking TrailsCount ordered alternating sequences of distinct east and west trails, bridged by x, whose total length falls in [C, D].	Hard8	Dynamic programmingBit manipulation+2	No attempts yet	1s	512 MB	Judgeable
HomeworkSchedule all n assignments, each revealed at time t[i] and incurring penalty (submit time - t[i]) * v[i], with at least 1 unit rest between submissions starting from time S, to minimize total penalty.	Hard8	GreedySorting+1	No attempts yet	1.5s	512 MB	Judgeable
Stop the Group Project!Split N students into two nonempty groups with leaders X and Y, and for each of Q queries find the minimum total contact cost so everyone hears the announcement.	Hard8	Minimum spanning treeGraph+2	No attempts yet	2s	512 MB	Judgeable
Leaping PiecesGiven N and M, find the minimum number of lattice points that must hold presents so that a leaping (N,M)-piece starting anywhere can always reach one of them.	Hard8	MathNumber theory+2	No attempts yet	0.5s	1024 MB	Judgeable
Sculpting a TreeGiven a tree and a set of vertices to remove, place bombs on some vertices so that exactly the marked vertices lie within distance p of a bomb, maximizing p.	Hard8	TreeBinary search+2	No attempts yet	2s	1024 MB	Judgeable
Kyojun StargazingCount the ordered splits of N points into two nonempty labeled groups that a single line, avoiding all points, can separate, modulo 1e9+7.	Hard8	GeometryCombinatorics+2	No attempts yet	1.5s	1024 MB	Judgeable
Nutella TreeCount the simple paths in a tree whose first vertex is black and whose other vertices are all red, and recount after each single color flip.	Hard8	TreeSegment tree	No attempts yet	7s	1024 MB	Judgeable
NewspapersGiven a connected undirected graph, decide whether Ankica can always catch Branko as he moves along edges, and output a shortest guessing sequence if she can.	Hard8	GraphImplementation	No attempts yet	2s	1024 MB	Judgeable
StonesIn this take-away game, each player points to a non-empty pile on their turn and the opponent chooses how many stones to remove; decide whether the first pointer (Ankica) wins.	Hard8	Game theoryGreedy+2	No attempts yet	3s	512 MB	Judgeable
UuuGiven N vertices and M edges, output an undirected simple graph that makes a buggy union-find implementation's inner loop run as many times as possible.	Hard8	Union-findGraph+2	No attempts yet	2s	1024 MB	Judgeable
Graph TravelGiven rooms with point rewards and shields that open only while the running total lies in [L, R], count the distinct orders of first-time room entries that end with exactly K points.	Hard8	GraphDynamic programming+2	No attempts yet	Not set	1024 MB	Judgeable