Problems

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Total results29,463 problems

Boxes
Medium4
Sorting, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Waterpark
Medium4
Dynamic programming, Graph
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
It’s tough being a teen!
Medium4
Graph, Topological sort+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Othello
Medium4
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Attack of the CipherTexts
Medium4
Hash map, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Groups
Medium4
Implementation, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Space Turtle
Medium4
Geometry, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Floor Plan
Medium4
DFS, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bridge Crossing
Medium4
Dynamic programming, Array+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Spirals
Medium4
Matrix, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Monkey Dance
Medium4
Graph, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Golf
Medium4
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Packet Routing
Medium4
Tree, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Year 2000
Medium4
String, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
You Can't Get There From Here
Medium4
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Common Words
Medium4
Hash map, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Lottery
Medium4
String, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Nasty Numbers
Medium4
Number theory, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Double Knockout Competition
Medium4
Simulation, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Long Division
Medium4
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Divisibility by 11
Medium4
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
When in Rome...
Medium4
String, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Maximum Distance
Medium4
Array, Two pointers+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Safebreaker
Medium4
Brute force, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Where's Waldorf?
Medium4
Array, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Double Trouble
Medium4
String, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Relief Supplies
Medium4
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Weather Forecasting
Medium4
String, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Recurring Decimals
Medium4
Hash map, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bad Cowtractors
Medium4
Minimum spanning tree, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Restore the Erased Numbers
Medium4
Brute force, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pencil Factory
Medium4
Math, Number theory+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Grandpa's Lottery Games
Medium4
Array, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Similar Triangles
Medium4
Geometry, Math+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Milk and Honey
Medium4
Greedy, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Positional number systems
Medium4
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Overlapping Maps
Medium4
Geometry, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Christmas Tree Ornament
Medium4
Tree, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Geocaching Coordinates
Medium4
Brute force, Implementation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Geopeitus
Medium4
Implementation, Brute force+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Walk
Medium4
Implementation, Math+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Paper Strips
Medium4
Implementation, Array+2
No attempts yet
Time limit
6s
Memory limit
1024 MB
Judgeable
Meli kalikamaka
Medium4
String, Simulation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Daisies and Love
Medium4
Math, Number theory+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Cosmic Assembly
Medium4
Math, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
The Impostor
Medium4
Simulation, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Quantum Computer
Medium4
Simulation, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Overshadowed Trees
Medium4
Sliding window, Array+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Pentago
Medium4
Simulation, Matrix
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Substring Reversal
Medium4
String, Two pointers
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Herb Trees
Medium4
Dynamic programming
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Bosses
Medium4
Graph, Greedy+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
The Race
Medium4
Simulation, Array+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Internet
Medium4
Greedy, Implementation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
House Numbers
Medium4
Implementation, Array+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Rotten Ropes
Medium4
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Grandpa's Other Estate
Medium4
Array, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Buggy Satellite
Medium4
Geometry, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Maya Calendar
Medium4
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Ancient Cipher
Medium4
String, Sorting+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Decoding Task
Medium4
Bit manipulation, Implementation
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Chemical Reactions
Medium4
String, Stack+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Buffer Manager
Medium4
Sliding window, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Disk Tree
Medium4
Trie, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Lock Manager
Medium4
Hash map, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Rating
Medium4
Implementation, Sorting
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Parliament
Medium4
Math, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Mysterious X Network
Medium4
Graph, BFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
On Storing Clothes
Medium4
Simulation, Array+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Making a Box
Medium4
Math, Binary search
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bowling
Medium4
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Factorial
Medium4
Math, Number theory+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Making Zero
Medium4
Backtracking, Brute force+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bukazoids
Medium4
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Dart Challenge
Medium4
Dynamic programming, Array+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Filthy Rich
Medium4
Dynamic programming, Matrix+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Tudoku
Medium4
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Mine Map
Medium4
BFS, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Holiday Gifts
Medium4
Tree, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Scavenger Hunt
Medium4
Graph, Hash map+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Acid Text
Medium4
Implementation, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Brainman
Medium4
Divide and conquer, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Friends
Medium4
Simulation, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Manhattan 2025
Medium4
BFS, Matrix+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Mayan Dates
Medium4
Implementation, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Knight's Move
Medium4
BFS, Graph+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Rat Attack
Medium4
Prefix sum, Matrix+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Ranking List
Medium4
Sorting, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Gathering Points
Medium4
Math, Sorting+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Tomatoes
Medium4
BFS, Graph+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Amicable Numbers
Medium4
Number theory, Brute force+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
SSSP (Shortest Path Queries)
Medium4
Shortest path, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Boundless Boxes
Medium4
Geometry, Brute force+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Dreadful Deadlines
Medium4
Greedy, Sorting
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Baking Cakes
Medium4
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Fibonacci
Medium4
Math, Matrix+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Numbers With No Repeated Digits
Medium4
Brute force, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Trigonometric Optimization
Medium4
Math, Brute force+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
People in the Company
Medium4
Hash map, Sorting+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
To Eat or Be Eaten
Medium4
Sorting, Two pointers+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
BoxesFor each item, find the standard box with the smallest volume that can contain it after 90-degree rotations, or report that none fits.	Medium4	SortingImplementation	No attempts yet	1s	128 MB	Judgeable
WaterparkCount the number of distinct paths from point 1 to point n in a DAG where every edge goes from a lower to a higher numbered point.	Medium4	Dynamic programmingGraph	No attempts yet	1s	128 MB	Judgeable
It’s tough being a teen!Given a fixed list of seven tasks with precedence rules plus up to ten extra constraints, output a valid order using the smallest available task first, or report that no order exists.	Medium4	GraphTopological sort+2	No attempts yet	1s	128 MB	Judgeable
OthelloSimulate up to 30 Othello moves on an 8x8 board starting from one of three configurations, then print the final black and white disc counts.	Medium4	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
Attack of the CipherTextsGiven one plaintext/ciphertext pair, invert the letter substitution to decrypt a second ciphertext, printing a period for undetermined characters.	Medium4	Hash mapString+1	No attempts yet	1s	128 MB	Judgeable
GroupsGiven a finite multiplication table on n elements, decide whether the operation is associative and has an identity and inverses, making it a group.	Medium4	ImplementationBrute force+2	No attempts yet	1s	128 MB	Judgeable
Space TurtleSimulate a 3D grid path of moves and 90-degree turns, and report the minimum distance from the path to a fixed target point.	Medium4	GeometrySimulation+1	No attempts yet	1s	128 MB	Judgeable
Floor PlanGiven a grid of walls and floor cells, count connected rooms, sort them by size, floor as many of the largest rooms as the wood supply allows, and report how many rooms got flooring plus the leftover wood.	Medium4	DFSSorting+2	No attempts yet	1s	128 MB	Judgeable
Bridge CrossingSplit a line of people into consecutive groups of at most M, where each group costs its slowest member's time, and minimize the total cost.	Medium4	Dynamic programmingArray+2	No attempts yet	1s	128 MB	Judgeable
SpiralsPlace the numbers x through y into a square-ish grid spiraling counter-clockwise outward from x at the center, then print the grid with numbers right-aligned to the width of y.	Medium4	MatrixSimulation+1	No attempts yet	1s	128 MB	Judgeable
The Monkey DanceEach monkey follows one outgoing arrow per step on a permutation; find the step count when all monkeys are back home, which is the LCM of the cycle lengths.	Medium4	GraphMath+2	No attempts yet	1s	128 MB	Judgeable
GolfGiven a target distance and up to 32 distinct club distances, find how many strokes give an exact sum, using unlimited repeats of each club.	Medium4	Dynamic programmingGreedy+2	No attempts yet	1s	128 MB	Judgeable
Packet RoutingGiven a tree with weighted edges connecting N computers, compute the travel time along the unique path between each query pair of computers.	Medium4	TreeDFS+2	No attempts yet	1s	128 MB	Judgeable
Year 2000Read n lines of text and expand the two-digit year in every date that matches one of three fixed formats, leaving all other characters unchanged.	Medium4	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
You Can't Get There From HereSimulate a dot bouncing diagonally inside a rectangular grid with mirror edges; report whether it reaches point B from A and after how many moves.	Medium4	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
Common WordsFor each data set, count word frequencies, find the k-th most common words, and print them alphabetically after a title line.	Medium4	Hash mapSorting+2	No attempts yet	1s	128 MB	Judgeable
LotteryInsert parentheses into arithmetic expressions so that multiplication is grouped before addition and subtraction, keeping the original spaces.	Medium4	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
Nasty NumbersFor each number under 32001, list its factor pairs and check whether the difference of one pair equals the sum of another pair.	Medium4	Number theoryBrute force+2	No attempts yet	1s	128 MB	Judgeable
Double Knockout CompetitionSimulate a double-elimination tournament round by round and print the number of undefeated, one-loss, and eliminated teams after each round.	Medium4	SimulationMath+2	No attempts yet	1s	128 MB	Judgeable
Long DivisionDivide a large integer by another using the schoolbook long-division method of shifting and repeated subtraction.	Medium4	MathImplementation+2	No attempts yet	1s	128 MB	Judgeable
Divisibility by 11Apply Dodgson's divisibility-by-11 test to numbers up to 50 digits, printing each intermediate value and the final verdict.	Medium4	MathImplementation+2	No attempts yet	1s	128 MB	Judgeable
When in Rome...Parse two Roman numerals, add them, and print the sum as a Roman numeral, or CONCORDIA CUM VERITATE when the sum exceeds 1000.	Medium4	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
Maximum DistanceGiven two non-increasing arrays, find the largest j - i such that j >= i and Y[j] >= X[i].	Medium4	ArrayTwo pointers+2	No attempts yet	1s	128 MB	Judgeable
SafebreakerGiven up to 10 guesses with correct-position and wrong-position digit counts, decide whether the secret 4-digit code is unique, impossible, or indeterminate.	Medium4	Brute forceImplementation+2	No attempts yet	1s	128 MB	Judgeable
Where's Waldorf?Given a grid of letters and a list of words, find the first-letter position of each word along any of eight straight directions, or the bottom-right cell if absent.	Medium4	ArrayString+2	No attempts yet	1s	128 MB	Judgeable
Double TroubleGiven an encrypted ciphertext formed by shifting letters and reversing blocks of size m, find the shift s and block size m that make a given crib appear.	Medium4	StringBrute force+2	No attempts yet	1s	128 MB	Judgeable
Relief SuppliesGiven line length N, T supply types, B boxes per type, and a needed type S, find the position that receives the second-most (or most, if tied) boxes of S.	Medium4	MathImplementation+2	No attempts yet	1s	128 MB	Judgeable
Weather ForecastingParse four weather forecast lines, score each sentence by phenomenon and qualifier, weight forecasts by day, and test whether the total is under 0.25.	Medium4	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
Recurring DecimalsFor each (a0, L), iterate the digit-rearrange-and-subtract map until a value repeats, then print the first repeated index j, the repeated value, and the cycle length.	Medium4	Hash mapSimulation+2	No attempts yet	1s	128 MB	Judgeable
Bad CowtractorsGiven an undirected weighted graph, find a spanning tree of maximum total edge cost, or report -1 if no spanning tree exists.	Medium4	Minimum spanning treeGreedy+2	No attempts yet	1s	128 MB	Judgeable
Restore the Erased NumbersSome of the four numbers a, b, a^2 b, ab^2 are replaced by 0; restore the original row, breaking ties toward the lexicographically smallest tuple.	Medium4	Brute forceMath+2	No attempts yet	1s	128 MB	Judgeable
Pencil FactoryCount how many of k pencils get painted and varnished when each machine skips every (n+1)th and (m+1)th pencil, grouped into four categories.	Medium4	MathNumber theory+1	No attempts yet	1s	128 MB	Judgeable
Grandpa's Lottery GamesGiven daily lottery spending and winnings, report the overall profit sign, the single day with the largest loss, and the consecutive run with the largest total loss.	Medium4	ArrayPrefix sum+2	No attempts yet	1s	1024 MB	Judgeable
Similar TrianglesGiven two triangles by integer vertex coordinates, decide whether they are similar and if so print the squared similarity coefficient as a reduced fraction p/q, else print -1.	Medium4	GeometryMath+2	No attempts yet	1s	1024 MB	Judgeable
Milk and HoneyAssign each field to cows or bees to maximize total happiness, where each field's output value declines linearly with each added unit.	Medium4	GreedyMath+1	No attempts yet	1s	1024 MB	Judgeable
Positional number systemsWrite integer R in a positional base B, which may be negative, fractional, or a reciprocal of an integer.	Medium4	MathImplementation+2	No attempts yet	1s	1024 MB	Judgeable
Overlapping MapsGiven a smaller rotated, scaled map lying inside a larger one, find the unique point that represents the same location on both maps.	Medium4	GeometryMath+2	No attempts yet	1s	128 MB	Judgeable
Christmas Tree OrnamentA tree of N lamps is built incrementally and recolored M times; after each recolor, report how many edges join two lamps of equal color.	Medium4	TreeImplementation	No attempts yet	1s	1024 MB	Judgeable
Geocaching CoordinatesGiven a coordinate formula with placeholder letters and each letter's allowed digit values, print every distinct resulting coordinate in lexicographic order.	Medium4	Brute forceImplementation+1	No attempts yet	1s	1024 MB	Judgeable
GeopeitusExpand each variable's value list, substitute every combination into the coordinate formula, and print each resulting coordinate in the specified digit order.	Medium4	ImplementationBrute force+2	No attempts yet	1s	1024 MB	Judgeable
WalkParse walking segments given as duration and pace per kilometre, then report total distance in metres and average speed in km/h.	Medium4	ImplementationMath+2	No attempts yet	1s	1024 MB	Judgeable
Paper StripsStrips are glued on a black strip in order, each hiding what lies below; print the visible color and length of each final segment, merging equal neighbors.	Medium4	ImplementationArray+2	No attempts yet	6s	1024 MB	Judgeable
Meli kalikamakaApply syllable and letter substitution rules to convert a lowercase text into a Polynesian-style pronunciation.	Medium4	StringSimulation+2	No attempts yet	1s	1024 MB	Judgeable
Daisies and LoveFind the largest M so that every petal count L_i is congruent to some common value modulo M, where all L_i are multiples of M.	Medium4	MathNumber theory+1	No attempts yet	1s	1024 MB	Judgeable
Cosmic AssemblyFind integer coordinates (x, y, z) minimizing the sum of Manhattan distances to N given points, breaking ties lexicographically.	Medium4	MathSorting+1	No attempts yet	1s	1024 MB	Judgeable
The ImpostorSimulate the rounds to find when too many crew members know the impostor's identity, or report N if he wins.	Medium4	SimulationImplementation	No attempts yet	1s	1024 MB	Judgeable
Quantum ComputerGiven a grid with obstacles and a sensor, decide whether a laser from a non-corner edge cell reaches the sensor with zero, one, or more than one mirror.	Medium4	SimulationImplementation	No attempts yet	1s	1024 MB	Judgeable
Overshadowed TreesFor each tree, check whether any taller tree within K positions exceeds its height by at least M, and list all such trees.	Medium4	Sliding windowArray+2	No attempts yet	1s	1024 MB	Judgeable
PentagoGiven a 6x6 Pentago board after white moves, find the lexicographically smallest square rotation (clockwise or counterclockwise) that gives white five in a row.	Medium4	SimulationMatrix	No attempts yet	1s	1024 MB	Judgeable
Substring ReversalGiven an original string and the result of reversing one substring of length at least two, find the reversed segment, preferring the smallest start then end.	Medium4	StringTwo pointers	No attempts yet	1s	1024 MB	Judgeable
Herb TreesPick trees to keep so that no two kept trees are adjacent, maximizing the sum of their berry counts.	Medium4	Dynamic programming	No attempts yet	1s	1024 MB	Judgeable
BossesGiven a graph of projects where the lower-numbered endpoint is the boss, find the max number of edges so every vertex has at most one boss, minimizing cancellations.	Medium4	GraphGreedy+2	No attempts yet	1s	1024 MB	Judgeable
The RaceGiven the starting order of cars and a recorded list of adjacent overtakes, verify the sequence is valid and print the final order or the first impossible overtake.	Medium4	SimulationArray+2	No attempts yet	1s	1024 MB	Judgeable
InternetGiven measurements with connection states, where the first and last show a connection, find the longest possible time the connection could have been down.	Medium4	GreedyImplementation+1	No attempts yet	1s	1024 MB	Judgeable
House NumbersGiven add and remove sub-orders over ranges of house numbers, find the set of numbers kept and count how many of each digit 0 to 9 appear across them.	Medium4	ImplementationArray+2	No attempts yet	1s	128 MB	Judgeable
Rotten RopesGiven the tear-off weights of n ropes, find the maximum object weight that a chosen subset can carry so that no rope in the subset breaks.	Medium4	GreedySorting+2	No attempts yet	1s	128 MB	Judgeable
Grandpa's Other EstateGiven up to 100 points and a square side length r, place the axis-aligned square to cover as many points as possible, counting border points as inside.	Medium4	ArraySorting+2	No attempts yet	1s	128 MB	Judgeable
Buggy SatelliteEach test case gives cities with coordinates and a list of regions; report which region is the outer one.	Medium4	GeometryImplementation	No attempts yet	1s	128 MB	Judgeable
Maya CalendarConvert n dates from the Haab calendar to the Tzolkin calendar using modular arithmetic on the day index.	Medium4	MathImplementation+2	No attempts yet	1s	128 MB	Judgeable
Ancient CipherGiven two equal-length strings of capital letters, decide whether the first can be obtained from the second by a substitution cipher followed by a permutation.	Medium4	StringSorting+2	No attempts yet	2s	128 MB	Judgeable
Decoding TaskGiven an encrypted message and the same message with a space prepended, recover the shared XOR key bytes.	Medium4	Bit manipulationImplementation	No attempts yet	2s	128 MB	Judgeable
Chemical ReactionsParse chemical formulas with nested parentheses and multipliers, then compare element counts between the left side and each candidate right side.	Medium4	StringStack+1	No attempts yet	1s	128 MB	Judgeable
Buffer ManagerGiven buffer states (free, digit worthiness, or locked) in a string, find the starting position of the K-length window without locked buffers whose digit sum is smallest.	Medium4	Sliding windowPrefix sum+2	No attempts yet	1s	128 MB	Judgeable
Disk TreeGiven full directory paths, rebuild the tree and print every directory name on its own line, indented by depth, with siblings in ASCII order.	Medium4	TrieSorting+1	No attempts yet	1s	128 MB	Judgeable
Lock ManagerProcess lock requests in order, granting an S or X lock when it conflicts with no granted lock, denying it and blocking the transaction otherwise, and ignoring later requests from blocked transactions.	Medium4	Hash mapSimulation+2	No attempts yet	1s	128 MB	Judgeable
RatingMerge two contest result tables into one ordering by the rules: teams present in both contests are ranked by the sum of their two places, and single-contest teams are placed where the rules allow.	Medium4	ImplementationSorting	No attempts yet	1s	128 MB	Judgeable
ParliamentSplit N delegates into groups of distinct sizes so that the product of the sizes is maximized, and print the sizes in ascending order.	Medium4	MathGreedy+1	No attempts yet	1s	128 MB	Judgeable
The Mysterious X NetworkGiven an undirected graph of N people, find the minimum number of intermediate people on a shortest path between two given people.	Medium4	GraphBFS+2	No attempts yet	1s	128 MB	Judgeable
On Storing ClothesSimulate a circular rail of hooks, depositing batches into the first fitting empty block and withdrawing them by ticket, printing freed hooks.	Medium4	SimulationArray+1	No attempts yet	1s	1024 MB	Judgeable
Making a BoxGiven a square panel of side a, find the corner cut b in (0, a/2) that maximizes the open box volume b(a-2b)^2.	Medium4	MathBinary search	No attempts yet	1s	128 MB	Judgeable
BowlingGiven the pins knocked down on each delivery of a valid ten-frame bowling game, compute the total score.	Medium4	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
FactorialFor each n up to 1000, report the last non-zero digit of n!.	Medium4	MathNumber theory+1	No attempts yet	1s	128 MB	Judgeable
Making ZeroInsert +, -, or a space between consecutive numbers 1 to N and print every expression that evaluates to 0, in ASCII order.	Medium4	BacktrackingBrute force+1	No attempts yet	1s	128 MB	Judgeable
BukazoidsGiven cell counts and a fixed number of single and double jumps, maximize collected bukazoids and output the lexicographically smallest optimal visit sequence.	Medium4	Dynamic programmingGreedy+2	No attempts yet	1s	128 MB	Judgeable
Dart ChallengeFor each dartboard, count how many distinct total scores k darts can produce, where each dart misses or scores s_i, 2s_i, or 3s_i (no triple on the top area).	Medium4	Dynamic programmingArray+2	No attempts yet	1s	128 MB	Judgeable
Filthy RichGiven a grid of gold amounts, find the maximum sum along a path from the top-left to the bottom-right cell, moving only east, south, or south-east.	Medium4	Dynamic programmingMatrix+1	No attempts yet	2s	128 MB	Judgeable
TudokuFill in each 9x9 Sudoku board: whenever a row, column, or 3x3 block has exactly one empty cell, that cell is forced, and repeating this finishes every board.	Medium4	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
Mine MapMark each cell of a grid as mine, safely entered, risky, or unreachable, following a detector-driven walk from the center.	Medium4	BFSSimulation+1	No attempts yet	1s	128 MB	Judgeable
Holiday GiftsAssign one of two priced gifts to each node of a rooted tree so no two adjacent employees share a gift, minimizing total cost.	Medium4	TreeDynamic programming+2	No attempts yet	1s	128 MB	Judgeable
Scavenger HuntGiven S-1 ordered pairs of steps from a route of S steps, reconstruct the full sequence of steps in order.	Medium4	GraphHash map+1	No attempts yet	1s	128 MB	Judgeable
Acid TextParse a simplified CSS style sheet, resolve each graphic's absolute or relative position, then composite the graphics by layer order into one canvas with a black background.	Medium4	ImplementationSimulation+2	No attempts yet	1s	128 MB	Judgeable
BrainmanGiven a sequence, find the minimum number of adjacent swaps needed to sort it in non-decreasing order; this equals the number of inversions.	Medium4	Divide and conquerSorting+1	No attempts yet	1s	128 MB	Judgeable
FriendsGiven which of six friends attend, apply the conditional voting rules, count votes per place, and report the winner or a tie.	Medium4	SimulationImplementation	No attempts yet	1s	128 MB	Judgeable
Manhattan 2025Given at most 9 units of fuel, print the smallest cube of grid intersections reachable from the origin, digit by digit, slice by slice.	Medium4	BFSMatrix+1	No attempts yet	1s	128 MB	Judgeable
Mayan DatesConvert between Gregorian dates and Maya Long Count plus ritual dates (Tzolk'in and Haab), handling leap years and BC years.	Medium4	ImplementationMath+1	No attempts yet	1s	128 MB	Judgeable
Knight's MoveGiven an l by l board and two squares, find the minimum number of knight moves between them.	Medium4	BFSGraph+1	No attempts yet	1s	256 MB	Judgeable
Rat AttackGiven weighted points on a 1025x1025 grid and a Chebyshev distance d, find the integer center covering the maximum total weight, breaking ties by smallest x then y.	Medium4	Prefix sumMatrix+1	No attempts yet	2s	128 MB	Judgeable
Ranking ListBuild a contest scoreboard: rank teams by solved problems then total time, with ties sharing a rank and listed alphabetically.	Medium4	SortingImplementation+1	No attempts yet	1s	128 MB	Judgeable
Gathering PointsGiven M points on an N by N grid, find a cell minimizing the sum of Manhattan distances from all points to it.	Medium4	MathSorting+1	No attempts yet	1s	256 MB	Judgeable
TomatoesGiven a grid of ripe, unripe, and empty cells, find how many days until every tomato ripens or report -1 if some never can.	Medium4	BFSGraph+2	No attempts yet	1s	256 MB	Judgeable
Amicable NumbersFor each N, print all pairs of distinct numbers up to N where each equals the sum of the other's proper divisors.	Medium4	Number theoryBrute force+1	No attempts yet	1s	128 MB	Judgeable
SSSP (Shortest Path Queries)Run the given SPFA shortest-path algorithm for each query and also output a push counter that accumulates across all queries.	Medium4	Shortest pathGraph+2	No attempts yet	1s	128 MB	Judgeable
Boundless BoxesGiven a grid and up to 1000 seed cells, find the largest Chebyshev distance from any cell to its nearest seed, plus one.	Medium4	GeometryBrute force+1	No attempts yet	1s	128 MB	Judgeable
Dreadful DeadlinesGiven n jobs with durations and deadlines, find the latest start time from which all jobs can still be finished by their deadlines.	Medium4	GreedySorting	No attempts yet	1s	128 MB	Judgeable
Baking CakesGiven up to 40 cake baking times and 3 ovens, find the minimum time to bake all cakes.	Medium4	Dynamic programmingGreedy+2	No attempts yet	1s	128 MB	Judgeable
FibonacciRead integers n until -1 and print F_n mod 10000 for each, with n up to one billion.	Medium4	MathMatrix+1	No attempts yet	1s	128 MB	Judgeable
Numbers With No Repeated DigitsGiven n up to one million, print the n-th positive integer whose decimal digits are all distinct.	Medium4	Brute forceDynamic programming+1	No attempts yet	1s	128 MB	Judgeable
Trigonometric OptimizationChoose positive integers x, y, z summing to S to optimize sin/cos(x)+sin/cos(y)+sin/cos(z), rounded to 10 decimals.	Medium4	MathBrute force+1	No attempts yet	2s	128 MB	Judgeable
People in the CompanyGiven access-card records of enter and leave events, list the names of employees who are currently inside the office, sorted in reverse alphabetical order.	Medium4	Hash mapSorting+1	No attempts yet	1s	256 MB	Judgeable
To Eat or Be EatenCount pairs where an A creature is strictly larger than a B creature, given two lists of sizes.	Medium4	SortingTwo pointers+2	No attempts yet	1s	256 MB	Judgeable