Problems

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Total results29,455 problems

Pocket Ball
Medium5
Math, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Taekwondo
Medium5
Dynamic programming, Sorting
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bridge
Medium5
Sorting, Math
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Canoe Athletes
Medium5
Binary search, Sorting+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Order
Medium5
Simulation, Math
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sum of Two Numbers
Medium5
Two pointers, Sorting
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Widest Path
Medium5
Minimum spanning tree, Union-find+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bridge
Medium5
Minimum spanning tree, Geometry
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Message Broadcasting
Medium5
Greedy, Tree+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Rankings
Medium5
Segment tree, Sorting+1
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
The Janitor's Nightly Shutdown
Medium5
Brute force, Greedy
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Servicing Clients
Medium5
Dynamic programming, Shortest path
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Janggi Horse
Medium5
BFS, Shortest path+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Wiring Cost
Medium5
Greedy, Sorting
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Minesweeper
Medium5
Backtracking, Brute force
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Shuttle Bus
Medium5
Greedy, Sorting
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tug of War
Medium5
Dynamic programming
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tiling Up Blocks
Medium5
Dynamic programming, Sorting
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Colour Sequence
Medium5
Greedy, Two pointers
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Project staffing
Medium5
Dynamic programming, Probability+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bonus Word
Medium5
String, Brute force+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Escape
Medium5
BFS, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Tired Traveling Salesman
Medium5
Sorting, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Space
Medium5
Hash map, Geometry
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Herbert
Medium5
Math, Combinatorics
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Communication
Medium5
Minimum spanning tree, Union-find+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Fishnet
Medium5
Geometry, Math
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
77377
Medium5
Dynamic programming, Trie+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Beehives
Medium5
Geometry, String matching+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Nested Shrubbery Boxes
Medium5
Dynamic programming, Sorting
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
No Left Turns
Medium5
BFS, Shortest path+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Gone Fishing
Medium5
Greedy, Heap+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Square Cipher
Medium5
Simulation, Matrix+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hierarchical Democracy
Medium5
Tree, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pretty good numbers
Medium5
Number theory, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The First Term
Medium5
Simulation, String
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Road Trip
Medium5
Greedy
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Family Trees
Medium5
Graph, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Reconstructing the Longest Common Subsequence
Medium5
Dynamic programming, Greedy
No attempts yet
Time limit
0.1s
Memory limit
256 MB
Judgeable
Call Me Back, Please!
Medium5
Two pointers, Hash map+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Code Breakers
Medium5
Number theory, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Count Values in a Sorted Matrix
Medium5
Binary search, Matrix
No attempts yet
Time limit
15s
Memory limit
512 MB
Judgeable
Points
Medium5
Dynamic programming
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Flower Vases
Medium5
Brute force, Geometry
No attempts yet
Time limit
6s
Memory limit
128 MB
Judgeable
The Hopeless Queue
Medium5
Dynamic programming, Combinatorics
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Frozen Sprinklers
Medium5
Dynamic programming, Tree+1
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Sprinkler Layout
Medium5
Simulation, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Public Transit
Medium5
Shortest path, Graph
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Triangular Matrices
Medium5
Simulation, Stack+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Property Lines
Medium5
Geometry, Brute force+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Opening the Safe
Medium5
Backtracking, Brute force
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
MI6
Medium5
Number theory, Sorting
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Freeing Up Capacity
Medium5
Dynamic programming
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Keys
Medium5
BFS, Simulation
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
IQ Test
Medium5
Math, Brute force
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Social Advertising
Medium5
Brute force, Bit manipulation+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Random Walk That Never Goes Negative
Medium5
Combinatorics, Math
No attempts yet
Time limit
2s
Memory limit
64 MB
Judgeable
Road
Medium5
Minimum spanning tree, Union-find+1
No attempts yet
Time limit
2s
Memory limit
64 MB
Judgeable
Manhattan Sort
Medium5
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cracking the Code
Medium5
String matching, Brute force+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Unidentified Destination
Medium5
Shortest path, Graph
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
deltree
Medium5
Tree, Simulation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Drop7
Medium5
Simulation, Matrix
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Killbots
Medium5
Simulation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Best Friends
Medium5
BFS, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Wrestling Team Selection
Medium5
Dynamic programming
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Outpost Navigation
Medium5
Shortest path, Graph
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Virology
Medium5
Backtracking, Brute force
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Adding Numbers
Medium5
Brute force, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Energy Tycoon
Medium5
Greedy, Simulation
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
The number of students
Medium5
Math, Number theory+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Permutation Graph
Medium5
Divide and conquer, Sorting
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
Term Project
Medium5
DFS, Graph
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Algorithm Final Exam
Medium5
Combinatorics, Math
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Ping!
Medium5
Greedy, Number theory+1
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Cut the Cake
Medium5
Geometry, Combinatorics
No attempts yet
Time limit
20s
Memory limit
128 MB
Judgeable
Decimal Representation Length
Medium5
Simulation, Hash map+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bones's Battery
Medium5
Binary search, Graph+1
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Sleepy
Medium5
Simulation, Math+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Counting Ones in a Range
Medium5
Bit manipulation, Math
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Crane
Medium5
BFS, Graph+1
No attempts yet
Time limit
4s
Memory limit
128 MB
Judgeable
Encrypted password
Medium5
Sliding window, Hash map+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Archery
Medium5
Geometry, Probability
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Farmer John has no large brown cow
Medium5
Combinatorics, Sorting
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Crowded Cows
Medium5
Sliding window, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Shopping Malls
Medium5
Shortest path, Graph
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Joe is learning to speak
Medium5
Hash map, Sliding window+1
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Trending Topic
Medium5
Sliding window, Hash map+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Ham and the man of the year
Medium5
Math, Intervals
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Alphabet Sticker
Medium5
Combinatorics, String
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Modified LCS
Medium5
Number theory, Math
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Omar's Bug
Medium5
Binary search, Greedy
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Stone Game 7
Medium5
Game theory, Math
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
N-Queen
Medium5
Backtracking, Bit manipulation
No attempts yet
Time limit
10s
Memory limit
128 MB
Judgeable
Sumo
Medium5
Union-find, Graph
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
SMS Poll
Medium5
String, Hash map+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Charity Booth Rental
Medium5
Combinatorics, Math
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Find the Marbles
Medium5
Geometry, Hash map
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Lights
Medium5
Greedy, Prefix sum
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Prefix-Free Subsets
Medium5
Trie, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Pocket BallStarting from a corner with slope p/q, list each side the ball hits in order and the corner pocket where it stops.	Medium5	MathSimulation+1	No attempts yet	1s	128 MB	Judgeable
TaekwondoSort both weight lists and pair players to minimize the total absolute weight difference across all matches.	Medium5	Dynamic programmingSorting	No attempts yet	1s	128 MB	Judgeable
BridgeFind the bridge height that minimizes the total crossing distance over every pair of left and right houses.	Medium5	SortingMath	No attempts yet	3s	128 MB	Judgeable
Canoe AthletesPick one weight from each of four lists so the total is closest to the target, preferring the smaller total on ties.	Medium5	Binary searchSorting+1	No attempts yet	3s	256 MB	Judgeable
OrderRecover the permutation from counts of smaller previous elements, printing IMPOSSIBLE when the counts allow no permutation.	Medium5	SimulationMath	No attempts yet	1s	128 MB	Judgeable
Sum of Two NumbersCount the pairs of distinct given integers whose sum has the smallest absolute difference from K.	Medium5	Two pointersSorting	No attempts yet	1s	128 MB	Judgeable
Widest PathFind the path between two given nodes whose smallest edge weight is as large as possible.	Medium5	Minimum spanning treeUnion-find+1	No attempts yet	1s	128 MB	Judgeable
BridgeConnect all axis-parallel rectangular islands with bridges of minimum total squared shortest gap distance.	Medium5	Minimum spanning treeGeometry	No attempts yet	1s	128 MB	Judgeable
Message BroadcastingCompute the fewest rounds to spread a message from the root when each informed node calls at most one child per round.	Medium5	GreedyTree+2	No attempts yet	1s	128 MB	Judgeable
RankingsPlayers accumulate points through updates and each query asks for the current rank of one player among up to 100000 players.	Medium5	Segment treeSorting+1	No attempts yet	3s	128 MB	Judgeable
The Janitor's Nightly ShutdownDecide for each lit office whether to switch it off on the way up or down so elevator rides plus floor round trips are shortest.	Medium5	Brute forceGreedy	No attempts yet	1s	128 MB	Judgeable
Servicing ClientsChoose clients whose distance-times-demand costs fit the budget to maximize total priority.	Medium5	Dynamic programmingShortest path	No attempts yet	1s	128 MB	Judgeable
Janggi HorseCompute the fewest Janggi horse moves from start to target on an infinite board where standing pieces block the orthogonal step of some moves.	Medium5	BFSShortest path+1	No attempts yet	1s	128 MB	Judgeable
Wiring CostPay for wire pieces so every cheaper piece becomes free, then choose the price tier that reaches the required length at the lowest cost.	Medium5	GreedySorting	No attempts yet	1s	128 MB	Judgeable
MinesweeperCount the largest possible number of second-row mines, including the marked ones, that fits the first-row digit clues.	Medium5	BacktrackingBrute force	No attempts yet	1s	128 MB	Judgeable
Shuttle BusFind the smallest fleet of buses that can run every scheduled trip between the school and the terminal given the one-way travel time.	Medium5	GreedySorting	No attempts yet	1s	128 MB	Judgeable
Tug of WarDecide whether N student weights (4 to 30) split into two teams whose total strengths differ by at most X.	Medium5	Dynamic programming	No attempts yet	1s	128 MB	Judgeable
Tiling Up BlocksFind the largest subset of blocks that stacks so both knob counts never decrease from bottom to top.	Medium5	Dynamic programmingSorting	No attempts yet	1s	128 MB	Judgeable
Colour SequenceDecide whether a target colour string appears as a subsequence of a card row when each card shows one of its two sides and jokers match any colour.	Medium5	GreedyTwo pointers	No attempts yet	1s	128 MB	Judgeable
Project staffingAssign at most n hired workers to m projects so the total expected profit from rewards, fines, and conditional wages is maximal.	Medium5	Dynamic programmingProbability+1	No attempts yet	1s	128 MB	Judgeable
Bonus WordFind every pair of dictionary words that joins to ten letters and matches each query fixed and shuffled letters, listed in order.	Medium5	StringBrute force+1	No attempts yet	1s	128 MB	Judgeable
EscapeFind the fewest steps from the start cell to any border cell in a grid while turning at each tile unless both sides are blocked.	Medium5	BFSShortest path+2	No attempts yet	1s	128 MB	Judgeable
The Tired Traveling SalesmanFind the integer point off all customer sites that minimizes total Manhattan distance and count how many such points tie.	Medium5	SortingMath+1	No attempts yet	1s	128 MB	Judgeable
SpaceCount, for each test case, the pairs of up to 100000 points whose Euclidean distance is strictly less than d.	Medium5	Hash mapGeometry	No attempts yet	1s	128 MB	Judgeable
HerbertCount distinct squares a robot starting at the origin can end on within n moves when each step or ninety-degree turn costs one move.	Medium5	MathCombinatorics	No attempts yet	1s	128 MB	Judgeable
CommunicationConnect all rooms in a 3D grid with the cheapest new links given some existing links and fixed horizontal and vertical costs.	Medium5	Minimum spanning treeUnion-find+1	No attempts yet	1s	128 MB	Judgeable
FishnetThreads join opposite sides of a unit square, and the program reports the largest cell area in the net they form.	Medium5	GeometryMath	No attempts yet	1s	128 MB	Judgeable
77377Split a digit string into dictionary words whose telephone-keypad encoding matches each segment.	Medium5	Dynamic programmingTrie+1	No attempts yet	1s	128 MB	Judgeable
BeehivesThe program decides whether two move records describe the same hexagonal layout under rotation and reversed reading, with mirror images treated as different.	Medium5	GeometryString matching+1	No attempts yet	1s	128 MB	Judgeable
Nested Shrubbery BoxesChoose the largest subset of boxes that nest when every box is rotated to fit strictly inside the next box.	Medium5	Dynamic programmingSorting	No attempts yet	1s	128 MB	Judgeable
No Left TurnsFind the shortest path from start to finish in a maze where each step goes straight ahead or turns right.	Medium5	BFSShortest path+1	No attempts yet	1s	128 MB	Judgeable
Gone FishingSplit limited fishing time across roadside lakes with travel costs and declining catches to maximize total fish.	Medium5	GreedyHeap+1	No attempts yet	1s	128 MB	Judgeable
Square CipherEncode each message into letter pairs with a 5x5 square built from the keyword, applying the row, column, and rectangle substitution rules.	Medium5	SimulationMatrix+1	No attempts yet	1s	128 MB	Judgeable
Hierarchical DemocracyCompute the smallest popular vote total that wins the presidency through nested majority votes in districts.	Medium5	TreeGreedy+1	No attempts yet	1s	128 MB	Judgeable
Pretty good numbersCount the integers in each interval whose absolute gap between the proper-divisor sum and the number is within the limit.	Medium5	Number theorySorting+1	No attempts yet	1s	128 MB	Judgeable
The First TermTrace each given term backward through the reverse look-and-say rule until it reaches its earliest valid ancestor.	Medium5	SimulationString	No attempts yet	1s	128 MB	Judgeable
Road TripBuy and resell fuel at each town's price within tank capacity to complete every leg of each journey at minimum cost.	Medium5	Greedy	No attempts yet	1s	128 MB	Judgeable
Family TreesEach person lists two parents, so answer each query with the inherited share one person contributes to another as a reduced fraction, or report no relation.	Medium5	GraphDynamic programming+1	No attempts yet	1s	128 MB	Judgeable
Reconstructing the Longest Common SubsequenceFind the length of the longest common subsequence of two uppercase strings and output the lexicographically smallest one.	Medium5	Dynamic programmingGreedy	No attempts yet	0.1s	256 MB	Judgeable
Call Me Back, Please!Read call records with start times and durations and list every pair of numbers with opposite-direction calls that fit in one 24-hour window.	Medium5	Two pointersHash map+2	No attempts yet	1s	128 MB	Judgeable
Code BreakersFactor each RSA modulus up to 10^9, recover the private exponent, and decrypt the given ciphertext.	Medium5	Number theoryMath+1	No attempts yet	1s	128 MB	Judgeable
Count Values in a Sorted MatrixCount entries in each query range [X, Y] inside a matrix whose rows and columns are sorted ascending.	Medium5	Binary searchMatrix	No attempts yet	15s	512 MB	Judgeable
PointsPick a subset of targets in a row to maximize the total where each picked target scores based on how many neighbors are also picked.	Medium5	Dynamic programming	No attempts yet	3s	128 MB	Judgeable
Flower VasesGiven two pairs of pentominoes, decide whether each pair can be joined edge to edge into the same ten-square outline.	Medium5	Brute forceGeometry	No attempts yet	6s	128 MB	Judgeable
The Hopeless QueueCount fillings of the movable spots with equal coin totals so every prefix keeps at least as many 50 coins as 100 coins, modulo 1000000.	Medium5	Dynamic programmingCombinatorics	No attempts yet	2s	128 MB	Judgeable
Frozen SprinklersCut pipes with minimum total force so no water flows from the central node to any leaf sprinkler in the tree.	Medium5	Dynamic programmingTree+1	No attempts yet	3s	128 MB	Judgeable
Sprinkler LayoutTile every empty cell with 3-cell sprinklers in the prescribed row-major order, then drill fence holes and assign letters a to z greedily.	Medium5	SimulationImplementation	No attempts yet	1s	128 MB	Judgeable
Public TransitWalk once from the start, then take timed one-way buses with waiting to arrive earliest, breaking ties by fewer stops then smaller stop numbers.	Medium5	Shortest pathGraph	No attempts yet	1s	128 MB	Judgeable
Triangular MatricesEvaluate a postfix expression over triangular matrices with custom addition and template-match multiplication, or report an invalid expression.	Medium5	SimulationStack+1	No attempts yet	1s	128 MB	Judgeable
Property LinesGiven up to 100 claimed rectangles inside a W by H city, compute the area claimed twice or more, at least once, and never.	Medium5	GeometryBrute force+1	No attempts yet	1s	128 MB	Judgeable
Opening the SafeDecide for each given quadruple of digits whether its four numbers can be combined with arithmetic operations and parentheses to make 24.	Medium5	BacktrackingBrute force	No attempts yet	1s	128 MB	Judgeable
MI6Given an integer, output its prime power components, one per prime factor, in increasing order.	Medium5	Number theorySorting	No attempts yet	1s	128 MB	Judgeable
Freeing Up CapacityChoose RAID-1 sets to convert so the gained capacity reaches e GB while the total size of converted sets is minimal.	Medium5	Dynamic programming	No attempts yet	2s	512 MB	Judgeable
KeysEnter the grid from any open border cell, pick up keys to open matching doors, and collect the most reachable documents.	Medium5	BFSSimulation	No attempts yet	1s	256 MB	Judgeable
IQ TestGiven 8 to 12 integers fitting an integer linear recurrence of order at most 3, use the smallest fitting order to output the next term.	Medium5	MathBrute force	No attempts yet	2s	128 MB	Judgeable
Social AdvertisingPick the fewest users so that every user is picked or is a friend of someone picked.	Medium5	Brute forceBit manipulation+1	No attempts yet	2s	128 MB	Judgeable
Random Walk That Never Goes NegativeCount length-2N walks from 0 back to 0 with steps of plus or minus 1 that never drop below 0, modulo 1,000,000,007.	Medium5	CombinatoricsMath	No attempts yet	2s	64 MB	Judgeable
RoadDecide whether the road between p and q can belong to a cheapest network that connects all cities.	Medium5	Minimum spanning treeUnion-find+1	No attempts yet	2s	64 MB	Judgeable
Manhattan SortSort each sequence of distinct integers with swaps that cost the distance between positions and report the minimum total cost.	Medium5	GreedySorting+1	No attempts yet	1s	128 MB	Judgeable
Cracking the CodeGiven a plaintext and ciphertext candidates under a substitution cipher, keep every consistent match and decrypt X, printing '?' for ambiguous letters.	Medium5	String matchingBrute force+1	No attempts yet	2s	128 MB	Judgeable
Unidentified DestinationList the candidate destinations whose shortest route from s passes through the road between g and h.	Medium5	Shortest pathGraph	No attempts yet	3s	256 MB	Judgeable
deltreeFrom a log of cd and dir commands, find the minimum space a final deltree command is guaranteed to free.	Medium5	TreeSimulation	No attempts yet	1s	128 MB	Judgeable
Drop7Simulate n disc drops on a 7 by 7 board with simultaneous number-match eliminations and gravity, then print the final board.	Medium5	SimulationMatrix	No attempts yet	1s	128 MB	Judgeable
KillbotsSimulate robots and fastbots moving toward a stationary hero in two phases each turn, resolving collisions and junkheaps, and count the hero kills.	Medium5	Simulation	No attempts yet	1s	128 MB	Judgeable
Best FriendsGiven two numbered circles in a triangular packing, compute the fewest adjacent moves between them.	Medium5	BFSGraph+1	No attempts yet	1s	128 MB	Judgeable
Wrestling Team SelectionSplit up to 100 wrestlers into two teams of nearly equal size so the total weights differ as little as possible.	Medium5	Dynamic programming	No attempts yet	1s	128 MB	Judgeable
Outpost NavigationFind the lowest-encounter safe route to a supply outpost, optionally collecting ammo at the one cache without overspending.	Medium5	Shortest pathGraph	No attempts yet	2s	128 MB	Judgeable
VirologyDecide for each 14-gene sample whether the genes split into four triples or runs plus one pair.	Medium5	BacktrackingBrute force	No attempts yet	3s	128 MB	Judgeable
Adding NumbersSplit the given digits into two numbers with no leading zero so their sum is as small as possible.	Medium5	Brute forceSorting+1	No attempts yet	1s	128 MB	Judgeable
Energy TycoonPlace each offered one-slot or two-slot plant on an n-slot board, removing blocking plants when full, to maximize the total plant count summed over all turns.	Medium5	GreedySimulation	No attempts yet	2s	256 MB	Judgeable
The number of studentsFind the smallest numbers of girls and boys whose within-group and cross-group friend counts match the given a, b, c, and d.	Medium5	MathNumber theory+1	No attempts yet	2s	256 MB	Judgeable
Permutation GraphGiven two permutations of 1 to n drawn on two parallel lines, count the pairs of segments joining equal numbers that cross.	Medium5	Divide and conquerSorting	No attempts yet	5s	256 MB	Judgeable
Term ProjectEach student picks exactly one partner, only directed cycles form teams, so count the students outside all cycles.	Medium5	DFSGraph	No attempts yet	3s	256 MB	Judgeable
Algorithm Final ExamCount permutations of N items in which the first k positions are all wrong.	Medium5	CombinatoricsMath	No attempts yet	1s	128 MB	Judgeable
Ping!Recover all satellite intervals within the record whose combined odd-even pings produce the given binary record.	Medium5	GreedyNumber theory+1	No attempts yet	3s	128 MB	Judgeable
Cut the CakeCount into how many regions the given infinite lines divide a circle.	Medium5	GeometryCombinatorics	No attempts yet	20s	128 MB	Judgeable
Decimal Representation LengthFor each n, report the longest decimal writing among all fractions a/b with a and b from 1 to n, where the count includes digits, the point, and parentheses.	Medium5	SimulationHash map+2	No attempts yet	1s	128 MB	Judgeable
Bones's BatteryFind the smallest battery range so every pair of schools connects with at most K charges over roads within range.	Medium5	Binary searchGraph+1	No attempts yet	5s	128 MB	Judgeable
SleepyGiven the word seen after X shuffles that weave the back half into the front half, recover the original word.	Medium5	SimulationMath+1	No attempts yet	1s	256 MB	Judgeable
Counting Ones in a RangeAdd up the number of 1 bits in the binary form of every integer from A to B.	Medium5	Bit manipulationMath	No attempts yet	1s	128 MB	Judgeable
CraneGiven a permutation of up to 8 crates, find the fewest block-half swaps of any even-length interval needed to sort it.	Medium5	BFSGraph+1	No attempts yet	4s	128 MB	Judgeable
Encrypted passwordDecide whether the original password's letters can be rearranged to match a contiguous block inside the encrypted password.	Medium5	Sliding windowHash map+1	No attempts yet	2s	128 MB	Judgeable
ArcheryA ray from the origin fires in a uniform random direction, and the task asks the expected number of segments it pierces.	Medium5	GeometryProbability	No attempts yet	1s	128 MB	Judgeable
Farmer John has no large brown cowFind the Kth adjective combination in alphabetical order among all combinations except the N forbidden ones.	Medium5	CombinatoricsSorting	No attempts yet	1s	128 MB	Judgeable
Crowded CowsCount cows that have a cow at least twice as tall within distance D on both the left and the right.	Medium5	Sliding windowSorting+1	No attempts yet	1s	128 MB	Judgeable
Shopping MallsFind the least-walking path between queried places in a mall graph with asymmetric costs and break cost ties by lexicographic order.	Medium5	Shortest pathGraph	No attempts yet	1s	128 MB	Judgeable
Joe is learning to speakTrack every word block up to length n from known sentences and ask about each unknown word and each new sentence with an unseen block.	Medium5	Hash mapSliding window+1	No attempts yet	3s	128 MB	Judgeable
Trending TopicMaintain word counts over a rolling 7-day window and answer each top N query in frequency order with ties included.	Medium5	Sliding windowHash map+1	No attempts yet	1s	128 MB	Judgeable
Ham and the man of the yearFind the smallest ham total up to 10^7 whose ratio shares added to eaten amounts rank people 1 to N from most to least.	Medium5	MathIntervals	No attempts yet	1s	128 MB	Judgeable
The Alphabet StickerCount completions of a sticker pattern where each question mark becomes a visible letter and every letter forms one contiguous block.	Medium5	CombinatoricsString	No attempts yet	1s	128 MB	Judgeable
Modified LCSCount the terms shared by two strictly increasing arithmetic progressions, which equals their longest common subsequence.	Medium5	Number theoryMath	No attempts yet	1s	128 MB	Judgeable
Omar's BugFor each query with N, X and a flag, build the lexicographically smallest sorted array that makes the buggy lower bound return a right or wrong answer.	Medium5	Binary searchGreedy	No attempts yet	1s	128 MB	Judgeable
Stone Game 7Two players alternately remove a power of four stones from the pile, and the program reports the winner when both play perfectly.	Medium5	Game theoryMath	No attempts yet	1s	128 MB	Judgeable
N-QueenCount the ways to place N non-attacking queens on an N by N board for N under 15.	Medium5	BacktrackingBit manipulation	No attempts yet	10s	128 MB	Judgeable
SumoFind the earliest scheduled fight that forces two wrestlers on the same team to meet under the best two-team split.	Medium5	Union-findGraph	No attempts yet	1s	128 MB	Judgeable
SMS PollNormalize phone formats to identify each sender, keep only the earliest valid vote per sender, and print truncated percentages and participant count.	Medium5	StringHash map+1	No attempts yet	1s	128 MB	Judgeable
Charity Booth RentalCount the strictly increasing positive triples GP, GA and PC that sum to T for each query.	Medium5	CombinatoricsMath	No attempts yet	1s	128 MB	Judgeable
Find the MarblesGiven up to 99 distinct integer points per test case, report the largest number of points that lie on one straight line.	Medium5	GeometryHash map	No attempts yet	1s	128 MB	Judgeable
LightsYou press switches that flip the rectangle from the origin to the switch and need the fewest presses to turn every bulb on.	Medium5	GreedyPrefix sum	No attempts yet	1s	128 MB	Judgeable
Prefix-Free SubsetsCount the subsets of the given word set in which no word is a prefix of another word.	Medium5	TrieDynamic programming+1	No attempts yet	1s	128 MB	Judgeable