Problems

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Total results29,419 problems

Cakes
Hard8
Graph, Sorting+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Cards
Hard8
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Fibonacci Machine
Hard8
Segment tree, Matrix+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Permutations
Hard8
Combinatorics, Dynamic programming+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Tram
Hard8
Graph, DFS+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Paper Clips
Hard8
Greedy, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Turns
Hard8
String, String matching+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cliquers
Hard8
Combinatorics, Number theory+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Journey
Hard8
Dynamic programming, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cliquers Strike Back
Hard8
Combinatorics, Number theory+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Near 2
Hard8
Divide and conquer, Geometry+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Idempotent Functions
Hard8
Combinatorics, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Return of the Cliquers
Hard8
Combinatorics, Number theory+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Enumeration of Road Network Plans
Hard8
Combinatorics, Tree+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Conference - Rectification
Hard8
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Clouds
Hard8
Geometry, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Subsets
Hard8
Dynamic programming, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Almost Conjugates
Hard8
String, String matching+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Segments
Hard8
Geometry, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Worms
Hard8
Tree, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Crayfish
Hard8
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Travel Agency
Hard8
Graph, Minimum spanning tree+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Straight Lines
Hard8
Geometry, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Temple
Hard8
Geometry, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sum of Polygons
Hard8
Geometry, Two pointers+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Motorways
Hard8
Shortest path, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tetris
Hard8
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cyclic Numbers
Hard8
String matching, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Holey Chessboard
Hard8
Combinatorics, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Supercomputer
Hard8
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cranes
Hard8
Graph, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Courier Services
Hard8
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Screensaver
Hard8
Geometry, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Jasiek's Drawing
Hard8
Geometry, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Gordian Dances
Hard8
Math, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Swift Fawn
Hard8
Dynamic programming, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Ninja
Hard8
Geometry, Graph
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bachelor Party
Hard8
Graph, DFS+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Graph and Queries
Hard8
Graph, BFS+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Power of the Array
Hard8
Array, Prefix sum+2
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Non-Squarefree Numbers
Hard8
Binary search, Math+2
No attempts yet
Time limit
2s
Memory limit
32 MB
Judgeable
Creative Accounting
Hard8
Prefix sum, Math+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Keyboard
Hard8
Graph, BFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Life of the Party
Hard8
Graph, Dynamic programming
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Party
Hard8
Graph, Union-find+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Chessboard
Hard8
Combinatorics, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Godzilla
Hard8
Graph, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Excursion
Hard8
Dynamic programming, Sliding window+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Express Delivery
Hard8
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Spy Satellites
Hard8
Geometry, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Ciąg
Hard8
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Jumpers
Hard8
Graph, Number theory+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bajtori
Hard8
Geometry, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Binary Tree Lexicographic Number
Hard8
Dynamic programming, Tree+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Folding the Map
Hard8
Simulation, Divide and conquer+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Fence In Godzilla!
Hard8
Geometry, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Untamed Tree
Hard8
Tree, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Interval Partition Generator
Hard8
Segment tree, Binary search+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Three-Bit Computers
Hard8
Dynamic programming, String
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Leonardo's Numbers
Hard8
Matrix, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sailboat
Hard8
Dynamic programming, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Viruses
Hard8
Geometry, BFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Company Choir
Hard8
Tree, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Walkie-talkie
Hard8
Graph, Geometry+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Staircase Function Approximation
Hard8
Dynamic programming, Divide and conquer+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
General Bytor
Hard8
Brute force, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Maps
Hard8
Geometry, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Races
Hard8
Tree, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Divers
Hard8
Graph, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Timetable
Hard8
Graph, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Ritual
Hard8
Dynamic programming, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Lost Fraction
Hard8
Number theory, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Wrocław Zoo
Hard8
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Beetles
Hard8
Binary search, Geometry+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tournament
Hard8
Graph, Topological sort+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Fibonacci Game
Hard8
String matching, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Spiders
Hard8
Graph, Tree+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Gnomes
Hard8
BFS, Graph
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Stamps
Hard8
Backtracking, Brute force+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Dams
Hard8
Heap, Union-find+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Settling Salaries
Hard8
Greedy, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
House of Cards
Hard8
Dynamic programming, Tree
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
City Wall
Hard8
Geometry, Sorting
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Strike
Hard8
Dynamic programming, Topological sort+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Punch Cards
Hard8
Prefix sum, Matrix+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Conductors
Hard8
Binary search, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Mutations
Hard8
String matching, Hash map+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Train
Hard8
Dynamic programming, String matching+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Drzewa
Hard8
Tree, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Robot
Hard8
Dynamic programming, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Trójmiasto
Hard8
Geometry, Divide and conquer+1
No attempts yet
Time limit
10s
Memory limit
128 MB
Judgeable
Maximum Mean Cycle
Hard8
Graph, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Heavy Blocks
Hard8
Dynamic programming, Stack+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Explosive Materials
Hard8
Shortest path, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Slides
Hard8
Dynamic programming, Divide and conquer+1
No attempts yet
Time limit
10s
Memory limit
128 MB
Judgeable
March of Primality
Hard8
Geometry, Binary search
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Messengers
Hard8
Graph, Topological sort+1
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Kangaroo Enclosure
Hard8
Geometry, Math
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Safe
Hard8
Matrix, Dynamic programming+1
No attempts yet
Time limit
4s
Memory limit
128 MB
Judgeable
Ski Routes
Hard8
Dynamic programming, Graph+1
No attempts yet
Time limit
10s
Memory limit
128 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
CakesSum, over every triangle in an undirected graph, of the maximum vertex weight in that triangle.	Hard8	GraphSorting+1	No attempts yet	2s	512 MB	Judgeable
CardsCount binary strings with r reds and b blacks where the first card is black or some black run is preceded by a shorter-than-k-times red run, modulo a prime p.	Hard8	Dynamic programmingCombinatorics+1	No attempts yet	2s	512 MB	Judgeable
Fibonacci MachineMaintain registers under range increment, answering range queries of the sum of Fibonacci values at the register entries, modulo 1e9+7.	Hard8	Segment treeMatrix+2	No attempts yet	2s	512 MB	Judgeable
PermutationsCount completions of a partial permutation on 2n points that is an involution and encodes a correct bracket sequence.	Hard8	CombinatoricsDynamic programming+2	No attempts yet	2s	512 MB	Judgeable
TramFor each junction, find the greatest common divisor of all cycle lengths reachable from and returning to it, or -1 if no return is possible.	Hard8	GraphDFS+2	No attempts yet	2s	512 MB	Judgeable
Paper ClipsFind the minimum number of 180-degree turns needed to separate a chain of clips joined in two possible ways, where clips sit in four orientations.	Hard8	GreedyDynamic programming+1	No attempts yet	1s	128 MB	Judgeable
TurnsFor each starting position, find how many turns must be observed before the position on the map becomes uniquely determined.	Hard8	StringString matching+2	No attempts yet	1s	128 MB	Judgeable
CliquersCount assignments of grades from 1..m to all integer partitions of n, modulo 10^9-401.	Hard8	CombinatoricsNumber theory+2	No attempts yet	1s	128 MB	Judgeable
JourneyCount length-d walks in a small (n<=20) graph that visit each of the first k<=7 cities at least once, modulo 1e9+9.	Hard8	Dynamic programmingGraph+2	No attempts yet	1s	128 MB	Judgeable
Cliquers Strike BackCount assignments of m grades to all labeled graphs on n vertices whose connected components are cliques, modulo 10^9-401.	Hard8	CombinatoricsNumber theory+1	No attempts yet	1s	128 MB	Judgeable
Near 2Given n tree points and m apple points, find the minimum over all apples of the Manhattan distance to the nearest tree.	Hard8	Divide and conquerGeometry+2	No attempts yet	1s	128 MB	Judgeable
Idempotent FunctionsGiven f on {1..n}, count pairs (g, h) with g a permutation and h idempotent such that f = h composed with g, modulo 1e9+7.	Hard8	CombinatoricsMath+2	No attempts yet	1s	128 MB	Judgeable
Return of the CliquersCount the number of grade assignments to all symmetric labeled cliquers on n vertices, raised to m modulo 10^9-401 with n and m up to 2*10^9.	Hard8	CombinatoricsNumber theory+2	No attempts yet	1s	128 MB	Judgeable
Enumeration of Road Network PlansCount the isomorphism classes of trees on n vertices whose diameter equals d, modulo a prime p.	Hard8	CombinatoricsTree+2	No attempts yet	1s	128 MB	Judgeable
Conference - RectificationChoose a subset of whole reservations to keep so that total income from ticket sales minus room rent is maximized.	Hard8	Dynamic programmingGreedy+2	No attempts yet	1s	128 MB	Judgeable
CloudsGiven disjoint simple polygons and a fixed wind direction, place a point so the number of polygons that cross the vertical ray above it at some time is maximized.	Hard8	GeometrySorting+2	No attempts yet	1s	128 MB	Judgeable
SubsetsCount k-element subsets of {1,...,n} in which no two chosen numbers differ by a factor of x, modulo m, with n up to 1e18.	Hard8	Dynamic programmingCombinatorics+2	No attempts yet	1s	128 MB	Judgeable
Almost ConjugatesDecide whether two length-n words are almost conjugates and, if so, list every rotation of the first that differs from the second in exactly one position.	Hard8	StringString matching+2	No attempts yet	1s	128 MB	Judgeable
SegmentsGiven n disjoint vertical segments, find the maximum possible number of pairs that can see each other via an unobstructed horizontal segment.	Hard8	GeometryCombinatorics+1	No attempts yet	1s	128 MB	Judgeable
WormsOn a tree, worms each move every hour to an adjacent house; decide whether they can all meet and find the minimum number of hours.	Hard8	TreeGraph+2	No attempts yet	1s	128 MB	Judgeable
CrayfishFor each house, count how many turtles are reachable on a round trip that starts and ends moving backward, where special edges flip the direction of travel.	Hard8	GraphDFS+2	No attempts yet	1s	128 MB	Judgeable
Travel AgencyChoose customers for a trip; each unpaid social requirement between a chosen customer and an unchosen one costs a penalty. Maximize profit.	Hard8	GraphMinimum spanning tree+2	No attempts yet	1s	128 MB	Judgeable
Straight LinesGiven two crossing lines and an integer point, find the integer point in the same region that is closest to the intersection, breaking ties lexicographically.	Hard8	GeometryMath+2	No attempts yet	1s	128 MB	Judgeable
The TempleGiven circles (columns) and two points, find the shortest path between the points that cannot pass through any circle.	Hard8	GeometryGraph+2	No attempts yet	1s	128 MB	Judgeable
Sum of PolygonsAdd two convex polygons by Minkowski sum and print twice the area of the resulting polygon.	Hard8	GeometryTwo pointers+2	No attempts yet	1s	128 MB	Judgeable
MotorwaysEach directed toll changes linearly by day; find the day among the first d that minimizes the cost of a round trip from a to b and back.	Hard8	Shortest pathGraph+2	No attempts yet	1s	128 MB	Judgeable
TetrisEach block is a horizontal strip 1 unit tall; given its length and left offset, choose the drop order that minimizes the final stack height. Output that minimum.	Hard8	GreedySorting+2	No attempts yet	1s	128 MB	Judgeable
Cyclic NumbersFind the smallest B >= n that is a multiple m*A (1<=m<=k) of some k-digit number A whose multiples 1..k are all cyclic rotations.	Hard8	String matchingMath+2	No attempts yet	1s	128 MB	Judgeable
Holey ChessboardGiven a K by W board with holes, drill the most hole-free cells while keeping the permanent (count of non-attacking rook placements) unchanged.	Hard8	CombinatoricsGraph+2	No attempts yet	1s	128 MB	Judgeable
SupercomputerGiven jobs with arrival times and required processor-time, schedule them with preemption on a single 100% processor to minimize the sum of completion-minus-arrival times.	Hard8	GreedySorting+2	No attempts yet	1s	128 MB	Judgeable
CranesGiven a permutation, each time unit lets several disjoint swaps happen at once; find the minimum number of time units to sort it.	Hard8	GraphGreedy+2	No attempts yet	1s	128 MB	Judgeable
Courier ServicesFind all Pareto-optimal (cost, time) pairs among routes from a class-C source to a class-C destination in a network with a special office-class structure and cycles.	Hard8	GraphShortest path+2	No attempts yet	1s	128 MB	Judgeable
ScreensaverA point moves diagonally and reflects off a set of disjoint horizontal and vertical wall segments; report its position after t seconds.	Hard8	GeometrySimulation+2	No attempts yet	1s	128 MB	Judgeable
Jasiek's DrawingGiven a counter-clockwise walk around a polyomino's border cells, count the total number of blackened cells in the drawing.	Hard8	GeometryImplementation+1	No attempts yet	1s	128 MB	Judgeable
Gordian DancesGiven a sequence of S (string swap) and R (quarter-turn) moves, find the minimum number of further moves that returns the dance to a horizontal, parallel, untangled state.	Hard8	MathString+2	No attempts yet	1s	128 MB	Judgeable
Swift FawnWith energy starting at 1 and moves that double, halve, or negate the current level, find the fewest jumps to reach distance n and then stop.	Hard8	Dynamic programmingMath+2	No attempts yet	1s	128 MB	Judgeable
NinjaGiven n points in the plane, decide whether two disjoint non-crossing polylines can connect point 1 to 2 and point 3 to 4 using points as vertices.	Hard8	GeometryGraph	No attempts yet	1s	128 MB	Judgeable
Bachelor PartyGiven a tree and one-way tickets, decide if a vertex-simple walk from s to t uses every ticket exactly once.	Hard8	GraphDFS+1	No attempts yet	1s	128 MB	Judgeable
Graph and QueriesAfter some directed edges are deleted, report the shortest path length from vertex 1 to given vertices at each query.	Hard8	GraphBFS+2	No attempts yet	2s	256 MB	Judgeable
Power of the ArrayGiven an array and t range queries, compute for each subarray the sum over values s of s times the square of s's frequency in the range.	Hard8	ArrayPrefix sum+2	No attempts yet	3s	128 MB	Judgeable
Non-Squarefree NumbersGiven n up to 10^10, find the n-th positive integer that is divisible by some square d^2 with d > 1.	Hard8	Binary searchMath+2	No attempts yet	2s	32 MB	Judgeable
Creative AccountingGiven daily balances, pick a contiguous period whose sum modulo m (with nonnegative remainder) is as large as possible, and report that maximum remainder.	Hard8	Prefix sumMath+2	No attempts yet	2s	128 MB	Judgeable
KeyboardA 1x2 domino slides around a grid through the single uncovered cell; find the fewest moves to uncover every vowel cell at least once.	Hard8	GraphBFS+2	No attempts yet	1s	128 MB	Judgeable
Life of the PartyGiven a bipartite acquaintance graph, list every vertex whose removal strictly decreases the maximum matching.	Hard8	GraphDynamic programming	No attempts yet	1s	128 MB	Judgeable
PartyEvery pair of students is either friends or enemies; pick a set with no enemy pair that is closed under friends, maximizing size and counting the ways.	Hard8	GraphUnion-find+2	No attempts yet	1s	128 MB	Judgeable
ChessboardCount permutations of 1..n whose i-th rook avoids row i and column i, modulo m.	Hard8	CombinatoricsDynamic programming+1	No attempts yet	1s	128 MB	Judgeable
GodzillaEach day Godzilla starts at junction 1, walks a path, eats a building and destroys buildings on the way; each night one person leaves every standing building. Maximize the total eaten.	Hard8	GraphGreedy+2	No attempts yet	1s	128 MB	Judgeable
ExcursionSplit a path of n weighted roads into contiguous segments of total length at most D, minimizing the sum of squared segment impression sums.	Hard8	Dynamic programmingSliding window+2	No attempts yet	1s	128 MB	Judgeable
Express DeliveryGiven a depot and clients with distinct x and y coordinates, find the fewest monotone (shortest-path) routes from the depot that cover all clients.	Hard8	GreedySorting+2	No attempts yet	1s	128 MB	Judgeable
Spy SatellitesGiven a terrain polyline with some marked points, place satellites on the line y=H so their visibility segments cover all marked points, minimizing the count.	Hard8	GeometryGreedy+2	No attempts yet	1s	128 MB	Judgeable
CiągBajtek needs the shortest string over the given alphabet that is not a subsequence of the word, and the lexicographically smallest among shortest such strings.	Hard8	Dynamic programmingGreedy+2	No attempts yet	1s	128 MB	Judgeable
JumpersDecide whether a set of distinct white start cells and closed jump sequences can cover every white cell without landing on any black cell.	Hard8	GraphNumber theory+2	No attempts yet	1s	128 MB	Judgeable
BajtoriSelect a subset of squares to maximize the sum of the squared red total and squared green total.	Hard8	GeometrySorting+1	No attempts yet	1s	128 MB	Judgeable
Binary Tree Lexicographic NumberGiven binary trees with ordered left and right children, find each tree's rank in height-first lexicographic order modulo 1000000000.	Hard8	Dynamic programmingTree+2	No attempts yet	1s	128 MB	Judgeable
Folding the MapDecide whether an n by m map with convex or concave creases folds to one square.	Hard8	SimulationDivide and conquer+1	No attempts yet	1s	128 MB	Judgeable
Fence In Godzilla!The task is to find the smallest nonzero area among triangles with vertices from n points.	Hard8	GeometrySorting+1	No attempts yet	1s	128 MB	Judgeable
Untamed TreeThe task is to output for each leaf label the compressed subtree of its leaves and branching ancestors in preorder.	Hard8	TreeSorting+2	No attempts yet	1s	128 MB	Judgeable
Interval Partition GeneratorThe task is to decode each given lexicographic interval index on the remaining set and report the total interval count with the chosen endpoints.	Hard8	Segment treeBinary search+1	No attempts yet	1s	128 MB	Judgeable
Three-Bit ComputersThe task is to decide whether a target string over a, b and c can be built from uninitialized cells with the two pair operations.	Hard8	Dynamic programmingString	No attempts yet	1s	128 MB	Judgeable
Leonardo's NumbersThe task is to compute the sum of kth powers of Leonardo numbers up to n modulo 1000000000.	Hard8	MatrixMath+2	No attempts yet	1s	128 MB	Judgeable
SailboatFind a path from buoy 1 to buoy n in a DAG maximizing the sum of squared differences between consecutive edge weights.	Hard8	Dynamic programmingGraph+1	No attempts yet	1s	128 MB	Judgeable
VirusesGiven up to 24 virus sources with distinct daily hours, determine how many cells each one ends up occupying on an n by n board.	Hard8	GeometryBFS+2	No attempts yet	1s	128 MB	Judgeable
The Company ChoirGiven a rooted tree where each node has a pitch and a distinct ability score, answer queries that ask for the k highest-ability subordinates of a node whose pitch lies in a range [a,b].	Hard8	TreeDFS+2	No attempts yet	1s	128 MB	Judgeable
Walkie-talkieGiven a planar track network, find all cities Slawek can visit while Mirek positions himself elsewhere so they stay within distance d at all times.	Hard8	GraphGeometry+2	No attempts yet	1s	128 MB	Judgeable
Staircase Function ApproximationPartition the sequence f(0..n-1) into at most k contiguous groups, each approximated by a constant, minimizing the sum of \|value - f(i)\|^p over all i, and output the reduced fraction.	Hard8	Dynamic programmingDivide and conquer+1	No attempts yet	1s	128 MB	Judgeable
General BytorGiven two permutations of n unit types and m cyclic position-shift orders, find the shortest (then lexicographically smallest) sequence of at most 10 orders that transforms the start into the target.	Hard8	Brute forceString+2	No attempts yet	1s	128 MB	Judgeable
MapsGiven up to a million arbitrarily rotated rectangles, find the number of edges of their common intersection polygon.	Hard8	GeometryImplementation+2	No attempts yet	1s	128 MB	Judgeable
RacesGiven a tree and a set of allowed endpoints, find the maximum number of vertex-disjoint paths whose endpoints both lie in the allowed set.	Hard8	TreeDynamic programming+2	No attempts yet	1s	128 MB	Judgeable
DiversWith a shared torch and a graph of divers who refuse to pair up, find the minimum total time to ferry everyone out under the rock, or IMPOSSIBLE.	Hard8	GraphDynamic programming+2	No attempts yet	1s	128 MB	Judgeable
TimetableGiven p subjects as (teacher, class) pairs and s rooms, find the minimum number of parallel hours so no teacher, class, or room is used twice per hour.	Hard8	GraphCombinatorics+2	No attempts yet	1s	128 MB	Judgeable
RitualCount the subsequences of a long digit string that form a palindrome divisible by 666, then report ((count - 1) mod 666) + 1.	Hard8	Dynamic programmingString+2	No attempts yet	1s	128 MB	Judgeable
The Lost FractionGiven n and a, list every reduced fraction with denominator at most n that lies in the closed interval [a/n^2, (a+1)/n^2], in increasing order.	Hard8	Number theoryMath+1	No attempts yet	1s	128 MB	Judgeable
Wrocław ZooFind the shortest walk through a planar zoo graph that visits k animal enclosures in a fixed order, entering any entrance and leaving any exit gate.	Hard8	GraphShortest path+2	No attempts yet	1s	128 MB	Judgeable
BeetlesGiven n segments, find the smallest axis-aligned square that contains at least k of them entirely, with boundary counted as inside.	Hard8	Binary searchGeometry+2	No attempts yet	1s	128 MB	Judgeable
TournamentGiven a partial tournament (a directed acyclic graph), produce the valid topological order that is lexicographically smallest when read from highest rank to lowest.	Hard8	GraphTopological sort+2	No attempts yet	1s	128 MB	Judgeable
The Fibonacci GameDetermine whether the first player wins a game that erases Fibonacci words only from the right end of a given a/b string.	Hard8	String matchingDynamic programming+2	No attempts yet	1s	128 MB	Judgeable
SpidersGiven two planar triangulations built by repeatedly attaching a new vertex to an outer edge, decide whether they are isomorphic as graphs.	Hard8	GraphTree+2	No attempts yet	1s	128 MB	Judgeable
GnomesFind the earliest hour when a token starting at station 1 can reach station n using swaps within unwatched stations each hour.	Hard8	BFSGraph	No attempts yet	1s	512 MB	Judgeable
StampsDecide whether given stamps can cover every # cell of a picture up to 100 by 100 without coloring any . cell.	Hard8	BacktrackingBrute force+1	No attempts yet	1s	512 MB	Judgeable
DamsEach of n sectors fills at its own rate behind dams of given heights, and you compute when water first spills past an end dam.	Hard8	HeapUnion-find+1	No attempts yet	1s	512 MB	Judgeable
Settling SalariesWorkers on a ring compare contract pay to cash received and settle every balance with the fewest transfers between neighbors.	Hard8	GreedyPrefix sum+1	No attempts yet	1s	512 MB	Judgeable
House of CardsMarcel removes at most k cards in whole leaning pairs, clearing cards above before the cards they rest on, to maximize the recovered sum.	Hard8	Dynamic programmingTree	No attempts yet	1s	512 MB	Judgeable
City WallDecide whether every segment of a polygonal city wall is visible from an interior church point without occlusion by other segments.	Hard8	GeometrySorting	No attempts yet	1s	512 MB	Judgeable
StrikeChoose one train to hold for k minutes in a DAG rail network so the total delay passed on to all trains is largest.	Hard8	Dynamic programmingTopological sort+1	No attempts yet	1s	128 MB	Judgeable
Punch CardsChoose the largest a by b stamp whose repeated presses punch exactly the marked cells without ever punching an intact cell.	Hard8	Prefix sumMatrix+2	No attempts yet	1s	256 MB	Judgeable
ConductorsConductors with different speeds start at their own compartments and take the smallest unchecked one when free, and the goal is the last compartment of each.	Hard8	Binary searchMath+1	No attempts yet	1s	128 MB	Judgeable
MutationsAnswer many queries whether a fragment of the second array matches a fragment of the first after changing all copies of one value.	Hard8	String matchingHash map+1	No attempts yet	1s	128 MB	Judgeable
TrainSum over all n! orders of the wagon strings the number of occurrences of their concatenation in t.	Hard8	Dynamic programmingString matching+1	No attempts yet	1s	128 MB	Judgeable
DrzewaFor each node of a labeled rooted tree, find the leaf below it whose downward label string is lexicographically largest, breaking ties by smaller leaf number.	Hard8	TreeGreedy+2	No attempts yet	1s	128 MB	Judgeable
RobotWrite the shortest down-right program of at most k steps whose repetition exits the board without hitting an obstacle, ties broken lexicographically.	Hard8	Dynamic programmingMath+1	No attempts yet	1s	128 MB	Judgeable
TrójmiastoPick three of up to one million points in the plane so the sum of their three pairwise distances is smallest.	Hard8	GeometryDivide and conquer+1	No attempts yet	10s	128 MB	Judgeable
Maximum Mean CycleFind the directed cycle with the largest mean edge weight and print it as a reduced fraction.	Hard8	GraphDynamic programming+1	No attempts yet	1s	128 MB	Judgeable
Heavy BlocksTopple n distinct-weight blocks with the fewest pushes when each push fells lighter neighbors in one direction until a heavier block or gap.	Hard8	Dynamic programmingStack+2	No attempts yet	1s	128 MB	Judgeable
Explosive MaterialsFill each huge truck capacity exactly with unlimited explosive sizes using as few units as possible, or report impossibility.	Hard8	Shortest pathMath+1	No attempts yet	1s	128 MB	Judgeable
SlidesCount the non-empty slide subsets that keep slide-number order and rise in both rankings, modulo 1000000007.	Hard8	Dynamic programmingDivide and conquer+1	No attempts yet	10s	128 MB	Judgeable
March of PrimalityPick a meeting point minimizing the latest arrival from N homes so the joint march still reaches the finish by time E.	Hard8	GeometryBinary search	No attempts yet	2s	128 MB	Judgeable
MessengersGiven merchant journals of letter sends and receives, answer for each query which of two letters was sent first or whether the order is unknown.	Hard8	GraphTopological sort+1	No attempts yet	5s	128 MB	Judgeable
Kangaroo EnclosureCount the grid cells inside the smallest convex enclosure with horizontal, vertical, and diagonal sides that covers all marked cells.	Hard8	GeometryMath	No attempts yet	1s	128 MB	Judgeable
The SafeCount the ordered sequences of exactly R dial turns that leave target k at the top, modulo 1000033.	Hard8	MatrixDynamic programming+1	No attempts yet	4s	128 MB	Judgeable
Ski RoutesCount closed tours that chain one or more uphill lifts and then ski down to the start through strictly lower adjacent cells.	Hard8	Dynamic programmingGraph+1	No attempts yet	10s	128 MB	Judgeable