Problems

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Total results29,425 problems

Castle Walls
Medium6
Sorting, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Period of a Repeating Fraction
Medium6
Math, Number theory+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Dory's Phonebook
Medium6
Trie, Backtracking+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Lining Up in Order
Medium6
Array, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Virus
Medium6
String, String matching+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Probe
Medium6
Array, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
App
Medium6
Dynamic programming, Array
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Team Selection
Medium6
Simulation, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Stars
Medium6
Geometry, Hash map+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Infinite Game
Medium6
Number theory, Dynamic programming+2
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Another Rock-Paper-Scissors Problem
Medium6
Recursion, Divide and conquer+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Hidden Code
Medium6
String, Math+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Counting Lit Pixels
Medium6
Math, Geometry+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Four Gate Push
Medium6
Dynamic programming, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bonsai
Medium6
Tree, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Number Game
Medium6
Game theory, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Leap Frog
Medium6
Dynamic programming, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Earthquake Emendations
Medium6
Geometry, Hash map+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Folded Fixtures
Medium6
Graph, BFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Honed Hops
Medium6
Math, Geometry+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Spam
Medium6
Dynamic programming, String
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sudoku
Medium6
Backtracking, Matrix
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Colored Stones
Medium6
Dynamic programming, Bit manipulation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cake Cutting
Medium6
Dynamic programming, Divide and conquer+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Brackets
Medium6
Dynamic programming, Intervals+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hiring the Crew
Medium6
Graph, DFS
No attempts yet
Time limit
4s
Memory limit
64 MB
Judgeable
Shortest Computer Reboot Tour
Medium6
Dynamic programming, Bit manipulation+1
No attempts yet
Time limit
0.1s
Memory limit
128 MB
Judgeable
Cars
Medium6
BFS
No attempts yet
Time limit
1s
Memory limit
32 MB
Judgeable
Cell phone tunes
Medium6
String matching, Implementation+1
No attempts yet
Time limit
1s
Memory limit
32 MB
Judgeable
Parabolic Teleports
Medium6
Geometry, Graph+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Magic Pyramid
Medium6
BFS, Simulation+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Aztec Pyramid
Medium6
Math, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Final Ranking
Medium6
Greedy, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Burger, French Fries, Soft Drink
Medium6
Dynamic programming, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Taxi!
Medium6
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Playing With Domino
Medium6
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Adventure in Panda Land Part I: Panda Number
Medium6
Math, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Transitive Closure
Medium6
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Add Them Up
Medium6
Combinatorics, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pizza Delivery Schedule
Medium6
Brute force, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Count Squares
Medium6
Geometry, Hash map+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Terrarium
Medium6
Simulation, Implementation+1
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Radio Coverage
Medium6
Geometry, Brute force+1
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Water pipe
Medium6
BFS, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Burned Calendar
Medium6
Implementation, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Falling Cards
Medium6
Geometry, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Spreadsheet
Medium6
Implementation, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
PreQueL
Medium6
Brute force, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Jack's Socks
Medium6
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Two Professors
Medium6
Sorting, Greedy+1
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
A Number Game
Medium6
Game theory, Number theory+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Euro Efficiency
Medium6
Dynamic programming, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Will It Stop?
Medium6
Math, Number theory+1
No attempts yet
Time limit
3s
Memory limit
64 MB
Judgeable
Triangulation
Medium6
Dynamic programming, Geometry
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Random Walk
Medium6
Geometry, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Checksum
Medium6
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Exotic Mechanical System
Medium6
Graph, BFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Signal
Medium6
String matching, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Fifth Dimension
Medium6
Graph, Combinatorics
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Highway Racing Tracks
Medium6
Graph, Combinatorics
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Dragon
Medium6
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Skewers
Medium6
Dynamic programming, Matrix
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cave
Medium6
Graph, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Treasure
Medium6
BFS, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
A Journey to Mars
Medium6
Greedy, Prefix sum+1
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Double Row
Medium6
Graph, Union-find+1
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Chris Martin
Medium6
Dynamic programming, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Bridge
Medium6
Greedy, Sorting+1
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Castle
Medium6
Graph, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Counting-Out Rhyme
Medium6
Simulation, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Antiprime Numbers
Medium6
Number theory, Brute force+2
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Travel Plan (Small)
Medium6
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Agents
Medium6
Graph, BFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Speleology
Medium6
Graph, Dynamic programming+2
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Three-Coloring of Binary Trees
Medium6
Tree, DFS+2
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Water
Medium6
Heap, BFS+2
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
One-sequence
Medium6
Greedy, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Frogman
Medium6
Dynamic programming, Greedy
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Rectangles
Medium6
Union-find, Geometry+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Jumps
Medium6
Greedy, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cheap Travels
Medium6
Dynamic programming, Array+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
XOR Nets
Medium6
Bit manipulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Airports
Medium6
Graph, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Petrol
Medium6
Greedy, Stack
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Lecture Halls Reservation
Medium6
Dynamic programming, Sorting+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Fibonacci Words
Medium6
String, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Knights
Medium6
Dynamic programming, Bit manipulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Zeros and Ones
Medium6
BFS, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Zeros and Ones - 2
Medium6
BFS, Graph+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
The Right-Turn Drivers' Club
Medium6
BFS, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Board Covering
Medium6
Math, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Coding of Permutations
Medium6
Segment tree, Binary search+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Concatenation of Words
Medium6
Dynamic programming, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Teddies
Medium6
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Fairy Lights
Medium6
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pebbles
Medium6
Game theory, Greedy+1
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Arrays
Medium6
Hash map, Sorting+1
No attempts yet
Time limit
4s
Memory limit
128 MB
Judgeable
Temperature
Medium6
Greedy, Two pointers+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Taxis
Medium6
Greedy, Sorting
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Two Cakes
Medium6
Greedy, Array+2
No attempts yet
Time limit
4s
Memory limit
128 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Castle WallsGiven blue and red hooks with distinct line positions, count blue-red pairs whose endpoints satisfy the crossing inequality.	Medium6	SortingPrefix sum+1	No attempts yet	1s	128 MB	Judgeable
Period of a Repeating FractionGiven base b, numerator x and denominator y in that base, find the length of the repeating cycle when x/y is written in base b.	Medium6	MathNumber theory+1	No attempts yet	1s	128 MB	Judgeable
Dory's PhonebookGiven a dictionary of words and a phone number, find every encoding of the number as a space-separated sequence of dictionary words, sorted lexicographically.	Medium6	TrieBacktracking+2	No attempts yet	1s	128 MB	Judgeable
Lining Up in OrderGiven a permutation of 1..N, find the fewest children to move to either end so the line becomes increasing; the answer is N minus the longest run of consecutive values that already appears in increasing order.	Medium6	ArrayDynamic programming+1	No attempts yet	1s	256 MB	Judgeable
VirusDecide whether every one of N integer sequences shares some contiguous fragment of length at least K, counting reversals as the same fragment.	Medium6	StringString matching+2	No attempts yet	1s	128 MB	Judgeable
ProbeGiven range-sum probe results on a length-K binary road, find the lexicographically smallest object placement satisfying all of them, or NONE.	Medium6	ArrayPrefix sum+2	No attempts yet	1s	128 MB	Judgeable
AppChoose a subset of active apps to deactivate whose freed memory is at least M while minimizing the total deactivation cost.	Medium6	Dynamic programmingArray	No attempts yet	1s	128 MB	Judgeable
Team SelectionGiven n students in a circle and step k, report the last four positions removed by Josephus elimination.	Medium6	SimulationMath+1	No attempts yet	1s	128 MB	Judgeable
StarsGiven a star map of points with brightness and several constellation point sets, count how many rotated or scaled copies of each occur and report the brightest such occurrence.	Medium6	GeometryHash map+2	No attempts yet	1s	128 MB	Judgeable
Infinite GameGiven sets A and B of positive steps taken alternately right and left, decide whether every integer can be reached.	Medium6	Number theoryDynamic programming+2	No attempts yet	5s	128 MB	Judgeable
Another Rock-Paper-Scissors ProblemGiven a game number N up to 10^12, determine the move that beats Sonny's move in his self-similar rock-paper-scissors sequence.	Medium6	RecursionDivide and conquer+1	No attempts yet	2s	512 MB	Judgeable
Hidden CodeGiven plaintext/ciphertext pairs encrypted with a common repeating key, recover the shortest key or report that none works.	Medium6	StringMath+2	No attempts yet	2s	512 MB	Judgeable
Counting Lit PixelsFor each integer circle center and radius, count the unit grid squares the disk covers, ignoring squares touched only along an edge or corner.	Medium6	MathGeometry+2	No attempts yet	1s	128 MB	Judgeable
Four Gate PushGiven mineral and gas budgets and per-unit strengths, maximize total strength over non-negative counts of three unit types.	Medium6	Dynamic programmingMath+1	No attempts yet	1s	128 MB	Judgeable
BonsaiRoot a weighted tree and cut edges of minimum total weight so that no original leaf stays connected to the root.	Medium6	TreeDFS+2	No attempts yet	1s	128 MB	Judgeable
Number GameWith Ellie's responses fixed by a1..a20, decide if the first player can force reaching 0 in a subtraction game.	Medium6	Game theoryDynamic programming+1	No attempts yet	1s	128 MB	Judgeable
Leap FrogGiven sorted positions, Jack and Jill alternate hopping over each other within distance 10; find the minimum total jumps until one lands on the last position.	Medium6	Dynamic programmingGreedy+1	No attempts yet	1s	128 MB	Judgeable
Earthquake EmendationsMatch each scattered polygon piece to its rotated location in the shattered window schematic.	Medium6	GeometryHash map+1	No attempts yet	1s	128 MB	Judgeable
Folded FixturesGiven a connected structure of unit links, decide whether hanging it from some sphere makes every link hang vertically, and report the shortest such height.	Medium6	GraphBFS+2	No attempts yet	1s	128 MB	Judgeable
Honed HopsGiven two sets of sampled points on a nonnegative quadratic jump arc, decide whether they necessarily come from the same parabola, cannot, or it is undecidable.	Medium6	MathGeometry+1	No attempts yet	1s	128 MB	Judgeable
SpamCount how many plain-text messages encode to the same spam encoding as a given message.	Medium6	Dynamic programmingString	No attempts yet	1s	128 MB	Judgeable
SudokuFill every empty cell of a 9x9 Sudoku grid so each row, column, and 3x3 box contains the digits 1 through 9 exactly once.	Medium6	BacktrackingMatrix	No attempts yet	1s	128 MB	Judgeable
Colored StonesRemove the fewest stones so that in the remaining row every color appears in one contiguous block.	Medium6	Dynamic programmingBit manipulation	No attempts yet	1s	128 MB	Judgeable
Cake CuttingSplit a w by h rectangle into m axis-aligned integer rectangles, each cut dividing one piece, to minimize the largest piece's area.	Medium6	Dynamic programmingDivide and conquer+1	No attempts yet	1s	128 MB	Judgeable
BracketsGiven a bracket string, find the maximum length of a regular bracket sequence obtainable as a subsequence.	Medium6	Dynamic programmingIntervals+1	No attempts yet	1s	128 MB	Judgeable
Hiring the CrewGiven a directed graph of sailor demands, find the smallest non-empty vertex set closed under outgoing edges.	Medium6	GraphDFS	No attempts yet	4s	64 MB	Judgeable
Shortest Computer Reboot TourGiven up to 12 points, find the shortest closed tour that visits every point exactly once and returns to the start.	Medium6	Dynamic programmingBit manipulation+1	No attempts yet	0.1s	128 MB	Judgeable
CarsGiven a 6x6 grid of horizontal and vertical cars and trucks, find the fewest slides to drive the first car off the eastern edge.	Medium6	BFS	No attempts yet	1s	32 MB	Judgeable
Cell phone tunesDecide whether a given tune is good (no adjacent equal-multiset blocks), contains all n sounds, and cannot be extended by a single sound on either end.	Medium6	String matchingImplementation+1	No attempts yet	1s	32 MB	Judgeable
Parabolic TeleportsGiven up to 100 parabolic arcs you can ride for free, find the minimum walking time from point V to point W.	Medium6	GeometryGraph+1	No attempts yet	2s	128 MB	Judgeable
Magic PyramidGiven the 36 colored triangles and a repaint permutation, find the fewest moves (face turns or repaint) to make each tetrahedron face one solid color.	Medium6	BFSSimulation+1	No attempts yet	2s	128 MB	Judgeable
Aztec PyramidGiven n unit cubes stacked under contact and stability rules, find the greatest achievable height of a stable pyramid.	Medium6	MathGreedy+2	No attempts yet	1s	128 MB	Judgeable
Final RankingGiven n students, total score p, and exactly d distinct scores among the top k, output the lexicographically greatest non-increasing score list of non-negative integers, or report that none exists.	Medium6	GreedyImplementation+2	No attempts yet	1s	128 MB	Judgeable
Burger, French Fries, Soft DrinkCount the ways to cut a B/F/S stream into N consecutive blocks where every block has equal positive counts of each letter, or report Impossible.	Medium6	Dynamic programmingPrefix sum+2	No attempts yet	1s	128 MB	Judgeable
Taxi!Given a bidirectional weighted graph where each road has a traversal time and a fare, find the minimum total time from s to d whose total fare stays within budget r.	Medium6	GraphShortest path+2	No attempts yet	1s	128 MB	Judgeable
Playing With DominoGiven up to 1000 dominoes with faces numbered 0 to 6, find the largest number of tiles that can be linked in a single chain where touching squares match.	Medium6	GraphDFS+2	No attempts yet	1s	128 MB	Judgeable
The Adventure in Panda Land Part I: Panda NumberSum the bamboo-stick counts of the Panda numeral representation for every integer from A to B, including negatives and zero.	Medium6	MathImplementation+1	No attempts yet	1s	128 MB	Judgeable
Transitive ClosureCount off-diagonal pairs (X, Y) with a directed path from X to Y in a graph of up to 2500 vertices and 10000 edges.	Medium6	GraphDFS+2	No attempts yet	1s	128 MB	Judgeable
Add Them UpGiven counts of each digit 1-9, sum every distinct number formable using each digit at most as often as it appears, modulo 1e9+7.	Medium6	CombinatoricsDynamic programming+2	No attempts yet	1s	128 MB	Judgeable
Pizza Delivery ScheduleGiven recorded pizza deliveries by week and weekday, find the fixed weekly-cycle schedule of period 1 to 4 weeks that minimizes mismatched days.	Medium6	Brute forceImplementation+2	No attempts yet	1s	128 MB	Judgeable
Count SquaresGiven up to 2000 distinct integer points, count how many squares have all four vertices among them, including tilted squares.	Medium6	GeometryHash map+1	No attempts yet	1s	128 MB	Judgeable
TerrariumSimulate up to 26 snakes crawling one cell per second on an N x N grid for T seconds and print the final board.	Medium6	SimulationImplementation+1	No attempts yet	3s	128 MB	Judgeable
Radio CoverageChoose a non-overlapping subset of at most 10 candidate disks inside a base disk to maximize the union area of the base and chosen disks.	Medium6	GeometryBrute force+1	No attempts yet	3s	128 MB	Judgeable
Water pipeConnect two points with axis-aligned pipe segments of given lengths and counts, turning only 90 degrees, and minimize the number of segments used.	Medium6	BFSGraph+2	No attempts yet	1s	128 MB	Judgeable
Burned CalendarGiven a small surviving rectangle of a printed calendar, find every year from 1900 to 2100 whose calendar could contain that rectangle as a contiguous block.	Medium6	ImplementationSimulation+2	No attempts yet	1s	128 MB	Judgeable
Falling CardsSimulate a row of non-intersecting standing cards: when a card falls it sweeps a rectangle of height H, knocking over any card it touches, and each touched card topples away from the pusher.	Medium6	GeometrySimulation+1	No attempts yet	1s	128 MB	Judgeable
SpreadsheetEvaluate a small 9x26 spreadsheet where each cell holds an integer expression with +, -, *, / and cell references, reporting 1000000 if cell A1 is part of a circular reference.	Medium6	ImplementationDFS+2	No attempts yet	1s	128 MB	Judgeable
PreQueLGiven several small tables and equality conditions, print every tuple of the Cartesian product that satisfies all conditions, sorted.	Medium6	Brute forceImplementation+2	No attempts yet	1s	128 MB	Judgeable
Jack's SocksGiven an undirected graph of similar socks, decide whether a perfect matching exists and is unique, and print that matching if it is.	Medium6	GraphDFS+2	No attempts yet	1s	512 MB	Judgeable
Two ProfessorsFind the minimum number of rooms for fixed-interval classes, given that professors 1 and 2 must never share a room.	Medium6	SortingGreedy+1	No attempts yet	3s	128 MB	Judgeable
A Number GameA game on a blackboard starting from one number: split composites, subtract 1 from primes, take 1s for a point. Both play optimally; report final scores.	Medium6	Game theoryNumber theory+2	No attempts yet	1s	128 MB	Judgeable
Euro EfficiencyGiven six coin denominations, find the minimum coins (paid plus change) for each amount from 1 to 100 and report their average and maximum.	Medium6	Dynamic programmingShortest path+2	No attempts yet	1s	128 MB	Judgeable
Will It Stop?Given n up to 10^14, decide whether the loop halts, where even n halves and odd n becomes 3n+3.	Medium6	MathNumber theory+1	No attempts yet	3s	64 MB	Judgeable
TriangulationGiven a convex polygon, find the triangulation whose total diagonal length is minimum and report it rounded to two decimals.	Medium6	Dynamic programmingGeometry	No attempts yet	1s	128 MB	Judgeable
Random WalkGiven a recorded sequence of moves on a square grid, decide whether he can walk back to the start without crossing his previous trail.	Medium6	GeometryImplementation+1	No attempts yet	1s	128 MB	Judgeable
ChecksumAppend zeros to a bit message, divide the polynomial over F2 by a generator, output the remainder as decimal, or ERROR if the generator is composite.	Medium6	MathNumber theory+2	No attempts yet	1s	128 MB	Judgeable
Exotic Mechanical SystemGiven gears linked by shafts or teeth with color-orientation constraints, find each gear's angular velocity when gear 1 is driven, or report that it cannot spin.	Medium6	GraphBFS+2	No attempts yet	1s	128 MB	Judgeable
SignalGiven sequence s and a pattern f, find the smallest starting position where f occurs as a contiguous block that can be one of exactly k fragments of lengths in [a,b].	Medium6	String matchingGreedy+1	No attempts yet	1s	128 MB	Judgeable
The Fifth DimensionCount ordered simple paths with 6 distinct vertices and 5 edges in an undirected graph.	Medium6	GraphCombinatorics	No attempts yet	1s	128 MB	Judgeable
Highway Racing TracksCount the 5-vertex paths (chains of four edges on five distinct vertices) in a simple graph, treating each path as unordered.	Medium6	GraphCombinatorics	No attempts yet	1s	128 MB	Judgeable
The DragonPick an order of pastures from either end each day, losing a sheep per day everywhere, to maximize total sheep eaten.	Medium6	GreedySorting+1	No attempts yet	1s	128 MB	Judgeable
SkewersCount strings of length n over p letters that avoid a given set of forbidden bigrams and trigrams, modulo m.	Medium6	Dynamic programmingMatrix	No attempts yet	1s	128 MB	Judgeable
CaveGiven a transitive reachability matrix of a DAG, find the minimum number of downward paths needed to cover every node.	Medium6	GraphGreedy+2	No attempts yet	1s	128 MB	Judgeable
TreasureFind a shortest grid path from S to * avoiding chasms, and among all shortest paths output the one whose move string comes first lexicographically.	Medium6	BFSGraph+2	No attempts yet	1s	128 MB	Judgeable
A Journey to MarsFor each station on a circle, decide whether starting there with two direction choices lets Byteazar complete a full loop without running out of fuel.	Medium6	GreedyPrefix sum+1	No attempts yet	3s	512 MB	Judgeable
Double RowChoose which columns to swap so that both rows end up with distinct heights, minimizing the number of swaps.	Medium6	GraphUnion-find+1	No attempts yet	3s	512 MB	Judgeable
Chris MartinGiven a DNA string S of length n, find the smallest possible LCS length between S and any other length-n DNA string.	Medium6	Dynamic programmingString+2	No attempts yet	1s	128 MB	Judgeable
The BridgeGiven sorted crossing times for n tourists and one torch that allows at most two to cross at a time, find the minimum total time to get everyone across.	Medium6	GreedySorting+1	No attempts yet	3s	128 MB	Judgeable
CastleFind a walk from chamber e to chamber p, possibly revisiting chambers with repeated charges, whose total entry cost is exactly b, and print the lexicographically smallest such walk.	Medium6	GraphDynamic programming+2	No attempts yet	1s	128 MB	Judgeable
Counting-Out RhymeGiven the order children leave a Josephus-style circle, find the smallest rhyme length k that produces exactly that leaving order, or report none exists.	Medium6	SimulationBrute force+2	No attempts yet	1s	128 MB	Judgeable
Antiprime NumbersGiven n up to 2e9, find the largest highly composite number (one with more divisors than every smaller positive integer) that does not exceed n.	Medium6	Number theoryBrute force+2	No attempts yet	3s	512 MB	Judgeable
Travel Plan (Small)Given bus lines with fixed departure frequencies, find the earliest arrival time at a target station starting from a station at a given clock time.	Medium6	GraphShortest path+2	No attempts yet	1s	128 MB	Judgeable
AgentsGiven a directed graph and two starting cities, find the fewest days for both agents to reach the same city, moving one edge each day without staying put.	Medium6	GraphBFS+2	No attempts yet	1s	128 MB	Judgeable
SpeleologyGiven a DAG where chambers are numbered top to bottom, find the maximum number of downward paths from chamber 1 to chamber n that use distinct first corridors and distinct last corridors.	Medium6	GraphDynamic programming+2	No attempts yet	3s	512 MB	Judgeable
Three-Coloring of Binary TreesGiven a binary tree as a digit specification, color each node red, green, or blue so adjacent nodes differ and siblings differ, then report the maximum and minimum number of green nodes.	Medium6	TreeDFS+2	No attempts yet	3s	128 MB	Judgeable
WaterGiven a grid of cuboid heights, find the total volume of water trapped in the depressions after rain, where water cannot escape past the grid boundary.	Medium6	HeapBFS+2	No attempts yet	3s	128 MB	Judgeable
One-sequenceFind the lexicographically smallest walk of length n starting at 0 with +/-1 steps whose total sum is S, or report that none exists.	Medium6	GreedyImplementation+2	No attempts yet	1s	128 MB	Judgeable
FrogmanChoose whole cylinders so their combined oxygen and nitrogen meet required volumes while total weight is minimal.	Medium6	Dynamic programmingGreedy	No attempts yet	1s	128 MB	Judgeable
RectanglesGiven up to 7000 axis-aligned integer rectangles, count connected components where rectangles merge if their overlap contains a segment of positive length.	Medium6	Union-findGeometry+2	No attempts yet	1s	128 MB	Judgeable
JumpsGiven piles of pieces on numbered squares, repeatedly apply the jump rules until no two neighbouring squares together hold two or more pieces, then print the occupied squares.	Medium6	GreedySimulation+2	No attempts yet	1s	128 MB	Judgeable
Cheap TravelsPick a sequence of hotels so consecutive stops are at most 800 km apart, minimizing total price (ties: fewest nights), and also minimizing nights (ties: lowest price).	Medium6	Dynamic programmingArray+2	No attempts yet	1s	128 MB	Judgeable
XOR NetsGiven a XOR net with n inputs, count how many binary words in the range [a, b] make the net output 1.	Medium6	Bit manipulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
AirportsGiven the required degree of each vertex, decide whether a simple undirected graph on n vertices can realize exactly those degrees.	Medium6	GraphGreedy+1	No attempts yet	1s	128 MB	Judgeable
PetrolGiven fuel prices at ordered stations and distances between them, find the minimum fuel cost to travel from A to B with a fixed tank capacity.	Medium6	GreedyStack	No attempts yet	1s	128 MB	Judgeable
Lecture Halls ReservationChoose a set of non-overlapping intervals (open at both ends) to maximize the total length covered, given n up to 10000 and times up to 30000.	Medium6	Dynamic programmingSorting+2	No attempts yet	1s	256 MB	Judgeable
Fibonacci WordsCount the occurrences of a given a/b pattern as a contiguous substring of the n-th Fibonacci word, overlaps included.	Medium6	StringDynamic programming+1	No attempts yet	1s	128 MB	Judgeable
KnightsOn a 3 by n board with one possibly blocked square per column, place the maximum number of non-attacking knights and count the number of maximum placements.	Medium6	Dynamic programmingBit manipulation+2	No attempts yet	1s	128 MB	Judgeable
Zeros and OnesFor each N up to 20000, find the smallest multiple of N whose decimal digits are only 0 and 1, or report none within 100 digits.	Medium6	BFSGraph+2	No attempts yet	1s	128 MB	Judgeable
Zeros and Ones - 2For each N, output the smallest positive multiple of N whose decimal digits are only 0 and 1, or BRAK if none exists.	Medium6	BFSGraph+2	No attempts yet	1s	256 MB	Judgeable
The Right-Turn Drivers' ClubOn a grid with blocked cells, find the shortest A-to-B path that never turns left or makes a U-turn, counting squares visited.	Medium6	BFSGraph+2	No attempts yet	1s	128 MB	Judgeable
Board CoveringGiven an odd n by n board with three unit squares removed, decide whether the rest tiles perfectly with dominoes.	Medium6	MathCombinatorics+1	No attempts yet	1s	128 MB	Judgeable
Coding of PermutationsGiven a Lehmer-like code B, decide whether it encodes a permutation of 1..n and if so output that permutation, otherwise print NIE.	Medium6	Segment treeBinary search+2	No attempts yet	1s	128 MB	Judgeable
The Concatenation of WordsCount the increasing selections of given words whose concatenation equals a pattern, capped at 1000000, and print the lexicographically smallest selection.	Medium6	Dynamic programmingString+1	No attempts yet	1s	128 MB	Judgeable
TeddiesCount the distinct safe arrangements of up to 152 teddies in four models so that no three consecutive share a letter or a digit, modulo 1000000.	Medium6	Dynamic programmingCombinatorics+1	No attempts yet	1s	128 MB	Judgeable
Fairy LightsFor each pressed button, compute the limiting fraction of integers whose final color is that button's color.	Medium6	MathNumber theory+2	No attempts yet	1s	128 MB	Judgeable
PebblesPiles are sorted; a move reduces one pile without breaking the order. Determine whether the first player wins.	Medium6	Game theoryGreedy+1	No attempts yet	3s	512 MB	Judgeable
ArraysGiven two n by m arrays of distinct integers, decide whether one can be turned into the other by permuting rows and permuting columns.	Medium6	Hash mapSorting+1	No attempts yet	4s	128 MB	Judgeable
TemperatureEach day gives an interval the temperature could lie in; find the longest run of consecutive days that can be assigned non-decreasing values.	Medium6	GreedyTwo pointers+2	No attempts yet	1s	128 MB	Judgeable
TaxisGiven a depot on a line and n taxi fuel ranges, find the fewest taxis needed to cover the remaining distance, or 0 if impossible.	Medium6	GreedySorting	No attempts yet	1s	128 MB	Judgeable
Two CakesTwo cakes must be built layer by layer from two given permutations, using one dedicated worker per layer type; find the minimum total time.	Medium6	GreedyArray+2	No attempts yet	4s	128 MB	Judgeable