Problems

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Total results29,431 problems

Ferries
Medium6
Simulation, Binary search+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Secret Sharing
Medium6
Greedy, String+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Block Stacking
Medium6
Greedy, Math+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Lie
Medium6
Union-find, Bit manipulation+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Collecting Items
Medium6
Combinatorics, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Rock Climbing
Medium6
BFS, Graph+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Similar Permutation
Medium6
Greedy, Array+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Doors
Medium6
Graph, Union-find+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sua's Candy Baskets
Medium6
Dynamic programming, Greedy+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Piggy Banks
Medium6
Dynamic programming, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Turn On the Light
Medium6
Shortest path, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
2012 End of the World
Medium6
Math, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Mirror-Symmetric Tree Graph
Medium6
Graph, Tree+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Star Printing - 11
Medium6
Recursion, Implementation+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Bulbs
Medium6
Dynamic programming, Array
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Arranging Shapes
Medium6
Sliding window, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Grid Game
Medium6
BFS, Graph+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Princess's Garden
Medium6
Greedy, Intervals+1
No attempts yet
Time limit
1s
Memory limit
192 MB
Judgeable
Wire Cutting
Medium6
Geometry, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Representative Players
Medium6
Heap, Greedy+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Line Reconstruction
Medium6
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Reconstructing the Hidden Ladder Row
Medium6
Simulation, Brute force+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Chain Store Location
Medium6
Shortest path, Graph+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Lock
Medium6
Array, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hamming Path
Medium6
BFS, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Diamond Excavation
Medium6
Math, Brute force+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Median String
Medium6
Greedy, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pebble Game of Chance
Medium6
Dynamic programming, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Two Reversals
Medium6
Array, Two pointers+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Rescuing the Princess
Medium6
Dynamic programming, Array+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
School Bus
Medium6
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Automatic Sprinklers
Medium6
Matrix, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Exhibition Hall
Medium6
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Rotating Dining Table
Medium6
Dynamic programming, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pancake Love 2
Medium6
Math, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Ladder
Medium6
Simulation, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Food Chain
Medium6
Binary search, Sorting+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Social Network Service
Medium6
Tree, Dynamic programming+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Bus Transfers
Medium6
Graph, BFS+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Mosaic
Medium6
Binary search, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Eggs
Medium6
Greedy, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Switches and Bulbs
Medium6
Dynamic programming, Binary search+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Last Nonzero Factorial Digit
Medium6
Math, Number theory+1
No attempts yet
Time limit
0.3s
Memory limit
128 MB
Judgeable
Three Reversals
Medium6
Array, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Electric Wires 2
Medium6
Binary search, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Arranging Cargo
Medium6
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Board Game
Medium6
Dynamic programming, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Iceberg
Medium6
Simulation, BFS+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Sequence
Medium6
Math, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sudoku
Medium6
Backtracking, Matrix+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Coin Flipping 2
Medium6
Brute force, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Light Aircraft
Medium6
Binary search, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Colored Paper
Medium6
Greedy, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Elevator
Medium6
BFS, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Building Columns
Medium6
Brute force, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pairing Students
Medium6
Greedy, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
DNA Similarity
Medium6
Dynamic programming, String
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Small Locomotives
Medium6
Dynamic programming, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Police Cars
Medium6
Dynamic programming, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Helipad
Medium6
Geometry, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pizza Sales
Medium6
Prefix sum, Hash map+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Continuing Numbers
Medium6
Math, Number theory+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cheese
Medium6
BFS, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Restoring Equal-Length Sticks
Medium6
Backtracking, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Simple Rectangle
Medium6
Geometry, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Car Race Maintenance
Medium6
Dynamic programming, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Build the Tallest Tower
Medium6
Dynamic programming, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Finding a Right Isosceles Triangle
Medium6
Geometry, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Good Sequence
Medium6
Greedy, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Moving Closet Doors
Medium6
Greedy, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Total Area of Several Rectangles
Medium6
Geometry, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Rascal Triangle
Medium6
Math, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Roads of Manchester
Medium6
Graph, Shortest path+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
QR Decoding
Medium6
Bit manipulation, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Rancher Seunghwan Baek's Gift
Medium6
Geometry, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Maximum Cycle Value of 1
Medium6
Combinatorics, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Lattice Point Convex Hull
Medium6
Geometry, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hexagonal Puzzle
Medium6
BFS, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Recursive Palindrome Partitions
Medium6
Dynamic programming, Recursion+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sangbeom's Magic Pancake House
Medium6
Greedy, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hanging Monkeys
Medium6
Recursion, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Model Rocket Height
Medium6
Geometry, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tile Filling
Medium6
Dynamic programming, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Press to Unlock
Medium6
Combinatorics, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sum of Powers of 2 and 3
Medium6
Greedy, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Today Is the OS Homework Deadline
Medium6
Math, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
1379 and Cubes
Medium6
Number theory, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Kindergarten Graduation
Medium6
Simulation, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
No-Fold Hold'em
Medium6
Brute force, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Model Rocket Launch
Medium6
Geometry, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Making a Good Array
Medium6
Array, Hash map+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Region Filling
Medium6
Simulation, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tax Note XML Conversion
Medium6
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Logical Expression Equivalence
Medium6
String, Brute force+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Center of the Outer Triangles
Medium6
Geometry, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Amusement Park
Medium6
BFS, Graph+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Childhood Toy Boxes
Medium6
Bit manipulation, Dynamic programming+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
DNA Discovery
Medium6
Greedy, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Square Crossword
Medium6
Hash map, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Smallest Prime Factor
Medium6
Number theory, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
FerriesSimulate a mixed road/ferry route to find the minimum arrival time waiting for scheduled ferries, then compute the lowest constant driving speed on the road segments that still achieves that same minimum total travel time.	Medium6	SimulationBinary search+1	No attempts yet	2s	128 MB	Judgeable
Secret SharingConcatenate all given digit strings in the order that yields the smallest possible integer without a leading zero, or print INVALID if impossible.	Medium6	GreedyString+1	No attempts yet	2s	128 MB	Judgeable
Block StackingGiven max-per-row and max-per-column height arrays for a grid, determine feasibility and compute the minimum and maximum total block counts consistent with both views.	Medium6	GreedyMath+1	No attempts yet	2s	128 MB	Judgeable
LieDetect the first parity query in a sequence that becomes inconsistent with earlier ones, using weighted union-find over prefix-sum parities.	Medium6	Union-findBit manipulation+1	No attempts yet	2s	128 MB	Judgeable
Collecting ItemsCount monotone right/up paths from bottom-left to top-right on a grid that must pass through every item cell and avoid obstacle cells.	Medium6	CombinatoricsDynamic programming+1	No attempts yet	2s	128 MB	Judgeable
Rock ClimbingGiven holds on a wall with a bounded step distance, find the minimum number of moves from (0,0) to reach height y=T using BFS-style shortest path on a reachability graph.	Medium6	BFSGraph+1	No attempts yet	2s	128 MB	Judgeable
Similar PermutationGiven a permutation, construct the lexicographically smallest permutation where each position differs from the original by at most 1.	Medium6	GreedyArray+1	No attempts yet	1s	128 MB	Judgeable
DoorsGiven switches controlling pairs of doors per waterway with on/off closing conditions, decide a switch assignment that closes every waterway (2-SAT style constraint satisfaction) or report impossibility.	Medium6	GraphUnion-find+1	No attempts yet	1s	128 MB	Judgeable
Sua's Candy BasketsGiven baskets on a line each decaying one candy per time unit, find the maximum total candy collectible starting from position 0 with optimal movement order.	Medium6	Dynamic programmingGreedy+1	No attempts yet	1s	512 MB	Judgeable
Piggy BanksGiven N, choose the order of incrementing two counters from (1,1) to (N,N) so that concatenating the pair as a number gives a prime as often as possible, and output the maximum count.	Medium6	Dynamic programmingMath+1	No attempts yet	1s	128 MB	Judgeable
Turn On the LightGiven an N by M grid of diagonal tiles ('/' or '\'), find the minimum number of tile rotations needed to create a diagonal path from top-left to bottom-right corner, using shortest path on a corner graph with 0/1 edge weights.	Medium6	Shortest pathGraph+1	No attempts yet	1s	128 MB	Judgeable
2012 End of the WorldGiven N, P, V, find the minimum total time to reduce N members to one opinion via recursively splitting into groups that each meet at cost k*P+V.	Medium6	MathDynamic programming+1	No attempts yet	1s	128 MB	Judgeable
Mirror-Symmetric Tree GraphDecide whether a given connected graph can be formed by gluing a rooted tree to its mirrored copy at every non-root leaf.	Medium6	GraphTree+1	No attempts yet	1s	128 MB	Judgeable
Star Printing - 11Recursively build and print a Sierpinski-like star triangle of height N=3·2^k using the fractal rule of stacking scaled copies with exact spacing.	Medium6	RecursionImplementation+1	No attempts yet	1s	256 MB	Judgeable
BulbsGiven N colored bulbs where changing one bulb also flips its contiguous same-colored neighbors, find the minimum number of changes to make all bulbs one color (classic zuma-like merging interval DP).	Medium6	Dynamic programmingArray	No attempts yet	1s	128 MB	Judgeable
Arranging ShapesGiven a sequence of three shape types, compute the minimum swaps needed to group each type into one contiguous block, in any order of blocks.	Medium6	Sliding windowGreedy+1	No attempts yet	1s	128 MB	Judgeable
Grid GameGiven an M×N grid of black and white stones, compute the minimum number of monochromatic-region flood-fill flips needed to make the whole grid one color.	Medium6	BFSGraph+1	No attempts yet	2s	256 MB	Judgeable
Princess's GardenSelect the minimum number of intervals (flower bloom ranges) to cover every day from March 1 to November 30, or report 0 if impossible.	Medium6	GreedyIntervals+1	No attempts yet	1s	192 MB	Judgeable
Wire CuttingGiven a closed wire path on a grid described by bend points, find the longest resulting segment after cutting it with a vertical line at a given position.	Medium6	GeometrySimulation+1	No attempts yet	1s	128 MB	Judgeable
Representative PlayersGiven N classes each with M distinct scores, pick one student per class to minimize the range between the highest and lowest chosen scores.	Medium6	HeapGreedy+1	No attempts yet	2s	256 MB	Judgeable
Line ReconstructionGiven N heights and, for each position, the count of earlier people with height at most that person's, reconstruct the original front-to-back order.	Medium6	GreedySorting+1	No attempts yet	1s	128 MB	Judgeable
Reconstructing the Hidden Ladder RowGiven a ladder diagram with one hidden row and the final permutation, reconstruct the missing row of bars consistent with the no-adjacent-bar rule.	Medium6	SimulationBrute force+1	No attempts yet	1s	128 MB	Judgeable
Chain Store LocationGiven a graph, compute shortest distances from every node to three fixed nodes and answer queries about whether a node is Pareto-dominated by another node on those three distances.	Medium6	Shortest pathGraph+1	No attempts yet	1s	256 MB	Judgeable
LockGiven the final arrangement after a left shift, a reversal of a subrange, and another left shift, recover valid parameters k, p, q, k that reproduce it.	Medium6	ArraySimulation+1	No attempts yet	1s	128 MB	Judgeable
Hamming PathGiven N binary codes, build implicit graph edges between codes at Hamming distance 1 and output shortest paths from code 1 to each queried code via BFS.	Medium6	BFSBit manipulation+1	No attempts yet	1s	128 MB	Judgeable
Diamond ExcavationFind the center (with integer coordinates on the map) of an axis-aligned diamond shape of fixed diagonal length K that covers the maximum number of given points, using a rotated-coordinate transform and brute force over candidate centers.	Medium6	MathBrute force+1	No attempts yet	1s	128 MB	Judgeable
Median StringGiven three equal-length strings, construct a string minimizing the maximum Hamming distance to all three and output that minimum radius.	Medium6	GreedyString+1	No attempts yet	1s	128 MB	Judgeable
Pebble Game of ChanceCount the sequences of N wheel spins whose cumulative pebble cost never exceeds K, modulo 42043.	Medium6	Dynamic programmingMath+1	No attempts yet	1s	128 MB	Judgeable
Two ReversalsGiven a permutation of 1..N produced by two interval reversals of the sorted sequence, find two reversal operations that restore sorted order.	Medium6	ArrayTwo pointers+1	No attempts yet	1s	128 MB	Judgeable
Rescuing the PrincessCount round trips from Yusi Island to Hooper Island and back on a line, using each island's directional-strength springboard at most once except the start, modulo 1000.	Medium6	Dynamic programmingArray+1	No attempts yet	1s	128 MB	Judgeable
School BusGiven a school and apartments on a line with student counts and bus capacity K, find the minimum total distance for a bus doing round trips to bring everyone to school.	Medium6	GreedySorting+1	No attempts yet	1s	128 MB	Judgeable
Automatic SprinklersReconstruct the placement of fertilizer and herbicide sprinklers on an 8x8 grid given the resulting yields per row and column effects, along with the sprinkler count.	Medium6	MatrixMath+1	No attempts yet	1s	128 MB	Judgeable
Exhibition HallOrder stacked paintings of equal width but different heights front to back to maximize the total price of paintings whose exposed visible height is at least S.	Medium6	GreedySorting+1	No attempts yet	1s	256 MB	Judgeable
Rotating Dining TableGiven three ordered dish requests on a rotating table shared by father, mother, and Hyeon at fixed offsets, find the minimum total rotation steps to satisfy all sequences.	Medium6	Dynamic programmingSimulation+1	No attempts yet	1s	128 MB	Judgeable
Pancake Love 2Compute the maximum pancakes makeable given batter limits from five basic ingredients and topping constraints from four toppings across seven recipe types.	Medium6	MathGreedy+1	No attempts yet	1s	128 MB	Judgeable
LadderSimulate oscillating bars on each floor and find the minimum time to climb from the bottom bar to the top bar given interval-overlap climbing rules.	Medium6	SimulationMath+1	No attempts yet	1s	128 MB	Judgeable
Food ChainGiven N intervals, find the longest chain where each interval strictly contains the next (with ties allowed on one endpoint), essentially a longest chain problem solvable via sorting and LIS-style binary search.	Medium6	Binary searchSorting+1	No attempts yet	1s	256 MB	Judgeable
Social Network ServiceGiven a friendship tree, find the minimum dominating set size so every non-selected person has all neighbors selected.	Medium6	TreeDynamic programming+1	No attempts yet	3s	256 MB	Judgeable
Bus TransfersGiven a grid and k horizontal or vertical bus segments, find the minimum number of bus transfers to get from a start point to a destination point.	Medium6	GraphBFS+1	No attempts yet	1s	256 MB	Judgeable
MosaicGiven up to 1000 stained cells on an R by C grid, find the smallest square sheet size so that at most P bottom-aligned squares of that size can cover all stained cells.	Medium6	Binary searchGreedy+1	No attempts yet	1s	128 MB	Judgeable
EggsGiven eggs in four baskets, output the sequence of allowed two-remove-one-add operations that gathers all eggs into a single basket using the minimum number of steps.	Medium6	GreedySimulation+1	No attempts yet	1s	128 MB	Judgeable
Switches and BulbsGiven two orderings of numbers 1..N, find the longest set of wires that pairwise don't cross, which reduces to longest increasing subsequence with reconstruction.	Medium6	Dynamic programmingBinary search+1	No attempts yet	1s	128 MB	Judgeable
Last Nonzero Factorial DigitCompute the last nonzero digit of N! for N up to 20000 without directly computing the huge factorial.	Medium6	MathNumber theory+1	No attempts yet	0.3s	128 MB	Judgeable
Three ReversalsGiven an array formed by reversing three intervals of 1..N, find three interval reversals (with trivial ones allowed) that restore it to sorted order.	Medium6	ArraySimulation+1	No attempts yet	1s	128 MB	Judgeable
Electric Wires 2Given N wires between two poles, remove the minimum number of wires so the rest form an increasing sequence (longest increasing subsequence based removal), listing the removed A-positions.	Medium6	Binary searchSorting+1	No attempts yet	1s	128 MB	Judgeable
Arranging CargoGiven a permutation of distinct weights, find the minimum total swap cost (sum of swapped weights) needed to sort it into increasing order using cycle decomposition.	Medium6	GreedySorting+1	No attempts yet	1s	128 MB	Judgeable
Board GameGiven a colored card sequence and a colored graph, find a walk starting at village 1 that uses cards in order to maximize color matches with traversed roads.	Medium6	Dynamic programmingGraph+1	No attempts yet	1s	128 MB	Judgeable
IcebergSimulate yearly melting of an iceberg grid based on adjacent sea cells and find the first year it splits into multiple connected components, or 0 if it fully melts first.	Medium6	SimulationBFS+1	No attempts yet	1s	256 MB	Judgeable
SequenceGiven M, find the sequence length maximizing product for fixed sum M (breaking into 2s and 3s), and separately the length minimizing sum for fixed product M (prime factorization based).	Medium6	MathGreedy+1	No attempts yet	1s	128 MB	Judgeable
SudokuSolve a standard 9x9 sudoku puzzle by filling empty cells so every row, column, and 3x3 box contains digits 1 through 9, using backtracking search.	Medium6	BacktrackingMatrix+1	No attempts yet	1s	256 MB	Judgeable
Coin Flipping 2Given an N x N grid of H/T coins, find the minimum number of tails achievable by flipping any subset of rows and columns.	Medium6	Brute forceBit manipulation+1	No attempts yet	1s	128 MB	Judgeable
Light AircraftGiven up to 1000 airfields between fixed start and end points, find the minimum tank capacity (max edge fuel cost) enabling a path using at most k intermediate stops, via binary search plus a path-existence check.	Medium6	Binary searchGraph+1	No attempts yet	1s	128 MB	Judgeable
Colored PaperGiven counts of six square sizes (1-6 cm), determine the minimum number of 6x6 boards needed to place all squares without overlap or crossing edges.	Medium6	GreedyMath+1	No attempts yet	1s	128 MB	Judgeable
ElevatorGiven elevators that stop at arithmetic-progression floors, find the shortest sequence of elevators to travel between two floors and output a valid path.	Medium6	BFSGraph+1	No attempts yet	1s	128 MB	Judgeable
Building ColumnsCount distinct stacked-cube columns from four dice-like cubes where each column's four side faces show all four colors, up to rotation about the vertical axis.	Medium6	Brute forceCombinatorics+1	No attempts yet	1s	128 MB	Judgeable
Pairing StudentsDecide if boys and girls from three schools can be perfectly matched avoiding same-school pairs, and construct a valid pairing if possible.	Medium6	GreedyMath+1	No attempts yet	1s	128 MB	Judgeable
DNA SimilarityFind substrings of two DNA sequences that maximize a local sequence-alignment score with custom match and mismatch/gap penalties, and output the score and substrings.	Medium6	Dynamic programmingString	No attempts yet	1s	128 MB	Judgeable
Small LocomotivesChoose three disjoint consecutive-car segments (each up to a fixed length) from a train to maximize total passengers carried.	Medium6	Dynamic programmingPrefix sum+1	No attempts yet	1s	128 MB	Judgeable
Police CarsAssign a sequence of incidents to one of two police cars moving along Manhattan-distance shortest paths so that total travel distance is minimized, and output the assignment.	Medium6	Dynamic programmingGreedy+1	No attempts yet	1s	128 MB	Judgeable
HelipadFind the point minimizing the maximum distance to a set of up to 1000 given points (minimum enclosing circle), and output its coordinates and radius.	Medium6	GeometryMath+1	No attempts yet	1s	128 MB	Judgeable
Pizza SalesGiven two circular arrays of pizza-slice sizes, count ways to pick a contiguous arc from one pizza, from the other, or one arc from each, summing exactly to K.	Medium6	Prefix sumHash map+1	No attempts yet	2s	128 MB	Judgeable
Continuing NumbersGiven a starting positive integer, choose a second term so that the Fibonacci-like subtraction sequence a_i = a_{i-2}-a_{i-1} runs as long as possible before going negative, and output that longest sequence.	Medium6	MathNumber theory+1	No attempts yet	1s	128 MB	Judgeable
CheeseSimulate hourly melting of cheese cells on a grid, where a cell melts if at least two sides touch outside air reachable via BFS/flood fill, and output total hours until all cheese disappears.	Medium6	BFSSimulation+1	No attempts yet	1s	128 MB	Judgeable
Restoring Equal-Length SticksGiven stick pieces, find the smallest common stick length so all pieces can be partitioned into groups summing to that length, and output the grouping.	Medium6	BacktrackingMath+1	No attempts yet	1s	128 MB	Judgeable
Simple RectangleGiven a robot's rectilinear path on a grid up to 100x100, find the smallest-area empty rectangle bounded purely by the drawn segments.	Medium6	GeometrySimulation+1	No attempts yet	1s	128 MB	Judgeable
Car Race MaintenanceGiven a maximum travel range and per-station maintenance times, select a minimum-cost subset of stations so consecutive gaps never exceed the range, and output the chosen stations.	Medium6	Dynamic programmingGreedy+1	No attempts yet	1s	128 MB	Judgeable
Build the Tallest TowerSelect and order bricks with strictly increasing area and weight from bottom to top to maximize total height, then output the chosen brick indices top to bottom.	Medium6	Dynamic programmingSorting+1	No attempts yet	1s	128 MB	Judgeable
Finding a Right Isosceles TriangleGiven a 10x10 binary grid, decide whether the filled cells exactly form one axis-aligned right isosceles triangle and output its three vertices or 0.	Medium6	GeometrySimulation+1	No attempts yet	1s	128 MB	Judgeable
Good SequenceConstruct the lexicographically smallest square-free string of length N over the alphabet {1,2,3} (no two adjacent equal-length substrings identical).	Medium6	GreedyString+1	No attempts yet	1s	128 MB	Judgeable
Moving Closet DoorsGiven n closets with two open slots and doors that shift into open neighbors, find the minimum total door moves to make each requested closet open in a given sequence.	Medium6	GreedySimulation+1	No attempts yet	1s	128 MB	Judgeable
Total Area of Several RectanglesGiven up to 30 axis-aligned rectangles, compute the total area of their union.	Medium6	GeometrySorting+1	No attempts yet	1s	128 MB	Judgeable
Rascal TriangleGiven a recursively defined 'Rascal triangle' with a division-based rule, compute R(n,m) efficiently for n,m up to 50,000 across up to 1000 queries.	Medium6	MathCombinatorics+1	No attempts yet	1s	128 MB	Judgeable
Roads of ManchesterGiven a directed graph with edge capacities, compute the ratio of max flow from A to B to the maximum bottleneck-capacity path from A to B.	Medium6	GraphShortest path+1	No attempts yet	1s	128 MB	Judgeable
QR DecodingParse a 19-byte QR data payload bit by bit and decode its numeric, alphanumeric, byte, and kanji mode segments into a formatted output string.	Medium6	Bit manipulationString+2	No attempts yet	1s	128 MB	Judgeable
Rancher Seunghwan Baek's GiftGiven a convex quadrilateral, compute five sub-region areas formed by connecting vertices to midpoints of the opposite sides plus the perimeter of the central quadrilateral, using geometry formulas.	Medium6	GeometryImplementation+1	No attempts yet	1s	128 MB	Judgeable
Maximum Cycle Value of 1Given n and k, count permutations of 1..n whose cycle containing element 1 has maximum element exactly k.	Medium6	CombinatoricsMath+1	No attempts yet	1s	128 MB	Judgeable
Lattice Point Convex HullCompute the convex hull of up to 50 lattice points and print its vertices starting from the topmost-leftmost point in clockwise order.	Medium6	GeometrySorting+1	No attempts yet	1s	128 MB	Judgeable
Hexagonal PuzzleFind the shortest sequence of coin moves on a 7-cell hexagonal puzzle graph to restore each labeled coin to its matching outer cell, or report impossibility.	Medium6	BFSGraph+1	No attempts yet	1s	128 MB	Judgeable
Recursive Palindrome PartitionsCount recursive palindrome partitions of N, where a partition is valid if it is a palindrome and both halves are recursively valid.	Medium6	Dynamic programmingRecursion+2	No attempts yet	1s	128 MB	Judgeable
Sangbeom's Magic Pancake HouseGiven a stack of pancakes with sizes and burn orientations, find a sequence of at most 3M-2 prefix flips that sorts them by size with burned side down.	Medium6	GreedySimulation+1	No attempts yet	1s	128 MB	Judgeable
Hanging MonkeysParse a nested bracket string representing a binary vine structure and compute the minimum monkeys needed so every split has equal counts on both sides.	Medium6	RecursionString+2	No attempts yet	1s	128 MB	Judgeable
Model Rocket HeightGiven angle measurements from two observers with fixed geometry, compute the rocket's smoke-point height using 3D line intersection, or flag disqualification or measurement error based on given thresholds.	Medium6	GeometryMath+1	No attempts yet	1s	128 MB	Judgeable
Tile FillingCount the number of ways to tile a 4×N board with 2×1 dominoes for multiple queries, bounded so the answer fits in a 32-bit integer.	Medium6	Dynamic programmingMath+1	No attempts yet	1s	128 MB	Judgeable
Press to UnlockCount the number of ordered sequences of disjoint nonempty subsets (a set partition of any subset of buttons into an ordered sequence of blocks) for given B up to 11.	Medium6	CombinatoricsMath+1	No attempts yet	1s	128 MB	Judgeable
Sum of Powers of 2 and 3Represent an integer N as a sum of terms 2^a*3^b such that no term divides another, for up to 1000 queries with N under 2^31.	Medium6	GreedyMath+1	No attempts yet	1s	128 MB	Judgeable
Today Is the OS Homework DeadlineGiven a yearless deadline and a yearless report date, assign the report a plausible year and classify it as prior, after, same day, or out of range within a 7 day window.	Medium6	MathImplementation+1	No attempts yet	1s	128 MB	Judgeable
1379 and CubesGiven a number S ending in 1,3,7 or 9 with up to 10 digits, find any integer x (no longer than S) whose cube's last digits exactly match S.	Medium6	Number theoryMath+1	No attempts yet	1s	128 MB	Judgeable
Kindergarten GraduationGiven counts of girls and boys arranged around one empty gap, output a bounded sequence of slide/hop moves that swaps the two groups' positions.	Medium6	SimulationGreedy+1	No attempts yet	1s	128 MB	Judgeable
No-Fold Hold'emGiven hole cards and four community cards in Texas Hold'em, find which possible river cards make you win, or otherwise tie, else print LOSER.	Medium6	Brute forceSimulation+2	No attempts yet	1s	128 MB	Judgeable
Model Rocket LaunchGiven two observers' 3D lines of sight (from elevation and azimuth angles plus fixed instrument heights and baseline geometry), compute the midpoint of the closest points between the two skew lines and output the rocket's height above the launch pad for each of N launches.	Medium6	GeometryMath+1	No attempts yet	1s	128 MB	Judgeable
Making a Good ArrayCount pairs of indices to remove from an array so that the remaining elements have one value equal to the sum of the rest.	Medium6	ArrayHash map+1	No attempts yet	1s	512 MB	Judgeable
Region FillingTrace region boundaries from direction strings, validate them for out-of-bounds moves, closure, and overlaps, then flood-fill each closed boundary with its letter.	Medium6	SimulationImplementation+1	No attempts yet	1s	128 MB	Judgeable
Tax Note XML ConversionParse shorthand tax notes with rate, end month/year, and start month/day, then output valid entries as strict XML or mark ambiguous or invalid lines as bad data.	Medium6	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
Logical Expression EquivalenceParse two concatenated boolean expressions with C-style operator precedence and decide if they are logically equivalent for all variable assignments.	Medium6	StringBrute force+1	No attempts yet	1s	128 MB	Judgeable
Center of the Outer TrianglesGiven a triangle, construct outward squares on each side, form outer triangles, and compute the common intersection point of three specific medians (Vecten point).	Medium6	GeometryMath+1	No attempts yet	1s	128 MB	Judgeable
Amusement ParkOn a grid where entering a cell costs 1/C and each minute-long interval allows a cumulative cost of at most 1, find the minimum number of minutes to travel from start to destination.	Medium6	BFSGraph+1	No attempts yet	2s	128 MB	Judgeable
Childhood Toy BoxesCount subsets of N boxes (as bitmasks over M<=20 toy types) whose union covers all M types, modulo 1e9+7.	Medium6	Bit manipulationDynamic programming+2	No attempts yet	2s	128 MB	Judgeable
DNA DiscoveryGiven a binary string, find the minimum number of single-character flips or whole-prefix flips needed to turn every character into A.	Medium6	GreedyDynamic programming+1	No attempts yet	1s	128 MB	Judgeable
Square CrosswordCount distinct ways to pick four distinct equal-length words to fill a square crossword so top/bottom rows and left/right columns match corner letters.	Medium6	Hash mapBrute force+2	No attempts yet	1s	128 MB	Judgeable
Smallest Prime FactorGiven N and prime P, find the N-th positive integer whose smallest prime factor equals P, or print 0 if it exceeds 10^9.	Medium6	Number theoryMath+1	No attempts yet	1s	128 MB	Judgeable