Problems

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Total results29,250 problems

Rinsing the Cream Can
Medium7
Math, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Mall Mania
Medium7
Geometry, BFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cousin Strings
Medium7
Graph, BFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Eventually Periodic Sequence
Medium7
Math, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Point of View in Flatland
Medium7
Geometry, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
How Many Zeros?
Medium7
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Go
Medium7
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Crabbles
Medium7
Trie, Backtracking+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
So You Want to Be a 2ⁿ-aire?
Medium7
Dynamic programming, Probability+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pick-up Sticks
Medium7
Geometry, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cutting a Polygon
Medium7
Geometry, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Practice
Medium7
Math, Probability+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Help!
Medium7
String, Hash map+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Personality Diagnostic Test
Medium7
Graph, Union-find
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Grid Speed
Medium7
Graph, Shortest path+2
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Tango Tango Insurrection
Medium7
Dynamic programming, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
XYZZY
Medium7
Graph, Shortest path+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Dumb Bones
Medium7
Dynamic programming, Probability+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Arctic Network
Medium7
Minimum spanning tree, Union-find+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Trains
Medium7
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Faucet Flow
Medium7
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Beavergnaw
Medium7
Geometry, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Adventures in Moving - Part V
Medium7
Geometry, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Edit Step Ladders
Medium7
Dynamic programming, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Origami
Medium7
Geometry, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Fire Station
Medium7
Graph, Shortest path+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Gas Station Numbers
Medium7
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Doublets
Medium7
BFS, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Yahtzee
Medium7
Dynamic programming, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Polylops
Medium7
Geometry, String matching+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Fangorn Forest
Medium7
Geometry, Sorting+2
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Rings and Runes
Medium7
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bilbo's Birthday
Medium7
Sorting, Divide and conquer+2
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Temple Build
Medium7
Dynamic programming, Math+2
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Bracelets
Medium7
Dynamic programming, String+2
No attempts yet
Time limit
30s
Memory limit
256 MB
Judgeable
Sangkeun's Girlfriend
Medium7
Math, Binary search+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Vampire Count Kim Sang-geun
Medium7
Number theory, Math+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Building Zombie Fences
Medium7
Backtracking, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Save the Python Programmers!
Medium7
BFS, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Zombie Blast!
Medium7
BFS, Graph+2
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Blenjeel Sand Worms and Color Wriggles
Medium7
BFS, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Rescue Beacon
Medium7
Geometry, Sorting+2
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Crazy Circuits
Medium7
Graph, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Frogger
Medium7
BFS, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Beads
Medium7
BFS, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Lightbulb Testing
Medium7
Implementation, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
YO!
Medium7
Dynamic programming, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Rank and File
Medium7
Simulation, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Screen Behind the Mirror
Medium7
Geometry, Simulation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Another Version of the Truth
Medium7
Graph, BFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
'Roid Rage
Medium7
Geometry, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pegs
Medium7
DFS, Backtracking+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Syntax Included
Medium7
String, Recursion+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Know When to Hold 'em
Medium7
Brute force, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Revenge of Pythagoras
Medium7
Number theory, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Laser Tag
Medium7
Geometry, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Shut the Box
Medium7
Dynamic programming, Bit manipulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Queen Collisions
Medium7
Math, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Up and Down
Medium7
BFS, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cell Towers
Medium7
Geometry, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hex Tile Equations
Medium7
Backtracking, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Law of the Jungle
Medium7
Simulation, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Serial Numbers
Medium7
Intervals, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Power Cables to Sewer Pipes
Medium7
Graph, Minimum spanning tree+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Falling Ice
Medium7
Geometry, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Connect
Medium7
Graph, Union-find+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Get Them All
Medium7
Simulation, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Data Mining?
Medium7
Simulation, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tournament Brackets
Medium7
Implementation, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Transmitters
Medium7
Geometry, Two pointers+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Triangle Game
Medium7
Backtracking, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Find the Winning Move
Medium7
Game theory, Backtracking+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Component Testing
Medium7
Greedy, Sorting+2
No attempts yet
Time limit
20s
Memory limit
128 MB
Judgeable
Collision Detection
Medium7
Math, Geometry+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Thunk and Plunk
Medium7
Geometry, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Line of Sight
Medium7
Geometry, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Road Rally
Medium7
BFS, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Two Mountaineers
Medium7
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Trie, Again Trie
Medium7
Tree, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Stems Sell
Medium7
String, String matching+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Safety in Alchemy
Medium7
Graph, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Enigmatic Travel
Medium7
Combinatorics, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Mobiles
Medium7
Tree, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Right-Hand Rule
Medium7
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
All Roads Lead to Rome
Medium7
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Apply a Cold Compress
Medium7
Recursion, Divide and conquer+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Chambers Ceramic Conundrum
Medium7
Backtracking, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Fraction Subtraction
Medium7
Number theory, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Covered Walkway
Medium7
Dynamic programming, Divide and conquer+1
No attempts yet
Time limit
10s
Memory limit
128 MB
Judgeable
Double Dealing
Medium7
Simulation, Math+1
No attempts yet
Time limit
15s
Memory limit
32 MB
Judgeable
Estimation
Medium7
Dynamic programming, Divide and conquer+2
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Red-Blue Spanning Tree
Medium7
Union-find, Graph+2
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Science!
Medium7
Graph, Combinatorics+2
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Shape Number
Medium7
String, String matching+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Wealthy Family
Medium7
Tree, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Chain Code
Medium7
Geometry, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Clickomania
Medium7
Dynamic programming, Intervals+1
No attempts yet
Time limit
10s
Memory limit
128 MB
Judgeable
Walk in the Park
Medium7
Sorting, Hash map+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Coin Toss
Medium7
Probability, Geometry+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Team Work
Medium7
Backtracking, Brute force+1
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Rinsing the Cream CanMinimize the whiskey left in a can after at most k rinses, each adding water then pouring out with a fixed residual volume, using at most Vb water.	Medium7	MathGreedy+2	No attempts yet	1s	128 MB	Judgeable
Mall ManiaTwo disjoint polyomino malls are given by boundary lattice points; find the shortest Manhattan walking distance along the grid between any intersection of one mall and any of the other.	Medium7	GeometryBFS+2	No attempts yet	1s	128 MB	Judgeable
Cousin StringsFind the smallest n such that x is an n-th cousin of y, where each cousin step requires a common string reachable by deleting at most half of each string, or report that no n exists.	Medium7	GraphBFS+2	No attempts yet	1s	128 MB	Judgeable
Eventually Periodic SequenceGiven N, a start n, and a function f written in postfix, follow the iteration x -> f(x) mod N and report the length of its eventual cycle.	Medium7	MathSimulation+2	No attempts yet	1s	128 MB	Judgeable
Point of View in FlatlandGiven three disjoint discs, find the point from which all three subtend the same angle, choosing the one with the largest angular diameter.	Medium7	GeometryMath+2	No attempts yet	1s	128 MB	Judgeable
How Many Zeros?For each range n to m, count how many times the digit 0 appears when every integer in the range is written in decimal without leading zeros.	Medium7	MathImplementation+2	No attempts yet	1s	128 MB	Judgeable
GoGiven a sequence of legal Go stone placements on an odd n x n board, apply capture and territory rules to compute each player's final score.	Medium7	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
CrabblesGiven a dictionary and hands of at most 10 lettered tiles with values, find the maximum-scoring dictionary word formable from each hand's tiles.	Medium7	TrieBacktracking+2	No attempts yet	1s	128 MB	Judgeable
So You Want to Be a 2ⁿ-aire?A contestant with a current prize faces n questions; each question's success chance p is uniform on [t,1]. Find the optimal expected prize, to three decimals.	Medium7	Dynamic programmingProbability+2	No attempts yet	1s	128 MB	Judgeable
Pick-up SticksGiven line segments thrown in order, report the segments not crossed by any later segment, using segment intersection tests.	Medium7	GeometryBrute force+2	No attempts yet	1s	128 MB	Judgeable
Cutting a PolygonFor each of several cutting lines, compute the total length of the intersection of the line with a given simple polygon.	Medium7	GeometryImplementation+2	No attempts yet	1s	128 MB	Judgeable
PracticeGiven pairs (n, w), fit a logistic regression by maximizing the product of per-observation likelihoods and report the slope and intercept to four decimals.	Medium7	MathProbability+2	No attempts yet	1s	128 MB	Judgeable
Help!Given two patterns of literal words and named placeholders, find the lexicographically smallest word phrase matching both, or output a minus sign if none exists.	Medium7	StringHash map+2	No attempts yet	1s	128 MB	Judgeable
Personality Diagnostic TestFrom each question's preference of one activity over four others, group all activities whose derived preferences are mutually contradictory.	Medium7	GraphUnion-find	No attempts yet	1s	128 MB	Judgeable
Grid SpeedGiven a grid of streets with speed limits, find the earliest arrival time within a time window and the most fuel-efficient trip, choosing speeds per segment.	Medium7	GraphShortest path+2	No attempts yet	5s	128 MB	Judgeable
Tango Tango InsurrectionGiven a sequence of required taps or rests, find the minimum total energy for the two feet under per-foot cost and crossover rules.	Medium7	Dynamic programmingSimulation+2	No attempts yet	1s	128 MB	Judgeable
XYZZYGiven rooms with energy values and one-way doors, decide if the player can reach room n from room 1 while energy stays above zero, where rooms may repeat.	Medium7	GraphShortest path+1	No attempts yet	1s	128 MB	Judgeable
Dumb BonesGiven the chance that each placed domino tips left or right, find the minimum expected total placements needed to finish a run of n dominoes.	Medium7	Dynamic programmingProbability+1	No attempts yet	1s	128 MB	Judgeable
Arctic NetworkGiven P outposts and S satellite channels, find the minimum radio range D so that all outposts stay connected, where satellite-linked outposts communicate freely.	Medium7	Minimum spanning treeUnion-find+2	No attempts yet	1s	128 MB	Judgeable
TrainsGiven daily train schedules over at most 20 stations, list every Pareto-optimal departure time and travel time from an origin to a destination.	Medium7	GraphShortest path+2	No attempts yet	1s	128 MB	Judgeable
Faucet FlowWater pours at 1 cubic unit per second into a 1-wide tank with vertical dividers of given heights; find the time when it first overflows the outermost divider.	Medium7	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
BeavergnawGiven a cylinder of diameter D and height D, find the inner cylinder diameter d so that the remaining wood (two frustums plus a middle cylinder) has the requested volume. Output d to three decimals for each test case.	Medium7	GeometryMath+1	No attempts yet	1s	128 MB	Judgeable
Adventures in Moving - Part VDecide whether a rectangular box can pass through a height-limited doorway and rest flat on the floor against the front wall of a van.	Medium7	GeometryMath+2	No attempts yet	1s	128 MB	Judgeable
Edit Step LaddersGiven a lexicographically sorted dictionary, find the longest sequence of words where each consecutive pair differs by one insertion, deletion, or substitution, and the sequence follows dictionary order.	Medium7	Dynamic programmingString+2	No attempts yet	1s	128 MB	Judgeable
OrigamiGiven up to 8 folds of a square sheet, count how many layers of paper a query point pierces, ignoring points on edges.	Medium7	GeometrySimulation+2	No attempts yet	1s	128 MB	Judgeable
Fire StationGiven a weighted city graph and existing fire stations, pick the intersection that minimizes the maximum distance from any intersection to its nearest station.	Medium7	GraphShortest path+1	No attempts yet	1s	128 MB	Judgeable
Gas Station NumbersGiven a price written with digit tiles, find the next higher price achievable by permuting and flipping the same tiles, or report that none exists.	Medium7	GreedySorting+2	No attempts yet	1s	128 MB	Judgeable
DoubletsGiven a dictionary, answer queries for the shortest chain of words where consecutive words differ in exactly one letter, choosing the lexicographically smallest chain.	Medium7	BFSGraph+2	No attempts yet	1s	128 MB	Judgeable
YahtzeeGiven 13 rounds of five dice, assign each round to a distinct Yahtzee category to maximize total score including the upper-section bonus.	Medium7	Dynamic programmingBit manipulation+1	No attempts yet	1s	128 MB	Judgeable
PolylopsGiven the vertices of a simple polygon, count how many distinct lines reflect it exactly onto itself.	Medium7	GeometryString matching+1	No attempts yet	1s	128 MB	Judgeable
Fangorn ForestFind the smallest-angle oriented line through the rectangle's center and at least one tree that splits trees into two equal halves by the left-side rule.	Medium7	GeometrySorting+2	No attempts yet	3s	128 MB	Judgeable
Rings and RunesValidate the runes for several gates, report the highest-priority error, then decide if the resulting 3-CNF formula is satisfiable.	Medium7	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
Bilbo's BirthdayGiven two permutations of the same N names, find an ordering of the names that minimizes the total number of pairs ordered differently from Frodo's chart plus pairs ordered differently from Sam's chart.	Medium7	SortingDivide and conquer+2	No attempts yet	3s	256 MB	Judgeable
Temple BuildGiven an ideal truncated square pyramid and three brick cube sizes, stack square layers fully inside the shape to maximize total volume.	Medium7	Dynamic programmingMath+2	No attempts yet	3s	128 MB	Judgeable
BraceletsGiven two circular strings, find the longest common subsequence that can be read in the same or opposite orientation on the two bracelets, and report twice its length.	Medium7	Dynamic programmingString+2	No attempts yet	30s	256 MB	Judgeable
Sangkeun's GirlfriendChoose a constant driving speed that minimizes travel time given a fuel budget over a fixed distance, output truncated to two decimals.	Medium7	MathBinary search+1	No attempts yet	1s	128 MB	Judgeable
Vampire Count Kim Sang-geunFor each n under 10000, find natural a, b, c with a >= c, a^3 + c^3 = n*b^3, minimizing a + b + c + b, or print No value if the minimum exceeds 4000.	Medium7	Number theoryMath+1	No attempts yet	2s	128 MB	Judgeable
Building Zombie FencesOn an n x n grid with n at most 6, find the longest single closed fence loop using lattice-point walls so every numbered plot has exactly that many of its four sides walled.	Medium7	BacktrackingBrute force+2	No attempts yet	1s	128 MB	Judgeable
Save the Python Programmers!Six labeled teams on a graph must swap houses, moving one team per night into an adjacent empty house while strictly alternating team type; find the minimum number of nights or report impossibility.	Medium7	BFSGraph+2	No attempts yet	1s	128 MB	Judgeable
Zombie Blast!For each grid map, find the largest squared Euclidean distance from any zombie cell to its nearest mine cell and print that maximum.	Medium7	BFSGraph+2	No attempts yet	5s	128 MB	Judgeable
Blenjeel Sand Worms and Color WrigglesA snake of n cells starts filling the left column of an n by m colored grid and must reach the right column, moving one end per wriggle, always keeping n distinct-colored cells; find the minimum number of wriggles.	Medium7	BFSSimulation+2	No attempts yet	1s	128 MB	Judgeable
Rescue BeaconFor each convex triangulated polyhedron, find the maximum number of facets visible from any single viewing direction, where visible means the facet normal has positive dot product with the direction.	Medium7	GeometrySorting+2	No attempts yet	3s	128 MB	Judgeable
Crazy CircuitsGiven a directed acyclic circuit with current demands on edges, find the minimum supply current at the + terminal so every component gets its required current, or report impossible.	Medium7	GraphDynamic programming+2	No attempts yet	1s	128 MB	Judgeable
FroggerOn a wrapping grid with moving cars, find the least number of seconds Phil spends standing on road cells before reaching water, or report the route impossible.	Medium7	BFSGraph+2	No attempts yet	1s	128 MB	Judgeable
BeadsGiven two 13-bead rings, each with 13 gray and 13 yellow beads, find the fewest swaps of a 3-bead block between the rings to put all gray on top.	Medium7	BFSString+2	No attempts yet	1s	128 MB	Judgeable
Lightbulb TestingGiven a bulb life n and a periodic on/off pattern (with nested repeating groups), find the real time elapsed when total on-time reaches n.	Medium7	ImplementationMath+2	No attempts yet	1s	128 MB	Judgeable
YO!Count paint-over patterns of a short string whose remaining letters, read left to right, form one or more dictionary words without overlap.	Medium7	Dynamic programmingString+2	No attempts yet	1s	128 MB	Judgeable
Rank and FileGiven a pawnless chess position and the side to move, decide whether that side's king is safe, in check, or checkmated.	Medium7	SimulationBrute force+2	No attempts yet	1s	128 MB	Judgeable
The Screen Behind the MirrorSimulate a laser beam in a square region bouncing off mirrors and splitting at splitters, and list every detector that absorbs a beam.	Medium7	GeometrySimulation	No attempts yet	1s	128 MB	Judgeable
Another Version of the TruthOn a hexagonal rhombus board, compute for each player the best Influence they can reach by placing one extra piece or passing, each evaluated independently from the original board.	Medium7	GraphBFS+2	No attempts yet	1s	128 MB	Judgeable
'Roid RageGiven up to 10 simple polygons with integer vertices, report every pair that overlaps or touches, listing pairs in sorted order.	Medium7	GeometryImplementation+2	No attempts yet	1s	128 MB	Judgeable
PegsGiven a 5x5 peg solitaire board with empty, peg, and blocked cells, find the minimum number of pegs reachable by any sequence of horizontal or vertical jumps.	Medium7	DFSBacktracking+2	No attempts yet	1s	128 MB	Judgeable
Syntax IncludedParse each HTML-like string against the given grammar and decide whether it is syntactically valid.	Medium7	StringRecursion+2	No attempts yet	1s	128 MB	Judgeable
Know When to Hold 'emGiven seven visible cards, find the best five-card poker hand an opponent holding two unknown hole cards could make, and print it with wildcard suits for ties.	Medium7	Brute forceImplementation+2	No attempts yet	1s	128 MB	Judgeable
Revenge of PythagorasGiven a natural number A, count the values B > A such that A, B and hypotenuse C form a right triangle with natural C.	Medium7	Number theoryMath+2	No attempts yet	1s	128 MB	Judgeable
Laser TagFind every firing angle from the origin whose laser beam returns to the origin after at most 7 reflections off flat mirrors, and print the angles in order.	Medium7	GeometrySimulation+1	No attempts yet	1s	128 MB	Judgeable
Shut the BoxGiven N pieces labeled 1 to N and up to T turn values, mark disjoint sets of unmarked pieces summing exactly to each turn value in order, and find the largest total number of pieces markable.	Medium7	Dynamic programmingBit manipulation+2	No attempts yet	1s	128 MB	Judgeable
Queen CollisionsGiven groups of queens placed along arithmetic progressions on an n by n board, count pairs that share a row, column, or diagonal with no queen between them.	Medium7	MathSorting+2	No attempts yet	1s	128 MB	Judgeable
Up and DownGiven ladders and chutes on a path up to 1e9 and jumps of at most s (2 to 6), find the minimum number of turns to reach space w.	Medium7	BFSGreedy+1	No attempts yet	1s	128 MB	Judgeable
Cell TowersWalk a polyline road at every mile marker, compute each tower's signal p/d^2 rounded to nearest integer, and report only markers where the best tower (ties by alphabetical label) changes.	Medium7	GeometrySimulation+2	No attempts yet	1s	128 MB	Judgeable
Hex Tile EquationsFind the unique Hamiltonian path through a small hex grid of digit and operator tiles that spells a valid left-to-right equation with both sides equal.	Medium7	BacktrackingDFS+2	No attempts yet	1s	128 MB	Judgeable
The Law of the JungleGiven up to 20 bridges with capacity and crossing time, simulate the two rules to find the minimum total time for all people to cross.	Medium7	SimulationGreedy+2	No attempts yet	1s	128 MB	Judgeable
Serial NumbersApply range assignments of a status letter and a transfer code to serial numbers, then print the minimal merged list of ranges.	Medium7	IntervalsSorting+1	No attempts yet	1s	128 MB	Judgeable
Power Cables to Sewer PipesFor each graph, remove a maximum-length set of edges while keeping the graph connected, then count the integer partitions of the removed length in meters.	Medium7	GraphMinimum spanning tree+2	No attempts yet	1s	128 MB	Judgeable
Falling IceSimulate disks falling one at a time into a box, each settling at the lowest reachable resting spot, and report the final pile height.	Medium7	GeometrySimulation+2	No attempts yet	1s	128 MB	Judgeable
ConnectDetermine whether the last of alternating Twixt pegs placed on a bounded board completes a connected path joining the placing player's two opposing endzones.	Medium7	GraphUnion-find+2	No attempts yet	1s	128 MB	Judgeable
Get Them AllSimulate the vehicle dispatch and routing rules to find when all contestants reach the contest site, or how many arrive by the time limit.	Medium7	SimulationImplementation+1	No attempts yet	1s	128 MB	Judgeable
Data Mining?Given a small Minesweeper board and one initial click, simulate the two deterministic clearing rules and find the starting cell that leaves the fewest covered safe cells.	Medium7	SimulationBrute force+2	No attempts yet	1s	128 MB	Judgeable
Tournament BracketsGiven team pairings listed in column-major order and the champion, reconstruct the tournament bracket and render it with slashes, backslashes, and underscores.	Medium7	ImplementationSimulation+2	No attempts yet	1s	128 MB	Judgeable
TransmittersGiven a fixed center, a radius, and up to 150 points, find the largest number of points that fit inside some semicircular half-disk at any rotation.	Medium7	GeometryTwo pointers+2	No attempts yet	1s	128 MB	Judgeable
The Triangle GameGiven six triangles with numbered edges, rotate and arrange them into a hexagon where touching edges match, maximizing the sum of the six outer edges.	Medium7	BacktrackingBrute force+2	No attempts yet	1s	128 MB	Judgeable
Find the Winning MoveGiven a 4x4 tic-tac-toe position with x to move, find the earliest cell in row-major order where x has a forced win, or report none.	Medium7	Game theoryBacktracking+2	No attempts yet	1s	128 MB	Judgeable
Component TestingGiven component classes each needing a set number of distinct reviewers per component, and engineer ranks each able to review a limited number of components, decide if all components can be reviewed.	Medium7	GreedySorting+2	No attempts yet	20s	128 MB	Judgeable
Collision DetectionGiven two recent position/time/speed readings per car, decide whether the cars pass within 18 ft at any moment in the next 30 seconds.	Medium7	MathGeometry+2	No attempts yet	1s	128 MB	Judgeable
Thunk and PlunkGiven scattered points labeled as hitting water or solid ground, decide whether any solid point is provably surrounded by water under the stated smoothness guarantee.	Medium7	GeometryGraph+1	No attempts yet	1s	128 MB	Judgeable
Line of SightGiven a rectangular floor, a rectangular blocker, and a camera sliding along one wall, find the percentage of open floor area hidden in the blocker's shadow.	Medium7	GeometryMath+2	No attempts yet	1s	128 MB	Judgeable
Road RallyFind the shortest time for a momentum-based motorcycle to visit checkpoints 0 through the last one in order on a grid with walls.	Medium7	BFSShortest path+2	No attempts yet	1s	128 MB	Judgeable
Two MountaineersGiven a polygonal mountain profile with equal endpoints, find the minimum total elevation change for two climbers who swap endpoints while staying at equal height.	Medium7	Dynamic programmingGreedy+2	No attempts yet	1s	128 MB	Judgeable
Trie, Again TrieGiven trees encoded in preorder, find the repeated subtree whose replacement by one shared copy saves the most nodes, breaking ties by size then preorder.	Medium7	TreeDFS+2	No attempts yet	1s	128 MB	Judgeable
Stems SellApply ordered pattern-to-replacement rewrite rules, which support *, V, C, and back-references, to every word in each paragraph.	Medium7	StringString matching+2	No attempts yet	1s	128 MB	Judgeable
Safety in AlchemyGiven reaction heats between pairs of chemicals and limited amounts of each chemical, find the maximum total heat that can be produced.	Medium7	GraphDynamic programming+2	No attempts yet	1s	128 MB	Judgeable
Enigmatic TravelFor each complete graph size L, compute the average cost of a random walk, a random simple path, and a random simple cycle.	Medium7	CombinatoricsMath+1	No attempts yet	1s	128 MB	Judgeable
MobilesGiven a mobile tree with one unknown object weight, find the weight that balances every bar and check that no two bars collide when they rotate.	Medium7	TreeDFS+2	No attempts yet	1s	128 MB	Judgeable
Right-Hand RuleSimulate the right-hand wall-following rule from each entrance in a maze and count how many entrances let the walker see or step on the single goal.	Medium7	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
All Roads Lead to RomeGiven a connected weighted graph, choose two hub nodes and assign every node to a hub to minimize the total routed distance over all ordered pairs.	Medium7	GraphShortest path+2	No attempts yet	1s	128 MB	Judgeable
Apply a Cold CompressDecode each compression-expression into its smallest pixel picture by parsing split tags and computing the relative scaling of the two halves, then draw the framed grid.	Medium7	RecursionDivide and conquer+2	No attempts yet	1s	128 MB	Judgeable
Chambers Ceramic ConundrumGiven nine tetromino-like tiles with fixed shapes and a strict placement order, decide whether the forced backtracking rule can cover a 6x6 grid and print the layout.	Medium7	BacktrackingSimulation+2	No attempts yet	1s	128 MB	Judgeable
Fraction SubtractionFor each fraction b/n, list every numerator a and denominator m with a >= 0, m > 0 such that the wrong subtraction (a-b)/(m-n) equals the correct one a/m - b/n.	Medium7	Number theoryMath+2	No attempts yet	1s	128 MB	Judgeable
Covered WalkwayCover all required points on a line with segments, where covering from x to y costs c plus (x - y) squared, minimizing total cost.	Medium7	Dynamic programmingDivide and conquer+1	No attempts yet	10s	128 MB	Judgeable
Double DealingSimulate dealing and gathering the deck to find the number of repetitions after which the card order returns to the start.	Medium7	SimulationMath+1	No attempts yet	15s	32 MB	Judgeable
EstimationPartition an array into k contiguous sections, each replaced by one constant value, to minimize the total absolute error. Multiple test cases until 0 0.	Medium7	Dynamic programmingDivide and conquer+2	No attempts yet	5s	128 MB	Judgeable
Red-Blue Spanning TreeGiven a connected graph with red and blue edges, decide whether some spanning tree has exactly k blue edges.	Medium7	Union-findGraph+2	No attempts yet	3s	256 MB	Judgeable
Science!Given a bipartite allowance graph on n people and n buttons, find the largest number of edge-disjoint perfect matchings (a maximum k-regular subgraph).	Medium7	GraphCombinatorics+2	No attempts yet	3s	128 MB	Judgeable
Shape NumberGiven a chain code, take its first difference mod 8 and print the lexicographically smallest cyclic rotation of that sequence.	Medium7	StringString matching+1	No attempts yet	2s	128 MB	Judgeable
Wealthy FamilyGiven a rooted tree with a weight on each node, pick exactly k nodes with no ancestor relation between any two, maximizing the total weight, over multiple test cases.	Medium7	TreeDynamic programming+2	No attempts yet	1s	128 MB	Judgeable
Chain CodeGiven the chain code of a hole-free pixel region, compute its area in pixels using the shoelace formula on the boundary walk.	Medium7	GeometryMath+2	No attempts yet	1s	128 MB	Judgeable
ClickomaniaGiven a string over uppercase letters, decide whether the one dimensional Clickomania puzzle can be fully cleared.	Medium7	Dynamic programmingIntervals+1	No attempts yet	10s	128 MB	Judgeable
Walk in the ParkCount trees visible from at least one given horizontal or vertical path, where a tree is visible if no other tree blocks the line of sight.	Medium7	SortingHash map+2	No attempts yet	1s	128 MB	Judgeable
Coin TossGiven a grid of m by n tiles of side t and a coin of diameter c, compute the percentage chance the coin covers exactly 1, 2, 3, or 4 tiles when its center lands uniformly at random in the rectangle.	Medium7	ProbabilityGeometry+2	No attempts yet	1s	128 MB	Judgeable
Team WorkSplit the given pieces into three groups of equal total length, using each piece at most once, and report the largest such length or 0.	Medium7	BacktrackingBrute force+1	No attempts yet	5s	128 MB	Judgeable