Problems

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Total results29,085 problems

Airplane Boarding
Medium7
Segment tree, Simulation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Secret Message
Medium7
Dynamic programming, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Circle Regions
Medium7
Stack, Sorting+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Hash function
Medium7
Divide and conquer, Hash map+2
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Bytecomputer
Medium7
Dynamic programming, Array
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Laser
Medium7
Dynamic programming, Geometry+2
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Traveling Saga
Medium7
Tree, Segment tree+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Oar Tester
Medium7
Graph, Shortest path+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
The Lazy Cow
Medium7
Sliding window, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Fair Photography
Medium7
Prefix sum, Hash map
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Code Breaking
Medium7
Dynamic programming, Tree+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Xiao Long Bao
Medium7
Dynamic programming, Intervals
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cutting Lines
Medium7
Geometry, Union-find+2
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Messenger
Medium7
Geometry, Binary search
No attempts yet
Time limit
4s
Memory limit
128 MB
Judgeable
Skiing
Medium7
Dynamic programming, Math+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Wire Crossing
Medium7
Shortest path, Graph+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
KOSTA
Medium7
Binary search, Geometry
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
Palindrome
Medium7
String matching, String
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Split the sequence
Medium7
Dynamic programming, Divide and conquer+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
CATS
Medium7
Simulation, Stack+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Strategy
Medium7
Number theory, Simulation
No attempts yet
Time limit
1s
Memory limit
16 MB
Judgeable
Maximum XOR of Consecutive Integers
Medium7
Bit manipulation, Math
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Cyclic Marathon
Medium7
Heap, Linked list+2
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Cop and Robber
Medium7
Game theory, Graph+1
No attempts yet
Time limit
1.5s
Memory limit
256 MB
Judgeable
Portals
Medium7
Shortest path, BFS+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Werewolf
Medium7
Graph, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Early Exam Evacuation
Medium7
Dynamic programming, Sorting+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Hotels
Medium7
Tree, Dynamic programming+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Bricks
Medium7
Greedy, Heap
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Couriers
Medium7
Segment tree, Binary search
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
The Little Bird
Medium7
Dynamic programming, Stack+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
FarmCraft
Medium7
Greedy, Tree+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Around the world
Medium7
Greedy, Prefix sum+1
No attempts yet
Time limit
5s
Memory limit
24 MB
Judgeable
Ant colony
Medium7
Tree, Math+2
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Solar Panels
Medium7
Number theory, Math+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Freight
Medium7
Greedy, Simulation
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Packing
Medium7
Dynamic programming, Bit manipulation
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Teams
Medium7
Dynamic programming, Segment tree+1
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
Carpet
Medium7
Stack, Prefix sum+1
No attempts yet
Time limit
4s
Memory limit
256 MB
Judgeable
Bulb replacement
Medium7
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Password
Medium7
Dynamic programming, String matching
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Ring road bus routes
Medium7
Intervals, Sorting+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Gold Mines
Medium7
Dynamic programming, Prefix sum+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Relay Horses
Medium7
Dynamic programming, Greedy+1
No attempts yet
Time limit
1s
Memory limit
64 MB
Judgeable
Safe Emergency Contact Network
Medium7
Minimum spanning tree, Tree+1
No attempts yet
Time limit
1s
Memory limit
64 MB
Judgeable
XH Company
Medium7
Stack, Prefix sum+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Blind Maze Escape
Medium7
BFS, Graph+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Languages
Medium7
Simulation, Implementation+2
No attempts yet
Time limit
10s
Memory limit
256 MB
Judgeable
Bridge Removal
Medium7
Dynamic programming, Tree+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Banjo and the lava pit
Medium7
Geometry, Math
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Diplomacy
Medium7
Graph, Shortest path+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Highway
Medium7
Geometry, Sorting+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Mattress stain removal
Medium7
Dynamic programming, Bit manipulation
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Switch Array
Medium7
Recursion, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Basin City Surveillance
Medium7
Backtracking, Graph+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
The Club Trip
Medium7
Graph, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Road Work
Medium7
Dynamic programming, Simulation
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Beam me out!
Medium7
Graph, DFS+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Bounty Hunter Jeong-eun
Medium7
Dynamic programming, Geometry
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Jewelry Exhibition
Medium7
Graph, DFS
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Laser Cutting
Medium7
Geometry, Brute force+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Choosing Ice Cream
Medium7
Number theory, Math
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Spy Network
Medium7
Graph, Topological sort+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Pontoon Bridge
Medium7
Shortest path, Dynamic programming
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Direct Visibility
Medium7
BFS, Geometry+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Self-Intersecting Path
Medium7
Geometry, Simulation
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Picture Validator
Medium7
Geometry, Intervals+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Zombie Apocalypse
Medium7
Graph, Simulation
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Floating Formation
Medium7
Graph, Tree+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Highway Hassle
Medium7
Shortest path, Graph+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Fibonacci Problem Solving Strategy
Medium7
Number theory, Math
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Key to Knowledge
Medium7
Backtracking, Brute force+1
No attempts yet
Time limit
10s
Memory limit
256 MB
Judgeable
Shopping
Medium7
Dynamic programming, Intervals
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Space Golf
Medium7
Binary search, Math+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
There is No Alternative
Medium7
Minimum spanning tree, Union-find+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Flipping Parentheses
Medium7
Segment tree, Prefix sum
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
Cornering at Poles
Medium7
Geometry, Shortest path+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Banks
Medium7
Greedy, Simulation+1
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
Circle of digits
Medium7
Binary search, Dynamic programming+1
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
UFO
Medium7
Segment tree, Simulation+2
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
Most Influential Pumpkin
Medium7
Segment tree, Binary search+1
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
Strange Antennas
Medium7
Geometry, Prefix sum+1
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
Circle and Marble
Medium7
Game theory, Tree+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Best Position
Medium7
String matching, Matrix+1
No attempts yet
Time limit
10s
Memory limit
256 MB
Judgeable
Equal Digit Sums
Medium7
Math, Greedy+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Fragmentation
Medium7
Greedy, Sorting
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Hiking in the Hills
Medium7
Union-find, Minimum spanning tree+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Kebab House
Medium7
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
A Cure for the Common Code
Medium7
Dynamic programming, String
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
Generalized Roman Numerals
Medium7
Dynamic programming, Intervals+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Path of Least Persistence
Medium7
Graph, Shortest path+2
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Black and White Stones
Medium7
Dynamic programming, Greedy+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Dividing the names
Medium7
Trie, Dynamic programming
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Even distribution
Medium7
Number theory, Graph+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Repeated Substring Count
Medium7
String matching, String
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
Locked Treasure
Medium7
Combinatorics
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
The Magic Potion
Medium7
Combinatorics, Math+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Mancala
Medium7
Math, Simulation+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Infinite Rational Tree
Medium7
Math, Number theory
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
The Queen's Terrace
Medium7
Geometry, Math
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Airplane BoardingCows walk single-file to assigned seats and each blocks the line while stowing baggage, so compute the time until every cow sits.	Medium7	Segment treeSimulation	No attempts yet	1s	128 MB	Judgeable
Secret MessageCount the operation sequences that build the given string by repeatedly prepending or appending a proper prefix or suffix.	Medium7	Dynamic programmingString+1	No attempts yet	1s	128 MB	Judgeable
Circle RegionsCount how many regions N circles with centers on the x-axis and no crossings cut the plane into.	Medium7	StackSorting+2	No attempts yet	1s	256 MB	Judgeable
Hash functionCount the length-N lowercase words whose repeated multiply-by-33 xor hash modulo 2^M equals K.	Medium7	Divide and conquerHash map+2	No attempts yet	3s	256 MB	Judgeable
BytecomputerRepeatedly add an entry to its right neighbor in a -1, 0, 1 sequence to make it non-decreasing with the fewest operations, or report BRAK if impossible.	Medium7	Dynamic programmingArray	No attempts yet	3s	512 MB	Judgeable
LaserChoose up to K rays from the origin to hit the most first-quadrant segments, with no segment hit by two rays.	Medium7	Dynamic programmingGeometry+2	No attempts yet	3s	512 MB	Judgeable
Traveling SagaPrint the order in which an apple from vertex 1 visits every tree vertex by always moving to the farthest unvisited vertex, breaking ties by largest index.	Medium7	TreeSegment tree+1	No attempts yet	3s	256 MB	Judgeable
Oar TesterAssign each of n oar types a positive integer strength so every pair sums to at most x_ij and at least one of the two reaches y_ij.	Medium7	GraphShortest path+1	No attempts yet	1s	512 MB	Judgeable
The Lazy CowChoose a start point to maximize the total grass of patches within Manhattan distance K of it.	Medium7	Sliding windowSorting+2	No attempts yet	1s	128 MB	Judgeable
Fair PhotographyAfter sorting cows by position, find the widest contiguous group containing at least K breeds with each present breed appearing equally often.	Medium7	Prefix sumHash map	No attempts yet	1s	128 MB	Judgeable
Code BreakingCount digit assignments to a rooted tree that place at least one of M forbidden 5-digit strings on its specified upward path, modulo 1234567.	Medium7	Dynamic programmingTree+1	No attempts yet	1s	128 MB	Judgeable
Xiao Long BaoChoose the order to eat N dumplings in a row to maximize total flavor, with each eaten dumpling adding its bonus to uneaten dumplings within its reach.	Medium7	Dynamic programmingIntervals	No attempts yet	1s	128 MB	Judgeable
Cutting LinesCount the pieces of a W by H rectangle after cutting along N axis-parallel interior segments.	Medium7	GeometryUnion-find+2	No attempts yet	3s	256 MB	Judgeable
MessengerA unit-speed messenger runs straight from the first of two speed-1 polygonal routes to intercept the second, so minimize the carry time.	Medium7	GeometryBinary search	No attempts yet	4s	128 MB	Judgeable
SkiingStarting at (0,0) with fixed downhill speed and bounded lateral acceleration, choose the longest reachable target sequence with smallest indices on ties.	Medium7	Dynamic programmingMath+1	No attempts yet	2s	128 MB	Judgeable
Wire CrossingFind the smallest number of wire segments a path between the two given points must cross without passing through a point where wires meet.	Medium7	Shortest pathGraph+1	No attempts yet	2s	128 MB	Judgeable
KOSTAPlace one or two machines on given restaurant sites to minimize the farthest Manhattan delivery distance, and report that distance with the chosen sites.	Medium7	Binary searchGeometry	No attempts yet	5s	256 MB	Judgeable
PalindromeFind the palindromic substring that maximizes its length times its number of occurrences in the given string.	Medium7	String matchingString	No attempts yet	2s	128 MB	Judgeable
Split the sequenceSplit the sequence into k+1 contiguous parts so the total product score from the cuts is maximal, and print the score with one optimal cut list.	Medium7	Dynamic programmingDivide and conquer+2	No attempts yet	2s	128 MB	Judgeable
CATSGiven X, L and N, simulate the buggy two-stack counter program with global bit flips and output the number it prints.	Medium7	SimulationStack+2	No attempts yet	2s	512 MB	Judgeable
StrategyGiven the first two terms of the sequence where each next term is the absolute difference of the previous two, find the K-th term.	Medium7	Number theorySimulation	No attempts yet	1s	16 MB	Judgeable
Maximum XOR of Consecutive IntegersFind the largest XOR of any block of n consecutive integers inside the interval from a to b.	Medium7	Bit manipulationMath	No attempts yet	1s	256 MB	Judgeable
Cyclic MarathonRunners spaced around a circular track catch and eliminate the runner ahead, and the program prints the elimination order and the survivors.	Medium7	HeapLinked list+2	No attempts yet	3s	256 MB	Judgeable
Cop and RobberDecide if one starting corner lets the chasing officer force a catch on a connected graph and print the best corner with its worst-case move count.	Medium7	Game theoryGraph+1	No attempts yet	1.5s	256 MB	Judgeable
PortalsFind the shortest walk from start to cake on a grid where two portals fired at walls teleport you in one step.	Medium7	Shortest pathBFS+1	No attempts yet	1s	256 MB	Judgeable
WerewolfCount the role assignments with exactly W werewolves that satisfy all accusations and defenses, modulo 1000000007.	Medium7	GraphDynamic programming+1	No attempts yet	1s	256 MB	Judgeable
Early Exam EvacuationEach of M writers seated in an N-row auditorium exits front or back to minimize passing plus crowding cost.	Medium7	Dynamic programmingSorting+1	No attempts yet	2s	256 MB	Judgeable
HotelsCount triplets of distinct towns in a tree whose three pairwise distances are all equal.	Medium7	TreeDynamic programming+1	No attempts yet	3s	256 MB	Judgeable
BricksArrange every brick so neighbors differ and the ends are p and q, printing the lexicographically smallest valid line or 0.	Medium7	GreedyHeap	No attempts yet	3s	256 MB	Judgeable
CouriersGiven the courier numbers in shipment order, report the courier that appears more than half the time in each query interval, or 0 if none does.	Medium7	Segment treeBinary search	No attempts yet	3s	512 MB	Judgeable
The Little BirdA bird jumps from tree 1 to tree n in flights of at most k and minimizes landings on trees at least as tall as the takeoff tree.	Medium7	Dynamic programmingStack+1	No attempts yet	2s	256 MB	Judgeable
FarmCraftChoose a tour of the tree from the root that visits every house and returns, so the latest moment of arrival plus install time is as early as possible.	Medium7	GreedyTree+1	No attempts yet	3s	256 MB	Judgeable
Around the worldFor each plane range, find the fewest refueling landings to circle all airports from the best start, or report impossible.	Medium7	GreedyPrefix sum+1	No attempts yet	5s	24 MB	Judgeable
Ant colonyAnt groups enter from every leaf, split evenly at each chamber with the rest eaten, and you count groups crossing one corridor with exactly k ants.	Medium7	TreeMath+2	No attempts yet	3s	256 MB	Judgeable
Solar PanelsYou pick a width and a height from the given ranges to make their greatest common divisor as large as possible.	Medium7	Number theoryMath+1	No attempts yet	1s	256 MB	Judgeable
FreightSchedule n freight trains over a single track with travel time s and one-minute departure gaps so the last train returns to Upper Bytown as early as possible.	Medium7	GreedySimulation	No attempts yet	1s	256 MB	Judgeable
PackingBuy the fewest backpacks from the shop so all items fit without splitting items or exceeding capacities.	Medium7	Dynamic programmingBit manipulation	No attempts yet	1s	256 MB	Judgeable
TeamsSplit the row into the most contiguous teams so each student's team size lies within their given range, and count those optimal splits.	Medium7	Dynamic programmingSegment tree+1	No attempts yet	5s	256 MB	Judgeable
CarpetFind the area of the largest subrectangle of a flawed carpet grid that holds at most one flaw.	Medium7	StackPrefix sum+1	No attempts yet	4s	256 MB	Judgeable
Bulb replacementByteasar assigns his bulbs to rooms and swaps at most k of them for store bulbs so every room meets its minimum and the total power is smallest.	Medium7	GreedySorting+1	No attempts yet	1s	256 MB	Judgeable
PasswordCount length-N strings over the first K uppercase letters that avoid ABCBC and ABABC as substrings, modulo 1,000,000,009.	Medium7	Dynamic programmingString matching	No attempts yet	1s	256 MB	Judgeable
Ring road bus routesPrint the numbers of the clockwise arcs on an N-stop ring that no other given arc fully covers, in increasing order.	Medium7	IntervalsSorting+1	No attempts yet	2s	256 MB	Judgeable
Gold MinesPick an axis-aligned rectangle over weighted points to maximize the sum of enclosed weights.	Medium7	Dynamic programmingPrefix sum+1	No attempts yet	3s	256 MB	Judgeable
Relay HorsesMove all petitions sitting on a ring of stations to the capital so the sum of horse days used and days each petition spends traveling is smallest.	Medium7	Dynamic programmingGreedy+1	No attempts yet	1s	64 MB	Judgeable
Safe Emergency Contact NetworkFor each road, report the cheapest total cost of a network connecting all villages without that road, or -1 when impossible.	Medium7	Minimum spanning treeTree+1	No attempts yet	1s	64 MB	Judgeable
XH CompanyFor each query day D, report the length of the shortest suffix ending on day D-1 with the largest average.	Medium7	StackPrefix sum+1	No attempts yet	2s	256 MB	Judgeable
Blind Maze EscapeFind the shortest tilt sequence of at most 10 moves that exits the marble from every empty cell, breaking ties lexicographically.	Medium7	BFSGraph+2	No attempts yet	2s	256 MB	Judgeable
LanguagesGuess the language of each 100-symbol excerpt, learning online from the correct answer returned after every guess, and maximize accuracy over 10000 turns.	Medium7	SimulationImplementation+2	No attempts yet	10s	256 MB	Judgeable
Bridge RemovalStarting from any island, a crew that spends a bridge length to cross or remove it must delete every bridge of a tree in the shortest total time.	Medium7	Dynamic programmingTree+1	No attempts yet	1s	256 MB	Judgeable
Banjo and the lava pitWalk from the start to the destination in the shortest time without staying strictly inside a circular pit for more than t seconds in a row.	Medium7	GeometryMath	No attempts yet	3s	256 MB	Judgeable
DiplomacyEach month one same-party friend group switches parties with the two sides alternating, and the goal is the fewest months to unite all governors in one party.	Medium7	GraphShortest path+1	No attempts yet	1s	256 MB	Judgeable
HighwayGiven up to 200,000 points per test case, output the lexicographically smallest pair with the largest Euclidean distance.	Medium7	GeometrySorting+1	No attempts yet	2s	256 MB	Judgeable
Mattress stain removalCover all stained cells on an m by n grid with the fewest 3 by 3 blocks placed inside the grid.	Medium7	Dynamic programmingBit manipulation	No attempts yet	3s	256 MB	Judgeable
Switch ArrayFind the fewest restricted toggles that turn each given bit string into all zeros.	Medium7	RecursionDynamic programming+1	No attempts yet	1s	256 MB	Judgeable
Basin City SurveillanceDecide whether k vertices can be chosen so no two are adjacent in a graph of degree at most four.	Medium7	BacktrackingGraph+1	No attempts yet	2s	256 MB	Judgeable
The Club TripEach of n classmates rides only if one named classmate also rides; fill up to k bus seats with the largest group that respects every such condition.	Medium7	GraphDynamic programming+1	No attempts yet	1s	256 MB	Judgeable
Road WorkSchedule cars from both ends through one shared lane to minimize how many drivers wait past their patience limit.	Medium7	Dynamic programmingSimulation	No attempts yet	1s	512 MB	Judgeable
Beam me out!Decide whether a random walk from room 1 reaches room n with certainty and whether every possible walk ends within a bounded number of steps.	Medium7	GraphDFS+1	No attempts yet	1s	256 MB	Judgeable
Bounty Hunter Jeong-eunA ship visits every planet sorted by x on an outward and a return monotone leg with minimum total Euclidean length.	Medium7	Dynamic programmingGeometry	No attempts yet	1s	256 MB	Judgeable
Jewelry ExhibitionYou choose the fewest unit-wide horizontal or vertical strips on integer lines to cover every exhibit point.	Medium7	GraphDFS	No attempts yet	1s	256 MB	Judgeable
Laser CuttingCheck axis-aligned polylines for closure and self-intersection, then report touching polygons, bad nesting, or correctness in priority order.	Medium7	GeometryBrute force+1	No attempts yet	1s	256 MB	Judgeable
Choosing Ice CreamGiven n flavors and a k-sided die, find the smallest worst-case number of throws that allows a perfectly fair choice, or report unbounded.	Medium7	Number theoryMath	No attempts yet	1s	256 MB	Judgeable
Spy NetworkValues spread along directed edges by repeated gcd updates until stable, and you count how many employees end at L.	Medium7	GraphTopological sort+1	No attempts yet	2s	256 MB	Judgeable
Pontoon BridgeFind the smallest connected set of water squares that touches both banks of a river given as water intervals per row.	Medium7	Shortest pathDynamic programming	No attempts yet	1s	256 MB	Judgeable
Direct VisibilityFind the fewest grid steps between two stations under climb limits while a station stays in line of sight at each stop.	Medium7	BFSGeometry+1	No attempts yet	2s	256 MB	Judgeable
Self-Intersecting PathCheck a robot path that moves forward and always turns right for any self-touching and report the longest valid prefix.	Medium7	GeometrySimulation	No attempts yet	2s	256 MB	Judgeable
Picture ValidatorDecide whether two robot-drawn line pictures cover the same point set up to translation.	Medium7	GeometryIntervals+1	No attempts yet	1s	256 MB	Judgeable
Zombie ApocalypseMove up to g people from the start across directed roads with entry limits and travel times to get the most to a hospital by time s.	Medium7	GraphSimulation	No attempts yet	5s	512 MB	Judgeable
Floating FormationPlace up to k spare boats on pieces linked pairwise by boats to minimize pieces lost in the cascade where a piece with fewer than two boats sinks.	Medium7	GraphTree+2	No attempts yet	1s	256 MB	Judgeable
Highway HasslePlan the cheapest route and refueling stops for a tank-limited truck when each station charges its own price per milliliter.	Medium7	Shortest pathGraph+1	No attempts yet	2s	256 MB	Judgeable
Fibonacci Problem Solving StrategyFind the smallest starting pair (a, b) with 0 < a <= b whose Fibonacci-like sum sequence contains n.	Medium7	Number theoryMath	No attempts yet	2s	256 MB	Judgeable
Key to KnowledgeReconstruct the true-or-false key of up to 30 questions from each student's answers and score, printing the unique key or the count of matching keys.	Medium7	BacktrackingBrute force+1	No attempts yet	10s	256 MB	Judgeable
ShoppingA shopper starts at the entrance, visits each of N shops in a row under the given order constraints, and ends at the exit with the shortest total walk.	Medium7	Dynamic programmingIntervals	No attempts yet	1s	256 MB	Judgeable
Space GolfFind the smallest launch speed that lands a bouncing projectile exactly on a distant target while clearing thin vertical obstacles within a bounce limit.	Medium7	Binary searchMath+1	No attempts yet	1s	256 MB	Judgeable
There is No AlternativeCount the bridges that appear in every minimum-cost set connecting all islands and report their total cost.	Medium7	Minimum spanning treeUnion-find+1	No attempts yet	3s	256 MB	Judgeable
Flipping ParenthesesAfter each single-bracket flip that breaks a balanced parenthesis string, find the leftmost second flip that restores balance.	Medium7	Segment treePrefix sum	No attempts yet	5s	256 MB	Judgeable
Cornering at PolesGuide a disc robot of radius 100 from the origin to the goal along the shortest path that stays clear of up to eight pole obstacles.	Medium7	GeometryShortest path+1	No attempts yet	3s	256 MB	Judgeable
BanksFlipping a negative bank in a circle to positive takes the same amount from both neighbors; the goal is the fewest flips leaving every capital nonnegative.	Medium7	GreedySimulation+1	No attempts yet	5s	256 MB	Judgeable
Circle of digitsSplit the circular digit string into K contiguous parts so the largest part value is as small as possible, and output that value.	Medium7	Binary searchDynamic programming+1	No attempts yet	5s	256 MB	Judgeable
UFOSimulate K laser shots that each remove the first R cells reaching one layer along a row or column, then find the P by P square with the largest remaining sum.	Medium7	Segment treeSimulation+2	No attempts yet	5s	256 MB	Judgeable
Most Influential PumpkinAfter each range increment on an odd-length array, report the median value of the array.	Medium7	Segment treeBinary search+1	No attempts yet	5s	256 MB	Judgeable
Strange AntennasCount grid cells covered by an odd number of diagonal triangular antenna signals.	Medium7	GeometryPrefix sum+1	No attempts yet	5s	256 MB	Judgeable
Circle and MarbleEach move shifts one marble along an arrow to the next circle, and you decide if the first or second player wins under best play.	Medium7	Game theoryTree+1	No attempts yet	1s	256 MB	Judgeable
Best PositionFor each binary blueprint, find the placement with the most matching cells, tie-broken by row then column, and report the grain and livestock counts.	Medium7	String matchingMatrix+1	No attempts yet	10s	256 MB	Judgeable
Equal Digit SumsPick n distinct positive integers with the same digit sum so their total is as small as possible.	Medium7	MathGreedy+1	No attempts yet	2s	256 MB	Judgeable
FragmentationCut the array into the fewest contiguous blocks that can be reordered into non-decreasing order.	Medium7	GreedySorting	No attempts yet	2s	256 MB	Judgeable
Hiking in the HillsFind a route from camp A to lookout B across the triangulated landscape whose highest point is as low as possible.	Medium7	Union-findMinimum spanning tree+2	No attempts yet	2s	256 MB	Judgeable
Kebab HouseCount subsets of the work seconds with gaps of at least t+1 such that each kebab misses at most q_i minus x_i ingredients, modulo 1e9+7.	Medium7	Dynamic programmingCombinatorics+1	No attempts yet	2s	256 MB	Judgeable
A Cure for the Common CodeCompute the shortest encoded length of each lowercase string using count-plus-parentheses notation for repeats.	Medium7	Dynamic programmingString	No attempts yet	5s	256 MB	Judgeable
Generalized Roman NumeralsGiven a string of Roman letters, list every distinct value it can take under all parenthesizations of the subtract-when-smaller rule.	Medium7	Dynamic programmingIntervals+1	No attempts yet	3s	256 MB	Judgeable
Path of Least PersistenceChange at most one square's jump so the walk from the top-left corner to the bottom-right corner is as short as possible.	Medium7	GraphShortest path+2	No attempts yet	3s	256 MB	Judgeable
Black and White StonesShagga reorders black and white stones so all black stones stand left of white ones with minimum cost, paying A per swap and A minus B for adjacent swaps.	Medium7	Dynamic programmingGreedy+1	No attempts yet	3s	256 MB	Judgeable
Dividing the namesSplit 2N names into N streets and N avenues so the total length of shortest unique prefixes on all N by N crossing signs is minimal.	Medium7	TrieDynamic programming	No attempts yet	3s	256 MB	Judgeable
Even distributionCount how many integers occur as the greatest common divisor of candy counts along some walk in the island graph.	Medium7	Number theoryGraph+1	No attempts yet	3s	256 MB	Judgeable
Repeated Substring CountCount the distinct substrings that occur at least twice in each string of up to 100000 letters.	Medium7	String matchingString	No attempts yet	5s	256 MB	Judgeable
Locked TreasureGiven n bandits and threshold m, compute the fewest locks whose keys allow every group of m or more members to open the door but no smaller group to do so.	Medium7	Combinatorics	No attempts yet	1s	256 MB	Judgeable
The Magic PotionFind the fewest testers that always locate the single magic bag among N within E rounds of pooled tasting.	Medium7	CombinatoricsMath+1	No attempts yet	1s	256 MB	Judgeable
MancalaFor each marble count N, print the pits of the unique Tchoukaillon board that sweeps every marble into the Roumba.	Medium7	MathSimulation+1	No attempts yet	1s	256 MB	Judgeable
Infinite Rational TreeGiven a reduced fraction in the Calkin-Wilf tree, print the fraction that follows it in level order.	Medium7	MathNumber theory	No attempts yet	1s	256 MB	Judgeable
The Queen's TerraceCompute each ring stone radius from circle tangency and the convex perimeter around the outermost ring.	Medium7	GeometryMath	No attempts yet	1s	256 MB	Judgeable