Problems

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Total results29,262 problems

Exploding Balls
Medium7
Simulation, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Build the Fence
Medium7
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Beautiful Numbers
Medium7
Math, Number theory+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tower Defense
Medium7
Simulation, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tunnel
Medium7
Greedy, Geometry+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Songs
Medium7
Greedy, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sierpinski Triangle
Medium7
String, Recursion+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bulbs
Medium7
Dynamic programming, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Formula Substitution
Medium7
Recursion, String matching+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Road Repair
Medium7
Binary search, Tree+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Highway
Medium7
Dynamic programming, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Railway Route Cover
Medium7
Dynamic programming, Tree+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
ABCD
Medium7
Geometry, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
TV Switches
Medium7
BFS, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pilot Crews
Medium7
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Kidnapping
Medium7
Simulation, Brute force+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Interval Groups
Medium7
Greedy, Stack+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Elevators
Medium7
Shortest path, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Teleport
Medium7
Shortest path, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tram Line Coloring
Medium7
Graph, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Jozo's Train Trip
Medium7
Shortest path, Graph+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Two Snow Plows
Medium7
Tree, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cola
Medium7
Simulation, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Maximum-Vertex Convex Polygon
Medium7
Dynamic programming, Geometry+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Job Scheduling
Medium7
Greedy, Binary search+1
No attempts yet
Time limit
1s
Memory limit
32 MB
Judgeable
After the Contest: Balloons
Medium7
Binary search, Geometry+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Largest Rectangle
Medium7
Dynamic programming, Greedy+2
No attempts yet
Time limit
0.6s
Memory limit
128 MB
Judgeable
Royal Treasury
Medium7
Tree, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Queue
Medium7
Segment tree, Binary search+2
No attempts yet
Time limit
2s
Memory limit
32 MB
Judgeable
Link
Medium7
Graph, Greedy+1
No attempts yet
Time limit
2s
Memory limit
64 MB
Judgeable
Lanterns
Medium7
Graph, Union-find+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Power Plant on the Highway
Medium7
Binary search, Geometry+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Candy Machine
Medium7
Greedy, Sorting+1
No attempts yet
Time limit
4s
Memory limit
128 MB
Judgeable
Handshakes
Medium7
Simulation, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Escape
Medium7
Graph, Shortest path+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bitwise Expressions
Medium7
Bit manipulation, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Coin Collector
Medium7
Greedy, Binary search+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bus Trip
Medium7
Shortest path, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Submarines
Medium7
Stack, Segment tree+1
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Electronical Plate
Medium7
Graph, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Mutexes
Medium7
BFS, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bankrupt Kingdoms
Medium7
Graph, Simulation+1
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Non-boring Sequences
Medium7
Divide and conquer, Array+1
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Character Equation
Medium7
Dynamic programming, String+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Jewel Heist
Medium7
Two pointers, Sorting+1
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
The Dragon and the Knights
Medium7
Geometry, Hash map+1
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Conservation
Medium7
Topological sort, Graph+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Boring Card Game
Medium7
Simulation, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Unique Encryption Keys
Medium7
Segment tree, Binary search+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Strange Billboard
Medium7
Bit manipulation, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Most Stable Water Level
Medium7
Math, Binary search+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Desperate Electrician
Medium7
Math, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Dice Contest
Medium7
Shortest path, BFS+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Which is Next
Medium7
Recursion, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Alice and Bob
Medium7
Graph, DFS+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Binary Stirling Numbers
Medium7
Bit manipulation, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Bulk
Medium7
Geometry, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Complicated Expressions
Medium7
String, Recursion+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
I-Keyboard
Medium7
Dynamic programming, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Proper Key
Medium7
Simulation, Matrix+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hares and Foxes
Medium7
Math, Matrix+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Caption
Medium7
Dynamic programming, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Size of the Dictionary
Medium7
Trie, String matching+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Mitochondrial Eve
Medium7
Union-find, Tree+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
High Security
Medium7
String, Combinatorics+2
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Kids Like Cakes
Medium7
Dynamic programming, Geometry+1
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
The Ideal Path
Medium7
BFS, Shortest path+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Jungle Outpost
Medium7
Geometry, Binary search+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Horrible Truth
Medium7
Combinatorics, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Kitchen Robot
Medium7
Dynamic programming, Geometry+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Inspection
Medium7
Graph, DFS+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Auxiliary Question of the Universe
Medium7
Dynamic programming, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Kripke Model
Medium7
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Clock
Medium7
Math, Greedy+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
KINA Is Not Abbreviation
Medium7
String matching, Hash map+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Ants
Medium7
Graph, Math+1
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Diver
Medium7
Binary search, Simulation+2
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
DFA
Medium7
Trie, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
A+B
Medium7
Math, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
64 MB
Judgeable
Orthogonal Closure
Medium7
String matching, Bit manipulation+1
No attempts yet
Time limit
2s
Memory limit
64 MB
Judgeable
Circular Cellular Automaton
Medium7
Math, Matrix+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Deciphering
Medium7
Dynamic programming, String+2
No attempts yet
Time limit
2s
Memory limit
64 MB
Judgeable
A Certain Pumpkin's Halloween Trip
Medium7
Geometry, Math+1
No attempts yet
Time limit
2s
Memory limit
64 MB
Judgeable
K Best
Medium7
Binary search, Greedy+1
No attempts yet
Time limit
2s
Memory limit
64 MB
Judgeable
Digital Clock
Medium7
Bit manipulation, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Castle Guards
Medium7
Dynamic programming, Tree+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Binomial Coefficient
Medium7
Math, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Gunfight
Medium7
Graph, Topological sort+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Birthday Gift
Medium7
Greedy, Binary search+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Risk
Medium7
Graph
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Mountain Road
Medium7
Dynamic programming, Greedy+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Mobile
Medium7
Tree, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
March of the Penguins
Medium7
Graph, Greedy+1
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Escape from Enemy Territory
Medium7
Binary search, BFS+1
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Ambiguous
Medium7
Dynamic programming, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Unequalled Consumption
Medium7
Dynamic programming, Binary search+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Day Trip
Medium7
Graph, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Up the Stairs
Medium7
Simulation, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Choosing a camera
Medium7
Binary search, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Multiprocessor Scheduling
Medium7
Dynamic programming, Greedy+1
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Exploding BallsGiven N balls moving in one of four axis directions at unit speed, find which balls never collide with another ball at the same point and time.	Medium7	SimulationMath+1	No attempts yet	1s	128 MB	Judgeable
Build the FenceAssign Taewoo's priced boards to Doyun's fence positions, using a height covering rule, to maximize total paid price and output the matching.	Medium7	GreedySorting+1	No attempts yet	1s	128 MB	Judgeable
Beautiful NumbersGiven a base-p labeled infinite binary tree, decide for four large numbers whether each is expressible as a sum of two distinct node values in exactly one way.	Medium7	MathNumber theory+1	No attempts yet	1s	128 MB	Judgeable
Tower DefenseAssign one of four right-angle firing directions to each tower on a grid so simultaneous shots destroy every clone without hitting any other tower.	Medium7	SimulationGraph+1	No attempts yet	1s	128 MB	Judgeable
TunnelGiven a tunnel's ceiling and floor y-coordinates over N columns, construct the shortest axis-aligned path from (0,0) to (N,0) that never touches either boundary.	Medium7	GreedyGeometry+1	No attempts yet	1s	128 MB	Judgeable
SongsGiven hints that certain sets of songs must occupy the top B ranking slots, determine every song whose exact position is logically forced and print them in order.	Medium7	GreedyGraph+2	No attempts yet	1s	128 MB	Judgeable
Sierpinski TriangleGiven a Sierpinski-triangle sub-triangle's name string, output the names of all triangles it leans against based on the fractal's midpoint-subdivision structure.	Medium7	StringRecursion+2	No attempts yet	1s	128 MB	Judgeable
BulbsGiven a target 2×N binary grid, find the minimum number of toggle operations on contiguous row or column segments to reach that pattern.	Medium7	Dynamic programmingGreedy+1	No attempts yet	1s	128 MB	Judgeable
Formula SubstitutionGiven two formula strings with variables 0 and 1, find basic-formula substitutions for both variables that make the two formulas syntactically identical, similar to unification.	Medium7	RecursionString matching+2	No attempts yet	1s	128 MB	Judgeable
Road RepairGiven a tree with per-edge reducible travel times and a total repair budget, minimize the maximum distance from city 1 to any other city by optimally allocating budget across edges.	Medium7	Binary searchTree+2	No attempts yet	2s	128 MB	Judgeable
HighwayGiven a road profile and costs for flat, sloped, tunnel or viaduct travel, find the minimum time to cross using at most K equal-height shortcut structures.	Medium7	Dynamic programmingGreedy+1	No attempts yet	1s	128 MB	Judgeable
Railway Route CoverGiven a tree, partition all vertices into vertex-disjoint paths covering every node so that the total edge weight used by the paths is maximized, using tree DP.	Medium7	Dynamic programmingTree+1	No attempts yet	1s	128 MB	Judgeable
ABCDGiven distances between four parallel rails A, B, C, D, decide if points on them can form a rectangle and find its minimum possible area.	Medium7	GeometryMath+1	No attempts yet	1s	128 MB	Judgeable
TV SwitchesFind the minimum number of switch presses, where pressing a switch releases only a fixed subset of others, to reach a state where only switch 3 is pressed.	Medium7	BFSBit manipulation+1	No attempts yet	1s	128 MB	Judgeable
Pilot CrewsGiven pilots sorted by age with captain and assistant salaries, pair them into captain-older-than-assistant crews minimizing total salary paid.	Medium7	GreedySorting+1	No attempts yet	1s	128 MB	Judgeable
KidnappingGiven a grid of building heights and a sequence of left/right building heights seen while driving with turns allowed at each step, find a valid ending intersection consistent with some starting point and direction.	Medium7	SimulationBrute force+1	No attempts yet	1s	128 MB	Judgeable
Interval GroupsGiven a permutation of 1..N arranged on a board, decide if adjacent groups can be merged repeatedly into intervals until one group remains, and output the merge sequence if possible.	Medium7	GreedyStack+2	No attempts yet	1s	128 MB	Judgeable
ElevatorsFind the minimum time for Mirko to travel from floor 1 to floor K by transferring between periodically oscillating elevators only at their endpoint floors.	Medium7	Shortest pathGraph+1	No attempts yet	1s	128 MB	Judgeable
TeleportGiven all-pairs shortest paths without a hidden zero-cost teleport edge and observed shortest trip times that include it, determine the unique pair of rooms the teleport connects.	Medium7	Shortest pathGraph+1	No attempts yet	1s	128 MB	Judgeable
Tram Line ColoringGiven a tree covered by paths (tram lines) that share stations, assign colors to lines so that lines sharing a station differ, using the minimum number of colors.	Medium7	GraphGreedy+1	No attempts yet	1s	128 MB	Judgeable
Jozo's Train TripGiven stations, railways, and scheduled trains, find the minimum station-waiting time for a trip starting at station 1 at time 1 and returning to station 1 within a given time window.	Medium7	Shortest pathGraph+1	No attempts yet	2s	128 MB	Judgeable
Two Snow PlowsGiven a tree rooted at S, find minimum total edge traversal cost for two walks starting at S that together cover every edge, without returning to S.	Medium7	TreeDynamic programming+1	No attempts yet	1s	128 MB	Judgeable
ColaGiven final cola levels after N people each drank from the fullest (W) or emptiest nonempty (E) bottle in turn, reconstruct the lexicographically smallest sequence of bottle choices.	Medium7	SimulationGreedy+1	No attempts yet	1s	128 MB	Judgeable
Maximum-Vertex Convex PolygonGiven up to 100 points plus the origin, find the maximum number of vertices of a convex polygon using origin and some points with no three collinear consecutive vertices.	Medium7	Dynamic programmingGeometry+1	No attempts yet	1s	128 MB	Judgeable
Job SchedulingFind the minimum number of identical machines needed to schedule M jobs, each submitted on a day and requiring one day of processing within D days, over N days.	Medium7	GreedyBinary search+1	No attempts yet	1s	32 MB	Judgeable
After the Contest: BalloonsSimulate balloons inflated left to right on a line, each stopping at its max radius or when it touches an earlier balloon, and output the final radii efficiently.	Medium7	Binary searchGeometry+1	No attempts yet	1s	128 MB	Judgeable
Largest RectangleGiven a binary matrix where columns may be freely reordered, find the maximum area rectangle of all-1 cells after computing per-cell run heights and sorting rows to combine widths.	Medium7	Dynamic programmingGreedy+2	No attempts yet	0.6s	128 MB	Judgeable
Royal TreasuryGiven a tree hierarchy, find the maximum matching between parent-child pairs and count the number of maximum matchings, likely modulo something implicit.	Medium7	TreeDynamic programming+1	No attempts yet	1s	128 MB	Judgeable
QueueSimulate people repeatedly leaving a queue and reinserting before another person, then answer position and label lookup queries efficiently using a balanced structure like a Fenwick tree or order-statistics tree.	Medium7	Segment treeBinary search+2	No attempts yet	2s	32 MB	Judgeable
LinkGiven a functional graph where each node has exactly one outgoing edge, find the minimum number of edges to add so every node is reachable from node 1 within K hops.	Medium7	GraphGreedy+1	No attempts yet	2s	64 MB	Judgeable
LanternsGiven tree coordinates, find the largest connected component when trees within distance 2r are linked, then find the minimum number of lanterns (circles of radius r centered on chosen trees) needed to cover every tree in that component while keeping the union connected.	Medium7	GraphUnion-find+2	No attempts yet	1s	128 MB	Judgeable
Power Plant on the HighwayGiven base stations anywhere in the plane, find the point on a fixed highway segment that maximizes the minimum distance to any station, and output the squared distance as an exact reduced fraction.	Medium7	Binary searchGeometry+1	No attempts yet	1s	128 MB	Judgeable
Candy MachineGiven candies with slot and time, find the minimum number of wagons (each moving at unit speed) needed to catch all candies, which reduces to a minimum path cover / patience sorting style problem.	Medium7	GreedySorting+1	No attempts yet	4s	128 MB	Judgeable
HandshakesGiven a row of L/R facing people who flip and shake hands each second when an R stands left of an L, compute total seconds until stabilization and total handshakes, or report it never ends.	Medium7	SimulationGreedy+1	No attempts yet	1s	128 MB	Judgeable
EscapeFind the minimum number of soldiers with 100m detection radius to remove so a west-to-east path across a rectangular canyon avoids all remaining detection circles, modeled as a min vertex cut / shortest path with obstacle weights.	Medium7	GraphShortest path+1	No attempts yet	1s	128 MB	Judgeable
Bitwise ExpressionsGiven ranges for variables combined by OR within groups and AND across groups, find the maximum achievable value of the resulting bitwise expression.	Medium7	Bit manipulationGreedy+1	No attempts yet	1s	128 MB	Judgeable
Coin CollectorGiven coin denominations and a bill of K, find the purchase price whose greedy change contains the maximum number of not-yet-owned denominations, breaking ties by highest price.	Medium7	GreedyBinary search+1	No attempts yet	1s	128 MB	Judgeable
Bus TripFind a bus route plan from town 1 to town P arriving by time T that guarantees valid connections while minimizing worst-case total waiting time.	Medium7	Shortest pathGraph+1	No attempts yet	1s	128 MB	Judgeable
SubmarinesMaintain a sequence under adjacent swaps and repeatedly report the maximum in-degree in the 'nearest deeper element behind' functional graph.	Medium7	StackSegment tree+1	No attempts yet	3s	128 MB	Judgeable
Electronical PlateGiven an n by n grid of pins, find the maximum number of node-disjoint paths connecting non-boundary pins to the boundary without touching other pins or the boundary early, modeled as a max-flow problem.	Medium7	GraphMath+1	No attempts yet	1s	128 MB	Judgeable
MutexesGiven up to 5 threads each executing LOCK/UNLOCK instructions on mutexes, determine if a deadlock state is reachable via some interleaving and if so output the lexicographically smallest deadlock state description.	Medium7	BFSSimulation+2	No attempts yet	1s	128 MB	Judgeable
Bankrupt KingdomsDetermine, given pairwise debts among n kingdoms and a bankruptcy elimination rule based on negative balances, which kingdoms can be the sole survivor.	Medium7	GraphSimulation+1	No attempts yet	5s	128 MB	Judgeable
Non-boring SequencesDetermine whether every contiguous subarray of a sequence has at least one element unique within that subarray, using an efficient divide and conquer approach.	Medium7	Divide and conquerArray+1	No attempts yet	5s	128 MB	Judgeable
Character EquationGiven a recursive definition of a huge string T through variable concatenation equations, determine whether a pattern P is a subsequence of T without expanding T explicitly.	Medium7	Dynamic programmingString+2	No attempts yet	1s	256 MB	Judgeable
Jewel HeistGiven colored points, find the maximum number of points coverable by a horizontal-span rectangle extending down to minus infinity that avoids containing all k colors.	Medium7	Two pointersSorting+1	No attempts yet	5s	128 MB	Judgeable
The Dragon and the KnightsGiven n lines forming an arrangement with m marked points, determine whether every region of the arrangement contains at least one marked point.	Medium7	GeometryHash map+1	No attempts yet	3s	128 MB	Judgeable
ConservationGiven a DAG of tasks each labeled with one of two labs, find a topological order minimizing the number of switches between labs.	Medium7	Topological sortGraph+1	No attempts yet	2s	128 MB	Judgeable
Boring Card GameSimulate a deterministic card dealing and collecting process to find which player first collects cards 1-5, or detect an infinite cycle, with game counts up to 2^63.	Medium7	SimulationMath+1	No attempts yet	1s	128 MB	Judgeable
Unique Encryption KeysFor each of up to a million range queries over a sequence of keys, decide if the range has a duplicate and report the smallest repeated key value.	Medium7	Segment treeBinary search+2	No attempts yet	2s	128 MB	Judgeable
Strange BillboardFind the minimum number of tile taps (a Lights Out style toggle puzzle) needed to make an R x C grid all white, or report impossibility.	Medium7	Bit manipulationBrute force+2	No attempts yet	1s	128 MB	Judgeable
The Most Stable Water LevelGiven a solid-of-revolution cup with expression-defined radius and wall thickness, compute the water fill level that minimizes the combined center of mass, requiring expression parsing, integration, and numerical optimization.	Medium7	MathBinary search+2	No attempts yet	1s	128 MB	Judgeable
Desperate ElectricianGiven W wires connecting two floors with unmarked ends, determine the minimum number of up-down trips needed to fully identify and label all wires using grouping and measurement.	Medium7	MathCombinatorics+1	No attempts yet	1s	128 MB	Judgeable
Dice ContestFind the minimum total cost of rolling a labeled die across an infinite 4-row strip from a start square to a target square, tracking die orientation as state.	Medium7	Shortest pathBFS+1	No attempts yet	1s	128 MB	Judgeable
Which is NextGiven a binary tree's numeric identifier under a bijective encoding, compute the identifier of the next tree in a defined ordering among same-size trees, wrapping around if it is the largest.	Medium7	RecursionMath+1	No attempts yet	1s	128 MB	Judgeable
Alice and BobGiven all polygon sides and non-crossing diagonals as an unordered edge list, reconstruct the convex polygon's cyclic vertex order.	Medium7	GraphDFS+1	No attempts yet	1s	128 MB	Judgeable
Binary Stirling NumbersGiven n and m up to 1e9, determine the parity of the Stirling number of the second kind S(n, m) for many test cases efficiently.	Medium7	Bit manipulationMath+2	No attempts yet	1s	128 MB	Judgeable
The BulkGiven all polygonal faces (including inner cavity faces) of a 3D solid made of unit cubes, compute the total number of unit cubes forming it.	Medium7	GeometryMath+1	No attempts yet	1s	128 MB	Judgeable
Complicated ExpressionsParse an arithmetic expression with parentheses and reprint it with every redundant parenthesis removed while preserving exact operator precedence and associativity semantics.	Medium7	StringRecursion+1	No attempts yet	1s	128 MB	Judgeable
I-KeyboardPartition an ordered list of letter frequencies into K consecutive groups to minimize sum of frequency times in-group position, with a tie-break favoring later keys getting more letters, then output the resulting keyboard layout.	Medium7	Dynamic programmingGreedy+1	No attempts yet	1s	128 MB	Judgeable
The Proper KeySimulate how deep a rigid connected key can descend into a grid lock, moving only down or sideways, and report the maximum depth or whether it falls through entirely.	Medium7	SimulationMatrix+1	No attempts yet	1s	128 MB	Judgeable
Hares and FoxesGiven a linear recurrence matrix for hare and fox population differences, classify the long-term limiting behavior of the system into one of six fixed outcomes based on eigenvalue analysis.	Medium7	MathMatrix+1	No attempts yet	1s	128 MB	Judgeable
CaptionGiven a fixed current pixel grid layout and a new text with letter width k and spacing bounds smin/smax, find the layout minimizing flipped pixels using DP over positions and letters with precomputed per-letter overlap costs.	Medium7	Dynamic programmingString+1	No attempts yet	1s	128 MB	Judgeable
Size of the DictionaryCount distinct words formed as base words themselves, plus prefix-of-one-base-word concatenated with suffix-of-another-base-word combinations.	Medium7	TrieString matching+1	No attempts yet	2s	128 MB	Judgeable
Mitochondrial EveGiven birth and death events tracking maternal lineage and some sequenced mitochondrial DNA samples, determine whether all currently living individuals must share, might share, or must not share the same mitochondrial DNA.	Medium7	Union-findTree+2	No attempts yet	1s	128 MB	Judgeable
High SecurityGiven up to 50000 length-5 passwords over 62 characters, count pairs of passwords for each Hamming distance from 0 to 5.	Medium7	StringCombinatorics+2	No attempts yet	3s	256 MB	Judgeable
Kids Like CakesGiven a convex polygon, find the triangulation using only its vertices that maximizes the area difference between the largest and smallest triangle.	Medium7	Dynamic programmingGeometry+1	No attempts yet	5s	256 MB	Judgeable
The Ideal PathFind the shortest path from node 1 to node n in a colored undirected graph, breaking ties by lexicographically smallest edge-color sequence.	Medium7	BFSShortest path+1	No attempts yet	1s	128 MB	Judgeable
Jungle OutpostGiven the vertices of a convex polygon in order, find the placement inside it maximizing the minimum number of vertices whose removal destroys coverage, essentially finding the minimum piercing/hitting number related to diagonal crossing structure.	Medium7	GeometryBinary search+1	No attempts yet	1s	128 MB	Judgeable
Horrible TruthGiven n characters, compute the maximum number of episodes of alternating-type true	Medium7	CombinatoricsMath+1	No attempts yet	1s	128 MB	Judgeable
Kitchen RobotFind the shortest robot route that starts at a given point, visits n bottles, and drops each bottle off at the nearest border point, requiring TSP-style optimization with precomputed border distances.	Medium7	Dynamic programmingGeometry+1	No attempts yet	3s	256 MB	Judgeable
InspectionGiven a DAG representing ski slopes, find the minimum number of downhill paths needed to cover every edge, which reduces to a minimum path cover via bipartite matching.	Medium7	GraphDFS+1	No attempts yet	1s	128 MB	Judgeable
Auxiliary Question of the UniverseGiven a fragment of an arithmetic expression grammar (numbers, plus, parentheses), find the minimum insertions needed to make it a valid expression while keeping the fragment as a subsequence.	Medium7	Dynamic programmingString+1	No attempts yet	1s	128 MB	Judgeable
Kripke ModelGiven a Kripke model with n up to 10000 states, compute the set of states satisfying the CTL formula E(x U (AG y)) using fixed-point graph algorithms.	Medium7	GraphDFS+2	No attempts yet	1s	128 MB	Judgeable
ClockGiven hands rotating at nested integer-ratio speeds, choose how much to turn each hand (dragging slower ones) to move from one timestamp to another minimizing total handle travel, output the exact minimal distance as a reduced fraction.	Medium7	MathGreedy+1	No attempts yet	2s	128 MB	Judgeable
KINA Is Not AbbreviationGiven a text, find the abbreviation (initials of a consecutive word window) that is unambiguous per the stated rules and maximizes letter-count reduction, breaking ties lexicographically.	Medium7	String matchingHash map+2	No attempts yet	2s	512 MB	Judgeable
AntsFind the minimum-cost perfect matching between n points and n points using squared Euclidean distance as edge weight.	Medium7	GraphMath+1	No attempts yet	3s	128 MB	Judgeable
DiverGiven a diver moving along a vertical rope avoiding oscillating sharks whose horizontal distance follows a triangle wave, find the minimum time to reach the surface without ever coming within radius r of a shark, or report impossibility.	Medium7	Binary searchSimulation+2	No attempts yet	3s	128 MB	Judgeable
DFAGiven a finite set of words, compute the minimum number of states of a DFA recognizing exactly that language.	Medium7	TrieDynamic programming+1	No attempts yet	1s	128 MB	Judgeable
A+BGiven forbidden strings V, find the lexicographic index sum of A and B among all strings orthogonal to V, then output the string at that index modulo the count.	Medium7	MathCombinatorics+1	No attempts yet	2s	64 MB	Judgeable
Orthogonal ClosureGiven two binary strings, decide whether T equals the XOR of some pair of circular shifts of S, requiring an efficient algorithm beyond brute force for n up to 5000.	Medium7	String matchingBit manipulation+1	No attempts yet	2s	64 MB	Judgeable
Circular Cellular AutomatonSimulate k modular convolution steps on a circular array of n cells efficiently, using matrix exponentiation or polynomial power modulo m and x^n-1.	Medium7	MathMatrix+1	No attempts yet	1s	128 MB	Judgeable
DecipheringCount the ways to split an unspaced text into dictionary words, group them into sentences, and match each sentence to a valid part-of-speech rule, capping the huge counts.	Medium7	Dynamic programmingString+2	No attempts yet	2s	64 MB	Judgeable
A Certain Pumpkin's Halloween TripDetermine whether two annular rings with given outer and inner radii can be cut without overlapping from a circular gold plate of a given radius.	Medium7	GeometryMath+1	No attempts yet	2s	64 MB	Judgeable
K BestChoose exactly k jewels out of n to maximize the ratio of total value to total weight, using binary search on the answer with a fractional feasibility check, then output the exact reduced fraction.	Medium7	Binary searchGreedy+1	No attempts yet	2s	64 MB	Judgeable
Digital ClockDetermine every plausible starting real time for a broken seven-segment clock, given a sequence of minute-by-minute observed displays where some segments are permanently dead.	Medium7	Bit manipulationSimulation+2	No attempts yet	1s	128 MB	Judgeable
Castle GuardsGiven a recursively described tree of small buildings connected by corridors, compute the minimum vertex cover (guard placement) that watches every corridor in the whole castle.	Medium7	Dynamic programmingTree+2	No attempts yet	2s	128 MB	Judgeable
Binomial CoefficientGiven m up to 10^15, find all pairs (n,k) with binomial coefficient n choose k equal to m, listed in sorted order.	Medium7	MathCombinatorics+1	No attempts yet	1s	128 MB	Judgeable
GunfightGiven listener based constraints on when gunshot sounds arrive, determine the unique firing order of shooters, or report impossibility or ambiguity.	Medium7	GraphTopological sort+1	No attempts yet	1s	128 MB	Judgeable
Birthday GiftAssign integer payments capped by each friend's maximum so the sum equals the gift price while lexicographically minimizing sorted deviations from the fair share, breaking remaining ties by capacity and input order.	Medium7	GreedyBinary search+1	No attempts yet	1s	128 MB	Judgeable
Risknot used	Medium7	Graph	No attempts yet	3s	128 MB	Judgeable
Mountain RoadSchedule two queues of cars crossing a one-lane road with direction-blocking and same-direction spacing rules to minimize the last car's exit time.	Medium7	Dynamic programmingGreedy+1	No attempts yet	2s	128 MB	Judgeable
MobileGiven a recursively nested mobile of weighted objects, find the minimum number of object weights to change so every rod balances left and right.	Medium7	TreeDynamic programming+1	No attempts yet	1s	128 MB	Judgeable
March of the PenguinsDetermine, for each candidate ice floe, whether a max-flow feasibility check (respecting per-floe departure jump capacities and distance-limited edges) allows all penguins from every floe to reach it.	Medium7	GraphGreedy+1	No attempts yet	5s	128 MB	Judgeable
Escape from Enemy TerritoryGiven a grid with enemy bases, find the maximum possible minimum Manhattan distance to any base along a path from start to rendezvous, then the shortest such path's step count.	Medium7	Binary searchBFS+1	No attempts yet	3s	128 MB	Judgeable
AmbiguousSplit a scrambled, space-free string into a unique sequence of dictionary words matching letter multisets, first and last letters, reporting ambiguity or impossibility.	Medium7	Dynamic programmingString+2	No attempts yet	1s	128 MB	Judgeable
Unequalled ConsumptionGiven up to 5 candy weights, find for each query P the smallest total weight whose number of representations (as an unordered multiset count) is at least P, using binary search over weight combined with counting compositions via generating functions or DP.	Medium7	Dynamic programmingBinary search+2	No attempts yet	1s	128 MB	Judgeable
Day TripSelect the largest subset of students so every pair differs by more than 40cm in height, or shares gender, or differs in music genre, or shares sport, which reduces to a maximum independent set style selection solvable via clever graph structuring.	Medium7	GraphGreedy+1	No attempts yet	1s	128 MB	Judgeable
Up the StairsSimulate people passing boxes up a narrow staircase and determine the minimum time until all remaining boxes reach the top floor.	Medium7	SimulationGreedy+1	No attempts yet	1s	128 MB	Judgeable
Choosing a cameraProcess camera offers online and, at each query, report the earliest cheapest camera that is not dominated by any other offer seen so far in pixels and zoom.	Medium7	Binary searchSorting+1	No attempts yet	1s	128 MB	Judgeable
Multiprocessor SchedulingGiven two sequences of N processor-bound procedures each, find the minimum makespan when a shared processor forces ordering constraints between the two applications.	Medium7	Dynamic programmingGreedy+1	No attempts yet	3s	128 MB	Judgeable