Problems

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Total results29,431 problems

Cipher Decoder Choi Junmin
Medium6
String matching, Hash map+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sanggeun's Robot
Medium6
Prefix sum, Binary search+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Salary Management at a Car Factory
Medium6
Tree, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Conveyor Belt
Medium6
Dynamic programming, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
No U-Turns
Medium6
Graph, DFS+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Greatest Common Divisor
Medium6
Number theory, Math+1
No attempts yet
Time limit
1s
Memory limit
192 MB
Judgeable
Beautiful Matrix
Medium6
Matrix, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Dance Party
Medium6
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Water Taxi
Medium6
Greedy, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Lucky Wheel
Medium6
Simulation, Array+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Postman Han Sangdeok
Medium6
Binary search, BFS+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Marble
Medium6
Union-find, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
New Language Alphabet Order
Medium6
Topological sort, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Counting Pipe Installations
Medium6
Dynamic programming, Matrix+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Difficulty-Based Problem Selection
Medium6
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Interesting Sequence
Medium6
Binary search, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Debt Settlement in Wonseop City
Medium6
Graph, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Math Game
Medium6
Game theory, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sum of Sequence Values
Medium6
Stack, Array+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pretty Indentation
Medium6
Greedy, Array+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bored Jungyu
Medium6
Bit manipulation, Brute force+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
XOR Shapes
Medium6
Geometry, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Detective Hongz
Medium6
Topological sort, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Program
Medium6
Prefix sum, Array+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Math Is Too Easy
Medium6
Number theory, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Snow White and the Dwarfs
Medium6
Binary search, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Roman Numeral Rearrangement
Medium6
Brute force, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Wolf Hunter
Medium6
BFS, Binary search+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Card Solitaire
Medium6
Greedy, String matching+1
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Shuffle Tape
Medium6
Math, Graph+1
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Gas Pipeline
Medium6
Simulation, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Arranging Blocks
Medium6
Prefix sum, Brute force+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Card Purchase Reconstruction
Medium6
Greedy, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Rabbits
Medium6
Sliding window, Implementation+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
45-Degree Rotation
Medium6
Simulation, Matrix+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Binary Search Tree
Medium6
Tree, Binary search+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Nikola's Jumps
Medium6
Dynamic programming, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Birthday
Medium6
Dynamic programming, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Digit Sum in an Interval
Medium6
Dynamic programming, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Analog Dial
Medium6
Segment tree, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Turbo Sort
Medium6
Binary search, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Number Circle
Medium6
Math, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Valid Bracket Strings
Medium6
Dynamic programming, String
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Oasis Reunion
Medium6
Stack, Array
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Tetris
Medium6
Simulation, Brute force+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Stone Dropping
Medium6
Simulation, Matrix+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Confusion
Medium6
Dynamic programming, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Complete Binary Tree
Medium6
Recursion, Tree+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Counting Bicycle Race Routes
Medium6
Topological sort, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Doubly Linked List
Medium6
Linked list, Stack+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Agent Mission Assignment
Medium6
Dynamic programming, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Ladder
Medium6
Greedy, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tournament Rank Range
Medium6
Tree, DFS+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Way Home
Medium6
Graph, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Beautiful Names
Medium6
Trie, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Processor Design
Medium6
Union-find, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Grid Job Scheduling
Medium6
Math, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Breaking Flowerpots
Medium6
Union-find, Greedy+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Finding a Four-Leaf Clover
Medium6
Binary search, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
New Array Game
Medium6
Segment tree, Array+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Number of Pluses
Medium6
Dynamic programming, Matrix+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Social Network
Medium6
Graph, BFS+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Dot Matrix Printer
Medium6
Dynamic programming, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Permutation Rank
Medium6
Combinatorics, Segment tree+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
String Censorship
Medium6
String matching, Stack+1
No attempts yet
Time limit
1.5s
Memory limit
128 MB
Judgeable
Apples and Bananas
Medium6
Dynamic programming, Matrix+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Biologist
Medium6
Math, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Fair Distribution
Medium6
Tree, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cabbage
Medium6
Geometry, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Park Walk
Medium6
Graph, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hangman Game
Medium6
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Christmas Presents
Medium6
Binary search, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Company Restructuring
Medium6
Tree, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Vandalized Chessboard
Medium6
Math, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Efforts for a Joyful Life
Medium6
Number theory, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Magnets
Medium6
Greedy, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Geographic Map
Medium6
Implementation, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Lazy Telegraph
Medium6
Brute force, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bingo
Medium6
Combinatorics, Brute force+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Ant Town
Medium6
Math, Geometry+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Grasshopper Jumps
Medium6
Segment tree, Array+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
24 Matchstick Puzzle
Medium6
Backtracking, Brute force+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Turbo Mode
Medium6
Simulation, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Falling Ants
Medium6
Sorting, Simulation+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Pattern
Medium6
Math, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Smallest Number with Fives
Medium6
Math, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Table Soccer Path
Medium6
Simulation, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hyunju and Yunju's Fun Word Game
Medium6
Sorting, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Word Division
Medium6
Dynamic programming, String matching+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Road Network
Medium6
Tree, Binary search+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Kokos
Medium6
Trie, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Minimum Trailing Zeros Path
Medium6
Dynamic programming, Matrix+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Football Ranking
Medium6
Simulation, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Password Name Finder
Medium6
String, Backtracking+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hugo
Medium6
Dynamic programming, Greedy+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Memory Allocation Simulator
Medium6
Simulation, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Coin Statements
Medium6
Graph, DFS+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Moving Ants
Medium6
Simulation, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Map Labels
Medium6
Binary search, Sorting+1
No attempts yet
Time limit
4s
Memory limit
128 MB
Judgeable
Pizza Delivery
Medium6
Combinatorics, Brute force+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Cipher Decoder Choi JunminFind the earliest starting word position in an encoded word sequence that matches a pattern sentence under a bijective word-to-word substitution mapping.	Medium6	String matchingHash map+1	No attempts yet	1s	128 MB	Judgeable
Sanggeun's RobotTrack a moving point's total Manhattan distance to many fixed checkpoints after each move, requiring separate sorted-prefix-sum structures for x and y coordinates updated dynamically.	Medium6	Prefix sumBinary search+2	No attempts yet	1s	128 MB	Judgeable
Salary Management at a Car FactoryGiven a company tree with salary updates that add a value to all subordinates of a node and queries for a single employee's current salary, answer efficiently using an Euler tour and a range-update point-query structure.	Medium6	TreePrefix sum+1	No attempts yet	1s	256 MB	Judgeable
Conveyor BeltGiven worker base times and car complexities on a pipelined assembly line, compute the minimum total completion time respecting sequential handoff constraints.	Medium6	Dynamic programmingGreedy+1	No attempts yet	1s	128 MB	Judgeable
No U-TurnsGiven a grid with roads and buildings, decide if every road cell is free of dead ends by checking whether from each road cell you can return without an immediate U-turn.	Medium6	GraphDFS+1	No attempts yet	1s	128 MB	Judgeable
Greatest Common DivisorGiven two lists of up to 1000 factors whose products form huge numbers A and B, compute gcd(A,B) modulo the last 9 digits using prime factorization instead of big integers.	Medium6	Number theoryMath+1	No attempts yet	1s	192 MB	Judgeable
Beautiful MatrixGiven an N x N matrix (N up to 400), find the maximum difference between the main diagonal sum and anti-diagonal sum over all possible square submatrices.	Medium6	MatrixPrefix sum+1	No attempts yet	1s	128 MB	Judgeable
Dance PartyGiven men and women with heights and taller/shorter partner preferences, find the maximum number of mutually satisfying man-woman pairs.	Medium6	GreedySorting+1	No attempts yet	1s	128 MB	Judgeable
Water TaxiGiven pickup and drop-off points along a line for many passengers picked up by a boat starting at 0 that must end at M, compute the minimum travel distance covering everyone.	Medium6	GreedyPrefix sum+1	No attempts yet	1s	128 MB	Judgeable
Lucky WheelReconstruct the letters on a rotating wheel of N distinct-letter slots from a sequence of spin distances and resulting letters, or report impossibility.	Medium6	SimulationArray+1	No attempts yet	1s	128 MB	Judgeable
Postman Han SangdeokFind the minimum altitude range of a passable set of cells so that the post office and all houses stay connected via 8-directional moves within that range.	Medium6	Binary searchBFS+1	No attempts yet	3s	256 MB	Judgeable
MarbleMaintain a functional graph with path queries to find the endpoint of a chain (or detect a cycle) and edge deletions, using union-find with path compression.	Medium6	Union-findGraph+1	No attempts yet	1s	128 MB	Judgeable
New Language Alphabet OrderGiven a sorted list of words in an unknown alphabet, reconstruct the unique letter order or report impossibility or ambiguity.	Medium6	Topological sortGraph+1	No attempts yet	1s	128 MB	Judgeable
Counting Pipe InstallationsCount the ways to lay a single connected pipe path with six pipe shapes from the top-left entry to the bottom-right exit through a grid with blocked cells, modulo 10007.	Medium6	Dynamic programmingMatrix+1	No attempts yet	2s	128 MB	Judgeable
Difficulty-Based Problem SelectionCount ways to pick exactly one problem per difficulty level 1..N given fixed-difficulty and flexible dual-difficulty problem pools, modulo 1e9+7.	Medium6	Dynamic programmingCombinatorics+1	No attempts yet	1s	128 MB	Judgeable
Interesting SequenceFor each starting index, find the maximum even-length window whose first half sum and second half sum are both at most S, using binary search and prefix sums.	Medium6	Binary searchPrefix sum+1	No attempts yet	1s	128 MB	Judgeable
Debt Settlement in Wonseop CityGiven a functional graph where each citizen owes money to exactly one creditor, find the minimum total money injected so all debts can be paid via chains of repayments.	Medium6	GraphGreedy+1	No attempts yet	1s	128 MB	Judgeable
Math GameGiven N coins in a Fibonacci-like alternating take game, find the minimum first move Sangdeok can make to guarantee a win under optimal play.	Medium6	Game theoryMath+1	No attempts yet	1s	128 MB	Judgeable
Sum of Sequence ValuesGiven an array, compute the sum over all contiguous subarrays of (max - min) efficiently for up to 300,000 elements.	Medium6	StackArray+1	No attempts yet	1s	128 MB	Judgeable
Pretty IndentationGiven current and target tab counts per line, find the minimum number of range increment/decrement operations to transform one array into the other, with the constraint that decrements can't push a value below zero.	Medium6	GreedyArray+1	No attempts yet	1s	128 MB	Judgeable
Bored JungyuGiven XOR values of a lowercase/period/space plaintext with a digit key, decide for each position whether the original was a letter or a period/space.	Medium6	Bit manipulationBrute force+1	No attempts yet	1s	128 MB	Judgeable
XOR ShapesGiven up to 10 right isosceles triangles drawn with XOR-style color inversion, compute the total black area after all draws.	Medium6	GeometryBit manipulation+1	No attempts yet	1s	128 MB	Judgeable
Detective HongzGiven a DAG of causal relations and a set of known events, determine every additional event forced to have occurred by forward implication and the backward rule that a caused event needs at least one occurring predecessor.	Medium6	Topological sortGraph+1	No attempts yet	1s	128 MB	Judgeable
ProgramSimulate marking multiples of several jump values into an array using a difference/counting trick, then answer many range-sum queries with prefix sums.	Medium6	Prefix sumArray+1	No attempts yet	2s	256 MB	Judgeable
Math Is Too EasyGiven N numbers, redistribute prime factors between pairs to maximize the GCD of all numbers and find the minimum number of moves to reach that GCD.	Medium6	Number theoryGreedy+1	No attempts yet	1s	128 MB	Judgeable
Snow White and the DwarfsGiven a sequence of hat colors and range queries, determine for each range whether a majority color exists and identify it.	Medium6	Binary searchPrefix sum+1	No attempts yet	1s	256 MB	Judgeable
Roman Numeral RearrangementGiven a Roman numeral for a number under 100, rearrange all its characters to form the valid Roman numeral with the smallest possible value.	Medium6	Brute forceString+2	No attempts yet	1s	128 MB	Judgeable
Wolf HunterGiven a grid with trees, find the path from start to goal maximizing the minimum Manhattan-distance-to-nearest-tree value along the path, typically via multi-source BFS plus binary search or Union-Find.	Medium6	BFSBinary search+1	No attempts yet	1s	128 MB	Judgeable
Card SolitaireGiven several queues of cards, repeatedly pop the front of some queue to append to an answer sequence so that the final sequence is lexicographically smallest.	Medium6	GreedyString matching+1	No attempts yet	5s	128 MB	Judgeable
Shuffle TapeGiven a permutation applied repeatedly, count how many of the A-th to B-th shuffles keep the visible middle positions fixed relative to the initial order.	Medium6	MathGraph+1	No attempts yet	5s	128 MB	Judgeable
Gas PipelineFind the single missing pipe cell and its correct connector type so gas can flow from M to Z through a unique valid path using all pipe blocks.	Medium6	SimulationGraph+1	No attempts yet	1s	128 MB	Judgeable
Arranging BlocksGiven M unit blocks stacked on cells of an N by N board, find the minimum moves to rearrange them into a rectangle with exactly one block per cell.	Medium6	Prefix sumBrute force+1	No attempts yet	1s	128 MB	Judgeable
Card Purchase ReconstructionReconstruct a full sequence of paired card purchases (each giving 0/1/2 cards to each buyer) that includes given mandatory pairs and yields specified final card counts per child.	Medium6	GreedyGraph+2	No attempts yet	1s	128 MB	Judgeable
RabbitsGiven a range update per day using sqrt-decomposition blocks with per-block cup counters and per-rabbit matchbox counters, report the sum of newly incremented counters each day.	Medium6	Sliding windowImplementation+2	No attempts yet	2s	128 MB	Judgeable
45-Degree RotationRotate a character grid clockwise by a multiple of 45 degrees, including diagonal renderings, keeping letters upright and output compact.	Medium6	SimulationMatrix+1	No attempts yet	1s	128 MB	Judgeable
Binary Search TreeSimulate BST insertion of a permutation and output the running total of comparison steps after each insertion, efficiently for up to 300000 elements.	Medium6	TreeBinary search+1	No attempts yet	1s	128 MB	Judgeable
Nikola's JumpsFind the minimum-cost path to square N where forward jumps grow by 1 each time and backward jumps match the last forward jump length.	Medium6	Dynamic programmingGraph+1	No attempts yet	1s	128 MB	Judgeable
BirthdayGiven N intervals, find and print the longest chain of distinct intervals where each contains the next one.	Medium6	Dynamic programmingSorting+1	No attempts yet	1s	128 MB	Judgeable
Digit Sum in an IntervalCount integers in [A,B] with a given digit sum and output the smallest such integer, for bounds up to 10^15.	Medium6	Dynamic programmingMath+1	No attempts yet	1s	128 MB	Judgeable
Analog DialSimulate M range-sum queries followed by range +1-with-wraparound-to-0 updates on N digit dials, using a data structure that supports both efficiently.	Medium6	Segment treePrefix sum+1	No attempts yet	1s	256 MB	Judgeable
Turbo SortSimulate a bubble-sort-like process that alternately moves the smallest and largest remaining values to the boundary, printing swap counts needed at each of N steps efficiently.	Medium6	Binary searchImplementation+2	No attempts yet	1s	128 MB	Judgeable
Number CircleGiven a circular array of sums of each element and its two neighbors, reconstruct one valid original positive-integer circular array.	Medium6	MathSimulation+1	No attempts yet	1s	128 MB	Judgeable
Valid Bracket StringsCount ways to replace question marks in a bracket string with one of three bracket types so it becomes a valid nested bracket sequence, output last five digits.	Medium6	Dynamic programmingString	No attempts yet	1s	128 MB	Judgeable
Oasis ReunionGiven a line of heights, count pairs who can mutually see each other using a monotonic stack while handling equal-height ties correctly.	Medium6	StackArray	No attempts yet	1s	256 MB	Judgeable
TetrisGiven column heights and a chosen tetromino, count valid rotations and horizontal placements where the piece rests flush against the surface with no gaps underneath.	Medium6	SimulationBrute force+1	No attempts yet	1s	128 MB	Judgeable
Stone DroppingSimulate stones falling one at a time down a grid with walls, sliding left or right when blocked, and print the final board.	Medium6	SimulationMatrix+1	No attempts yet	1s	128 MB	Judgeable
ConfusionCount permutations of 1..N with exactly C inversions, modulo 1e9+7, using DP with prefix sums for the given constraints.	Medium6	Dynamic programmingPrefix sum+1	No attempts yet	1s	128 MB	Judgeable
Complete Binary TreeFill a complete binary tree of level N with numbers 1 to 2^N-1 so each internal node's left/right subtree sums differ by exactly 2^D, then output preorder.	Medium6	RecursionTree+2	No attempts yet	1s	128 MB	Judgeable
Counting Bicycle Race RoutesCount directed paths from village 1 to village 2 in a graph, printing the last 9 digits or 'inf' if a reachable cycle makes the count infinite.	Medium6	Topological sortDynamic programming+1	No attempts yet	1s	128 MB	Judgeable
Doubly Linked ListGiven a sequence of doubly linked list move operations, output the minimum number of operations that reverse them and restore the original order.	Medium6	Linked listStack+1	No attempts yet	1s	128 MB	Judgeable
Agent Mission AssignmentGiven an N x N matrix of success percentages, assign one mission per agent to maximize the product of chosen probabilities, essentially an assignment problem with a product (log-sum) objective.	Medium6	Dynamic programmingBit manipulation+1	No attempts yet	1s	128 MB	Judgeable
LadderGiven a target permutation for a ladder game, find the minimum number of horizontal rungs (adjacent-position swaps) needed to realize it.	Medium6	GreedyCombinatorics+1	No attempts yet	1s	128 MB	Judgeable
Tournament Rank RangeGiven a single-elimination bracket's match winners, determine each queried player's best possible and worst possible final ranking consistent with the known beat relations.	Medium6	TreeDFS+1	No attempts yet	1s	128 MB	Judgeable
The Way HomeGiven a grid with children and homes, find the minimum total Manhattan-distance movement cost of a minimum-cost perfect matching between children and homes.	Medium6	GraphGreedy+1	No attempts yet	1s	128 MB	Judgeable
Beautiful NamesCount the number of orderings of N distinct strings such that all strings sharing a common prefix always form a contiguous block, modulo 1e9+7.	Medium6	TrieCombinatorics+1	No attempts yet	1s	512 MB	Judgeable
Processor DesignReconstruct lexicographically smallest initial 32-bit register values consistent with a sequence of bit-rotation and XOR-output commands, using union-find over bits with XOR relations.	Medium6	Union-findBit manipulation+1	No attempts yet	1s	128 MB	Judgeable
Grid Job SchedulingGiven an N x N grid where cell (x,y) needs its left and top neighbors done first and K computers process jobs in parallel, compute the minimum total seconds to finish all cells.	Medium6	MathCombinatorics+1	No attempts yet	1s	128 MB	Judgeable
Breaking FlowerpotsGiven N flowerpots each with 3 numbers where breaking one chain-breaks later pots sharing a number, find the minimum number of pots to break directly to break all pots.	Medium6	Union-findGreedy+1	No attempts yet	1s	256 MB	Judgeable
Finding a Four-Leaf CloverSimulate a point moving on a grid where each of up to 100,000 directional commands jumps it to the nearest clover point along that axis and direction, using sorted structures for efficient nearest-point queries.	Medium6	Binary searchSorting+2	No attempts yet	1s	128 MB	Judgeable
New Array GameSupport left and right rotations on subarray ranges plus point queries on an array of up to 100,000 elements with up to 100,000 operations.	Medium6	Segment treeArray+1	No attempts yet	2s	128 MB	Judgeable
Number of PlusesCount all plus-shaped patterns of odd size at least 3 in an N x N binary matrix, where every cell outside the cross must be 0.	Medium6	Dynamic programmingMatrix+1	No attempts yet	1s	128 MB	Judgeable
Social NetworkSimulate day-by-day friend-of-friend propagation using previous-day snapshots to find how many days until the whole graph becomes a clique, printing daily new-edge counts.	Medium6	GraphBFS+1	No attempts yet	1s	128 MB	Judgeable
Dot Matrix PrinterGiven a string, find the minimum number of SET/NEXT/WRITE printer commands needed to output it, where NEXT temporarily overrides the next WRITE.	Medium6	Dynamic programmingString+1	No attempts yet	1s	128 MB	Judgeable
Permutation RankGiven a permutation and many swap queries, compute the lexicographic rank modulo 1e9+7 for each swapped permutation efficiently.	Medium6	CombinatoricsSegment tree+1	No attempts yet	2s	128 MB	Judgeable
String CensorshipRepeatedly delete the first then last occurrence of a pattern string from a text until it's absent, and output the final text.	Medium6	String matchingStack+1	No attempts yet	1.5s	128 MB	Judgeable
Apples and BananasFind a monotone down/right/diagonal path in an RxC grid to maximize apples below plus bananas above it, with R,C up to 1500.	Medium6	Dynamic programmingMatrix+1	No attempts yet	1s	256 MB	Judgeable
BiologistSimulate N bacteria moving in fixed grid directions and find the earliest time when the maximum overlap count occurs at one cell.	Medium6	MathSimulation+1	No attempts yet	1s	128 MB	Judgeable
Fair DistributionGiven a tree of farmers with equal initial money and required amounts, find the minimum number of edge transactions, in valid order, to make everyone reach their requirement.	Medium6	TreeGreedy+1	No attempts yet	1s	128 MB	Judgeable
CabbageCompute the total roof area covered by N unit-radius circles clipped to a rectangle, allowing overlaps to be counted once.	Medium6	GeometryMath+1	No attempts yet	1s	128 MB	Judgeable
Park WalkCount simple cycles in a wheel graph (a cycle of N outer nodes each connected to a central hub) given which roads are missing.	Medium6	GraphGreedy+1	No attempts yet	1s	128 MB	Judgeable
Hangman GameGiven a hidden word, find the order to select each distinct letter starting from A on a circular alphabet dial that minimizes total LEFT/RIGHT/OK button presses.	Medium6	Dynamic programmingGreedy+2	No attempts yet	1s	128 MB	Judgeable
Christmas PresentsGiven N-1 sorted present prices, count possible positive integer values for a missing Nth price so that alternating greedy picking makes the older-younger total difference lie within [A, B].	Medium6	Binary searchGreedy+1	No attempts yet	1s	128 MB	Judgeable
Company RestructuringGiven a rooted tree where reporting edges may only be rewired within original parent-child-sibling triples, output a new tree with at most 2 children per node and at most one higher-IQ child than its manager.	Medium6	TreeGreedy+1	No attempts yet	1s	128 MB	Judgeable
Vandalized ChessboardGiven a board size and a blackened row, column, and two diagonals, compute the number of distinct blackened cells and how many should be repainted grey versus white based on the checkerboard color rule.	Medium6	MathCombinatorics+1	No attempts yet	1s	128 MB	Judgeable
Efforts for a Joyful LifeGiven up to 500,000 multipliers applied sequentially to a running product starting at 1, output after each step whether the product is a perfect square, using prime factorization parity tracking.	Medium6	Number theoryMath+1	No attempts yet	1s	128 MB	Judgeable
MagnetsGiven N unit magnets that auto-merge based on adjacent poles, find the minimum number of flips needed to create a merged magnet of exact length L.	Medium6	GreedySimulation+1	No attempts yet	1s	128 MB	Judgeable
Geographic MapGiven a grid with village markers 'x' and horizontal uppercase name strings, match each village to its adjacent name using adjacency and uniqueness constraints, then output village positions and names.	Medium6	ImplementationString+1	No attempts yet	1s	128 MB	Judgeable
Lazy TelegraphFor each dictionary word to be sent, find a same-length string minimizing total transmission time (dots=1s, dashes=2s) so that it is the unique closest dictionary word by Hamming distance, then sum the minimum times.	Medium6	Brute forceString+2	No attempts yet	1s	128 MB	Judgeable
BingoGiven a fixed call sequence, place numbers 1..N^2 on an NxN board to maximize how many rows exactly match some N-length window of consecutive calls in order.	Medium6	CombinatoricsBrute force+1	No attempts yet	1s	128 MB	Judgeable
Ant TownGiven up to 10 umbrella points on an H by V Manhattan grid, count intersections tied for minimum Manhattan distance to two or more umbrellas.	Medium6	MathGeometry+2	No attempts yet	1s	128 MB	Judgeable
Grasshopper JumpsGiven a line of grasshoppers that repeatedly move by jumping left or right over B neighbors, report the maximum height jumped over for each move using an order-statistics/segment-tree-like structure over positions.	Medium6	Segment treeArray+1	No attempts yet	2s	128 MB	Judgeable
24 Matchstick PuzzleGiven N and K, remove exactly N matchsticks from a 3x3 grid of 24 matchsticks so that exactly K complete squares remain and every leftover stick belongs to some square.	Medium6	BacktrackingBrute force+1	No attempts yet	1s	128 MB	Judgeable
Turbo ModeSimulate a TV remote where number keys change channels and repeated T presses cycle through a deduplicated history segment since the current channel's last appearance.	Medium6	SimulationImplementation+1	No attempts yet	1s	128 MB	Judgeable
Falling AntsSimulate colliding ants on a stick using the classic pass-through trick to find the k-th ant to fall off, breaking ties by smaller ID when falls tie in time.	Medium6	SortingSimulation+1	No attempts yet	1s	256 MB	Judgeable
PatternCount unit squares with max(x,y) odd inside a large rectangle using a closed-form counting formula instead of brute force.	Medium6	MathCombinatorics+1	No attempts yet	1s	128 MB	Judgeable
Smallest Number with FivesFind the smallest integer greater than N that contains the digit 5 at least K times in its decimal form.	Medium6	MathGreedy+1	No attempts yet	1s	128 MB	Judgeable
Table Soccer PathReposition each column of players (moving them vertically) so a diagonally bouncing ball never hits any player and reaches the right edge, then draw its path.	Medium6	SimulationMath+1	No attempts yet	1s	128 MB	Judgeable
Hyunju and Yunju's Fun Word GameCount unordered word pairs (A,B) where A<B lexicographically but reverse(B)<reverse(A), given up to 100,000 distinct words.	Medium6	SortingString+2	No attempts yet	1s	128 MB	Judgeable
Word DivisionCount the number of ways to split a long word (up to length 300,000) into consecutive substrings all belonging to a dictionary of up to 4000 short words, modulo 1337377.	Medium6	Dynamic programmingString matching+2	No attempts yet	1s	128 MB	Judgeable
Road NetworkFor a tree with weighted edges, answer many queries asking for the minimum and maximum edge weight on the path between two given nodes.	Medium6	TreeBinary search+1	No attempts yet	1s	256 MB	Judgeable
KokosGiven N words of length 2K, build a trie for the first K letters and a reversed trie for the last K letters and find the minimum vertex count of a graph satisfying strict in/out degree branching-then-merging structure.	Medium6	TrieString+1	No attempts yet	1s	128 MB	Judgeable
Minimum Trailing Zeros PathFind a path from top-left to bottom-right of an N×N grid, avoiding zero cells, that minimizes trailing zeros in the product of visited cells.	Medium6	Dynamic programmingMatrix+1	No attempts yet	1s	128 MB	Judgeable
Football RankingRank football teams by points with a recursive mini-league tiebreak among tied teams, falling back to goal difference, goals scored, wins, then team number.	Medium6	SimulationSorting+2	No attempts yet	1s	128 MB	Judgeable
Password Name FinderFind the minimum set of 2 to 5 distinct girl names of length 3 to 8 whose pairwise concatenations reconstruct all given passwords.	Medium6	StringBacktracking+1	No attempts yet	1s	128 MB	Judgeable
HugoGiven N tree positions with scheduled apple-fall times, find the maximum number of apples a character starting at the middle square (moving at most one square per second) can catch.	Medium6	Dynamic programmingGreedy+1	No attempts yet	2s	128 MB	Judgeable
Memory Allocation SimulatorSimulate first-fit memory allocation and freeing over 100,000 memory cells while processing malloc, free, and print commands on named variables.	Medium6	SimulationImplementation+1	No attempts yet	1s	128 MB	Judgeable
Coin StatementsGiven L positions and N clauses of the form (position i is X) OR (position j is Y), reconstruct any assignment satisfying all clauses, or report impossibility (2-SAT).	Medium6	GraphDFS+1	No attempts yet	1s	128 MB	Judgeable
Moving AntsGiven ants bouncing on a segment that pass through each other when they collide, compute each ant's position after T seconds while preserving left-to-right ordering.	Medium6	SimulationSorting+1	No attempts yet	1s	128 MB	Judgeable
Map LabelsGiven N points as top-left corners of fixed-ratio (3:1 width to height) axis-aligned rectangles, find the maximum height so no two rectangles overlap, using binary search on height and an overlap check.	Medium6	Binary searchSorting+1	No attempts yet	4s	128 MB	Judgeable
Pizza DeliveryChoose at most K of M candidate sites to maximize the total population within radius R, counting each building once even if covered multiple times.	Medium6	CombinatoricsBrute force+1	No attempts yet	1s	128 MB	Judgeable