Problems

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Total results29,425 problems

Couples
Medium6
Hash map, Combinatorics
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Tickets
Medium6
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Factorial Digit Count
Medium6
Math, Binary search+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Street Network
Medium6
Graph, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Billiards
Medium6
Math, Geometry+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Folded Sheet
Medium6
Geometry, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Strange Sequence
Medium6
Implementation, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cutting Out of Factorials
Medium6
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Series
Medium6
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Magician
Medium6
BFS, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Heating Main
Medium6
Backtracking, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Prime Scrabble
Medium6
Brute force, Math+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Algarvu-Scrabble
Medium6
Backtracking, Brute force+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Bacteria
Medium6
Math, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Õhne vanaraamatupood
Medium6
Implementation, Simulation+2
No attempts yet
Time limit
1s
Memory limit
1023 MB
Judgeable
Roads
Medium6
Graph, Union-find+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Job Postings
Medium6
Greedy, Sorting+2
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
Flipping a Pack of Cards
Medium6
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Puzzle of Numbers
Medium6
Backtracking, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Swimming Pool
Medium6
Heap, BFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Fireworks
Medium6
Simulation, DFS+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Operator Signs
Medium6
Dynamic programming, Backtracking+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
IP Addresses
Medium6
String, Hash map+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Turning a Tree
Medium6
Tree, DFS+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Dragon
Medium6
Dynamic programming, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Living Off the Interest
Medium6
Simulation, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Food Composition
Medium6
Greedy, Math+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Politicians
Medium6
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Buffet Table
Medium6
Number theory, Math+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Rock, Paper, Scissors
Medium6
Greedy, Math+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Courier
Medium6
Dynamic programming, Sorting
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Unit Transformation
Medium6
Dynamic programming, BFS+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Liars
Medium6
Graph, BFS+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
The Cat of Bitland
Medium6
Dynamic programming, Array+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Concert
Medium6
Dynamic programming, Greedy
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Word Grouping
Medium6
Bit manipulation, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Lawnmower
Medium6
Sorting, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Monthly Railway Pass
Medium6
Graph, DFS+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Fire drill
Medium6
Topological sort, Graph+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Metaprogramming
Medium6
Number theory, Math+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Swimming Competition
Medium6
Binary search, Greedy+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Television
Medium6
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Passengers
Medium6
Dynamic programming, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Airplane Passengers
Medium6
Dynamic programming, Sorting+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Alphariz Table Collapse
Medium6
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Vice City
Medium6
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Food Cubes
Medium6
BFS, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Optimal Keypad
Medium6
Dynamic programming, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Unfoldung
Medium6
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Dolphin Pool
Medium6
Geometry, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Remove Redundant Parentheses
Medium6
Stack, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Counting Rectangles
Medium6
Geometry, Hash map+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Calendar Game
Medium6
Game theory, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Gene Function
Medium6
Dynamic programming, String
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Moving Tables
Medium6
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
What's In A Name?
Medium6
Brute force, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sorting It All Out
Medium6
Graph, Topological sort+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Space Station Shielding
Medium6
BFS, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Square Ice
Medium6
Implementation, Matrix+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Checker's Check
Medium6
Simulation, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Watchdog
Medium6
Geometry, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Taxi Cab Scheme
Medium6
Graph, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Document Indexing
Medium6
Simulation, Implementation+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Joke with Turtles
Medium6
Dynamic programming, Greedy+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Code Formatting
Medium6
Implementation, Recursion+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Bricks
Medium6
Geometry, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cricket Field
Medium6
Geometry, Brute force+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
String Folding
Medium6
Dynamic programming, String
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Heroes of Might and Magic
Medium6
BFS, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cable Master
Medium6
Binary search, Greedy
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Toxic Barrier
Medium6
Geometry, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Number Pairs
Medium6
Math, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Flip Game
Medium6
Brute force, Bit manipulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Binary Search
Medium6
Binary search, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Garland
Medium6
Math, Binary search+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Loan
Medium6
Binary search, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Advertisement
Medium6
Greedy, Intervals+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Defragment
Medium6
Greedy, Array+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Dog Task
Medium6
Geometry, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Four Integers Summing to Zero
Medium6
Hash map, Sorting+2
No attempts yet
Time limit
12s
Memory limit
1024 MB
Judgeable
Keep the Customer Satisfied
Medium6
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Angry Teacher
Medium6
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Beth Tableaux
Medium6
Backtracking, Implementation+2
No attempts yet
Time limit
2s
Memory limit
64 MB
Judgeable
Fool's Day
Medium6
Geometry, Implementation+1
No attempts yet
Time limit
2s
Memory limit
64 MB
Judgeable
Graveyard Design
Medium6
Two pointers, Math+2
No attempts yet
Time limit
2s
Memory limit
64 MB
Judgeable
Honey and Milk Land
Medium6
Geometry, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Crankshaft
Medium6
Geometry, Math+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
ATM Game
Medium6
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Angry Larva
Medium6
Geometry, Intervals+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Embassy
Medium6
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Greatest Product
Medium6
Greedy, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Fractal Cake
Medium6
Divide and conquer, Recursion+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sum of Consecutive Primes
Medium6
Number theory, Prefix sum+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Citystar
Medium6
Sorting, Sliding window+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Soccer
Medium6
Dynamic programming, Probability+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
A Knight's Journey
Medium6
Backtracking, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pimp My Ride
Medium6
Dynamic programming, Bit manipulation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Jamie's Contact Groups
Medium6
Binary search, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Military Recruit
Medium6
Shortest path, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Forest Fires
Medium6
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
CouplesGiven N parties and their attendees, count pairs of people who appear together at more than K parties.	Medium6	Hash mapCombinatorics	No attempts yet	5s	128 MB	Judgeable
TicketsSplit L pages of non-increasing popularity into D contiguous channel blocks to minimize the popularity-weighted sum of within-block delay positions, breaking ties by the lexicographically smallest block boundaries.	Medium6	Dynamic programmingGreedy+2	No attempts yet	1s	128 MB	Judgeable
Factorial Digit CountGiven N, list every positive integer X for which X! has exactly N decimal digits, or report that none exists.	Medium6	MathBinary search+2	No attempts yet	1s	128 MB	Judgeable
Street NetworkDecide whether a directed multigraph has an Eulerian trail, count possible start nodes, and for S at most 3 count closed walks of length S from each node, sorted.	Medium6	GraphImplementation+2	No attempts yet	1s	128 MB	Judgeable
BilliardsA ball starts 13 from side R and 29 from side D and moves straight from a cue point on R, reflecting off the sides; find its distances from R and D after n centimeters.	Medium6	MathGeometry+2	No attempts yet	1s	128 MB	Judgeable
The Folded SheetA rectangle is folded along a segment connecting points on two adjacent edges; find the area of the union of the folded part and the remaining sheet.	Medium6	GeometryMath+2	No attempts yet	1s	128 MB	Judgeable
The Strange SequenceGiven a start value and index n, build the sequence where each next term is the smallest number greater than the previous one whose digit sum equals the digit sum of four times the previous term, then print the n-th term.	Medium6	ImplementationMath+2	No attempts yet	1s	128 MB	Judgeable
Cutting Out of FactorialsGiven k from 2 to 500, remove the fewest of 1!, 2!, ..., k! so the remaining product is a perfect square, and report that count.	Medium6	MathNumber theory+2	No attempts yet	1s	128 MB	Judgeable
SeriesWrite all integers from n to m as one digit string, sort the digits descending, and report the k-th digit, or NAV if the string is shorter.	Medium6	MathImplementation+2	No attempts yet	1s	128 MB	Judgeable
The MagicianGiven counts of four props and three conversion tricks, find the maximum reachable number of rabbits and the fewest tricks to get there.	Medium6	BFSGraph+1	No attempts yet	1s	128 MB	Judgeable
Heating MainCount the ways to lay a single non-crossing path of four fixed pipe shapes from the top-left top side to the bottom-right right side, respecting fixed pipes and blocked garden cells on a grid of at most 10 by 10.	Medium6	BacktrackingDFS+2	No attempts yet	1s	128 MB	Judgeable
Prime ScrabbleGiven up to 8 digit tiles, choose a placement order and direction to maximize the sum of prime-reading sums earned minus the values of unplaced tiles.	Medium6	Brute forceMath+2	No attempts yet	1s	1024 MB	Judgeable
Algarvu-ScrabbleGiven up to 8 digit tiles, place them one by one at either end of a row to maximize prime-direction scoring minus penalties for unused tiles.	Medium6	BacktrackingBrute force+2	No attempts yet	1s	1024 MB	Judgeable
BacteriaEach adult produces one young per second while young mature into adults; find the total population after T seconds modulo K, given initial counts.	Medium6	MathCombinatorics+2	No attempts yet	1s	1024 MB	Judgeable
Õhne vanaraamatupoodSimulate bots that repeatedly recompute their book price from the previous day's average, and print every bot's price on the morning of day T.	Medium6	ImplementationSimulation+2	No attempts yet	1s	1023 MB	Judgeable
RoadsGiven a graph with N cities and M edges, add exactly K new non-duplicate edges to minimize and maximize the resulting number of connected components.	Medium6	GraphUnion-find+2	No attempts yet	1s	128 MB	Judgeable
Job PostingsAssign each student one of four ranked job postings, respecting per-posting capacity and year-based weights, to maximize total satisfaction.	Medium6	GreedySorting+2	No attempts yet	5s	256 MB	Judgeable
Flipping a Pack of CardsSimulate a deck of n cards under m prefix-reversal-and-flip operations, then report the final position and face direction of s queried cards.	Medium6	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
Puzzle of NumbersGiven three digit-and-star patterns for A, B, and C with A + B = C, fill the stars to build the smallest valid equation.	Medium6	BacktrackingMath+2	No attempts yet	1s	128 MB	Judgeable
Swimming PoolGiven an m by n grid of tower heights, find the total volume of water trapped among the towers when the grid is flooded from the outside.	Medium6	HeapBFS+2	No attempts yet	1s	128 MB	Judgeable
FireworksA firework splits into two 45-degree branches after each vertical stage; count the distinct grid squares colored across all stages.	Medium6	SimulationDFS+2	No attempts yet	2s	1024 MB	Judgeable
Operator SignsInsert + or - between adjacent numbers so the left-to-right value equals the target, keeping every partial result within 10000, and print the lexicographically smallest expression.	Medium6	Dynamic programmingBacktracking+2	No attempts yet	1s	1024 MB	Judgeable
IP AddressesGiven a sequence of IP addresses added one by one, report which distinct addresses grep wrongly skipped because dots act as regex wildcards.	Medium6	StringHash map+2	No attempts yet	1s	1024 MB	Judgeable
Turning a TreeReroot a given ordered tree at a specified leaf so the counter-clockwise order of neighbors at each node stays the same, then print the new tree.	Medium6	TreeDFS+2	No attempts yet	1s	1024 MB	Judgeable
DragonPick two disjoint blocks of at most K consecutive heads each in a row of N heads to maximize the total fire power removed.	Medium6	Dynamic programmingPrefix sum+2	No attempts yet	1s	1024 MB	Judgeable
Living Off the InterestSimulate monthly deposits and yearly compound interest to find how many years pass before the yearly interest exceeds yearly expenses.	Medium6	SimulationMath+1	No attempts yet	1s	1024 MB	Judgeable
Food CompositionGiven ingredients in decreasing order, some with stated percentages, find the minimum and maximum possible percentage for each, or report impossibility.	Medium6	GreedyMath+2	No attempts yet	1s	1024 MB	Judgeable
PoliticiansGiven ratio relations between politicians that form a connected comparison graph, find the most and least important and their importance ratio to two decimals.	Medium6	GraphDFS+2	No attempts yet	1s	1024 MB	Judgeable
Buffet TableOn a circle of N trays, a walker repeatedly jumps K steps clockwise, collecting each visited tray once until it revisits a tray; find the start that maximizes the total.	Medium6	Number theoryMath+2	No attempts yet	1s	1024 MB	Judgeable
Rock, Paper, ScissorsGiven how many times each player threw rock, paper, and scissors, pair the throws to find the maximum and minimum possible score for Vilius.	Medium6	GreedyMath+2	No attempts yet	1s	1024 MB	Judgeable
CourierDeliver parcels to cities on a line before their deadlines, minimizing the time to return to the warehouse, or report impossibility.	Medium6	Dynamic programmingSorting	No attempts yet	1s	1024 MB	Judgeable
Unit TransformationFind the minimum cost to build a target number from 1 using only operations on the last digit.	Medium6	Dynamic programmingBFS+2	No attempts yet	1s	1024 MB	Judgeable
LiarsGiven claims that candidate a says candidate b lies or tells the truth, decide whether candidates can be split into liars and truth-tellers consistently.	Medium6	GraphBFS+2	No attempts yet	1s	1024 MB	Judgeable
The Cat of BitlandTwo rows of K (friendly) and A (allergic) students; the cat moves right in a row or jumps to any later room in the other row, and we want the most rooms it can visit.	Medium6	Dynamic programmingArray+2	No attempts yet	1s	1024 MB	Judgeable
ConcertGive K spectators a +1 height boost so that the maximum number of people stand strictly taller than everyone in front of them.	Medium6	Dynamic programmingGreedy	No attempts yet	1s	1024 MB	Judgeable
Word GroupingSplit N words into the fewest groups so that each group shares at least one common letter, with at most 15 distinct letters.	Medium6	Bit manipulationDynamic programming+1	No attempts yet	1s	1024 MB	Judgeable
LawnmowerSimulate a lawn that grows each morning and is mowed b_j times per day, reporting the total remaining grass height after each day.	Medium6	SortingPrefix sum+2	No attempts yet	1s	1024 MB	Judgeable
Monthly Railway PassA graph has train and bus edges. Count cities from which every other city is reachable using any number of train edges and at most one bus edge.	Medium6	GraphDFS+1	No attempts yet	2s	1024 MB	Judgeable
Fire drillOrder N buildings to minimize how many times a building is evacuated before one of its listed predecessors. Output the permutation.	Medium6	Topological sortGraph+1	No attempts yet	1s	1024 MB	Judgeable
MetaprogrammingFind the shortest program of add n, multiply n, and print commands that maps each given distinct input to its required output, or report that none exists.	Medium6	Number theoryMath+2	No attempts yet	1s	1024 MB	Judgeable
Swimming CompetitionSplit a sorted list of N swimmer times into consecutive heats of size A to B, minimizing the largest within-heat gap between fastest and slowest.	Medium6	Binary searchGreedy+2	No attempts yet	1s	1024 MB	Judgeable
TelevisionGiven N intervals on a line, choose the fewest intervals so that every point covered by any interval is covered by a chosen one, then print that count.	Medium6	GreedySorting+2	No attempts yet	1s	1024 MB	Judgeable
PassengersGiven each request's row and earliest time, find the least total time for the attendant to serve all and return to row 1.	Medium6	Dynamic programmingGreedy+1	No attempts yet	1s	1024 MB	Judgeable
Airplane PassengersGiven requests at row a made no earlier than minute b, find the minimum minutes for an attendant starting at row 1 to reach every request row on time.	Medium6	Dynamic programmingSorting+2	No attempts yet	1s	1024 MB	Judgeable
Alphariz Table CollapseGiven a letter grid and a list of chosen cells, repeatedly erase each chosen cell's 4-connected equal-letter region, then slide rows left and columns down, deleting empty rows and columns.	Medium6	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
Vice CityFind the fastest route from PayPhone to WKCharriot, where travel time depends on the vehicle you drive and each vehicle swap costs one minute.	Medium6	GraphShortest path+2	No attempts yet	1s	128 MB	Judgeable
Food CubesCount the empty unit cells trapped inside a set of food cubes, where a hole is a maximal face-connected empty region that cannot reach the outside.	Medium6	BFSGraph+2	No attempts yet	1s	128 MB	Judgeable
Optimal KeypadSplit a 30-character alphabet tape into 12 labeled pieces to minimize total keystrokes for a word dictionary, printing the lexicographically smallest optimal cut string.	Medium6	Dynamic programmingPrefix sum+1	No attempts yet	1s	128 MB	Judgeable
UnfoldungFor each cube-built surface, decide whether its graph splits along cut edges, and if not, whether the surface can be unfolded flat.	Medium6	GraphDFS+2	No attempts yet	1s	128 MB	Judgeable
Dolphin PoolGiven up to 20 circles with disjoint centers, count the bounded regions outside all circles that the circles enclose.	Medium6	GeometryGraph+1	No attempts yet	1s	128 MB	Judgeable
Remove Redundant ParenthesesGiven valid arithmetic expressions over single uppercase variables with + and -, remove every matching parenthesis pair whose removal keeps the expression's value unchanged.	Medium6	StackString+2	No attempts yet	1s	128 MB	Judgeable
Counting RectanglesCount rectangles whose four corners are all intersection points of horizontal and vertical segments in a figure.	Medium6	GeometryHash map+2	No attempts yet	1s	128 MB	Judgeable
Calendar GameOn a fixed 1900-2001 calendar, two players alternately advance a date by one day or to the same day next month; decide if the first player wins.	Medium6	Game theoryDynamic programming+1	No attempts yet	1s	128 MB	Judgeable
Gene FunctionAlign two DNA sequences by inserting blanks to maximize the sum of position-wise match values from a given table.	Medium6	Dynamic programmingString	No attempts yet	1s	128 MB	Judgeable
Moving TablesEach move occupies a corridor segment; find the minimum number of 10-minute rounds so that overlapping segments never share a round.	Medium6	GreedySorting+1	No attempts yet	1s	128 MB	Judgeable
What's In A Name?Given enter, leave, and message logs plus a list of user IDs, decide which criminal's ID is uniquely determined.	Medium6	Brute forceSimulation+1	No attempts yet	1s	128 MB	Judgeable
Sorting It All OutGiven up to n letter ordering constraints added one at a time, report the first point where a unique sorted order emerges or where the constraints contradict each other.	Medium6	GraphTopological sort+2	No attempts yet	1s	128 MB	Judgeable
Space Station ShieldingGiven occupied unit cells of a connected 3D station, count faces on the external surface, where enclosed hollow pockets do not count.	Medium6	BFSImplementation+2	No attempts yet	1s	128 MB	Judgeable
Square IceGiven an alternating sign matrix, render the corresponding square ice grid using H, O, dashes, bars, and an asterisk border.	Medium6	ImplementationMatrix+2	No attempts yet	1s	128 MB	Judgeable
Checker's CheckGiven a checkers position and a list of moves, report the first move that breaks the movement, capture, or promotion rules.	Medium6	SimulationImplementation+1	No attempts yet	1s	128 MB	Judgeable
WatchdogFind an integer roof point where a leash can be tied so the dog reaches every hatch but the leash never crosses the roof edge.	Medium6	GeometryBrute force+2	No attempts yet	1s	128 MB	Judgeable
Taxi Cab SchemeGiven taxi rides sorted by departure time, find the fewest cabs needed so each ride is served, where a cab reaches the next pickup at least one minute early.	Medium6	GraphSorting+1	No attempts yet	1s	128 MB	Judgeable
Document IndexingPaginate a document by line-count and paragraph rules, then print each word in uppercase with its pages, collapsing runs of three or more consecutive pages into ranges.	Medium6	SimulationImplementation+2	No attempts yet	2s	128 MB	Judgeable
Joke with TurtlesEach turtle claims a count of turtles ahead and behind it; choose positions to maximize how many claims hold at once.	Medium6	Dynamic programmingGreedy+2	No attempts yet	2s	128 MB	Judgeable
Code FormattingParse a TRIVIAL program given by a grammar and print it back with strict indentation and whitespace rules.	Medium6	ImplementationRecursion+2	No attempts yet	2s	128 MB	Judgeable
BricksGiven a rectangular brick and a rectangular hole, decide whether the brick can pass through the hole in any orientation.	Medium6	GeometryMath+1	No attempts yet	1s	128 MB	Judgeable
Cricket FieldGiven up to 100 tree points in a W by H rectangle, find the largest axis-aligned square inside the park with no tree strictly inside it.	Medium6	GeometryBrute force+1	No attempts yet	2s	128 MB	Judgeable
String FoldingFind the length of the shortest folded sequence, using repeat counts like 3(AB), that unfolds to the given uppercase string.	Medium6	Dynamic programmingString	No attempts yet	2s	128 MB	Judgeable
Heroes of Might and MagicDecide whether a mage hero can wipe out a monster pack using lightning, teleport, and heal, and give the minimum number of spells needed.	Medium6	BFSSimulation+2	No attempts yet	1s	128 MB	Judgeable
Cable MasterFind the largest centimeter-precision length such that cutting all stock cables yields at least K pieces of that length.	Medium6	Binary searchGreedy	No attempts yet	1s	128 MB	Judgeable
Toxic BarrierFind the convex hull of N points and add a buffer of distance L around it, giving the minimum closed barrier length rounded to the nearest integer.	Medium6	GeometrySorting+2	No attempts yet	1s	128 MB	Judgeable
Number PairsFor a given N, list all pairs (X, Y) with X + Y = N where deleting one digit from X yields Y, and count them.	Medium6	MathBrute force+2	No attempts yet	1s	128 MB	Judgeable
Flip GameFind the minimum number of flips to turn all 16 pieces white or all black, where each move flips a chosen cell and its orthogonal neighbors.	Medium6	Brute forceBit manipulation+2	No attempts yet	1s	128 MB	Judgeable
Binary SearchFind every array length N for which this binary search on a sorted array reports finding x at index i after exactly L comparisons.	Medium6	Binary searchMath+1	No attempts yet	1s	128 MB	Judgeable
GarlandGiven the leftmost height A and the sag rule H_i = (H_{i-1}+H_{i+1})/2 - 1, find the smallest rightmost height B so all heights stay nonnegative.	Medium6	MathBinary search+1	No attempts yet	1s	128 MB	Judgeable
LoanFind the smallest first annual payment that clears a loan in exactly K years, and output the schedule of equal or one-cent-decreasing yearly payments grouped by amount.	Medium6	Binary searchSimulation+2	No attempts yet	1s	128 MB	Judgeable
AdvertisementPlace the fewest advertisements so every jogger's interval of billboards contains at least min(K, length) of them.	Medium6	GreedyIntervals+2	No attempts yet	1s	128 MB	Judgeable
DefragmentGiven files spread over N disk clusters, find the minimum number of single-cluster moves to place them contiguously in order, with file i starting after file i-1.	Medium6	GreedyArray+2	No attempts yet	1s	128 MB	Judgeable
The Dog TaskBob walks a polygonal path through N points; Ralph may leave each segment to visit at most one interesting place and never reuse a place. Maximize places visited.	Medium6	GeometryGraph+2	No attempts yet	1s	128 MB	Judgeable
Four Integers Summing to ZeroCount the number of index tuples (a, b, c, d) with A[a] + B[b] + C[c] + D[d] = 0, given four arrays of size n.	Medium6	Hash mapSorting+2	No attempts yet	12s	1024 MB	Judgeable
Keep the Customer SatisfiedGiven orders with processing times and due dates on a single machine, choose the largest subset that can all finish on time.	Medium6	GreedySorting+2	No attempts yet	1s	1024 MB	Judgeable
Angry TeacherFor each of k consecutive integers starting at l, evaluate a polynomial with huge integer coefficients and output the sum of squares of the last m decimal digits of the value.	Medium6	MathImplementation+2	No attempts yet	1s	128 MB	Judgeable
Beth TableauxParse a propositional formula and either report it valid or print the lexicographically smallest falsifying assignment.	Medium6	BacktrackingImplementation+2	No attempts yet	2s	64 MB	Judgeable
Fool's DayFor each test case, decide whether a parallelogram postcard fits inside a parallelogram envelope, allowing rotation, translation, and flipping.	Medium6	GeometryImplementation+1	No attempts yet	2s	64 MB	Judgeable
Graveyard DesignFind all runs of consecutive positive integers whose squares sum to a given n up to 10^14, and list each run in order of its smallest element.	Medium6	Two pointersMath+2	No attempts yet	2s	64 MB	Judgeable
Honey and Milk LandGiven spacings between parallel north-south rivers and between parallel east-west rivers, find the shortest helicopter route crossing every river at least once, rounded up.	Medium6	GeometryGreedy+2	No attempts yet	1s	128 MB	Judgeable
CrankshaftGiven polygons listed clockwise, compute the area-weighted centroid of all plates and print each coordinate as a reduced fraction.	Medium6	GeometryMath+2	No attempts yet	1s	512 MB	Judgeable
ATM GameGiven two bill denominations a and b and an amount S, find non-negative counts of each summing to S with the fewest total bills, or report Impossible.	Medium6	MathNumber theory+2	No attempts yet	1s	128 MB	Judgeable
Angry LarvaEach snake is a vertical segment at some x-coordinate and height range. Find the launch angle whose parabola passes through the most segments.	Medium6	GeometryIntervals+1	No attempts yet	1s	128 MB	Judgeable
EmbassyOrder N people in a queue to minimize the total fee paid for those who finish after their train departure time.	Medium6	GreedySorting+1	No attempts yet	1s	128 MB	Judgeable
Greatest ProductGiven N up to two billion, find the largest product of digits over all integers from 1 to N.	Medium6	GreedyMath+1	No attempts yet	1s	128 MB	Judgeable
Fractal CakePrint the chocolate pattern of a rectangular window in a 2^(N+1) square grid built by recursively darkening the middle 2x2 of every 4x4 block N times.	Medium6	Divide and conquerRecursion+2	No attempts yet	1s	128 MB	Judgeable
Sum of Consecutive PrimesFor each query set of counts, find the smallest prime expressible as a sum of exactly n_i consecutive primes for every given n_i.	Medium6	Number theoryPrefix sum+2	No attempts yet	2s	128 MB	Judgeable
CitystarFor each street, find the five house numbers whose span (max minus min plus 1) is smallest, breaking ties by the smallest house numbers.	Medium6	SortingSliding window+2	No attempts yet	1s	128 MB	Judgeable
SoccerGiven 16 teams, a fixed bracket, and pairwise win probabilities, compute each team's probability of winning the single-elimination tournament.	Medium6	Dynamic programmingProbability+2	No attempts yet	1s	128 MB	Judgeable
A Knight's JourneyFind the lexicographically smallest knight's tour that visits every square of a rectangular board with at most 26 squares exactly once.	Medium6	BacktrackingDFS+2	No attempts yet	1s	128 MB	Judgeable
Pimp My RideGiven n jobs with base prices and pairwise surcharges paid when a later job follows an earlier one, find the cheapest order to finish all jobs.	Medium6	Dynamic programmingBit manipulation	No attempts yet	1s	128 MB	Judgeable
Jamie's Contact GroupsAssign each of N friends to one of M allowed groups so that every friend lands in exactly one group and the largest group size is as small as possible.	Medium6	Binary searchGraph+2	No attempts yet	1s	128 MB	Judgeable
Military RecruitGiven a directed weighted graph, find the smallest D so that at least p percent of ordered pairs of distinct sites have a shortest-path distance of at most D.	Medium6	Shortest pathGraph+2	No attempts yet	1s	128 MB	Judgeable
Forest FiresGiven a grid with plant cells, fire cells, and empty cells, compute when every burnable cell catches fire under Euclidean squared spark costs.	Medium6	GraphShortest path+2	No attempts yet	1s	128 MB	Judgeable