Problems

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Total results29,425 problems

Economic Phone Calls
Medium6
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Homogeneous Square
Medium6
Math, Matrix+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Decorate the Wall
Medium6
Geometry, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
European railroad tracks
Medium6
Brute force, Backtracking+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Even a Kindergartner Could Solve This
Medium6
String, Dynamic programming+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Boolean Logic
Medium6
Implementation, Recursion+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Run Length Encoding
Medium6
String, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Fixed Partition Contest Management
Medium6
Brute force, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Largest Rectangle in a Histogram
Medium6
Stack, Array+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
California Jones and the Gate to Freedom
Medium6
Combinatorics, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bound Found
Medium6
Prefix sum, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Fiber Network
Medium6
Graph, BFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Mondrian's Dream
Medium6
Dynamic programming, Bit manipulation+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Hike on a Graph
Medium6
BFS, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
From Dusk till Dawn (or Vladimir the Vampire)
Medium6
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Heavy Cargo
Medium6
Graph, Union-find+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Frogger
Medium6
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Arbitrage
Medium6
Shortest path, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Tower of Babylon
Medium6
Dynamic programming, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Ant Movement
Medium6
Simulation, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bug Catcher
Medium6
Stack, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Ambiguous Result
Medium6
Dynamic programming, Intervals+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Arable Area
Medium6
Geometry, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Roman Expressions
Medium6
String, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Crane
Medium6
Geometry, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Death to Binary?
Medium6
Math, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Electricity
Medium6
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Truck History
Medium6
Minimum spanning tree, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Interesting Maze Game
Medium6
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Frogger
Medium6
BFS, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Gallup
Medium6
Math, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Parallel Computer Simulator
Medium6
Simulation, Queue+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Moving Pianos
Medium6
Greedy, Intervals+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Collecting Beepers
Medium6
Dynamic programming, Bit manipulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Christmas Presents
Medium6
Dynamic programming, Greedy
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Directed mazes
Medium6
BFS, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
A Language for Constants
Medium6
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
A Model Railroad
Medium6
DFS, Backtracking+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Comment removal
Medium6
String, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Returning Books
Medium6
Sorting, Array+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Rectangle Cutting
Medium6
BFS, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Parallelogram Counting
Medium6
Hash map, Geometry+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
A Coin Game
Medium6
BFS, Simulation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
The Hungary Games
Medium6
Shortest path, Graph+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Sample Size
Medium6
Math, Number theory+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Blood Distribution
Medium6
Greedy, Math+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Vampire Tunnels
Medium6
Shortest path, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Reorganization
Medium6
Greedy, Tree+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Tree Pruning
Medium6
Tree, Dynamic programming+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Computer Purchase Return
Medium6
Dynamic programming, Array+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Space Miner
Medium6
Geometry, Implementation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Shop and Ship
Medium6
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Invasion of the Boxes
Medium6
Geometry, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Herding
Medium6
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Candy
Medium6
Dynamic programming, Bit manipulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Friends
Medium6
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bowling for Numbers
Medium6
Dynamic programming, Prefix sum
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cows
Medium6
Geometry, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tin Can Telephone
Medium6
Geometry, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
R & J
Medium6
Geometry, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Domino
Medium6
Graph, Union-find+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cross Spiral
Medium6
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Number Matrix
Medium6
Graph, BFS+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Primed Subsequences
Medium6
Prefix sum, Number theory+2
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
Fractals
Medium6
Recursion, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Return of Space Turtle
Medium6
Simulation, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Trucking Troubles
Medium6
Union-find, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Blindfold
Medium6
Simulation, Bit manipulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Game Show Math
Medium6
DFS, Backtracking+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Duathlon
Medium6
Geometry, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Connect the Campus
Medium6
Minimum spanning tree, Union-find+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Election Night
Medium6
Greedy, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sheep and Coyotes
Medium6
Geometry, Sorting
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Extension Cords
Medium6
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Maple Roundup
Medium6
Geometry, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sum of Products
Medium6
String, Recursion+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Mountain Passage
Medium6
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Quadtrees
Medium6
Recursion, Tree+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
World Cup
Medium6
Backtracking, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Stepping on Tiles
Medium6
Dynamic programming, Hash map+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Tree Isomorphism
Medium6
Tree, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Stacking Cubes
Medium6
Array, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
To bet, or not to bet
Medium6
Dynamic programming, Probability+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Building Snowmen
Medium6
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Snow Cones
Medium6
Greedy, Two pointers+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Letter Game
Medium6
String, Hash map+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Little Shop of Flowers
Medium6
Dynamic programming
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Flatten
Medium6
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Recycling Proteins
Medium6
Dynamic programming, String
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Grazing on the Run
Medium6
Dynamic programming, Intervals+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Dividing the Path
Medium6
Dynamic programming, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cleaning Shifts
Medium6
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Journey
Medium6
Tree, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Football League
Medium6
Math, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
A Decorative Fence
Medium6
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Royal Guards
Medium6
Graph, Union-find+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Printed Circuit
Medium6
Graph, Minimum spanning tree+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Diamonds
Medium6
Geometry, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cards
Medium6
Math, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
CPU
Medium6
Graph, Greedy+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Economic Phone CallsGiven a chronologically ordered call log with some entries marked important, keep the fewest entries so all important ones stay and the listed year-recovery rule still gives each kept call its original year.	Medium6	Dynamic programmingGreedy+2	No attempts yet	1s	128 MB	Judgeable
Homogeneous SquareGiven an n by n grid, decide whether every choice of n cells with distinct rows and distinct columns has the same sum.	Medium6	MathMatrix+2	No attempts yet	1s	128 MB	Judgeable
Decorate the WallGiven non-overlapping axis-aligned rectangles on a wall, find the lowest then leftmost position where a new w' by h' rectangle fits without overlapping any of them, or report failure.	Medium6	GeometrySorting+2	No attempts yet	1s	128 MB	Judgeable
European railroad tracksGiven up to 8 distinct gauge lengths, find the smallest number of points on a line such that every gauge appears as a distance between two points.	Medium6	Brute forceBacktracking+1	No attempts yet	1s	128 MB	Judgeable
Even a Kindergartner Could Solve ThisDecide whether each string over the alphabet {, }, and comma is a valid set by the given grammar, where brace characters can be either delimiters or atoms.	Medium6	StringDynamic programming+2	No attempts yet	2s	128 MB	Judgeable
Boolean LogicParse a fully parenthesized proposition formula, then print a truth table with each subformula's value placed at its symbol or operator column.	Medium6	ImplementationRecursion+2	No attempts yet	1s	128 MB	Judgeable
Run Length EncodingEncode each input line with run-length encoding: runs of 2 to 9 repeats become a count plus the character, longer runs split at 9, and everything else is wrapped in 1s with each 1 doubled.	Medium6	StringSimulation+2	No attempts yet	1s	128 MB	Judgeable
Fixed Partition Contest ManagementAssign up to 10 problems to at most 3 members and order each member's load to minimize the sum of completion times, where a problem's duration depends on the solver's brightness.	Medium6	Brute forceDynamic programming+2	No attempts yet	1s	128 MB	Judgeable
Largest Rectangle in a HistogramGiven a histogram of unit-width bars with varying heights, find the area of the largest rectangle that fits inside it, processing several test cases until a 0 terminates input.	Medium6	StackArray+2	No attempts yet	1s	256 MB	Judgeable
California Jones and the Gate to FreedomGiven n stones and a binary index b, decide whether the chosen n/2 stones are exactly the combination at lexicographic rank b among all size-n/2 subsets.	Medium6	CombinatoricsMath+2	No attempts yet	1s	128 MB	Judgeable
Bound FoundFor multiple targets, find the contiguous subarray whose absolute sum is closest to the target, reporting that absolute sum.	Medium6	Prefix sumSorting+2	No attempts yet	1s	128 MB	Judgeable
Fiber NetworkFor each query in a directed multigraph where every edge is labeled with a set of companies, list the companies that have a path from A to B using only their own edges.	Medium6	GraphBFS+2	No attempts yet	1s	128 MB	Judgeable
Mondrian's DreamCount the number of ways to tile an h by w rectangle (up to 11 by 11) with 2 by 1 dominoes, for several test cases.	Medium6	Dynamic programmingBit manipulation+2	No attempts yet	1s	256 MB	Judgeable
Hike on a GraphThree pieces on a complete edge-colored graph; a piece may move only along an edge whose color matches the edge between the other two, and we want the fewest moves to gather all three on one vertex.	Medium6	BFSGraph+2	No attempts yet	1s	128 MB	Judgeable
From Dusk till Dawn (or Vladimir the Vampire)Given nightly train routes between cities with departure and travel hours, find the route that minimizes the number of daytime waits, where a wait costs one litre of blood.	Medium6	GraphShortest path+2	No attempts yet	1s	128 MB	Judgeable
Heavy CargoGiven an undirected weighted graph, find the path between two cities whose minimum edge weight is as large as possible, for each test case.	Medium6	GraphUnion-find+2	No attempts yet	1s	128 MB	Judgeable
FroggerGiven n points, find the path from point 1 to point 2 that minimizes the longest edge, and report that minimized maximum edge length.	Medium6	GraphShortest path+2	No attempts yet	1s	128 MB	Judgeable
ArbitrageGiven currencies and exchange rates, decide whether some cycle of conversions turns one unit of a currency into more than one unit.	Medium6	Shortest pathGraph+2	No attempts yet	1s	128 MB	Judgeable
The Tower of BabylonGiven block types with unlimited copies, each reorientable, find the maximum height of a stack where each block's base is strictly smaller than the one below.	Medium6	Dynamic programmingSorting+1	No attempts yet	1s	128 MB	Judgeable
Ant MovementSimulate ants that reverse on collision and fall off the plank, and report the fall time and the original position(s) of the last ants.	Medium6	SimulationSorting+2	No attempts yet	1s	128 MB	Judgeable
Bug CatcherFor each code line, repeatedly remove the first occurrence of a given bug string until no occurrence remains, then print the result.	Medium6	StackString+1	No attempts yet	1s	128 MB	Judgeable
Ambiguous ResultGiven a parenthesis-free expression of numbers joined by + and *, restore parentheses to find the smallest and largest values it can evaluate to.	Medium6	Dynamic programmingIntervals+2	No attempts yet	1s	128 MB	Judgeable
Arable AreaGiven a lattice polygon, count the unit grid squares fully contained inside it.	Medium6	GeometryMath+2	No attempts yet	1s	128 MB	Judgeable
Roman ExpressionsParse lines of Roman numeral arithmetic with ten registers, evaluating each assignment and printing the result or Error, handling RESET and QUIT.	Medium6	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
CraneGiven a chain of segments with one joint angle changing per command, report the endpoint coordinates after each change within 0.02 and to two decimals.	Medium6	GeometryMath+2	No attempts yet	1s	128 MB	Judgeable
Death to Binary?Add two numbers written in the Fibonacci base and print the sum in canonical Zeckendorf form, aligned for display.	Medium6	MathGreedy+2	No attempts yet	1s	128 MB	Judgeable
ElectricityGiven an undirected graph, find the maximum number of connected components formed when any single vertex is removed.	Medium6	GraphDFS+2	No attempts yet	1s	128 MB	Judgeable
Truck HistoryConnect all truck codes so the total Hamming distance is minimized, then print 1/Q. This is a minimum spanning tree on a complete graph.	Medium6	Minimum spanning treeGraph+2	No attempts yet	1s	128 MB	Judgeable
Interesting Maze GameGiven a 7x7 labyrinth and one extra card, decide whether inserting and rotating that card lets the piece walk to the target in a single move.	Medium6	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
FroggerGiven a wrapping multi-lane road with alternating traffic, find the minimum number of turns for a frog to cross from one curb to the other, cars and frog moving at once.	Medium6	BFSSimulation+1	No attempts yet	1s	128 MB	Judgeable
GallupGiven reported percentages rounded to a fixed number of decimals, find the smallest population whose counts round to exactly those values.	Medium6	MathBrute force+2	No attempts yet	1s	128 MB	Judgeable
Parallel Computer SimulatorSimulate up to ten concurrent programs on one CPU with FIFO scheduling, quantum preemption, and lock/unlock mutual exclusion, then report prints in execution order.	Medium6	SimulationQueue+2	No attempts yet	1s	128 MB	Judgeable
Moving PianosEach piano job is a day interval; decide whether all jobs fit on weekdays, or only with weekends, or not at all, given p tuners doing floor(p/2) jobs per day.	Medium6	GreedyIntervals+2	No attempts yet	1s	128 MB	Judgeable
Collecting BeepersGiven Karel's start and up to 8 beepers on a grid, find the shortest Manhattan-distance round trip visiting every beeper.	Medium6	Dynamic programmingBit manipulation+2	No attempts yet	1s	128 MB	Judgeable
Christmas PresentsChoose a subset of children whose total price is at most p, maximizing excitement of chosen minus frustration of unchosen, and output the lexicographically smallest optimal 0/1 string.	Medium6	Dynamic programmingGreedy	No attempts yet	1s	128 MB	Judgeable
Directed mazesGiven a grid maze where each sign permits turns based on arrival direction, find the fewest intersections on a route from the entrance to the goal.	Medium6	BFSGraph+2	No attempts yet	1s	128 MB	Judgeable
A Language for ConstantsFor each nonzero integer C, output the shortest sequence of C+1/C-1 to start, then INCR and DBL, that builds C, breaking ties by total runtime with DBL cost T and INCR cost 2T.	Medium6	Dynamic programmingGreedy+2	No attempts yet	1s	128 MB	Judgeable
A Model RailroadPlace a non-self-crossing path of straight and curved rails in a small grid from a bottom connection to a top connection, maximizing the number of cells used.	Medium6	DFSBacktracking+2	No attempts yet	1s	128 MB	Judgeable
Comment removalStrip Pascal comments and collapse whitespace, honoring single-quote strings where doubled quotes are literals and comments can span lines.	Medium6	StringSimulation+2	No attempts yet	1s	128 MB	Judgeable
Returning BooksTrack which books are on the shelves and which sit at the desk, then on each SHELVE command report where each returned book belongs by comparing author and title in ASCII order.	Medium6	SortingArray+2	No attempts yet	1s	128 MB	Judgeable
Rectangle CuttingGiven a small cake and several rectangular outlines cut into it, count the number of connected pieces the cake is divided into.	Medium6	BFSImplementation+2	No attempts yet	1s	128 MB	Judgeable
Parallelogram CountingGiven n points, count how many 4-point subsets form a parallelogram by pairing points that share a midpoint.	Medium6	Hash mapGeometry+2	No attempts yet	1s	128 MB	Judgeable
A Coin GameGiven a starting row of 1 to n coins, find the minimum number of single-coin adjacent moves to sort them into increasing order, or report IMPOSSIBLE.	Medium6	BFSSimulation+2	No attempts yet	2s	512 MB	Judgeable
The Hungary GamesGiven a directed weighted graph, find the second smallest distinct total length among all walks from node 1 to node N, or -1 if fewer than two exist.	Medium6	Shortest pathGraph+2	No attempts yet	2s	512 MB	Judgeable
Sample SizeGiven a set of rounded percentages, find the smallest number of interviewees N such that each percentage equals 100k/N rounded to the nearest integer.	Medium6	MathNumber theory+2	No attempts yet	2s	512 MB	Judgeable
Blood DistributionGiven counts of eight blood types and matching patients, output the maximum number of patients who can each receive one compatible unit.	Medium6	GreedyMath+1	No attempts yet	2s	512 MB	Judgeable
Vampire TunnelsFind the shortest path from node 0 to N-1 where the total length of above-ground edges is at most S.	Medium6	Shortest pathDynamic programming+1	No attempts yet	2s	512 MB	Judgeable
ReorganizationGiven each employee's rank in ID order, decide whether a binary hierarchy exists where every non-root has a supervisor with a smaller ID and a better rank.	Medium6	GreedyTree+2	No attempts yet	2s	512 MB	Judgeable
Tree PruningGiven a rooted binary tree with colored nodes, prune subtrees to make the whites minus blacks equal exactly D, minimizing the number of prunes.	Medium6	TreeDynamic programming+2	No attempts yet	2s	512 MB	Judgeable
Computer Purchase ReturnChoose exactly one component of each of T types so the total cost stays within budget B and the total value is maximized.	Medium6	Dynamic programmingArray+2	No attempts yet	2s	512 MB	Judgeable
Space MinerTravel in straight segments through ordered 3D waypoints; for each planet, check whether any segment passes within distance ri+D of its center, then sum the resources of all planets you can reach at least once.	Medium6	GeometryImplementation+2	No attempts yet	2s	512 MB	Judgeable
Shop and ShipGiven an undirected weighted graph, city-specific pencil prices, and a destination D, find the cheapest price plus shipping cost to get a pencil to D.	Medium6	GraphShortest path+2	No attempts yet	1s	128 MB	Judgeable
Invasion of the BoxesSimulate a laser ray from the origin that destroys axis-aligned boxes and reflects off them, printing the order of destruction.	Medium6	GeometrySimulation+1	No attempts yet	1s	128 MB	Judgeable
HerdingPlace the fewest traps on a grid of arrows so that a cat starting anywhere and following arrows forever eventually enters a trapped cell.	Medium6	GraphDFS+2	No attempts yet	1s	128 MB	Judgeable
CandySplit multiset candies with counts and calorie values into two groups so the two calorie totals differ as little as possible.	Medium6	Dynamic programmingBit manipulation+2	No attempts yet	1s	128 MB	Judgeable
FriendsEach student points to exactly one friend, forming directed cycles; for each query, report whether two students lie on the same cycle and the forward distance between them.	Medium6	GraphDFS+2	No attempts yet	1s	128 MB	Judgeable
Bowling for NumbersGiven a row of valued pins, pick up to k non-overlapping blocks of exactly w consecutive pins to maximize the total score.	Medium6	Dynamic programmingPrefix sum	No attempts yet	1s	128 MB	Judgeable
CowsGiven up to 10000 tree coordinates, find the largest convex polygon using any subset as corners, then output its area divided by 50 rounded down.	Medium6	GeometrySorting+2	No attempts yet	1s	128 MB	Judgeable
Tin Can TelephoneCount how many polygon buildings touch or cross the straight segment between two windows, where touching a corner or edge blocks the view.	Medium6	GeometryImplementation+2	No attempts yet	1s	128 MB	Judgeable
R & JGiven two ships and n spheres in 3D, count how many spheres the segment between the ships intersects.	Medium6	GeometryMath+2	No attempts yet	1s	128 MB	Judgeable
DominoGiven a multiset of dominoes, find the minimum number of extra dominoes to add so all of them (old and new) form one end-to-end chain where touching halves match.	Medium6	GraphUnion-find+2	No attempts yet	1s	128 MB	Judgeable
Cross SpiralTrace a clockwise inward spiral walk on a cross-shaped tile grid and report the column and row after S steps, or where she gets trapped.	Medium6	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
Number MatrixGiven a digit grid, find the lexicographically smallest set of three digits such that some 4-directional path uses only those digits from row 1 to row M.	Medium6	GraphBFS+2	No attempts yet	2s	512 MB	Judgeable
Primed SubsequencesFind the shortest contiguous subsequence of length at least 2 whose sum is prime, printing the leftmost one if ties exist.	Medium6	Prefix sumNumber theory+2	No attempts yet	5s	256 MB	Judgeable
FractalsDraw a level-`level` block fractal of given width from (0,1) to (width,1) and list, in order, every integer y where the vertical line x meets a segment.	Medium6	RecursionImplementation+2	No attempts yet	1s	128 MB	Judgeable
Return of Space TurtleTwo objects travel closed rectangular paths on a grid; find the minimum distance between them, sampled once per minute at integer times.	Medium6	SimulationMath+2	No attempts yet	1s	128 MB	Judgeable
Trucking TroublesFind the maximum weight W such that keeping only bridges with capacity at least W still lets city 1 reach every destination city.	Medium6	Union-findGraph+2	No attempts yet	1s	128 MB	Judgeable
BlindfoldGiven a grid with obstacles and a fixed sequence of forward/turn moves, mark every walkable square that can be a final position for some unknown start and heading.	Medium6	SimulationBit manipulation+2	No attempts yet	1s	128 MB	Judgeable
Game Show MathInsert +, -, *, / between the given numbers in order, left to right, so the running value hits the target; output the smallest expression or NO EXPRESSION.	Medium6	DFSBacktracking+1	No attempts yet	2s	128 MB	Judgeable
DuathlonGiven each competitor's running and cycling speeds and a fixed total distance, choose the run and cycle legs so the last competitor wins by the largest margin, or report that no such split exists.	Medium6	GeometryMath+2	No attempts yet	1s	128 MB	Judgeable
Connect the CampusGiven N points in the plane and some already-built zero-cost edges, add edges connecting all points at minimum total Euclidean length.	Medium6	Minimum spanning treeUnion-find+2	No attempts yet	1s	128 MB	Judgeable
Election NightEach state is already won or has a set of possible winners; decide for every candidate whether they win the electoral college in all, some, or no assignment of undecided states.	Medium6	GreedyMath+2	No attempts yet	1s	128 MB	Judgeable
Sheep and CoyotesGiven sheep points in a square, find which sheep is nearest to some entry point on the south edge, possibly selected when there is a tie.	Medium6	GeometrySorting	No attempts yet	1s	128 MB	Judgeable
Extension CordsDecide whether the extension cords can be split into two groups, each long enough to reach a different-circuit outlet from one work location.	Medium6	GreedySorting+2	No attempts yet	1s	128 MB	Judgeable
Maple RoundupGiven up to 99 points, find the convex hull by repeatedly turning right through the smallest angle, and output its perimeter rounded to two decimals.	Medium6	GeometrySorting+2	No attempts yet	1s	128 MB	Judgeable
Sum of ProductsExpand a polynomial-like expression of variables into a sum of products, then sort each term's letters and sort the terms lexicographically.	Medium6	StringRecursion+2	No attempts yet	1s	128 MB	Judgeable
Mountain PassageFind the minimum count of steps that touch an elevation above the start height, moving on an n by n grid with height changes limited to 2 per step.	Medium6	GraphShortest path+2	No attempts yet	1s	128 MB	Judgeable
QuadtreesGiven two quadtree preorder strings for 32x32 black-and-white images, count the black pixels in their union by recursively merging overlapping quadrants.	Medium6	RecursionTree+2	No attempts yet	1s	128 MB	Judgeable
World CupGiven win/draw/loss records for 6 nations in a round-robin group, decide for each of four cases whether some assignment of the 15 match results produces those records.	Medium6	BacktrackingBrute force+2	No attempts yet	1s	128 MB	Judgeable
Stepping on TilesGiven N distinct increasing numbers, find the maximum sum of a 3-or-more element arithmetic subsequence with any common difference, or 0 if none exists.	Medium6	Dynamic programmingHash map+2	No attempts yet	1s	256 MB	Judgeable
Tree IsomorphismGiven two rooted trees in pre-order with '#' closing each node's child list, decide whether the trees are isomorphic ignoring node labels.	Medium6	TreeDFS+2	No attempts yet	1s	128 MB	Judgeable
Stacking CubesGiven a stacking pattern as non-increasing rows with non-increasing columns, print its left and right rotations as corner stackings.	Medium6	ArrayImplementation+2	No attempts yet	1s	128 MB	Judgeable
To bet, or not to betGiven a board of movement and skip instructions, compute the probability the chip reaches End within T turns and decide the bet.	Medium6	Dynamic programmingProbability+2	No attempts yet	1s	128 MB	Judgeable
Building SnowmenGiven snowball diameters, find the maximum number of triples where each triple's sizes satisfy the stacking ratio inequalities.	Medium6	GreedySorting+2	No attempts yet	1s	128 MB	Judgeable
Snow ConesGiven the handed-out and requested flavors for a line of children, find the minimum number of simultaneous-neighbor-swap time steps until each child holds the requested flavor.	Medium6	GreedyTwo pointers+2	No attempts yet	1s	128 MB	Judgeable
Letter GameGiven up to 7 collected letters and a dictionary, find all words or pairs of words with the maximum total letter-value score, using each collected letter at most as often as it appears.	Medium6	StringHash map+2	No attempts yet	1s	512 MB	Judgeable
Little Shop of FlowersPlace F ordered bunches into a row of V vases to maximize total aesthetic value, then output the lexicographically smallest optimal assignment.	Medium6	Dynamic programming	No attempts yet	1s	128 MB	Judgeable
FlattenDistribute chips between neighboring piles at a cost equal to the chips moved, and find the minimum total transferred to make all piles equal.	Medium6	Dynamic programmingGreedy+2	No attempts yet	1s	128 MB	Judgeable
Recycling ProteinsGiven a source and target chain of amino acids, compute the minimum cost to convert one into the other using delete, insert, and replace with per-type costs.	Medium6	Dynamic programmingString	No attempts yet	1s	128 MB	Judgeable
Grazing on the RunBessie starts at position L and walks a line to eat N grass clumps; minimize the sum of times at which each clump is eaten.	Medium6	Dynamic programmingIntervals+1	No attempts yet	1s	128 MB	Judgeable
Dividing the PathPartition the segment [0, L] into consecutive pieces of even length between 2A and 2B so no cut lands strictly inside any cow's interval, and minimize the number of pieces, or report that no partition exists.	Medium6	Dynamic programmingPrefix sum+2	No attempts yet	1s	128 MB	Judgeable
Cleaning ShiftsCover shifts 1 through T with the fewest intervals, where each interval covers a contiguous range of shifts. Return the minimum number of intervals or -1.	Medium6	GreedySorting+2	No attempts yet	1s	128 MB	Judgeable
JourneyGiven a weighted tree, a start city k, and a set of target cities, find the length of the shortest walk from k that visits every target at least once.	Medium6	TreeDFS+2	No attempts yet	1s	128 MB	Judgeable
Football LeagueGiven an even number of teams playing a single round-robin over n-1 turns, find the minimum total number of same-venue consecutive pairs across all teams.	Medium6	MathCombinatorics+2	No attempts yet	1s	128 MB	Judgeable
A Decorative FenceGiven N and a rank C, output the C-th alternating (zigzag) permutation of 1..N in lexicographic order.	Medium6	Dynamic programmingCombinatorics+1	No attempts yet	1s	128 MB	Judgeable
Royal GuardsPlace as many non-attacking rook-like guards on pit-free rooms as possible, where guards attack along rows and columns unless a wall blocks sight.	Medium6	GraphUnion-find+2	No attempts yet	1s	128 MB	Judgeable
Printed CircuitGiven a grid with some existing vertical and horizontal wires, add wires to connect all nodes, minimizing cost with vertical at 1 and horizontal at 2, then report the count and cost.	Medium6	GraphMinimum spanning tree+1	No attempts yet	1s	128 MB	Judgeable
DiamondsFor each count Pmin, find the smallest radius whose worst-case center covers at least Pmin points, then the best coverage at that radius.	Medium6	GeometryPrefix sum+2	No attempts yet	1s	128 MB	Judgeable
CardsGiven the final order of N cards after S double shuffles and the count S, recover the order the cards had before the shuffles.	Medium6	MathSimulation+2	No attempts yet	1s	128 MB	Judgeable
CPUGiven chords listed by importance with each vertex in at most one chord, find the longest prefix that can be 2-colored so no color class self-crosses.	Medium6	GraphGreedy+2	No attempts yet	2s	128 MB	Judgeable