Problems

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Total results29,077 problems

Waging War Peacefully
Hard9
Math, Number theory+2
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
Polynomial and Easy Queries
Hard9
Math, Segment tree+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Daily Commute
Hard9
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Boring Lesson
Hard9
Dynamic programming, String+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Back to Space
Hard9
String matching, Hash map+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Mail
Hard9
Array, Greedy+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Escape Route
Hard9
Graph, Shortest path+2
No attempts yet
Time limit
9s
Memory limit
2048 MB
Judgeable
Road Construction
Hard9
Divide and conquer, Sorting+2
No attempts yet
Time limit
10s
Memory limit
2048 MB
Judgeable
Bodyguard
Hard9
Dynamic programming, Sorting+1
No attempts yet
Time limit
25s
Memory limit
2048 MB
Judgeable
Navigation 2
Hard9
Graph, BFS+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Routing Schemes
Hard9
Graph, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Through Another Maze Darkly
Hard9
Tree, Graph+1
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Vote-Value Disparity 2
Hard9
Graph, BFS+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Vote-Value Disparity 3
Hard9
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Vote-Value Disparity 4
Hard9
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Vote-Value Disparity 5
Hard9
Graph, Divide and conquer+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Road Closure
Hard9
Tree, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Binary Subsequences
Hard9
Dynamic programming, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Deque Game
Hard9
Dynamic programming, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
The Grade
Hard9
Dynamic programming, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Football
Hard9
Game theory, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Crossing
Hard9
Segment tree, Math+2
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Broken Clocks
Hard9
Number theory, Math+2
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Double Move
Hard9
Game theory, Combinatorics+1
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Fountain Parks
Hard9
Graph, Union-find+1
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Forgotten Homework
Hard9
Matrix, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Dungeons Game
Hard9
Dynamic programming, Tree+1
No attempts yet
Time limit
4s
Memory limit
2048 MB
Judgeable
Mezhdurechye Bombs
Hard9
Geometry, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Fibonacci Numbers
Hard9
Math, Number theory+1
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
Table
Hard9
Combinatorics, Math+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Trisolarians
Hard9
Combinatorics, Dynamic programming+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Jawaian Weapon Set
Hard9
Number theory, Math+2
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Parade
Hard9
Geometry, Brute force+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Table 5
Hard9
Backtracking, Math+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Table 7
Hard9
Backtracking, Brute force+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Gahui and the Read-Write Game 2
Hard9
Greedy, Implementation+2
No attempts yet
Time limit
2.5s
Memory limit
512 MB
Judgeable
Truck
Hard9
Tree, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Tiles
Hard9
Dynamic programming, Segment tree+2
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Paper, Pen, Triangle
Hard9
Combinatorics, Math+2
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Edge First or Vertex First
Hard9
Game theory, Graph+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Feed candies
Hard9
Number theory, Math+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Watching Baseball
Hard9
Combinatorics, Math+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Air Pollution
Hard9
Math, Greedy+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Do use segment tree
Hard9
Segment tree, Tree+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Entangled with Lottery
Hard9
Dynamic programming, Probability+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Tiles are Colorful
Hard9
Simulation, DFS+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Carpenters' Language
Hard9
String, Stack+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Double Magic Made Clear
Hard9
Graph, Topological sort+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Webby Subway
Hard9
Geometry, Graph+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Exact Arithmetic
Hard9
Implementation, Simulation+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Cut out
Hard9
Geometry, Math+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Strange Key
Hard9
Graph, Geometry+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Bridge Crossing Game
Hard9
Graph, Game theory+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Pillar and Wall Defense Game
Hard9
Geometry, Brute force+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Setting an Exam Problem
Hard9
Dynamic programming, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Slide Circuits
Hard9
Graph, Union-find+2
No attempts yet
Time limit
Not set
Memory limit
1024 MB
Judgeable
Permutation CFG
Hard9
Recursion, Combinatorics+2
No attempts yet
Time limit
4s
Memory limit
2048 MB
Judgeable
Sinchon Sequence and Queries
Hard9
Segment tree, Dynamic programming+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Sinchon Defense Headquarters
Hard9
Geometry, Math+2
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Master of String Manipulation
Hard9
Dynamic programming, Combinatorics+2
No attempts yet
Time limit
2.5s
Memory limit
1024 MB
Judgeable
Cycle
Hard9
Dynamic programming, Graph+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Binary Operator
Hard9
Math, Hash map+2
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
RMQ
Hard9
Segment tree, Prefix sum+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Diversity
Hard9
Segment tree, Greedy+1
No attempts yet
Time limit
7s
Memory limit
512 MB
Judgeable
Calculate! 3
Hard9
Tree, Bit manipulation+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Pizzo Collectors
Hard9
Number theory, Math+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Tobacco Growing
Hard9
Dynamic programming, Combinatorics+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Screamers
Hard9
Graph, Union-find+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
How to Move the Beans
Hard9
Game theory, Graph+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Kingdoms and Quarantine
Hard9
Math, Graph+1
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Crab's Cannon
Hard9
String, String matching+1
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Elephants
Hard9
Graph, Math
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Interval Shuffle
Hard9
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Magic Box
Hard9
String matching, String+1
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Directed Acyclic Graph
Hard9
Graph, Topological sort+1
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Swapping Inversions
Hard9
Probability, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Minimal Cyclic Shift
Hard9
String, Number theory+2
No attempts yet
Time limit
1.5s
Memory limit
256 MB
Judgeable
Interval
Hard9
Divide and conquer, Segment tree+2
No attempts yet
Time limit
4s
Memory limit
512 MB
Judgeable
Nondeterministic Finite Automaton
Hard9
Graph, Number theory+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
The Struggle
Hard9
Bit manipulation, Math+1
No attempts yet
Time limit
4.5s
Memory limit
512 MB
Judgeable
Power Station of Art
Hard9
Graph, Union-find+1
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Game
Hard9
Game theory, Intervals+1
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Goldberg Machine 2
Hard9
Math, Segment tree+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
MIPT: Connecting People
Hard9
Minimum spanning tree, Divide and conquer+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
The Last Samurai
Hard9
Greedy, Simulation+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Rational Dimasik
Hard9
Number theory, Math+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Lamb's Respite
Hard9
Segment tree, Implementation+2
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Gene Folding
Hard9
String, String matching+2
No attempts yet
Time limit
5s
Memory limit
2048 MB
Judgeable
Deer-Proof Fence
Hard9
Geometry, Brute force+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Video Quality - Auto (480p)
Hard9
Greedy, Intervals+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Island Nations of the Planet Bilarbong
Hard9
Graph, Union-find+2
No attempts yet
Time limit
0.75s
Memory limit
8 MB
Judgeable
Gets and Puts (Hard)
Hard9
Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
QuackQuack (Hard)
Hard9
Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Kinking Cables
Hard9
Geometry, Implementation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Shooting
Hard9
Geometry, Math+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Black and White
Hard9
Combinatorics, Math
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Dirichlet k-th root
Hard9
Number theory, Math+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
King
Hard9
Number theory, Math+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Moon
Hard9
Geometry, Probability+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Permutation
Hard9
Dynamic programming, Combinatorics
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Waging War PeacefullyGiven group sizes A1..AN, find the largest rectangle width Y that fits all soldiers in row-major order with at most k row-boundary conflicts, for every k from 0 to N-1.	Hard9	MathNumber theory+2	No attempts yet	5s	256 MB	Judgeable
Polynomial and Easy QueriesMaintain an array under range applications of f(x)=2x^2-1 and g(x)=4x^3-3x, and answer point queries modulo 100003.	Hard9	MathSegment tree+2	No attempts yet	2s	256 MB	Judgeable
Daily CommuteAfter each of D swaps in a subway route permutation, find the shortest travel time from station 1 to station N using the train and W one-way walkways.	Hard9	GraphShortest path+2	No attempts yet	1s	1024 MB	Judgeable
Boring LessonGiven strings s and t and a list of n favorite strings, find the minimum edit distance from s to t and the largest subset of favorites that can all appear along a shortest edit path, then output that subset in order.	Hard9	Dynamic programmingString+2	No attempts yet	1s	512 MB	Judgeable
Back to SpaceGiven an r by c grid of colored tiles, find a panel size a by b and a row shift s so that the grid is covered by shifted copies of the panel, with minimal panel area.	Hard9	String matchingHash map+1	No attempts yet	2s	512 MB	Judgeable
MailGiven a ring of one-way segments with time-varying speeds, find the post office to start from and the earliest return time to it, where the start leaves at time 0 and goes around the full ring.	Hard9	ArrayGreedy+2	No attempts yet	2s	512 MB	Judgeable
Escape RouteEach road closes daily at a fixed time, so find the fastest travel time between two cities for each query's departure time in a repeating day.	Hard9	GraphShortest path+2	No attempts yet	9s	2048 MB	Judgeable
Road ConstructionGiven N points, output the K smallest Manhattan distances among all pairs, in increasing order, for N and K up to 250000.	Hard9	Divide and conquerSorting+2	No attempts yet	10s	2048 MB	Judgeable
BodyguardFor each query, find the maximum reward a bodyguard starting at coordinate X at time P can earn by escorting VIPs whose walks are given in space-time.	Hard9	Dynamic programmingSorting+1	No attempts yet	25s	2048 MB	Judgeable
Navigation 2Design a flag labeling on an N by N grid so that an agent who sees only its 3x3 neighborhood can walk from any unknown starting cell to a given target using labels alone, minimizing the largest label.	Hard9	GraphBFS+2	No attempts yet	1s	512 MB	Judgeable
Routing SchemesCount the ways to cover every edge of a graph with K backward edges by S paths, each running from a sender to a distinct receiver, modulo 1e9+7.	Hard9	GraphCombinatorics+1	No attempts yet	1s	512 MB	Judgeable
Through Another Maze DarklyGiven a tree maze where each room has a rotating laser pointer, find the room reached from room 1 after exactly K corridor moves for each of Q queries.	Hard9	TreeGraph+1	No attempts yet	8s	512 MB	Judgeable
Vote-Value Disparity 2Partition N voter-weighted provinces on a grid into K connected districts minimizing the ratio of largest to smallest district voter total, outputting one district id per province.	Hard9	GraphBFS+2	No attempts yet	1s	512 MB	Judgeable
Vote-Value Disparity 3Partition N provinces on a grid into K connected electoral districts so that the ratio between the largest and smallest district voter counts is minimized.	Hard9	GraphDFS+2	No attempts yet	1s	512 MB	Judgeable
Vote-Value Disparity 4Partition N connected provinces into K connected districts to minimize the ratio between the largest and smallest district voter totals, and output any assignment.	Hard9	GraphDFS+2	No attempts yet	1s	512 MB	Judgeable
Vote-Value Disparity 5Partition the provinces of a grid map into K connected districts to minimize the ratio between the largest and smallest district voter totals.	Hard9	GraphDivide and conquer+2	No attempts yet	1s	512 MB	Judgeable
Road ClosureGiven a weighted tree, find for each k the minimum total weight of edges to close so every junction keeps at most k open roads.	Hard9	TreeDynamic programming+1	No attempts yet	1s	1024 MB	Judgeable
Binary SubsequencesFor each K up to 10^6, count binary strings with exactly K distinct non-empty subsequences modulo 1e9+7 and output a shortest such string.	Hard9	Dynamic programmingCombinatorics+2	No attempts yet	1s	512 MB	Judgeable
Deque GameGiven two starting stacks over a K-letter alphabet, count for each how many distinct L-length stacks contain that starting stack as a contiguous block, and compare the counts.	Hard9	Dynamic programmingCombinatorics+2	No attempts yet	1s	1024 MB	Judgeable
The GradeAfter each insert or erase into a set A, count the ways to place all elements of A into a length-P list padded with zeros so that each positive value sits at least that far from the previous positive value, modulo 1e9+7, or print -1.	Hard9	Dynamic programmingCombinatorics+2	No attempts yet	1s	512 MB	Judgeable
FootballPlayers alternately take students from one class per turn, at most K and no more than the previous turn's count; decide who takes the last student.	Hard9	Game theoryDynamic programming+1	No attempts yet	2s	512 MB	Judgeable
CrossingGiven three seed strings over J,O,I and a crossing operation, decide after each of Q range-assignment updates whether the current string can be produced by repeated crossings.	Hard9	Segment treeMath+2	No attempts yet	3s	512 MB	Judgeable
Broken ClocksGiven n clocks with start times and per-second drift rates, count how many times during a 24-hour window all clocks show the same time.	Hard9	Number theoryMath+2	No attempts yet	3s	512 MB	Judgeable
Double MoveGiven n stones and some already declared pairs of candidate stones, count the scenarios in which Alice and Bob each win when both play optimally.	Hard9	Game theoryCombinatorics+1	No attempts yet	5s	512 MB	Judgeable
Fountain ParksDecide whether length-2 roads can connect all fountains, giving each road a distinct bench at an odd point beside it, and output a plan if one exists.	Hard9	GraphUnion-find+1	No attempts yet	3s	512 MB	Judgeable
Forgotten HomeworkGiven a matrix A and the first 2n-1 values of the sequence A^k(i,j), find the missing term A^{2n}(i,j) modulo 1e9+7.	Hard9	MatrixDynamic programming+2	No attempts yet	1s	512 MB	Judgeable
Dungeons GameGiven n dungeons with opponents of strength s[i] and q starting states (dungeon x, strength z), find the hero's final strength when the hero reaches dungeon n.	Hard9	Dynamic programmingTree+1	No attempts yet	4s	2048 MB	Judgeable
Mezhdurechye BombsFind the fewest translations of a fixed convex polygon that together touch every x-monotone polyline between the lines x=0 and x=T.	Hard9	GeometryCombinatorics+1	No attempts yet	2s	256 MB	Judgeable
Fibonacci NumbersFor each test, compute the sum of the k-th powers of the first n Fibonacci numbers modulo 10^9+23, with n up to 1e9 and k up to 1e18.	Hard9	MathNumber theory+1	No attempts yet	5s	256 MB	Judgeable
TableCount 2-colorings of an n by m grid with no monochromatic axis-parallel rectangle, modulo a given r, for huge n, m, r.	Hard9	CombinatoricsMath+2	No attempts yet	2s	256 MB	Judgeable
TrisolariansCount the maximum number of distinct life histories (strictly increasing chains of k-vectors with all-positive yearly increments) that end at a vector with coordinate sum n, modulo 7340033.	Hard9	CombinatoricsDynamic programming+2	No attempts yet	2s	256 MB	Judgeable
Jawaian Weapon SetFind the k-th triple of primes (d1<=d2<=d3) in lexicographic order satisfying three divisibility conditions involving squares minus one.	Hard9	Number theoryMath+2	No attempts yet	3s	256 MB	Judgeable
ParadeGiven a convex polygon, an interior center, and k fixed garland directions, rotate the whole system to minimize the total distance from the center to the polygon boundary along those directions.	Hard9	GeometryBrute force+2	No attempts yet	2s	256 MB	Judgeable
Table 5Build an N by N digit table (2 <= N <= 10) whose rows, columns, and two main diagonals all read as distinct multiples of M, with no leading zeros.	Hard9	BacktrackingMath+2	No attempts yet	1s	512 MB	Judgeable
Table 7Build an N by N digit table (2 <= N <= 10) where every row, column, and main diagonal forms an N-digit multiple of M with no leading zero and all numbers distinct.	Hard9	BacktrackingBrute force+2	No attempts yet	1s	512 MB	Judgeable
Gahui and the Read-Write Game 2Assign each turn to a player so that each player's constrained card order matches, producing the given final list of appended numbers.	Hard9	GreedyImplementation+2	No attempts yet	2.5s	512 MB	Judgeable
TruckGiven a weighted tree with per-edge tolls, handle toll updates and queries asking the minimum fuel to move G gold along a path, modulo 1e9+7.	Hard9	TreeDynamic programming+2	No attempts yet	1s	512 MB	Judgeable
TilesCount tilings of a 3 by N grid with 1 by 2 dominoes restricted to white squares, under point color flips and subrectangle queries, modulo 1e9+7.	Hard9	Dynamic programmingSegment tree+2	No attempts yet	4s	1024 MB	Judgeable
Paper, Pen, TriangleGiven a big equilateral triangle of side m and q lines drawn inside it parallel to its sides, count every equilateral triangle fully contained in the figure.	Hard9	CombinatoricsMath+2	No attempts yet	3s	1024 MB	Judgeable
Edge First or Vertex FirstGiven a directed graph, Edgeo picks a probability distribution over edges, then Vertexko picks a distribution over vertices to minimize the expected score; find the game value.	Hard9	Game theoryGraph+2	No attempts yet	8s	512 MB	Judgeable
Feed candiesCandy i has effect (s_i, t_i) generated by a complex recurrence; decide whether a subset sums to (X, Y) and print the chosen indices.	Hard9	Number theoryMath+2	No attempts yet	2s	512 MB	Judgeable
Watching BaseballCount ordered sequences of A+B+C games with A X-wins, B Y-wins, C draws, total runs SX and SY, modulo 1e9+7.	Hard9	CombinatoricsMath+2	No attempts yet	8s	512 MB	Judgeable
Air PollutionEach operation at shop i adds p_i to its two neighbors and subtracts 2p_i from it; find the minimum number of operations so every p_i reaches at least l_i, or -1.	Hard9	MathGreedy+1	No attempts yet	2s	512 MB	Judgeable
Do use segment treeOn a weighted tree, support path assignment to a constant and path queries for the maximum sum of a non-empty contiguous subsequence along the path. n is up to 200,000 and q up to 100,000.	Hard9	Segment treeTree+2	No attempts yet	2s	512 MB	Judgeable
Entangled with LotteryGiven an amidakuji with some horizontal bars already placed, the cat adds K more bars at uniformly random distinct valid heights, and we must compute the maximum over starting bars of the probability that the path ends at the labeled winning bar.	Hard9	Dynamic programmingProbability+2	No attempts yet	2s	512 MB	Judgeable
Tiles are ColorfulOn an M by N grid, each letter appears exactly twice; a move taps an empty cell and removes matching tiles seen first in the four directions, and you want the maximum total tiles removed.	Hard9	SimulationDFS+2	No attempts yet	2s	512 MB	Judgeable
Carpenters' LanguageAfter each of q insertions of a run of '(' or ')' at a given position, decide whether the whole string is a well-formed sentence of the grammar S -> SS \| (S) \| )S( \| epsilon.	Hard9	StringStack+2	No attempts yet	1s	512 MB	Judgeable
Double Magic Made ClearGiven a graph of N elements with compatible pairs, orient each edge to define a spell logic, and maximize the number of ordered pairs (u,v) reachable as a first and last keyword of a valid spell.	Hard9	GraphTopological sort+2	No attempts yet	8s	512 MB	Judgeable
Webby SubwayGiven N polyline subway lines, each a chain of segments, find the minimum number of floors so that lines placed on the same floor have no intersecting or touching segments.	Hard9	GeometryGraph+2	No attempts yet	8s	512 MB	Judgeable
Exact ArithmeticSimulate a stack calculator over numbers of the form a/b plus c/d times sqrt(r), maintaining exact arithmetic and canonical output formatting.	Hard9	ImplementationSimulation+2	No attempts yet	8s	512 MB	Judgeable
Cut outGiven a convex polyhedron as polygonal faces, find the maximum area of its cross section by a plane perpendicular to the z-axis.	Hard9	GeometryMath+2	No attempts yet	8s	512 MB	Judgeable
Strange KeyDecide whether two descriptions of a 3D polyline key, each a set of paths of unit axis-parallel bars, define congruent shapes under rotation and translation.	Hard9	GraphGeometry+2	No attempts yet	2s	512 MB	Judgeable
Bridge Crossing GameTwo players own private sets of directed bridges; from each start island, decide who wins or whether the game never ends, with optimal play.	Hard9	GraphGame theory+2	No attempts yet	1s	1024 MB	Judgeable
Pillar and Wall Defense GameGiven pillars, the wall is the convex hull; each expansion ticket adds rotated pillars at angle a, and we choose the ticket order to maximize the final hull perimeter.	Hard9	GeometryBrute force+2	No attempts yet	1s	1024 MB	Judgeable
Setting an Exam ProblemCount the monotone paths through an N by N grid whose length 2N-1 value sequence has maximum subarray sum exactly K.	Hard9	Dynamic programmingPrefix sum+2	No attempts yet	1s	1024 MB	Judgeable
Slide CircuitsAfter each range-and-multiple enable or disable operation on slides, report the single disabled slide whose activation makes every building lie on exactly one directed cycle, or X if none does.	Hard9	GraphUnion-find+2	No attempts yet	Not set	1024 MB	Judgeable
Permutation CFGStarting from n and applying a permutation-defined CFG expansion s times, answer queries counting occurrences of integer k in a prefix of the resulting list.	Hard9	RecursionCombinatorics+2	No attempts yet	4s	2048 MB	Judgeable
Sinchon Sequence and QueriesMaintain a sequence under point updates, and for each type 2 query find the maximum sum of a contiguous interval containing position i whose every element is at least j.	Hard9	Segment treeDynamic programming+2	No attempts yet	2s	1024 MB	Judgeable
Sinchon Defense HeadquartersGiven N missile points, count the lattice points that lie in the convex hull of the missiles (including boundary) but are not shield locations.	Hard9	GeometryMath+2	No attempts yet	1.5s	1024 MB	Judgeable
Master of String ManipulationCount distinct strings reachable from S after exactly M single-letter increments (z stays z), modulo 1e9+7, with N up to 300 and M up to 1e18.	Hard9	Dynamic programmingCombinatorics+2	No attempts yet	2.5s	1024 MB	Judgeable
CyclePartition every vertex into vertex-disjoint simple cycles of minimum total weight in a directed weighted graph, and output the cycles.	Hard9	Dynamic programmingGraph+2	No attempts yet	2s	1024 MB	Judgeable
Binary OperatorGroup fully parenthesized expressions with +, * and an arbitrary binary operator # into equivalence classes that agree for every possible meaning of #, then output the lexicographically smallest class numbering.	Hard9	MathHash map+2	No attempts yet	20s	1024 MB	Judgeable
RMQFor each query, sum min times max over every subarray [i, j] with l <= i <= r and s <= j <= e, modulo 1e9+7, given a permutation A.	Hard9	Segment treePrefix sum+1	No attempts yet	3s	1024 MB	Judgeable
DiversityGiven an array and range queries, find the minimum total diversity of each range after its elements are reordered.	Hard9	Segment treeGreedy+1	No attempts yet	7s	512 MB	Judgeable
Calculate! 3Maintain a weighted tree under edge-weight updates and answer how many simple paths have XOR sum equal to a query value c, with weights bounded by 30.	Hard9	TreeBit manipulation+2	No attempts yet	2s	1024 MB	Judgeable
Pizzo CollectorsAssign a category to each '?' house on a cycle of length N (a prime power) and choose non-conflicting collectors, each walking a fixed stride, to maximize total pizzo.	Hard9	Number theoryMath+2	No attempts yet	2s	1024 MB	Judgeable
Tobacco GrowingConstruct a configuration of planted, grass, and flower tiles so that after at most 100 days the harvestable total equals a given N up to 10^18.	Hard9	Dynamic programmingCombinatorics+2	No attempts yet	2s	1024 MB	Judgeable
ScreamersGiven a fixed ordered list of edges and many interval queries, count how many contiguous subintervals of the queried slice form a forest (acyclic graph).	Hard9	GraphUnion-find+2	No attempts yet	2s	1024 MB	Judgeable
How to Move the BeansOn a cylindrical grid of dishes, Alice and Bob alternately move beans that may never return to their own previous squares; the task is to find the winner under optimal play.	Hard9	Game theoryGraph+1	No attempts yet	2s	512 MB	Judgeable
Kingdoms and QuarantineGiven a bipartite graph of roads between two kingdoms, find the most roads that can be closed under parity rules and print one valid closing order.	Hard9	MathGraph+1	No attempts yet	8s	512 MB	Judgeable
Crab's CannonGiven a subset of the palindromic prefix lengths of an unknown string of length l, find the minimum number of palindromic prefixes such a string can have.	Hard9	StringString matching+1	No attempts yet	3s	512 MB	Judgeable
ElephantsColor each of n elephants black or white so that every group's black and white counts differ by at most 1, or report -1 if no coloring exists.	Hard9	GraphMath	No attempts yet	3s	256 MB	Judgeable
Interval ShuffleGiven a sequence and m interval operations that each either add 1 to one cell or rearrange the range, find the maximum reachable value of each A_k.	Hard9	GreedySorting+1	No attempts yet	1s	256 MB	Judgeable
Magic BoxGiven a string, count pairs of intervals that spell the same text, grouped by how many squares the two intervals activate, for each count from 0 to n.	Hard9	String matchingString+1	No attempts yet	5s	512 MB	Judgeable
Directed Acyclic GraphGiven a DAG, apply assign or chmin updates to every node reachable from u, and answer point queries for individual node values.	Hard9	GraphTopological sort+1	No attempts yet	5s	512 MB	Judgeable
Swapping InversionsSort a permutation by repeatedly swapping a uniformly random adjacent inversion, where each swap costs the absolute difference of the two values; find the expected total cost modulo 1e9+7.	Hard9	ProbabilityCombinatorics+2	No attempts yet	1s	256 MB	Judgeable
Minimal Cyclic ShiftGiven n lengths of random lowercase strings, compute the expected number of answers that still match after the answers are written in a shifted order, modulo 998244353.	Hard9	StringNumber theory+2	No attempts yet	1.5s	256 MB	Judgeable
IntervalGiven n intervals and m queries [A,B], find the expected union length of intervals over a uniformly random sub-range [L,R] within [A,B], modulo 998244353.	Hard9	Divide and conquerSegment tree+2	No attempts yet	4s	512 MB	Judgeable
Nondeterministic Finite AutomatonBuild an n-state NFA over 0 and 1 so that the shortest string it cannot recognize is longer than 18 for n=6 and longer than 400 for n=20.	Hard9	GraphNumber theory+1	No attempts yet	1s	256 MB	Judgeable
The StruggleGiven an ellipse with integer coefficients, compute the sum of (x XOR y)^33 / (x^2 * y) modulo 1e9+7 over all lattice points inside it.	Hard9	Bit manipulationMath+1	No attempts yet	4.5s	512 MB	Judgeable
Power Station of ArtGiven two numbered, red-or-black colored copies of the same graph, decide whether repeated edge swaps can make both copies identical.	Hard9	GraphUnion-find+1	No attempts yet	3s	512 MB	Judgeable
GameKoishi and Satori take turns removing the left or right end of an array, with special sub-segments set as wins or losses; decide the winner of each query [a, b].	Hard9	Game theoryIntervals+1	No attempts yet	8s	512 MB	Judgeable
Goldberg Machine 2After each flip of one arrow in either grid, report the fewest tokens needed for both grids to reach the same arrow configuration, or -1.	Hard9	MathSegment tree+1	No attempts yet	2s	512 MB	Judgeable
MIPT: Connecting PeopleGiven n skyscrapers with floor counts and vertical travel costs, choose n-1 horizontal corridors that keep the city connected and minimize the sum of all pairwise resident travel times.	Hard9	Minimum spanning treeDivide and conquer+1	No attempts yet	2s	512 MB	Judgeable
The Last SamuraiDesign a board of at most 200 by 200 with rooks, bishops, and knights so the greedy king strategy makes more than 10^6 moves.	Hard9	GreedySimulation+1	No attempts yet	1s	512 MB	Judgeable
Rational DimasikGiven n fractions, compute the product, over all pairs, of the denominator of their difference written in lowest terms, modulo 998244353.	Hard9	Number theoryMath+2	No attempts yet	2s	512 MB	Judgeable
Lamb's RespiteFor each query, a champion starts at health x with Lamb's Respite clamping health to ceil(x/10) during actions l..r; report final health after all n actions, with point updates to a_i.	Hard9	Segment treeImplementation+2	No attempts yet	3s	1024 MB	Judgeable
Gene FoldingGiven a DNA string, repeatedly fold it at a point where the sequence reads the same in both directions, merging matching nucleotides, and report the shortest length reachable.	Hard9	StringString matching+2	No attempts yet	5s	2048 MB	Judgeable
Deer-Proof FenceGiven up to 9 points and a margin M, partition them into groups and fence each group with the shortest curve keeping distance at least M from every point, minimizing total length.	Hard9	GeometryBrute force+2	No attempts yet	2s	1024 MB	Judgeable
Video Quality - Auto (480p)Given up to 500 viewers with intervals and per-quality satisfaction, choose each viewer's quality over time so total satisfaction is maximized under a shared bandwidth cap.	Hard9	GreedyIntervals+2	No attempts yet	2s	512 MB	Judgeable
Island Nations of the Planet BilarbongMaintain a forest under edge deletions and insertions, where each nation's cities form a subgraph; report the number of connected components per nation after each update.	Hard9	GraphUnion-find+2	No attempts yet	0.75s	8 MB	Judgeable
Gets and Puts (Hard)Design a program that completes within one million execution steps, but the statement gives no task details beyond this limit.	Hard9	Implementation	No attempts yet	1s	1024 MB	Judgeable
QuackQuack (Hard)Within 100000 execution steps, compute an answer for a problem whose statement is missing from the prompt.	Hard9	Implementation	No attempts yet	1s	1024 MB	Judgeable
Kinking CablesBuild a non-self-intersecting polyline from (0,0) to (n,m) inside the room, with marked points at least 1 apart, whose total length is exactly a given value.	Hard9	GeometryImplementation+2	No attempts yet	1s	1024 MB	Judgeable
ShootingFind the minimum launch speed for a projectile under gravity that starts at the first polyline vertex, ends at the last, and stays above every vertex in between.	Hard9	GeometryMath+2	No attempts yet	1s	256 MB	Judgeable
Black and WhiteCount monotone lattice paths from (0,0) to (n,m) whose white-minus-black cell score to the left equals k, modulo 998244353.	Hard9	CombinatoricsMath	No attempts yet	1s	256 MB	Judgeable
Dirichlet k-th rootGiven g on 1..n over F_p with g(1)=1, find f with f(1)=1 such that the k-fold Dirichlet convolution of f equals g, or report no solution.	Hard9	Number theoryMath+2	No attempts yet	1s	256 MB	Judgeable
KingGiven a prime p and a sequence B, find the longest subsequence where each term is the previous term times a fixed q mod p, or print -1 if it is under half of n.	Hard9	Number theoryMath+1	No attempts yet	2s	256 MB	Judgeable
MoonGiven n fixed points on a unit sphere, find the probability that a uniformly random extra point lets all points fit inside one hemisphere.	Hard9	GeometryProbability+1	No attempts yet	2s	256 MB	Judgeable
PermutationCount the distinct permutations reachable from a given one by rearranging elements next to an interval's minimum at either end, modulo 998244353.	Hard9	Dynamic programmingCombinatorics	No attempts yet	1s	256 MB	Judgeable