Math and counting

Number theory, combinatorics, and geometry

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Still being built. Things may change

Total results13,152 problems

Chair Dance
Hard8
Simulation, Number theory+1
No attempts yet
Time limit
8s
Memory limit
1024 MB
Judgeable
Galaxy Quest
Hard8
Shortest path, Dynamic programming+1
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
NL-Queen (mod N)
Hard8
Math, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Queens' Rye Cafe
Hard8
Number theory, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
N-Queen (Area)
Hard8
Backtracking, Geometry+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Coffee Milk
Hard8
Math, Geometry+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Ferris Wheel
Hard8
Combinatorics, Math+1
No attempts yet
Time limit
6s
Memory limit
1024 MB
Judgeable
Liquid Distribution
Hard8
Geometry, Graph+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Probing the Disk
Hard8
Geometry, Binary search+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
\sqrt{f}(x)
Hard8
Math, Number theory+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Derivatives of Polynomials and Remainders
Hard8
Math, Number theory+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Split the SSHS 2
Hard8
Graph, DFS+1
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Coloring Cards 2
Hard8
Combinatorics, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Random Shuffle
Hard8
Bit manipulation, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Five-pointed Queries
Hard8
Geometry, Combinatorics+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Hash Function
Hard8
Bit manipulation, Math+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Nonsense
Hard8
Math, Combinatorics
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Number Theory
Hard8
Number theory, Math+1
No attempts yet
Time limit
7s
Memory limit
1024 MB
Judgeable
Captivating process
Hard8
Graph, Number theory+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Buy and Delete
Hard8
Graph, Game theory+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Primes and XOR? Nonsense
Hard8
Number theory, Bit manipulation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Many LCS
Hard8
Combinatorics, Dynamic programming+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Median
Hard8
Divide and conquer, Dynamic programming+1
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Ancient Magic Circle in Teyvat
Hard8
Graph, Combinatorics
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Teleporters
Hard8
Number theory, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Opening Offices
Hard8
Tree, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Divide and Rule 2.0
Hard8
Number theory, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Connected dominating set
Hard8
Graph, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Hedgehog Graph 2
Hard8
Implementation, Math+1
No attempts yet
Time limit
2.5s
Memory limit
1024 MB
Judgeable
New Product Development
Hard8
Graph, Sorting+2
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Random Road
Hard8
Dynamic programming, Tree+2
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Missing Number
Hard8
String, Implementation+1
No attempts yet
Time limit
2s
Memory limit
2048 MB
Judgeable
Domino on Torus
Hard8
Combinatorics, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Inverse KMP
Hard8
String matching, Combinatorics
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Random Spanning Tree
Hard8
Minimum spanning tree, Math+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Tri-color Spanning Tree
Hard8
Graph, Matrix+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Dividing an orange
Hard8
Game theory, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Quadruples of Points
Hard8
Geometry, Hash map+1
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
In-order
Hard8
Tree, Divide and conquer+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
1D Stone Game 2
Hard8
Game theory, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
I hate even numbers
Hard8
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Merging Cells
Hard8
Dynamic programming, Divide and conquer+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Cowmpetency
Hard8
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Eggplant Field Path
Hard8
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Eggplant Summoning Magic
Hard8
Geometry, Math+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Target Practice II
Hard8
Geometry, Binary search+2
No attempts yet
Time limit
2.5s
Memory limit
1024 MB
Judgeable
Moorbles
Hard8
Dynamic programming, Game theory+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Pirate Code
Hard8
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Coins
Hard8
Game theory, Combinatorics+1
No attempts yet
Time limit
25s
Memory limit
1024 MB
Judgeable
Fish 3
Hard8
Greedy, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Fair Distribution
Hard8
Dynamic programming, Number theory+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Activating Robots
Hard8
Greedy, Binary search+2
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Yunny's Trip
Hard8
Math, Number theory+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Hula's Cardgame
Hard8
Game theory, Graph+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Carl's Vacation
Hard8
Geometry, Shortest path+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Three Kinds of Dice
Hard8
Probability, Sorting+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Strange Tree Hashing
Hard8
Tree, Math+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Farm Land Split
Hard8
Geometry, Segment tree+1
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
1D Game
Hard8
Shortest path, Graph+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Champernowne Substring
Hard8
Dynamic programming, String+2
No attempts yet
Time limit
10s
Memory limit
2048 MB
Judgeable
Square of Triangles
Hard8
Geometry, Math+1
No attempts yet
Time limit
5s
Memory limit
2048 MB
Judgeable
Binary Tree
Hard8
Tree, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Tiles
Hard8
Dynamic programming, Geometry
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Mineral deposits
Hard8
Math, Geometry+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Sequence
Hard8
Dynamic programming, Shortest path+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Chessboard
Hard8
Combinatorics, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Land
Hard8
Divide and conquer, Union-find+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Magic Show
Hard8
Graph, Math+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
City Hall
Hard8
Shortest path, Graph+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Cursed Game
Hard8
Bit manipulation, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Grid Game 2
Hard8
Game theory, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Five
Hard8
Segment tree, Matrix+1
No attempts yet
Time limit
0.7s
Memory limit
1024 MB
Judgeable
Magic Orbs
Hard8
Array, Simulation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Seongho and Dusan
Hard8
Tree, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
What Happens When All the Branches Fall From a Tree?
Hard8
Tree, Game theory+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
What if Jaewoo, who cannot eat spicy food, eats bibim naengmyeon?
Hard8
Probability, Math+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
At Last, Coprime
Hard8
Math, Number theory+1
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Equal remainders
Hard8
Number theory, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Board Game
Hard8
Game theory, Segment tree+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Natural Number Streamer
Hard8
String, String matching+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Treasure
Hard8
Implementation, Math+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Message
Hard8
Bit manipulation, Math+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Red and Blue Dots 2
Hard8
Dynamic programming, Geometry+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
정다각형을 만들어요
Hard8
Dynamic programming, Tree+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Make the remainder
Hard8
Math, Number theory+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Password Protection
Hard8
String matching, Combinatorics+1
No attempts yet
Time limit
8s
Memory limit
1024 MB
Judgeable
Bingo for the Win!
Hard8
Probability, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Tower of noiHa
Hard8
Bit manipulation, Recursion+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Circle Passing
Hard8
Graph, Shortest path+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Piece Game
Hard8
Game theory, Segment tree+1
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
LEX_GCD
Hard8
Number theory, Greedy+1
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Balatro
Hard8
Dynamic programming, Sorting+2
No attempts yet
Time limit
12s
Memory limit
1024 MB
Judgeable
Fractal Area
Hard8
Geometry, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Curious Jury
Hard8
Combinatorics, Prefix sum+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Geunsoo's Maze Game
Hard8
Game theory, Graph+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Repeating Number
Hard8
Math, Number theory+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Marks
Hard8
Combinatorics, Number theory+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Knight Polygon
Hard8
Geometry, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Tree With One Edge
Hard8
Tree, Game theory+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Ring Out
Hard8
Probability, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Chair DancePlayers on n chairs move by +x or *x (mod n) each command, and the shortest clockwise traveler keeps a contested chair; answer who sits on each queried chair.	Hard8	SimulationNumber theory+1	No attempts yet	8s	1024 MB	Judgeable
Galaxy QuestFor each query, find the least fuel needed to fly from planet 1 to a target planet within a time limit, where each highway's fuel cost depends on how long the trip takes.	Hard8	Shortest pathDynamic programming+1	No attempts yet	5s	1024 MB	Judgeable
NL-Queen (mod N)Place N queens on an N by N board whose opposite edges connect, so none attack each other, and print one placement that is not k-linear, or -1 if impossible.	Hard8	MathImplementation	No attempts yet	2s	1024 MB	Judgeable
Queens' Rye CafeGiven a fraction a/b in the Farey sequence of order N, find the fraction j positions after it, with N up to 10^18 and j up to 2 times 10^7.	Hard8	Number theoryGreedy+1	No attempts yet	2s	1024 MB	Judgeable
N-Queen (Area)Place N non-attacking queens on an N by N grid warped inside a convex quadrilateral to maximize the total area of the occupied cells.	Hard8	BacktrackingGeometry+1	No attempts yet	1s	1024 MB	Judgeable
Coffee MilkGiven a tetrahedron with integer vertices and N scale factors K, count the lattice points on its surface and inside it for each K, modulo 1003003001.	Hard8	MathGeometry+1	No attempts yet	3s	1024 MB	Judgeable
Ferris WheelCount colorings of 2n gondolas on a circle with k colors that allow a non-crossing pairing of same-colored gondolas, modulo 998244353, up to rotation.	Hard8	CombinatoricsMath+1	No attempts yet	6s	1024 MB	Judgeable
Liquid DistributionDecide whether pouring the mixed bottles together can produce exactly the amounts of liquids A and B each institute requires.	Hard8	GeometryGraph+1	No attempts yet	2s	1024 MB	Judgeable
Probing the DiskFind the integer center and radius of a hidden disk in a 10^5 by 10^5 square by probing with segments and reading the lit chord length.	Hard8	GeometryBinary search+1	No attempts yet	2s	1024 MB	Judgeable
\sqrt{f}(x)Given an integer polynomial f, find a polynomial g with coefficients from -100 to 100 such that g(g(x)) = f(x), or report -1.	Hard8	MathNumber theory+1	No attempts yet	1s	1024 MB	Judgeable
Derivatives of Polynomials and RemaindersCount the coefficient sequences c of degree at most n with entries in [a, b] whose k-th derivative has coefficients matching s mod m, and print the lexicographically smallest one.	Hard8	MathNumber theory+1	No attempts yet	1s	1024 MB	Judgeable
Split the SSHS 2Count the sets of three buildings such that deleting all roads among them leaves some two buildings unable to reach each other.	Hard8	GraphDFS+1	No attempts yet	1.5s	1024 MB	Judgeable
Coloring Cards 2Given the colors of the first row of an N by N grid, sum the number of white patterns over all valid colorings where diagonals match and every row has the same white count.	Hard8	CombinatoricsDynamic programming+1	No attempts yet	1s	1024 MB	Judgeable
Random ShuffleGiven n and the permutation produced by a xorshift-based Fisher-Yates shuffle, find a 64-bit seed x that generates that exact output.	Hard8	Bit manipulationMath	No attempts yet	1s	1024 MB	Judgeable
Five-pointed QueriesTowers form a convex k-gon; toggle subscribers' activity and count active ones inside the inner pentagon of a five-tower star.	Hard8	GeometryCombinatorics+1	No attempts yet	3s	1024 MB	Judgeable
Hash FunctionGiven n and H, find a 2n-bit number A such that the XOR-and-modular hash h_n(A) equals H.	Hard8	Bit manipulationMath+1	No attempts yet	3s	1024 MB	Judgeable
NonsenseGiven n, x, y, compute for each query (a, b) the sum over i of C(i,a) x^(i-a) C(n-i,b) y^(n-i-b) modulo 998244353.	Hard8	MathCombinatorics	No attempts yet	1s	1024 MB	Judgeable
Number TheoryGiven a huge integer n, write it as an integer combination of repunits o_i (the number with i ones) so that the sum of i times \|x_i\| is minimized.	Hard8	Number theoryMath+1	No attempts yet	7s	1024 MB	Judgeable
Captivating processGiven functions f and g on 1 to N, for each query (x, y) decide whether applying both functions in lockstep ever makes the two values equal.	Hard8	GraphNumber theory+1	No attempts yet	4s	1024 MB	Judgeable
Buy and DeleteAlice buys directed edges with total price at most c so that Bob needs as many acyclic deletion rounds as possible to remove every edge.	Hard8	GraphGame theory+1	No attempts yet	2s	1024 MB	Judgeable
Primes and XOR? NonsenseGiven L and R up to 1e12, count the integers that can be formed as the XOR of some subset of the primes in [L, R].	Hard8	Number theoryBit manipulation+1	No attempts yet	2s	1024 MB	Judgeable
Many LCSGiven K, construct two binary strings of length at most 8848 that have exactly K distinct longest common subsequences.	Hard8	CombinatoricsDynamic programming+1	No attempts yet	4s	1024 MB	Judgeable
MedianCount the ways to fill the unknown values in a sequence so that the recursive three-way magicThrees procedure returns the true median, modulo 10^9 + 7.	Hard8	Divide and conquerDynamic programming+1	No attempts yet	5s	1024 MB	Judgeable
Ancient Magic Circle in TeyvatGiven a complete graph on n vertices with m red edges, find the absolute difference between the number of all-red 4-cliques and all-blue 4-cliques.	Hard8	GraphCombinatorics	No attempts yet	2s	1024 MB	Judgeable
TeleportersGiven teleporters with frequencies in [L, R], find the minimum possible maximum frequency gap for Anna and Beka to meet, or report that they cannot.	Hard8	Number theoryMath+1	No attempts yet	2s	1024 MB	Judgeable
Opening OfficesCount the ways to choose T office buildings on a grid so that the shortest closed tour is the same on the full grid and on the night spanning tree, modulo 1000000007.	Hard8	TreeDynamic programming+1	No attempts yet	1s	1024 MB	Judgeable
Divide and Rule 2.0Given an array of distinct values, count the positions in each query range [l, r] whose value divides d or is a multiple of d.	Hard8	Number theoryPrefix sum+1	No attempts yet	1s	1024 MB	Judgeable
Connected dominating setGiven an n by m grid graph, output a connected dominating set of at most nm/2 cells, or print NO if none exists.	Hard8	GraphMath+1	No attempts yet	2s	1024 MB	Judgeable
Hedgehog Graph 2Given up to 10 functional graphs shaped like a cycle with trees of depth 1, find each cycle length using at most 900 queries that jump x steps from a chosen vertex.	Hard8	ImplementationMath+1	No attempts yet	2.5s	1024 MB	Judgeable
New Product DevelopmentGiven a graph where edges unlock by a counter threshold, simulate K steps from vertex 1 and print the final vertex and counter modulo 1000000007.	Hard8	GraphSorting+2	No attempts yet	1.5s	1024 MB	Judgeable
Random RoadGiven a tree with park beauties and randomly oriented one-way snake edges, find the expected beauty of a safe random walk from each starting park, modulo 1e9+7.	Hard8	Dynamic programmingTree+2	No attempts yet	3s	1024 MB	Judgeable
Missing NumberGiven the digits of consecutive integers from a to b joined together with one integer removed, list every value that could have been the eaten number.	Hard8	StringImplementation+1	No attempts yet	2s	2048 MB	Judgeable
Domino on TorusCount the valid white-black domino tilings of the outer surface of an A by B torus with a C by D rectangular hole cut out.	Hard8	CombinatoricsMath	No attempts yet	2s	1024 MB	Judgeable
Inverse KMPGiven a string's KMP prefix-function array and the alphabet size c, count the strings that produce that array, modulo 1e9+7.	Hard8	String matchingCombinatorics	No attempts yet	1s	1024 MB	Judgeable
Random Spanning TreeGiven a small connected graph with random uniform edge weights, the task is to compute the exact expected MST weight as a reduced fraction p/q.	Hard8	Minimum spanning treeMath+2	No attempts yet	1s	1024 MB	Judgeable
Tri-color Spanning TreeCount spanning trees of a three-colored graph with at most g green and at most b blue edges, modulo 1e9+7, for n up to 40.	Hard8	GraphMatrix+1	No attempts yet	2s	1024 MB	Judgeable
Dividing an orangeFor each wildcard rank, find the minimum and maximum number of oranges that person can get in the ranked voting game with n people and k oranges.	Hard8	Game theoryMath+1	No attempts yet	1s	1024 MB	Judgeable
Quadruples of PointsGiven n sets of four points and m axis-parallel rectangles, decide for each rectangle whether it contains exactly half of the points in every set.	Hard8	GeometryHash map+1	No attempts yet	5s	1024 MB	Judgeable
In-orderCount the distinct in-order traversals of binary trees matching given pre-order, post-order, and partial in-order lists, modulo 999999937.	Hard8	TreeDivide and conquer+1	No attempts yet	1s	1024 MB	Judgeable
1D Stone Game 2Two players take turns removing consecutive stones from a 1 by n row, with the move size capped by the previous move, and the task is to find the winner for each n.	Hard8	Game theoryMath+1	No attempts yet	1s	1024 MB	Judgeable
I hate even numbersFill an N by N grid with stones so every a by b rectangle with area K holds an odd number of stones, or report -1 if impossible.	Hard8	MathNumber theory+2	No attempts yet	1s	1024 MB	Judgeable
Merging CellsGiven N cells in a row with sizes, adjacent cells merge at random until one remains, and the task is to find the probability each original label ends as the winner modulo 1e9+7.	Hard8	Dynamic programmingDivide and conquer+1	No attempts yet	2s	1024 MB	Judgeable
CowmpetencyCount the score sequences of N cows, each score from 1 to C, that satisfy each pair where cow h is the first with a score above cows 1 through a, modulo 10^9+7.	Hard8	Dynamic programmingCombinatorics+1	No attempts yet	2s	1024 MB	Judgeable
Eggplant Field PathCount the distinct ways a monotone lattice path from (0,0) to (R,C) can split the planted branches into upper and lower sets without touching any branch.	Hard8	Dynamic programmingCombinatorics+1	No attempts yet	1s	1024 MB	Judgeable
Eggplant Summoning MagicGiven N integer points in 3D, pick a structure-preserving map and M of the points that become a regular M-gon, maximizing N times M.	Hard8	GeometryMath+1	No attempts yet	4s	1024 MB	Judgeable
Target Practice IIAssign each of the 4N cows on the y-axis to a distinct target vertex so no shot crosses a target interior, minimizing the largest distance between cows.	Hard8	GeometryBinary search+2	No attempts yet	2.5s	1024 MB	Judgeable
MoorblesGiven N marbles and M turns with K possible bets per turn, find the lexicographically smallest Even/Odd guess sequence that keeps Elsie from losing, or print -1.	Hard8	Dynamic programmingGame theory+1	No attempts yet	2s	1024 MB	Judgeable
Pirate CodeFor each length k up to n, sum the decoded values of all binary codes of length k under Fibonacci pirate splitting, modulo 10^9+7.	Hard8	Dynamic programmingCombinatorics+1	No attempts yet	2s	1024 MB	Judgeable
CoinsCount the ways to add stacks of blue and red coins so that the whole row is a second-player win, for each total stack count from k to n.	Hard8	Game theoryCombinatorics+1	No attempts yet	25s	1024 MB	Judgeable
Fish 3For each range of fish, find the fewest type A foods needed to match the target intelligence values, or -1 if the targets cannot be reached.	Hard8	GreedyMath+1	No attempts yet	2s	1024 MB	Judgeable
Fair DistributionGiven N buildings with ground height G and residential floor height R, decide whether they can be split between two children so each child's total height is equal.	Hard8	Dynamic programmingNumber theory+1	No attempts yet	1s	1024 MB	Judgeable
Activating RobotsGiven a circle of length L and activation points, find the minimum time for you and robots moving at speed 1/K to form R equally spaced robots.	Hard8	GreedyBinary search+2	No attempts yet	5s	1024 MB	Judgeable
Yunny's TripFind the minimum stamina needed to walk from (0, 0) to (Ex, Ey) with unit moves (cost 1) and repeatable item vectors (cost 2), never dropping below 0.	Hard8	MathNumber theory+1	No attempts yet	2s	512 MB	Judgeable
Hula's CardgameGiven tables whose three cards point to tables at or above their own number, decide for each E whether Geunsu can reach table E while Seunghyeong deletes one card per move.	Hard8	Game theoryGraph+1	No attempts yet	2s	512 MB	Judgeable
Carl's VacationFind the shortest walk between the apexes of two right square pyramids, moving only on their faces and the ground plane.	Hard8	GeometryShortest path+1	No attempts yet	1s	1024 MB	Judgeable
Three Kinds of DiceGiven two dice where the first beats the second, find a third die that ties or beats the first and report the lowest score it can get against the second, and the reverse bound.	Hard8	ProbabilitySorting+2	No attempts yet	1s	1024 MB	Judgeable
Strange Tree HashingGiven a target root hash h, output two non-isomorphic rooted trees whose root hash under H(K) = 2^(product of child hashes) equals h, or -1 if none exist.	Hard8	TreeMath+2	No attempts yet	1s	1024 MB	Judgeable
Farm Land SplitPick a rectangle and split it into two rectangles so no farm lies on a boundary, maximizing the total of both satisfaction sums.	Hard8	GeometrySegment tree+1	No attempts yet	5s	1024 MB	Judgeable
1D GameFind the earliest turn at which the character can reach cell L without standing on a temporary platform during a dangerous turn, where dangerous turns repeat every T turns.	Hard8	Shortest pathGraph+1	No attempts yet	2s	1024 MB	Judgeable
Champernowne SubstringFill each ? in the pattern with a digit to minimize the index where it first appears in the Champernowne string, printed mod 998244353.	Hard8	Dynamic programmingString+2	No attempts yet	10s	2048 MB	Judgeable
Square of TrianglesGiven the squared side lengths of four triangles, decide whether they can be rearranged without gaps or overlaps into a square.	Hard8	GeometryMath+1	No attempts yet	5s	2048 MB	Judgeable
Binary TreeFor each tree T_i built by joining two earlier trees, sum the fewest subtrees needed to cover each contiguous leaf range exactly.	Hard8	TreeDynamic programming+1	No attempts yet	1s	1024 MB	Judgeable
TilesGiven a simple axis-aligned polygon, find the largest k at most M such that the part left of x = k can be covered by non-overlapping 2 by 2 tiles.	Hard8	Dynamic programmingGeometry	No attempts yet	2s	1024 MB	Judgeable
Mineral depositsLocate k hidden deposits in a grid of half-width b using probe waves that return Manhattan distances, with as few waves as possible.	Hard8	MathGeometry+1	No attempts yet	2s	1024 MB	Judgeable
SequenceGiven a weight for each value from 1 to n, find for every v the minimum total weight of a good sequence that contains v.	Hard8	Dynamic programmingShortest path+1	No attempts yet	1s	1024 MB	Judgeable
ChessboardCount the pairs of non-meeting lattice paths from (1,1) to (N,M) on a board with K forbidden cells, where the first moves are fixed, modulo 1e9+7.	Hard8	CombinatoricsDynamic programming+1	No attempts yet	2s	512 MB	Judgeable
LandLines with coefficients in {-1,0,1} are added online, and for each query the task is to tell whether two points lie in the same region of the plane cut by all lines so far.	Hard8	Divide and conquerUnion-find+1	No attempts yet	2s	1024 MB	Judgeable
Magic ShowAlice must build a tree on n vertices so that Bob, given the tree after Catherine removes up to (n-2)/2 edges, can recover a number X up to 10^18.	Hard8	GraphMath+1	No attempts yet	1s	2048 MB	Judgeable
City HallGiven a weighted graph where edge cost is the squared altitude difference, find the minimum path energy from S to T after raising or lowering one vertex's altitude freely.	Hard8	Shortest pathGraph+2	No attempts yet	2s	1024 MB	Judgeable
Cursed GameFind the hidden set of holes in a secret 3x3 paper using parity queries on an N x N grid, with only 3 coins per round.	Hard8	Bit manipulationMath+1	No attempts yet	2s	1024 MB	Judgeable
Grid Game 2Given N black cells on a huge grid, each move toggles a square anchored at the chosen cell, and the task is to decide whether the first player wins under optimal play.	Hard8	Game theoryMath+1	No attempts yet	2s	1024 MB	Judgeable
FiveGiven an array, answer range queries for the sum of x at indices a_i modulo 10^8+543, and add a value to a_i over a range.	Hard8	Segment treeMatrix+1	No attempts yet	0.7s	1024 MB	Judgeable
Magic OrbsOrbs dropped on zone 1 roll right past strictly lower zones and raise the zone where they stop; report zone 1's value after each batch.	Hard8	ArraySimulation+1	No attempts yet	1s	1024 MB	Judgeable
Seongho and DusanPlayers alternately remove leaves from their own trees, and the removed marble's color picks the next player. Find the min and max marbles left at the end.	Hard8	TreeGreedy+1	No attempts yet	1s	1024 MB	Judgeable
What Happens When All the Branches Fall From a Tree?Two players take turns removing a root-to-vertex path from a tree, and a Nim game on the removed stones decides each turn. The task is to find the winner.	Hard8	TreeGame theory+2	No attempts yet	1s	1024 MB	Judgeable
What if Jaewoo, who cannot eat spicy food, eats bibim naengmyeon?Find the probability that after K random picks of member ingredient sets, every ingredient total is a multiple of its S_i.	Hard8	ProbabilityMath+2	No attempts yet	1s	1024 MB	Judgeable
At Last, CoprimeGiven N up to 10^11, sum i+j over all pairs (i, j) with 1 to N that are coprime, and output the result modulo 10^9+7.	Hard8	MathNumber theory+1	No attempts yet	5s	1024 MB	Judgeable
Equal remaindersGiven N distinct integers A and a value K, find the smallest positive M so that s^K lies in S(A^M) for every s in S(A), modulo 1e9+7, or -1.	Hard8	Number theoryMath	No attempts yet	1s	1024 MB	Judgeable
Board GameGiven two N by M grids of A and B cards, find who wins the alternating column-removal game at the start and after each of Q card swaps.	Hard8	Game theorySegment tree+2	No attempts yet	1s	1024 MB	Judgeable
Natural Number StreamerGiven a binary string, find the longest substring that is the concatenation of consecutive binary numbers starting from some l.	Hard8	StringString matching+1	No attempts yet	3s	1024 MB	Judgeable
TreasureEncode N distinct 2D integer points as a shuffled multiset of non-negative integers up to 2e9 using as few numbers as possible, then decode them.	Hard8	ImplementationMath+1	No attempts yet	3s	1024 MB	Judgeable
MessageAisha must send a bit message through 31-bit packets where Cleopatra flips 15 hidden positions, and Basma must recover the message from the tainted packets.	Hard8	Bit manipulationMath+1	No attempts yet	3s	1024 MB	Judgeable
Red and Blue Dots 2Given N points on a circle, each red or blue, find the fewest crossing pairs among same-color chords that touch every point at least once.	Hard8	Dynamic programmingGeometry+1	No attempts yet	1s	1024 MB	Judgeable
정다각형을 만들어요Count vertex sets of size 2 or more in a tree where exactly one vertex is equidistant from every chosen vertex, modulo 10^9+7.	Hard8	Dynamic programmingTree+2	No attempts yet	2s	1024 MB	Judgeable
Make the remainderFind hidden N and M by querying X and receiving the distance from N to its nearest multiple of X, taken mod M, using at most 100 queries.	Hard8	MathNumber theory+1	No attempts yet	1s	1024 MB	Judgeable
Password ProtectionCount length-n lowercase strings that contain the first name or the last name as a contiguous substring, modulo 1,000,000,007.	Hard8	String matchingCombinatorics+1	No attempts yet	8s	1024 MB	Judgeable
Bingo for the Win!Given each player's bingo sheet and a uniformly random calling order, find the probability that each player is the last to finish under Speed Bingo rules.	Hard8	ProbabilityCombinatorics+2	No attempts yet	1s	1024 MB	Judgeable
Tower of noiHaGiven n disks and k optimal Hanoi moves already made, find the fewest valid moves to finish after the son moves the whole stack in one move. Both k and the answer are binary.	Hard8	Bit manipulationRecursion+1	No attempts yet	1s	1024 MB	Judgeable
Circle PassingGiven 2N students in a circle with best-friend pairs placed directly opposite each other, find the fewest passes needed to move the ball from student x to student y for each query.	Hard8	GraphShortest path+1	No attempts yet	2s	1024 MB	Judgeable
Piece GameGiven an integer array with distinct values and a move limit D, answer whether the first player wins a piece game under optimal play, with point updates to the array.	Hard8	Game theorySegment tree+1	No attempts yet	1.5s	1024 MB	Judgeable
LEX_GCDFind the lexicographically smallest permutation that is K-gcd equivalent to a sequence, after optionally multiplying one element by a prime X.	Hard8	Number theoryGreedy+1	No attempts yet	1.5s	1024 MB	Judgeable
BalatroPick a subsequence of add and multiply cards, using at most k multiply cards, to maximize the final score for each length up to n.	Hard8	Dynamic programmingSorting+2	No attempts yet	12s	1024 MB	Judgeable
Fractal AreaGiven a generator polyline from (0,0) to (1,0), compute the area of the fractal built by recursively replacing each side of an equilateral triangle with scaled copies of it.	Hard8	GeometryMath+1	No attempts yet	1s	1024 MB	Judgeable
Curious JurySum the number of fixed points (rank equals penalty) over all 2^n ways to pick each team's last-submit or sum-of-submits penalty, modulo 1e9+7.	Hard8	CombinatoricsPrefix sum+1	No attempts yet	3s	1024 MB	Judgeable
Geunsoo's Maze GameGeunsoo walks a grid maze while Seunghyeong blocks one direction each turn; find the fewest turns to a goal under optimal play, or -1 if he cannot win.	Hard8	Game theoryGraph+1	No attempts yet	2s	1024 MB	Judgeable
Repeating NumberCount the K-repeating numbers in [A, B] that are divisible by M, where a K-repeating number is a periodic prefix of a repeated K-digit block.	Hard8	MathNumber theory+1	No attempts yet	1s	1024 MB	Judgeable
MarksFor each round with W and B, count the marks with an odd number of white squares and those with an even number, then print the winner and the difference modulo 1234543.	Hard8	CombinatoricsNumber theory+1	No attempts yet	1s	512 MB	Judgeable
Knight PolygonGiven integers p and q, find a simple lattice polygon whose edges are all knight moves and whose area is p/q, or print -1 if none exists.	Hard8	GeometryMath+1	No attempts yet	1s	1024 MB	Judgeable
Tree With One EdgeGiven a rooted tree, count the directed pairs (u, v) where adding one edge u to v lets Alice win the token game where players move token down to children.	Hard8	TreeGame theory+1	No attempts yet	1s	1024 MB	Judgeable
Ring OutFor each staff member, sum over rounds the probability that two or more of their balls come out consecutively when all balls in the round's range are shuffled and drawn.	Hard8	ProbabilityCombinatorics+2	No attempts yet	1s	1024 MB	Judgeable