Problems

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Total results29,440 problems

Number of Trees
Medium7
Tree, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Cowntact Tracing
Medium7
Tree, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Flight Routes
Medium7
Dynamic programming, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Cycle Correspondence
Medium7
Array, String matching+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Balanced Grades
Medium7
Segment tree, Sorting
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Ramen Delivery
Medium7
Tree, DFS+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Rectangle Flip 2
Medium7
Matrix, Simulation
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Square
Medium7
Number theory, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Emperor's Palace
Medium7
Matrix, Prefix sum+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Game Theory
Medium7
Segment tree, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Stringology
Medium7
String, String matching
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
3D Geometry
Medium7
Geometry, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Scalar Product
Medium7
Geometry, Math+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Numeral systems
Medium7
Backtracking, Number theory
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
A Hero Named Magnus
Medium7
Math, Probability
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
A Plus B Problem
Medium7
Segment tree, Math+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Assumption is all you need
Medium7
Array, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Occupy the Cities
Medium7
String, Binary search+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
PTSD
Medium7
Greedy, Dynamic programming
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Counting Phenomenal Arrays
Medium7
Math, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Flood Fill
Medium7
Graph, BFS+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Colourful Permutation Sorting
Medium7
Bit manipulation, Graph+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Babushka and her pierogi
Medium7
Greedy, Sorting+1
No attempts yet
Time limit
6s
Memory limit
1024 MB
Judgeable
Epidemic
Medium7
Union-find, Implementation+1
No attempts yet
Time limit
9s
Memory limit
1024 MB
Judgeable
Interesting Numbers
Medium7
Bit manipulation, Trie+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Xingqiu's Joke
Medium7
Number theory, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Phenomenal Frano
Medium7
Graph, Union-find
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Stretchy Rubber Band
Medium7
Geometry, Linked list+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Lazy Cows
Medium7
Divide and conquer, Segment tree+1
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Tree Search
Medium7
Tree, Binary search+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Team Building
Medium7
Greedy, Segment tree+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Around the World
Medium7
Dynamic programming, Geometry+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Folding a Cactus
Medium7
Graph, DFS+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
String Telephone
Medium7
Math, Number theory+1
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
Three Kingdoms
Medium7
Tree, DFS+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Convex Polygons
Medium7
Array, Two pointers+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Driving Test Track
Medium7
Math, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Planting Flags
Medium7
Greedy, Binary search+2
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Virtual Verification
Medium7
Math, Implementation+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Stop the overtime!!!
Medium7
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Supply Procurement
Medium7
Shortest path, Graph+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Vrsar
Medium7
Sorting, Greedy+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Fruit Game
Medium7
Segment tree, Dynamic programming
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
LR
Medium7
Greedy, String+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Removing Vertices
Medium7
Dynamic programming, Tree+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Two Paths
Medium7
Graph, Shortest path+1
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Digit Translation
Medium7
String, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
String
Medium7
String matching, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Big Bed
Medium7
Graph, BFS+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Triangles
Medium7
Geometry, Sorting+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Swimming
Medium7
Math, Geometry
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Faster Than Light
Medium7
Geometry, Sorting+1
No attempts yet
Time limit
6s
Memory limit
1024 MB
Judgeable
Maze in a Forest
Medium7
Graph, DFS+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Grammar
Medium7
Dynamic programming, Graph+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Chessboard Game
Medium7
Game theory, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Walls
Medium7
Minimum spanning tree, Union-find+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Survival Route
Medium7
Geometry, Graph+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Dispersed parentheses
Medium7
Dynamic programming, String+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Chocolate triangles
Medium7
Dynamic programming, Combinatorics
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
LWDB
Medium7
Tree, Divide and conquer
No attempts yet
Time limit
9s
Memory limit
1024 MB
Judgeable
Ceizenpok's formula
Medium7
Math, Number theory+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Add and Reverse
Medium7
Bit manipulation, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Physical Education
Medium7
Math, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Aris, Let's Clean! (Hard)
Medium7
Simulation, Implementation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Set Expression Transpiler
Medium7
Recursion, String+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Tree Explorer (Hard)
Medium7
Tree, DFS+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Decontamination Operation
Medium7
Sorting, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Hosting the Contest
Medium7
Two pointers, Sliding window+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Supply Warehouse Cleanup
Medium7
Binary search, Greedy+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Pancake Flipping
Medium7
Simulation, String+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
GCD Game
Medium7
Game theory, Number theory+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Road Network Management and Queries in Sinchon
Medium7
Minimum spanning tree, Union-find+1
No attempts yet
Time limit
2.5s
Memory limit
1024 MB
Judgeable
Linear Algebra: Concepts and Methods
Medium7
Math, Number theory+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Search Game
Medium7
Dynamic programming, Prefix sum
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Good Sequence
Medium7
Array, Prefix sum+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Almond Chocolate
Medium7
Combinatorics, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Chocolate and ㄱ나이트 Game (Bitter)
Medium7
Math, Graph+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Flag Performance
Medium7
Combinatorics, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Nicest view
Medium7
Array, Stack+1
No attempts yet
Time limit
0.25s
Memory limit
1024 MB
Judgeable
Table Legs
Medium7
Geometry, Sorting+1
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
Throwing dice
Medium7
Probability, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Multiplication in Base N (HUGE)
Medium7
String, Math+1
No attempts yet
Time limit
10s
Memory limit
1024 MB
Judgeable
Cramming for Finals
Medium7
Geometry, Sorting+1
No attempts yet
Time limit
4s
Memory limit
2048 MB
Judgeable
Eccentric Excursion
Medium7
Tree, Greedy+1
No attempts yet
Time limit
6s
Memory limit
2048 MB
Judgeable
Segment Drawing
Medium7
Geometry, Greedy+1
No attempts yet
Time limit
5s
Memory limit
2048 MB
Judgeable
Tournament Matchmaking
Medium7
Graph, Bit manipulation
No attempts yet
Time limit
3s
Memory limit
2048 MB
Judgeable
Diverse Contest
Medium7
Bit manipulation, Combinatorics+1
No attempts yet
Time limit
10s
Memory limit
2048 MB
Judgeable
I Hate Going to Work 2
Medium7
Combinatorics, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Extreme Multiples of K
Medium7
Combinatorics, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Mooball Teams III
Medium7
Combinatorics, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Potion Farming
Medium7
Tree, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Cowlendar
Medium7
Number theory, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Majority Opinion
Medium7
Array, Divide and conquer+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
XOR of Three Numbers and Queries
Medium7
Segment tree, Bit manipulation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Jump Game
Medium7
Dynamic programming, Segment tree+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
1-Color Coloring
Medium7
Binary search, Simulation+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Oriental P.A.D.A.K
Medium7
BFS, Greedy+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Candy Compress
Medium7
Implementation, Tree+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
There and Back Again
Medium7
Shortest path, Graph
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
XOR Operations
Medium7
Math, Bit manipulation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Number of TreesFor a tree with vertex durabilities, sum the pieces left by each subtree after removing vertices with durability at most j, over all j from 1 to K.	Medium7	TreeDynamic programming+1	No attempts yet	2s	1024 MB	Judgeable
Cowntact TracingGiven a tree of cows and which cows are infected after some nights, find the fewest cows that could have been infected at the start, for each night count.	Medium7	TreeDynamic programming+1	No attempts yet	2s	1024 MB	Judgeable
Flight RoutesGiven the parity of the number of routes between every pair of cities in a forward-only flight graph, count how many pairs have a direct flight.	Medium7	Dynamic programmingMath	No attempts yet	2s	1024 MB	Judgeable
Cycle CorrespondenceGiven two cycles of K barn labels, find the largest number of barns that can receive the same label in both assignments.	Medium7	ArrayString matching+1	No attempts yet	2s	1024 MB	Judgeable
Balanced GradesSplit students into three groups where each higher group beats the lower groups on both scores, minimizing the gap between the largest and smallest group size.	Medium7	Segment treeSorting	No attempts yet	1s	1024 MB	Judgeable
Ramen DeliveryGiven a tree rooted at room 1, sum over every K-subset of rooms the minimum walk time from room 1 that visits all of them, modulo 10^9+7.	Medium7	TreeDFS+1	No attempts yet	1s	1024 MB	Judgeable
Rectangle Flip 2Given an n by m grid whose cells break one at a time, count the rectangles made only of intact cells after each second.	Medium7	MatrixSimulation	No attempts yet	3s	1024 MB	Judgeable
SquareGiven a sequence a, choose positive integers t so that each adjacent pair a_i t_i a_{i+1} t_{i+1} is a perfect square, minimizing the product of all t_i modulo 1000000007.	Medium7	Number theoryGreedy+1	No attempts yet	1s	1024 MB	Judgeable
Emperor's PalacePlace the largest E-shaped palace (an a by 1 spine with three wings of length b, area a+3b) on free cells of a grid, or print -1.	Medium7	MatrixPrefix sum+1	No attempts yet	2s	1024 MB	Judgeable
Game TheoryAfter each range flip of a bit string, compute the number of moves Bobo makes before all bits are zero, modulo 998244353.	Medium7	Segment treeMath+1	No attempts yet	1s	1024 MB	Judgeable
StringologyFor each i from 0 to n-1, find the longest prefix of s, shorter than n, that is a suffix of pre(s, i) + t.	Medium7	StringString matching	No attempts yet	1s	1024 MB	Judgeable
3D GeometryGiven an axis-aligned tetrahedron and an axis-aligned cube in each test case, the task is to find the volume of their intersection.	Medium7	GeometryMath+1	No attempts yet	1s	1024 MB	Judgeable
Scalar ProductGiven integers a, b, and R, find the maximum dot product of (a, b) with an integer point (x, y) satisfying x^2 + y^2 <= R^2.	Medium7	GeometryMath+1	No attempts yet	3s	1024 MB	Judgeable
Numeral systemsGiven K and D, list all K-digit decimal notations X without a leading zero where X is greater than D and the hexadecimal reading Y is divisible by X minus D.	Medium7	BacktrackingNumber theory	No attempts yet	3s	1024 MB	Judgeable
A Hero Named MagnusGiven the game x where Team LGD starts banning Magnus, find the minimum odd best-of-n series length that lets LGD win the championship in the worst case.	Medium7	MathProbability	No attempts yet	1s	1024 MB	Judgeable
A Plus B ProblemAfter each single-digit change to the first or second row, report the requested digit of the sum's last n digits and how many digits of the machine change.	Medium7	Segment treeMath+1	No attempts yet	3s	1024 MB	Judgeable
Assumption is all you needGiven permutations A and B, output swaps that each undo an inversion of A to turn A into B, or report -1 if no sequence exists.	Medium7	ArraySorting+1	No attempts yet	1s	1024 MB	Judgeable
Occupy the CitiesGiven a row of cities with some occupied, find the fewest rounds needed for every occupied city to take one adjacent empty city until all are occupied.	Medium7	StringBinary search+1	No attempts yet	1s	1024 MB	Judgeable
PTSDSoldiers numbered 1 to n are split into groups so that the sum of power values of PTSD soldiers who are second strongest in their group is maximized.	Medium7	GreedyDynamic programming	No attempts yet	1s	1024 MB	Judgeable
Counting Phenomenal ArraysFor each size i from 2 to n, count arrays of i positive integers whose product equals their sum, modulo a prime P.	Medium7	MathCombinatorics+1	No attempts yet	2s	1024 MB	Judgeable
Flood FillGiven two N x M binary images, find the fewest cells where A can differ from B after repeatedly flipping the color of a connected component in A.	Medium7	GraphBFS+1	No attempts yet	2s	1024 MB	Judgeable
Colourful Permutation SortingSort a permutation whose positions are colored with k colors, using swaps that cost S or permutations of one color class that cost C_i, minimizing total coins.	Medium7	Bit manipulationGraph+1	No attempts yet	2s	1024 MB	Judgeable
Babushka and her pierogiGiven current and desired pierogi counts on plates, find the cheapest swap sequence (each swap costs \|x-y\|+C) that reaches the desired counts.	Medium7	GreedySorting+1	No attempts yet	6s	1024 MB	Judgeable
EpidemicProcess contacts and tests online; for each query, say whether only quarantined people can be infected, or name a person who still might be.	Medium7	Union-findImplementation+1	No attempts yet	9s	1024 MB	Judgeable
Interesting NumbersGiven n integers and k, find the longest subsequence in which the XOR of every pair of elements is at most k.	Medium7	Bit manipulationTrie+1	No attempts yet	3s	1024 MB	Judgeable
Xingqiu's JokeGiven two integers a and b, find the fewest operations (shifting both by 1 or dividing both by a common prime) needed to make a or b equal to 1.	Medium7	Number theoryMath+1	No attempts yet	2s	1024 MB	Judgeable
Phenomenal FranoGiven up to 1000 axis-parallel rectangles, find the fewest pen lifts needed to trace their borders with a turtle that starts at the origin.	Medium7	GraphUnion-find	No attempts yet	1s	1024 MB	Judgeable
Stretchy Rubber BandGiven points with distinct x and y, repeatedly remove the leftmost, rightmost, topmost, or bottommost point and report the convex hull area before each removal.	Medium7	GeometryLinked list+1	No attempts yet	1s	1024 MB	Judgeable
Lazy CowsFor each cow, count the daisies it can reach by moving only down or right in a 10^6 by 10^6 grid without crossing any rectangular fence.	Medium7	Divide and conquerSegment tree+1	No attempts yet	5s	1024 MB	Judgeable
Tree SearchFind a hidden special vertex in a rooted binary tree using at most 35 queries that ask whether it lies in a vertex's subtree.	Medium7	TreeBinary search+1	No attempts yet	1s	1024 MB	Judgeable
Team BuildingAfter each skill update, find the maximum team strength over all hiring orders of N programmers.	Medium7	GreedySegment tree+1	No attempts yet	1s	1024 MB	Judgeable
Around the WorldGiven up to 10 points with no three collinear, find the shortest closed tour that visits each point once without passing through visited points, or print -1.	Medium7	Dynamic programmingGeometry+1	No attempts yet	2s	1024 MB	Judgeable
Folding a CactusDecide whether each vertex of a cactus graph can get a one-dimensional coordinate so that every edge of length l spans exactly l between its endpoints.	Medium7	GraphDFS+1	No attempts yet	3s	1024 MB	Judgeable
String TelephoneGiven N people on a circle and a step K, count the pairs of string telephones (chords from i to i+K) that cross inside the circle.	Medium7	MathNumber theory+1	No attempts yet	0.5s	1024 MB	Judgeable
Three KingdomsSplit a tree of N cities with combat powers into three connected countries by cutting two edges, minimizing the sum of pairwise absolute differences.	Medium7	TreeDFS+1	No attempts yet	1s	1024 MB	Judgeable
Convex PolygonsFind the longest contiguous run of points that forms a convex polygon in counterclockwise order, and report its length.	Medium7	ArrayTwo pointers+1	No attempts yet	1s	1024 MB	Judgeable
Driving Test TrackGiven n front-radar cars and m corner-radar cars, find the minimum carrier capacity k and the fewest road crossings to move all cars west without mixed types on one side.	Medium7	MathGreedy+1	No attempts yet	2s	1024 MB	Judgeable
Planting FlagsGiven N flags already planted on a segment of length L, find for each start point the minimum walking distance to plant M more flags at least K apart.	Medium7	GreedyBinary search+2	No attempts yet	1.5s	1024 MB	Judgeable
Virtual VerificationStore a 14-digit password in 48 clocks that may be shuffled at random and shifted by magnetic fields, then recover the password from the hour hands.	Medium7	MathImplementation+1	No attempts yet	3s	1024 MB	Judgeable
Stop the overtime!!!Given tasks with deadlines and work units, move up to K deadlines later by one day each to minimize the overtime hours needed, with five regular days per week.	Medium7	GreedySorting+1	No attempts yet	1s	1024 MB	Judgeable
Supply ProcurementFind the shortest travel time between two units when intermediate units add inspection time, and inspection times rise over online updates.	Medium7	Shortest pathGraph+1	No attempts yet	1s	1024 MB	Judgeable
VrsarFor each start distance, find the maximum minutes of skating when climbing hills in order, each rink closes at t_i, and each descent costs s_i.	Medium7	SortingGreedy+2	No attempts yet	1s	1024 MB	Judgeable
Fruit GameGiven a subarray of values from 1 to 10, find the largest fruit the merge operation can produce, with point updates to the array.	Medium7	Segment treeDynamic programming	No attempts yet	4s	1024 MB	Judgeable
LRGiven string A, find the K-th smallest string among all 2^N strings built by repeatedly taking a character from the front or back of A.	Medium7	GreedyString+1	No attempts yet	2s	1024 MB	Judgeable
Removing VerticesGiven a graph where every cycle passes through vertex 0, remove the fewest vertices other than 0 so no cycles remain, and print which ones.	Medium7	Dynamic programmingTree+2	No attempts yet	2s	1024 MB	Judgeable
Two PathsGiven a DAG, find edge-disjoint simple paths from A to B and from C to D with the minimum total length, or report NO.	Medium7	GraphShortest path+1	No attempts yet	5s	1024 MB	Judgeable
Digit TranslationGiven a lowercase string, replace written digit words with digits to find the shortest reachable string length and count the distinct strings of that length modulo 9302023.	Medium7	StringDynamic programming+1	No attempts yet	1s	2048 MB	Judgeable
StringGiven a string A that is a prefix of the infinite string built by repeating a block k times and inserting symbols between copies, find the minimal k.	Medium7	String matchingMath+1	No attempts yet	1s	1024 MB	Judgeable
Big BedFind the integer box with the largest volume that can be carried through a graph of rectangular portals from portal 1 to portal n.	Medium7	GraphBFS+1	No attempts yet	1s	1024 MB	Judgeable
TrianglesGiven a green triangle and n marked points, find three of the points that form a blue triangle strictly containing the green one, or report NO.	Medium7	GeometrySorting+1	No attempts yet	2s	1024 MB	Judgeable
SwimmingGiven Ostap's start, Skumbriewitz's buoy, and Berlaga's position, find the length of a logarithmic spiral path around Berlaga that keeps a constant angle to the line of sight.	Medium7	MathGeometry	No attempts yet	1s	1024 MB	Judgeable
Faster Than LightPlace a segment of length L with one endpoint in a ship cell so that it touches the most total point value among the grid cells.	Medium7	GeometrySorting+1	No attempts yet	6s	1024 MB	Judgeable
Maze in a ForestFind a route from the southwest entrance to the northeast exit of an unknown n by n maze (n from 10 to 200) in at most 5n+300 moves, seeing only walls on each step.	Medium7	GraphDFS+1	No attempts yet	2s	1024 MB	Judgeable
GrammarGiven a context-free grammar over a and b, decide whether the language contains a string with more a characters than b characters.	Medium7	Dynamic programmingGraph+1	No attempts yet	2s	1024 MB	Judgeable
Chessboard GameGiven gate types on the top row and left column, answer for each query cell whether bobo wins when the piece moves one step up or left per turn.	Medium7	Game theoryGreedy+1	No attempts yet	1s	1024 MB	Judgeable
WallsGiven an n by m grid of diagonal walls, find the minimum total cost of flipping some cells so that no closed loop of walls encloses an area.	Medium7	Minimum spanning treeUnion-find+1	No attempts yet	2s	1024 MB	Judgeable
Survival RouteGiven two points and a circular forbidden cap on a sphere, find the shortest surface path from B to A that avoids the cap.	Medium7	GeometryGraph+1	No attempts yet	1s	1024 MB	Judgeable
Dispersed parenthesesCount the disperse parentheses sequences of length n whose depth is exactly k, modulo 10^9+9.	Medium7	Dynamic programmingString+1	No attempts yet	1s	1024 MB	Judgeable
Chocolate trianglesCount the ways to cut a convex n-gon along non-crossing diagonals so that exactly k of the resulting pieces are triangles, modulo 1e9+9.	Medium7	Dynamic programmingCombinatorics	No attempts yet	4s	1024 MB	Judgeable
LWDBPaint every tree vertex within weighted distance d of a given vertex with a color, and report a vertex's current color, with later paints overriding earlier ones.	Medium7	TreeDivide and conquer	No attempts yet	9s	1024 MB	Judgeable
Ceizenpok's formulaGiven n up to 10^18, k, and a modulus m from 2 to 10^6 that need not be prime, print the number of k-element subsets of an n-element set modulo m.	Medium7	MathNumber theory+1	No attempts yet	1s	1024 MB	Judgeable
Add and ReverseGiven n below 2^32, find the fewest add-one (mod 2^32) or 32-bit reverse operations needed to turn 0 into n.	Medium7	Bit manipulationGreedy+1	No attempts yet	1s	1024 MB	Judgeable
Physical EducationGiven n, count the numbers from 1 to n that keep their position when 1 to n are sorted by digit sum, then by value.	Medium7	MathDynamic programming+1	No attempts yet	1s	1024 MB	Judgeable
Aris, Let's Clean! (Hard)Given two rotation tables on an H by W grid, count the moves a dust-cleaning robot makes before it leaves the grid or can no longer remove dust.	Medium7	SimulationImplementation+1	No attempts yet	1s	1024 MB	Judgeable
Set Expression TranspilerGiven an Aniya expression over sets A to T using ~, &, and \|, print an equivalent Hayaku expression using &, \|, and \ within the length limit, or NO if none exists.	Medium7	RecursionString+1	No attempts yet	1s	1024 MB	Judgeable
Tree Explorer (Hard)Given a folder tree with collapsible nodes, process move and toggle commands on a cursor and print the folder under the cursor after each move.	Medium7	TreeDFS+2	No attempts yet	1s	1024 MB	Judgeable
Decontamination OperationGiven N contaminants on a line, pick a start point and skip one so the rest are purified nearest first, minimizing the total decontaminant refilled.	Medium7	SortingPrefix sum+1	No attempts yet	1s	1024 MB	Judgeable
Hosting the ContestPick one difficulty from each of N groups and order them so the sum of adjacent absolute differences is as small as possible.	Medium7	Two pointersSliding window+1	No attempts yet	1s	1024 MB	Judgeable
Supply Warehouse CleanupSplit N boxes into at most M consecutive groups, assign each group to a distinct squad, and minimize the largest per-soldier share of supplies.	Medium7	Binary searchGreedy+2	No attempts yet	1s	1024 MB	Judgeable
Pancake FlippingDecide whether a target W/B pancake pattern is reachable by prefix or suffix flips at equal adjacent pairs, and print one valid sequence of operations.	Medium7	SimulationString+1	No attempts yet	2s	1024 MB	Judgeable
GCD GameTwo players take turns picking cards so the board's GCD with the chosen card never becomes 1, and the task is to find who wins under optimal play.	Medium7	Game theoryNumber theory+1	No attempts yet	3s	1024 MB	Judgeable
Road Network Management and Queries in SinchonGiven a connected graph whose edges are colored by five schools, find the minimum spanning tree cost for each of Q new fee sets.	Medium7	Minimum spanning treeUnion-find+1	No attempts yet	2.5s	1024 MB	Judgeable
Linear Algebra: Concepts and MethodsGiven N, find a permutation of 1 to N where max minus min is not prime for every contiguous part of length at least 2, or report that none exists.	Medium7	MathNumber theory+1	No attempts yet	2s	1024 MB	Judgeable
Search GameFind the query strategy that minimizes the expected score of locating a hidden X from 1 to N, where each query of up to K numbers reports how many are below X.	Medium7	Dynamic programmingPrefix sum	No attempts yet	2s	1024 MB	Judgeable
Good SequenceAfter each range flip of a balanced 0/1 sequence, decide whether the four-element operation can reduce it to a sequence that contains N.	Medium7	ArrayPrefix sum+1	No attempts yet	4s	1024 MB	Judgeable
Almond ChocolateCount the ways to tile the rest of an equiangular hexagon with integer sides using rhombi of two unit triangles, after six corner rhombi are already placed.	Medium7	CombinatoricsMath+1	No attempts yet	2s	1024 MB	Judgeable
Chocolate and ㄱ나이트 Game (Bitter)Given a X by Y board and knight moves of (±x, ±y), find the maximum number of knights that can be placed so none can attack another.	Medium7	MathGraph+1	No attempts yet	2s	1024 MB	Judgeable
Flag PerformanceGiven an initial flag arrangement of N members, count the sequences of K pairwise swaps that restore every flag to its owner, modulo 1000000007.	Medium7	CombinatoricsDynamic programming+1	No attempts yet	2s	1024 MB	Judgeable
Nicest viewGiven altitudes at each kilometre of a linear trail, find the largest distance between two points at the same altitude, with the trail linear between marks.	Medium7	ArrayStack+1	No attempts yet	0.25s	1024 MB	Judgeable
Table LegsCount the triples of polygon vertices whose triangle strictly contains the polygon's center of gravity in its interior.	Medium7	GeometrySorting+1	No attempts yet	0.5s	1024 MB	Judgeable
Throwing diceGiven the side counts of Alice's and Bob's fair dice (each at least 4), decide whether Alice or Bob is more likely to get the strictly larger total, or whether the two chances are equal.	Medium7	ProbabilityMath	No attempts yet	1s	1024 MB	Judgeable
Multiplication in Base N (HUGE)Multiply two integers written in base N, where N may be negative, each up to 3,000,000 digits, and print the product in base N.	Medium7	StringMath+1	No attempts yet	10s	1024 MB	Judgeable
Cramming for FinalsGiven n students on an r by c grid, find the empty table with the fewest students within Euclidean distance d and report that count.	Medium7	GeometrySorting+1	No attempts yet	4s	2048 MB	Judgeable
Eccentric ExcursionGiven a tree of n cities, find the lexicographically smallest Hamiltonian ordering that uses exactly k non-road jumps between consecutive cities, or report -1.	Medium7	TreeGreedy+1	No attempts yet	6s	2048 MB	Judgeable
Segment DrawingEach point is paired with a segment on the x-axis. Connect every point to its segment without strict crossings, minimizing total length, or report -1.	Medium7	GeometryGreedy+1	No attempts yet	5s	2048 MB	Judgeable
Tournament MatchmakingPair up groups so that the combined players can fill all 15 roles exactly once, and find the maximum number of such pairs.	Medium7	GraphBit manipulation	No attempts yet	3s	2048 MB	Judgeable
Diverse ContestCount the k-problem subsets of n problems where no topic appears in more than half of the chosen problems.	Medium7	Bit manipulationCombinatorics+1	No attempts yet	10s	2048 MB	Judgeable
I Hate Going to Work 2Count the attendance patterns where each employee works exactly A_i of the M hours and at most 2 employees are absent at any hour, modulo 1e9+7.	Medium7	CombinatoricsDynamic programming+1	No attempts yet	1s	1024 MB	Judgeable
Extreme Multiples of KGiven N, M, and K where K divides N, count the nonempty subsets of the N*M balls (M balls per number from 1 to N) whose sum is divisible by K, modulo 1e9+7.	Medium7	CombinatoricsMath+1	No attempts yet	1s	1024 MB	Judgeable
Mooball Teams IIICount pairs of nonempty, disjoint red and blue cow sets that one horizontal or vertical net at a half-integer coordinate separates, modulo 1e9+7.	Medium7	CombinatoricsMath+1	No attempts yet	2s	1024 MB	Judgeable
Potion FarmingGiven a tree rooted at room 1 and a schedule of potion spawns, find the most potions collectible while covering every room with the fewest root-to-room paths.	Medium7	TreeGreedy+1	No attempts yet	2s	1024 MB	Judgeable
CowlendarGiven month lengths a_i, find the sum of all week lengths L where every month is at least 4 weeks and a_i mod L takes at most 3 values.	Medium7	Number theoryMath+1	No attempts yet	2s	1024 MB	Judgeable
Majority OpinionGiven each cow's preferred hay type, list every type that all cows can be made to like using majority focus groups on contiguous ranges, or print -1.	Medium7	ArrayDivide and conquer+1	No attempts yet	2s	1024 MB	Judgeable
XOR of Three Numbers and QueriesGiven an array of values below 64, answer whether some three distinct positions in a range XOR to x, and support adding x mod 64 to every element in a range.	Medium7	Segment treeBit manipulation+1	No attempts yet	2s	1024 MB	Judgeable
Jump GameGiven N platforms whose values come from Q range-increment operations, choose jump positions at least K apart to maximize the sum of their values.	Medium7	Dynamic programmingSegment tree+1	No attempts yet	3s	1024 MB	Judgeable
1-Color ColoringUsing at most 7300 Color instructions and 200 GetColor queries, make every spirit color 1 without knowing the initial arrangement.	Medium7	Binary searchSimulation+1	No attempts yet	1s	512 MB	Judgeable
Oriental P.A.D.A.KGiven a grid where sauce spreads from K cells each second, find the minimum and maximum pieces dippers can eat when both groups race to eat.	Medium7	BFSGreedy+1	No attempts yet	1s	512 MB	Judgeable
Candy CompressMaintain a string under insertions of single characters and deletions of substrings, and report the substring removed by each deletion.	Medium7	ImplementationTree+1	No attempts yet	2s	1024 MB	Judgeable
There and Back AgainFind the minimum total time for two round trips from city 1 to city n and back, where the two routes must use different sets of roads, or output -1.	Medium7	Shortest pathGraph	No attempts yet	2s	1024 MB	Judgeable
XOR OperationsCount the distinct sequences B reachable from all zeros by XOR-ing a_i xor a_j into both b_i and b_j, modulo 998244353.	Medium7	MathBit manipulation	No attempts yet	2s	1024 MB	Judgeable