Problems

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Total results29,429 problems

Any Way You Slice It
Medium6
Geometry, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bounce
Medium6
DFS, Backtracking+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Black Vienna
Medium6
Brute force, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bulletin Board
Medium6
Geometry, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Go Go Gorelians
Medium6
Graph, Tree+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Time to Graduate
Medium6
Graph, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Fingerpainting Paint Kits
Medium6
Greedy, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Robots
Medium6
Dynamic programming, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Oil Pipeline
Medium6
Implementation, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Double Vision
Medium6
Brute force, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Falling Leaves
Medium6
Tree, Recursion+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Exchange Rates
Medium6
Graph, Union-find+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Don't Get Rooked
Medium6
Backtracking, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
WIMP: A Window Manager Program
Medium6
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Galactic Import
Medium6
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
A Puzzling Problem
Medium6
Backtracking, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Party Games
Medium6
String, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tsunami
Medium6
Graph, Minimum spanning tree+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Raggedy, Raggedy
Medium6
Dynamic programming, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Not One Bit More
Medium6
Dynamic programming, Bit manipulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Roller Coaster
Medium6
Dynamic programming, Greedy+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Spy Cam
Medium6
Geometry, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Extended Manhattan Distance
Medium6
Geometry, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Stringer
Medium6
Combinatorics, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Gypsy Moths
Medium6
Two pointers, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Marbles in Three Baskets
Medium6
BFS, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Generic Units Conversion
Medium6
Implementation, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
HTML Editor
Medium6
String, Stack+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Context-Free Clock
Medium6
Math, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
WordStack
Medium6
Dynamic programming, Bit manipulation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Doggone Moles
Medium6
Simulation, Matrix+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
A Baron Landscape
Medium6
Brute force, Geometry+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
In Defence of a Garden
Medium6
Geometry, BFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Candy Store
Medium6
Dynamic programming, Implementation+2
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Chemistry
Medium6
Stack, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Dirichlet's Theorem on Arithmetic Progressions
Medium6
Number theory, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Iterated Difference
Medium6
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Contour Tracing
Medium6
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pills
Medium6
Dynamic programming, Combinatorics
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Citizenship Application
Medium6
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Removing Parentheses
Medium6
Stack, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Aronson's Sequence
Medium6
Simulation, Implementation
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Coverage
Medium6
Geometry, Intervals+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
XML Validator
Medium6
String, Stack+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Resistors
Medium6
String, Stack+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Wax
Medium6
Geometry, Math+2
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Server Relocation
Medium6
Graph, BFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Vacation Rentals
Medium6
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Toothpick Arithmetic
Medium6
Dynamic programming, Math
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Knots
Medium6
Combinatorics, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Last Digits
Medium6
Number theory, Math+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Mix and Build
Medium6
Hash map, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
TOYS
Medium6
Binary search, Geometry+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tobo or not Tobo
Medium6
BFS, Game theory+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Think I'll Buy Me a Football Team
Medium6
Array, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hide That Number
Medium6
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Writers' Club
Medium6
Graph, DFS+1
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Newton's Apple
Medium6
Tree, Recursion+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Chop Ahoy! Revisited!
Medium6
Dynamic programming, Prefix sum
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Off Balance
Medium6
DFS, Tree+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Monday-Saturday Numbers
Medium6
Number theory, Math+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Twirling Robot
Medium6
Shortest path, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cliff Climbing
Medium6
Shortest path, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Curling 2.0
Medium6
DFS, Backtracking+2
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
The Genome Database of All Space Life
Medium6
String, Recursion+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Earth Observation with a Mobile Robot Team
Medium6
Simulation, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Finding a Multiple
Medium6
BFS, Number theory+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bread Sorting
Medium6
Array, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Doorman
Medium6
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Juice
Medium6
Tree, DFS+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Complaint Sort
Medium6
Array, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Odd, Even, and Changyeong
Medium6
Dynamic programming, Game theory+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Moving the Trees
Medium6
Math, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Getting Gold
Medium6
Graph, BFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Introspective Caching
Medium6
Greedy, Simulation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cuckoo Hashing
Medium6
Graph, DFS+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Counting Problem
Medium6
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sanggeun Trapped in a Maze
Medium6
Combinatorics, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tian Ji — The Horse Racing
Medium6
Greedy, Two pointers+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Microspikes
Medium6
Simulation, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Adjacent Edges
Medium6
Hash map, Geometry+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
A Foldy but a Goody
Medium6
Recursion, Divide and conquer+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Chemical Analysis
Medium6
Bit manipulation, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Expansion Order
Medium6
Graph, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bus Wireless Network Bandwidth
Medium6
Simulation, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Monkeys at Typewriters
Medium6
Probability, Trie+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Swamp Kangaroo
Medium6
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Zebra Herd
Medium6
Dynamic programming, Bit manipulation+2
No attempts yet
Time limit
7s
Memory limit
128 MB
Judgeable
Arsenic and Old Lace
Medium6
Bit manipulation, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pizza!
Medium6
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Essay Writing
Medium6
Graph, BFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Warehouse Location Planning
Medium6
Brute force, Bit manipulation+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Computer Science
Medium6
Implementation, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Butterfly Ballots
Medium6
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Volleyball Scores
Medium6
Simulation, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Swimming with Sharks
Medium6
Dynamic programming, Binary search+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
New Friends
Medium6
String, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Beach Party
Medium6
Brute force, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Orange Bowl
Medium6
Dynamic programming, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Course Load
Medium6
Dynamic programming, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Any Way You Slice ItSimulate a laser cutter's path from turn and move instructions and report the first move that crosses an earlier cut segment, forming a hole.	Medium6	GeometrySimulation+2	No attempts yet	1s	128 MB	Judgeable
BounceFind the shortest non-self-intersecting path on a hex grid from the top row to the bottom and back to the top row on the right, whose letters form a repeated pattern of given length. Example	Medium6	DFSBacktracking+2	No attempts yet	1s	128 MB	Judgeable
Black ViennaGiven each player's hand, the hidden gang, and records of interrogations, find the earliest turn after which at least one player can deduce the gang from their own cards and the answers.	Medium6	Brute forceCombinatorics+2	No attempts yet	1s	128 MB	Judgeable
Bulletin BoardGiven up to 100 axis-aligned rectangles on a board, report the uncovered area, the maximum overlap depth, and the area covered at exactly that depth.	Medium6	GeometrySorting+2	No attempts yet	1s	128 MB	Judgeable
Go Go GoreliansBuild the network by linking each new planet to the nearest existing planet, then find the planet or two adjacent planets that minimize the maximum distance to all others.	Medium6	GraphTree+2	No attempts yet	1s	128 MB	Judgeable
Time to GraduateGiven up to 12 courses with prerequisites, fall or spring offerings, and a per-semester course cap, find the minimum number of semesters to finish all courses.	Medium6	GraphDynamic programming+2	No attempts yet	1s	128 MB	Judgeable
Fingerpainting Paint KitsGiven per-color and gray amounts and a kit of N colors, find the fewest kits whose colors can cover the demand plus produce the gray by mixing triples.	Medium6	GreedyImplementation+1	No attempts yet	1s	128 MB	Judgeable
RobotsGiven garbage cells in a grid, robots walk from the northwest corner to the southeast corner moving only east or south; find the fewest robots that collect all garbage.	Medium6	Dynamic programmingSorting+2	No attempts yet	1s	128 MB	Judgeable
Oil PipelineGiven well coordinates, find the E-W pipeline row minimizing total N-S pipe length, then render a scaled ASCII map if it fits within 69 by 19 cells.	Medium6	ImplementationSimulation+2	No attempts yet	1s	128 MB	Judgeable
Double VisionGiven n pixel grids of symbols, decide for each whether one or two pixels uniquely identify it, and mark the chosen pixels.	Medium6	Brute forceImplementation+2	No attempts yet	1s	128 MB	Judgeable
Falling LeavesGiven the leaf-removal stages of a binary search tree, reconstruct the unique tree and print its preorder traversal.	Medium6	TreeRecursion+2	No attempts yet	1s	128 MB	Judgeable
Exchange RatesMaintain exchange rates between named items as assertions arrive, then answer each query with the rate in lowest terms or question marks if unknown.	Medium6	GraphUnion-find+2	No attempts yet	1s	128 MB	Judgeable
Don't Get RookedFind the maximum number of non-attacking rooks on a board up to 4x4 where walls block rook attacks.	Medium6	BacktrackingBrute force+2	No attempts yet	1s	128 MB	Judgeable
WIMP: A Window Manager ProgramSimulate a window manager over a 1024x1024 screen, tracking overlapping windows and handling click, drag, zoom, close, create, and redraw events.	Medium6	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
Galactic ImportFor each galaxy, find the planet whose export value, after 5% is lost per intermediate hop or per connected Earth link, is highest, breaking ties alphabetically.	Medium6	GraphShortest path+2	No attempts yet	1s	128 MB	Judgeable
A Puzzling ProblemPlace up to 5 fixed-orientation polyomino pieces, each labeled by index, to tile a 4x4 square exactly, printing the lexicographically smallest labeled grid or a failure message.	Medium6	BacktrackingBrute force+2	No attempts yet	1s	128 MB	Judgeable
Party GamesGiven n distinct uppercase names, find the shortest string S such that exactly half the names are <= S and half are > S, breaking ties by the alphabetically smallest S.	Medium6	StringSorting+2	No attempts yet	1s	128 MB	Judgeable
TsunamiPlace a warning center and connect cities with cables so every city reaches the center, no city is warned from a city farther from the shore, and total cable length is minimized.	Medium6	GraphMinimum spanning tree+2	No attempts yet	1s	128 MB	Judgeable
Raggedy, RaggedyGiven word widths and a max line length, split the words into lines and minimize the sum of squared unused space on every line except the last.	Medium6	Dynamic programmingPrefix sum+2	No attempts yet	1s	128 MB	Judgeable
Not One Bit MoreCount integers in [LO, HI] whose repeated popcount chain reaches 1 at exactly step X, with LO up to 1e18 and X up to 10.	Medium6	Dynamic programmingBit manipulation+2	No attempts yet	1s	128 MB	Judgeable
Roller CoasterChoose open or closed eyes for each roller coaster section to maximize total fun while keeping dizziness within limit L, where closing decreases dizziness by K.	Medium6	Dynamic programmingGreedy+2	No attempts yet	2s	128 MB	Judgeable
Spy CamGiven a labeled pixel grid of axis-aligned overlapping rectangles, decide for each label whether the whole sheet is provably fully visible or may be partly hidden.	Medium6	GeometryImplementation+2	No attempts yet	1s	128 MB	Judgeable
Extended Manhattan DistanceGiven an axis-aligned city grid and two integer points, find the shortest path length when travel inside the grid is restricted to axis-parallel streets and travel outside is free in any direction.	Medium6	GeometryMath+2	No attempts yet	1s	128 MB	Judgeable
StringerGiven fixed counts of each of N letters, find the K-th string in alphabetical order among all arrangements, without listing them.	Medium6	CombinatoricsMath+2	No attempts yet	1s	128 MB	Judgeable
Gypsy MothsGiven tree directions from a fixed camera and a fixed angular width, find the tenth-of-a-degree angle centered on the most trees, counting only trees strictly inside the view.	Medium6	Two pointersSorting+2	No attempts yet	1s	128 MB	Judgeable
Marbles in Three BasketsFind the fewest moves to equalize three baskets, where each move doubles one basket using marbles from another that holds at least as many.	Medium6	BFSGraph+1	No attempts yet	1s	128 MB	Judgeable
Generic Units ConversionParse two measurement systems with internal conversion rules, then convert each quantity so every unit of the second system appears with a greedy integer count, rounding the smallest unit.	Medium6	ImplementationSimulation+2	No attempts yet	1s	128 MB	Judgeable
HTML EditorGiven a valid HTML string and a range, output that substring wrapped with the tags needed to preserve its formatting.	Medium6	StringStack+1	No attempts yet	1s	128 MB	Judgeable
Context-Free ClockGiven a measured clockwise angle and a start time, find the earliest time at or after it when the hour and minute hands form that angle, rounded down to the second.	Medium6	MathSimulation+2	No attempts yet	1s	128 MB	Judgeable
WordStackOrder the given words and pad each with leading spaces to maximize the total number of columns where a letter matches the letter directly above it.	Medium6	Dynamic programmingBit manipulation	No attempts yet	1s	128 MB	Judgeable
Doggone MolesTrack which grid cells the mole could occupy across observed terrier moves, since standing on or beside a terrier means capture.	Medium6	SimulationMatrix+1	No attempts yet	1s	128 MB	Judgeable
A Baron LandscapePlace a castle first on a grid; a rival then picks a legal square to minimize your tax advantage, and you maximize that worst case. Report the guaranteed advantage.	Medium6	Brute forceGeometry+2	No attempts yet	1s	128 MB	Judgeable
In Defence of a GardenGiven a fence drawn as an axis-aligned walk on a 100x100 grid, count the total area of cells fully enclosed by the fence.	Medium6	GeometryBFS+2	No attempts yet	1s	128 MB	Judgeable
The Candy StoreWith unlimited copies of each candy, find the maximum total calories obtainable with a given budget, where prices and the budget carry two decimal places.	Medium6	Dynamic programmingImplementation+2	No attempts yet	3s	512 MB	Judgeable
ChemistryParse a chemical formula with nested parentheses and multipliers, then output each element's total atom count in lexicographic order.	Medium6	StackString+2	No attempts yet	1s	128 MB	Judgeable
Dirichlet's Theorem on Arithmetic ProgressionsCount how many terms a*n+b in a given range of n are prime, with the terms reaching up to 10^12 and at most 10^6 values per case.	Medium6	Number theoryMath+2	No attempts yet	1s	128 MB	Judgeable
Iterated DifferenceFor each list, repeatedly replace every entry by the absolute difference with its cyclic successor and count iterations until all entries match, or report failure after 1000 steps.	Medium6	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
Contour TracingTrace each 8-connected object's boundary with the Moore tracking algorithm and print the contour length, ignoring objects smaller than 5 pixels.	Medium6	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
PillsCount how many distinct sequences of W and H can appear as a bottle of N pills is emptied, two halves per pill.	Medium6	Dynamic programmingCombinatorics	No attempts yet	1s	256 MB	Judgeable
Citizenship ApplicationGiven a residence start date, a landing date, and trips abroad, find the earliest date the 1095 qualifying days for Canadian citizenship are met.	Medium6	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
Removing ParenthesesGiven an expression of single-letter variables with addition and multiplication, remove every pair of parentheses that can go without changing the value, and print the result.	Medium6	StackString+2	No attempts yet	1s	128 MB	Judgeable
Aronson's SequenceCompute terms of Aronson's sequence, where each term is the position of the k-th letter T in the self-referential sentence listing those positions as ordinals.	Medium6	SimulationImplementation	No attempts yet	2s	128 MB	Judgeable
CoverageGiven up to 100 towers with integer centers and radii, compute the percentage of a line segment path covered by at least one tower, rounded to two decimals.	Medium6	GeometryIntervals+2	No attempts yet	1s	128 MB	Judgeable
XML ValidatorDecide for each input line whether it is valid XML: matching open and close tags, allowed plain text, and proper escape sequences.	Medium6	StringStack+1	No attempts yet	1s	128 MB	Judgeable
ResistorsParse a nested expression of series and parallel resistor connections and output the exact resistance as a reduced fraction.	Medium6	StringStack+2	No attempts yet	1s	128 MB	Judgeable
WaxDivide a rectangular room into equal-area connected pieces by drawing lines from the door to the walls, and print each segment endpoint.	Medium6	GeometryMath+2	No attempts yet	3s	128 MB	Judgeable
Server RelocationFind the minimum number of plug-ins needed to move a server between two outlets, where each move must stay within reach of a cord from an outlet.	Medium6	GraphBFS+2	No attempts yet	1s	128 MB	Judgeable
Vacation RentalsGiven a table of which units are free on each day, schedule a new guest's stay over [a,d) using the fewest unit changes, breaking ties by smallest unit label each night.	Medium6	Dynamic programmingGreedy+2	No attempts yet	1s	128 MB	Judgeable
Toothpick ArithmeticFor each N up to 5000, find the fewest toothpicks needed to write an expression equal to N using unary operands and + or x as operators.	Medium6	Dynamic programmingMath	No attempts yet	1s	128 MB	Judgeable
KnotsFor each even N up to 100, find the probability that two random perfect matchings on N points form a single cycle.	Medium6	CombinatoricsMath+1	No attempts yet	1s	128 MB	Judgeable
Last DigitsFor each test case, print the last n digits (with leading zeros) of the power tower of height i with base b.	Medium6	Number theoryMath+2	No attempts yet	2s	128 MB	Judgeable
Mix and BuildFind the longest sequence of given distinct words where each word is formed by adding one letter and rearranging.	Medium6	Hash mapDynamic programming+2	No attempts yet	1s	128 MB	Judgeable
TOYSGiven n nonintersecting partitions splitting a box into n+1 bins, count how many of m dropped toys land in each bin.	Medium6	Binary searchGeometry+1	No attempts yet	1s	128 MB	Judgeable
Tobo or not ToboGiven a shuffled 3x3 Tobo board and a turn budget Y, find the minimum number of dial turns to restore the standard arrangement, or -1 if impossible within Y.	Medium6	BFSGame theory+1	No attempts yet	1s	128 MB	Judgeable
Think I'll Buy Me a Football TeamGiven a matrix of inter-bank debts, compute the total cash needed to settle all debts and the minimum possible after netting and rerouting payments.	Medium6	ArrayGraph+2	No attempts yet	1s	128 MB	Judgeable
Hide That NumberGiven the disguised value (11 times the original, truncated to the original's digit count), recover the original number or report IMPOSSIBLE.	Medium6	MathNumber theory+2	No attempts yet	1s	128 MB	Judgeable
The Writers' ClubFor each writer, recommend every writer reachable through the favorites graph to readers who favor a writer that reaches this one, excluding self and existing favorites.	Medium6	GraphDFS+1	No attempts yet	5s	128 MB	Judgeable
Newton's AppleParse two binary trees from post-order tokens with nil markers, then decide whether one can be turned into the other by swapping left and right children at any nodes.	Medium6	TreeRecursion+2	No attempts yet	1s	128 MB	Judgeable
Chop Ahoy! Revisited!Count the ways to split a digit string into consecutive groups whose digit sums are non-decreasing across groups.	Medium6	Dynamic programmingPrefix sum	No attempts yet	1s	128 MB	Judgeable
Off BalanceGiven a 2D grid of digit-labeled blocks, group 4-block pieces, build the support tree, and check each piece's accumulated center of mass against its bottom-column span.	Medium6	DFSTree+2	No attempts yet	1s	128 MB	Judgeable
Monday-Saturday NumbersFor each number, list the Monday-Saturday numbers that are irreducible divisors within the set of integers congruent to 1 or 6 mod 7.	Medium6	Number theoryMath+1	No attempts yet	2s	128 MB	Judgeable
Twirling RobotFind the cheapest sequence of override commands to steer a robot from the top-left cell to the bottom-right goal, where each cell forces a default move.	Medium6	Shortest pathGraph+2	No attempts yet	1s	128 MB	Judgeable
Cliff ClimbingFind the minimum total time for Jack to climb a grid, moving feet alternately under distance constraints, from a bottom S block to a top T block.	Medium6	Shortest pathGraph+2	No attempts yet	1s	128 MB	Judgeable
Curling 2.0On a grid with destructible blocks, find the fewest throws to slide a curling stone from start to goal, where each slide continues until it hits a block or leaves the board.	Medium6	DFSBacktracking+2	No attempts yet	3s	128 MB	Judgeable
The Genome Database of All Space LifeDecode a run-length compressed genome string with nested parentheses and print the character at index i, or 0 if the index is out of range.	Medium6	StringRecursion+2	No attempts yet	1s	128 MB	Judgeable
Earth Observation with a Mobile Robot TeamSimulate robots moving on piecewise-linear paths and report which ones receive the first robot's data through wireless contact over time.	Medium6	SimulationGraph+2	No attempts yet	1s	128 MB	Judgeable
Finding a MultipleFor each n up to 200, print the smallest multiple of n whose decimal digits are only 0 and 1, with up to 100 digits.	Medium6	BFSNumber theory+2	No attempts yet	1s	128 MB	Judgeable
Bread SortingDecide whether one permutation of 1..n can be turned into another using only the operation that rotates any three adjacent elements right by one.	Medium6	ArrayGreedy+2	No attempts yet	1s	128 MB	Judgeable
DoormanGiven a queue of men and women and a limit X, repeatedly admit the front or second person so the running gender difference never exceeds X, and maximize the number admitted.	Medium6	Dynamic programmingGreedy+2	No attempts yet	1s	128 MB	Judgeable
JuiceGiven a rooted tree with cord capacities and house demands, choose which houses to power so that flow through each cord stays within capacity and the count is maximized.	Medium6	TreeDFS+2	No attempts yet	2s	128 MB	Judgeable
Complaint SortGiven a sequence of n values, count the strictly decreasing subsequence triples (i < j < k with a_i > a_j > a_k).	Medium6	ArrayCombinatorics+2	No attempts yet	1s	256 MB	Judgeable
Odd, Even, and ChangyeongThree players move in fixed order, each adding 1 or dividing by a prime, and each tries to minimize the smallest number they personally produce.	Medium6	Dynamic programmingGame theory+2	No attempts yet	1s	128 MB	Judgeable
Moving the TreesGiven N trees on the left side of a road of length L and width W, find the minimum total Euclidean distance to move them so that each side holds N/2 trees at identical equally spaced positions.	Medium6	MathSorting+2	No attempts yet	1s	128 MB	Judgeable
Getting GoldCompute how much gold a player can safely collect on a grid using only draft warnings to infer which squares are guaranteed trap-free.	Medium6	GraphBFS+2	No attempts yet	1s	128 MB	Judgeable
Introspective CachingGiven a cache of size c and a fixed sequence of accesses, find the minimum number of cache misses achievable with an optimal offline eviction policy.	Medium6	GreedySimulation	No attempts yet	1s	128 MB	Judgeable
Cuckoo HashingGiven each word's two hash slots, decide whether inserting all words in order avoids an infinite cuckoo eviction chain.	Medium6	GraphDFS+1	No attempts yet	1s	128 MB	Judgeable
The Counting ProblemFor each pair (a, b), count how many times each digit 0 through 9 appears when writing every integer between them, inclusive.	Medium6	MathImplementation+2	No attempts yet	1s	128 MB	Judgeable
Sanggeun Trapped in a MazeCount closed walks of length n on an infinite hexagonal lattice starting and ending at one room.	Medium6	CombinatoricsDynamic programming+1	No attempts yet	1s	128 MB	Judgeable
Tian Ji — The Horse RacingGiven two sets of n horse speeds, pair them one to one to maximize Tian Ji's score where a win counts 200, a loss counts -200, and a tie counts 0.	Medium6	GreedyTwo pointers+1	No attempts yet	1s	128 MB	Judgeable
MicrospikesGiven interleaved per-appliance power change records with relative times, reconstruct the total power timeline and count maximal above-threshold intervals of duration 1 to S that start and end.	Medium6	SimulationSorting+2	No attempts yet	1s	128 MB	Judgeable
Adjacent EdgesRead several triangle meshes, label distinct vertices by first appearance, and for each triangle report the opposite vertex of the triangle sharing each of its three edges, or X when none exists.	Medium6	Hash mapGeometry+2	No attempts yet	1s	128 MB	Judgeable
A Foldy but a GoodyGiven a string of U and L folds, find the coordinates of the m-th point (end or right angle) on the unfolded strip.	Medium6	RecursionDivide and conquer+2	No attempts yet	1s	128 MB	Judgeable
Chemical AnalysisGiven up to 12 element bitmasks and a target bitmask, find the fewest elements whose bitwise OR equals the target, or report that none does.	Medium6	Bit manipulationBrute force+2	No attempts yet	1s	128 MB	Judgeable
Expansion OrderGiven sets of stations and a network that starts as station 1, output the lexicographically smallest build order where each set touches the network when built, or Impossible.	Medium6	GraphGreedy+2	No attempts yet	1s	128 MB	Judgeable
Bus Wireless Network BandwidthSimulate passengers boarding and leaving a bus, assigning each the highest-proportion free seat, and compute the bandwidth share obtained by a specified passenger.	Medium6	SimulationSorting+2	No attempts yet	1s	128 MB	Judgeable
Monkeys at TypewritersGiven per-letter and space probabilities, find the probability that a random key sequence terminates at its first space in one of the given words.	Medium6	ProbabilityTrie+2	No attempts yet	1s	128 MB	Judgeable
Swamp KangarooOn a small grid of land and water, find the shortest time for a kangaroo to hop from K to G, where hop cost depends on the previous jump distance and direction.	Medium6	GraphShortest path+2	No attempts yet	1s	128 MB	Judgeable
Zebra HerdAssign each of z zebras one of two colors at each of t times, minimizing same-color distance costs, opposite-color bonuses, and color-change penalties.	Medium6	Dynamic programmingBit manipulation+2	No attempts yet	7s	128 MB	Judgeable
Arsenic and Old LaceGiven up to 20 base products as bitmasks over s substances, find the fewest products whose union exactly equals the poison mask, or report impossible.	Medium6	Bit manipulationBrute force+2	No attempts yet	1s	128 MB	Judgeable
Pizza!Given nuggets at polar positions on a unit circle, find the maximum number of equal-angle radial slices so every slice holds the same nugget count.	Medium6	MathNumber theory+2	No attempts yet	1s	128 MB	Judgeable
Essay WritingGiven a sample text, two keywords, and a target length w, decide whether a word sequence of exactly w words exists where every adjacent pair appears in the sample and both keywords occur at least once.	Medium6	GraphBFS+2	No attempts yet	1s	128 MB	Judgeable
Warehouse Location PlanningChoose any nonempty subset of up to 20 candidate warehouses and assign each of up to 100 stores to a chosen one so that building plus Euclidean shipping cost is minimum.	Medium6	Brute forceBit manipulation+2	No attempts yet	2s	128 MB	Judgeable
Computer ScienceScore each page for a query word using occurrences in the page and in linking pages weighted by word distance to the hyperlink, then print the highest scoring pages.	Medium6	ImplementationString+2	No attempts yet	1s	128 MB	Judgeable
Butterfly BallotsGiven even intended-vote counts, choose a top-to-bottom candidate order where a half-row box shift sends half of each candidate's voters to the next candidate, and decide whether candidate 1 can tie or win.	Medium6	GreedySorting+2	No attempts yet	1s	128 MB	Judgeable
Volleyball ScoresGiven a sequence of ball touches, ground hits, and out of bounds calls, compute the volleyball score while checking that the correct team serves each volley.	Medium6	SimulationImplementation+1	No attempts yet	1s	128 MB	Judgeable
Swimming with SharksOn a w by h grid starting and ending at (1,1), plan t moves (or stays) to maximize the minimum Euclidean distance to any shark present at each time step.	Medium6	Dynamic programmingBinary search+2	No attempts yet	1s	128 MB	Judgeable
New FriendsGiven up to 10 town names, partition them into the fewest groups where every pair of names in a group differ by at most one Levenshtein edit (case ignored).	Medium6	StringGraph+2	No attempts yet	1s	128 MB	Judgeable
Beach PartyGiven preference orders over music styles, assign distinct styles to s stages so that the most people share the stage you attend.	Medium6	Brute forceCombinatorics+2	No attempts yet	1s	128 MB	Judgeable
Orange BowlGiven plays with a yard gain and success probability, choose a sequence whose total gain reaches n yards while maximizing the product of probabilities.	Medium6	Dynamic programmingMath+2	No attempts yet	1s	128 MB	Judgeable
Course LoadPick a set of classes with pairwise disjoint meeting slots and total workload at most C, maximizing total utility.	Medium6	Dynamic programmingBit manipulation+1	No attempts yet	1s	128 MB	Judgeable