Problems

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Total results29,416 problems

Fantastic Beasts
Medium6
Math, Simulation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Sequences
Medium6
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Missing Bridges
Medium6
Graph, Union-find+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Chain
Medium6
Stack, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Oblongs and Right Triangles
Medium6
Brute force, Geometry+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Unique Substrings
Medium6
String, Greedy+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Hedwig's Ladder
Medium6
Dynamic programming, Recursion
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Left-Right-Win
Medium6
Probability, Math+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Subprime Fibonacci Sequence
Medium6
Simulation, Hash map+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Card Game
Medium6
Binary search, Greedy+2
No attempts yet
Time limit
1.2s
Memory limit
512 MB
Judgeable
Linked List
Medium6
Linked list, Array+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Substring Permutation
Medium6
Hash map, Two pointers+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
The Good, the Great, and the Superb
Medium6
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Collecting Stars
Medium6
Greedy, Binary search+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Hazardous Driving
Medium6
Graph, Binary search+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Ebony and Ivory
Medium6
Dynamic programming, Implementation
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Superdoku
Medium6
Graph, Matrix+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Generalized German Quotation
Medium6
Stack, Implementation+1
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Joined Vessels
Medium6
Array, Prefix sum+1
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Keyboard Consensus
Medium6
Game theory, Greedy+1
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Ahn Subin Number
Medium6
Number theory, Math
No attempts yet
Time limit
0.5s
Memory limit
128 MB
Judgeable
Liars
Medium6
Hash map, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
The Silence of the Lamps
Medium6
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Matrice
Medium6
Dynamic programming, Matrix+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Game of Stones
Medium6
Game theory, Math
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
JackRabbit Slim
Medium6
Dynamic programming, Array+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
T-net
Medium6
Dynamic programming, Sorting+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Arithmetic Progressions
Medium6
Array, Hash map+1
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Deblo
Medium6
Tree, Bit manipulation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Maja
Medium6
Matrix, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Circle Cross Stamps
Medium6
Dynamic programming, Greedy+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Xylophone
Medium6
Array, Math+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Marching Course
Medium6
Graph, Shortest path+1
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Route Calculator
Medium6
Dynamic programming, String+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Tiny Room
Medium6
Geometry, Sorting
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Colorful Drink
Medium6
Greedy, Binary search+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Dictionary
Medium6
Dynamic programming, String+1
No attempts yet
Time limit
4s
Memory limit
512 MB
Judgeable
Craziness
Medium6
Brute force, Bit manipulation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Maximum Matching of a Cactus
Medium6
Tree, Dynamic programming+1
No attempts yet
Time limit
0.3s
Memory limit
1024 MB
Judgeable
Pizza Cutting
Medium6
Geometry, Math+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Roman Holidays
Medium6
String, Math+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Watch Where You Step
Medium6
Graph, BFS+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Palace
Medium6
Math, Combinatorics+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Hotel Management
Medium6
Graph, DFS+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Finding Crosses
Medium6
Implementation, Brute force+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Making a Shape
Medium6
Graph, DFS+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Digit Rearrangement
Medium6
Backtracking, Greedy+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Breaking a Wall and Moving 4
Medium6
Graph, BFS+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Seoul Subway Line 2
Medium6
Graph, BFS+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
A → B
Medium6
Greedy, BFS+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Ball on a Chessboard
Medium6
Graph, Dynamic programming+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Teleport
Medium6
Graph, Shortest path+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
DFS Special Judge
Medium6
DFS, Tree+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Rectangle Escape
Medium6
BFS, Prefix sum+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Minhyuk's Game Party
Medium6
Union-find, Graph+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Bitaro the Brave
Medium6
Prefix sum, Array+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Insiders' Rock-Paper-Scissors
Medium6
Simulation, Implementation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Baaaaaaaaaduk2 (Easy)
Medium6
Brute force, Simulation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Magic Barrier
Medium6
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Traveling Salesman 3
Medium6
Dynamic programming, Bit manipulation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Busy Board
Medium6
Matrix, Greedy+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Cost of Living
Medium6
Graph, Union-find+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Cow Poetry
Medium6
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Sleepy Cow Sorting
Medium6
Array, Greedy+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Guess the Animal
Medium6
Implementation, Greedy+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Dishwashing
Medium6
Stack, Greedy+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Sleepy Cow Herding (Silver)
Medium6
Sorting, Sliding window+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Painting the Barn (Silver)
Medium6
Prefix sum, Array+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
The Great Revegetation (Silver)
Medium6
Union-find, Graph+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Parametriziran
Medium6
Bit manipulation, Hash map+2
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Horse Drawing
Medium6
Graph, BFS+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Sličice
Medium6
Dynamic programming, Greedy
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Mobitel
Medium6
Dynamic programming, Matrix
No attempts yet
Time limit
6s
Memory limit
512 MB
Judgeable
Alice in the Digital World
Medium6
Array, Divide and conquer+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Moving a Pipe 1
Medium6
Dynamic programming, Simulation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Coloring Practice
Medium6
Prefix sum, Hash map+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Hyper Tomato
Medium6
BFS, Graph+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Why the Cows Climbed onto the Information Island
Medium6
Implementation, Math+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Why the Fox Climbed Information Island
Medium6
Sorting, Binary search+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Lemoine's Conjecture
Medium6
Number theory, Prefix sum+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Candy Game
Medium6
Dynamic programming, Combinatorics+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
2D Array and Operations
Medium6
Simulation, Implementation+2
No attempts yet
Time limit
0.5s
Memory limit
512 MB
Judgeable
Fishing King
Medium6
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Hobson's Trains
Medium6
Graph, DFS+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Karel the Robot
Medium6
Simulation, Recursion+1
No attempts yet
Time limit
10s
Memory limit
512 MB
Judgeable
Miniature Golf
Medium6
Sorting, Prefix sum+1
No attempts yet
Time limit
6s
Memory limit
512 MB
Judgeable
Rainbow Beads
Medium6
Two pointers, Sliding window+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Voronoi Diagram Again
Medium6
Geometry, Sorting
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
A Plus Equals B
Medium6
Number theory, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Jealous Teachers
Medium6
Graph, Implementation+2
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Cake Cutting
Medium6
Binary search, Greedy+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Comparing Strings
Medium6
Dynamic programming, String+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Hangul Shortest Word on a Grid
Medium6
BFS, Matrix+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Space Probe
Medium6
Dynamic programming, Bit manipulation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Nautilus
Medium6
Implementation, Simulation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Snakes
Medium6
Dynamic programming, Array+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
In-jae, did you catch Mushmom?
Medium6
Simulation, Shortest path
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Life Game
Medium6
Simulation, Implementation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Scoring Hack
Medium6
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Team Selection
Medium6
Dynamic programming, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Fantastic BeastsEach of B beasts moves by a fixed map f: zoo i sends it to f(i) or itself; find the earliest time T and a zoo where all beasts coincide, or report never.	Medium6	MathSimulation+2	No attempts yet	2s	512 MB	Judgeable
SequencesCount non-decreasing length-n sequences over 1 to m where each integer appears at most k times. Use DP over the largest value and its count.	Medium6	Dynamic programmingCombinatorics+1	No attempts yet	2s	512 MB	Judgeable
Missing BridgesFind the fewest new bridges so that every bridge can be crossed once in a closed walk back to the start, and print those bridges.	Medium6	GraphUnion-find+1	No attempts yet	2s	512 MB	Judgeable
ChainFor each position, repeatedly jump to the first strictly greater element on its right and report the length of that chain.	Medium6	StackDynamic programming+1	No attempts yet	2s	512 MB	Judgeable
Oblongs and Right TrianglesCount 4-black-point sets forming a non-square rectangle and 3-white-point sets forming a right triangle, disjoint and with positive area.	Medium6	Brute forceGeometry+2	No attempts yet	1s	256 MB	Judgeable
Unique SubstringsBuild a lowercase string of length at most 4096 that has exactly K distinct substrings, where K is at most 2^22.	Medium6	StringGreedy+1	No attempts yet	1s	256 MB	Judgeable
Hedwig's LadderCount the paths of length N from A0 on a ladder graph that never revisit a junction, modulo 10007.	Medium6	Dynamic programmingRecursion	No attempts yet	2s	512 MB	Judgeable
Left-Right-WinFor players seated in a circle, compute how much of a $100 pot each should pay, given the spinner probabilities of moving left, moving right, or winning.	Medium6	ProbabilityMath+2	No attempts yet	2s	512 MB	Judgeable
Subprime Fibonacci SequenceGenerate terms with the divide-out recurrence and find the shortest repeating pair of consecutive terms within the first n terms, then print the cycle.	Medium6	SimulationHash map+2	No attempts yet	2s	512 MB	Judgeable
Card GameMinsu holds M distinct blue cards and must answer each of K plays by discarding the smallest blue card larger than Cheolsu's card, or answering 0 when none exists.	Medium6	Binary searchGreedy+2	No attempts yet	1.2s	512 MB	Judgeable
Linked ListMaintain a permutation of 1..N under slide(a,b) moves (move a to just after b), reporting how far a moves each time and printing the final list.	Medium6	Linked listArray+2	No attempts yet	1s	512 MB	Judgeable
Substring PermutationGiven strings S and P, decide whether some permutation of P is a substring of some permutation of S.	Medium6	Hash mapTwo pointers+1	No attempts yet	1s	512 MB	Judgeable
The Good, the Great, and the SuperbGiven a sequence of digits, find the minimum number of elements to change so the sequence becomes Good, Great, or Superb, where Superb is constant, Great has adjacent gaps at most 1, and Good splits into Great or Superb blocks.	Medium6	Dynamic programmingGreedy+2	No attempts yet	1s	512 MB	Judgeable
Collecting StarsGiven n stars with times and unlock thresholds, pick k in some order respecting the thresholds and minimize the total time.	Medium6	GreedyBinary search+2	No attempts yet	2s	512 MB	Judgeable
Hazardous DrivingGiven an undirected weighted graph, find an S to E route minimizing its maximum edge hazard, and among those the minimum total length.	Medium6	GraphBinary search+2	No attempts yet	2s	512 MB	Judgeable
Ebony and IvoryAssign fingers 1 to 5 to a monophonic piano passage given four ergonomic transition tables and output the minimum total difficulty of all adjacent intervals.	Medium6	Dynamic programmingImplementation	No attempts yet	2s	512 MB	Judgeable
SuperdokuGiven the first k rows of an n by n grid, decide whether the remaining rows can be filled so each row and column holds 1 to n, and print one completion.	Medium6	GraphMatrix+1	No attempts yet	2s	512 MB	Judgeable
Generalized German QuotationGiven a string of << and >> marks, decide whether it forms nested conventional or reversed German quotes and rewrite every mark as an opening [ or closing ], or report that none exists.	Medium6	StackImplementation+1	No attempts yet	3s	512 MB	Judgeable
Joined VesselsGiven n vessels joined by bridges at distinct heights, find how much water must be poured into vessel a before vessel b first receives any, for each of t queries.	Medium6	ArrayPrefix sum+1	No attempts yet	3s	512 MB	Judgeable
Keyboard ConsensusKolya and Kostya alternately delete keyboards, each minimizing the survivor's rank in their own list; find the survivor and Kolya's optimal first deletions.	Medium6	Game theoryGreedy+1	No attempts yet	3s	512 MB	Judgeable
Ahn Subin NumberFor each N up to 100,000,000, find a multiple of N whose decimal digit sum is odd, or print -1 if none exists.	Medium6	Number theoryMath	No attempts yet	0.5s	128 MB	Judgeable
LiarsGiven each person's claimed range for the truth-teller count, find the maximum possible number of truth-tellers within any consistent assignment.	Medium6	Hash mapPrefix sum+1	No attempts yet	1s	512 MB	Judgeable
The Silence of the LampsCount triples of integer side lengths (all distinct pairs give different areas) with volume at most N, so no face is a square and the three sides are pairwise distinct.	Medium6	MathNumber theory+2	No attempts yet	1s	512 MB	Judgeable
MatriceCount all triangular regions cut from squares by one diagonal whose cells all hold the same character.	Medium6	Dynamic programmingMatrix+1	No attempts yet	1s	512 MB	Judgeable
Game of StonesTwo players alternately remove stones from piles, with Petyr taking up to A per turn and Varys up to B. Determine who wins under optimal play.	Medium6	Game theoryMath	No attempts yet	2s	512 MB	Judgeable
JackRabbit SlimGiven sorted distinct carrot positions on a line, Slim repeatedly jumps to the nearest remaining carrot, breaking ties to the right; find the sum of total distances over all possible starting carrots.	Medium6	Dynamic programmingArray+2	No attempts yet	2s	512 MB	Judgeable
T-netGiven base station positions on a line and two antenna radii, the task finds the minimum total radius cost to connect all stations, or reports -1 if impossible.	Medium6	Dynamic programmingSorting+1	No attempts yet	2s	512 MB	Judgeable
Arithmetic ProgressionsGiven up to 5000 distinct numbers, find the length of the longest subset that forms an arithmetic progression.	Medium6	ArrayHash map+1	No attempts yet	5s	512 MB	Judgeable
DebloGiven a tree with numbers on its nodes, add up the XOR of every node-value along every path between two nodes, counting single-node paths too.	Medium6	TreeBit manipulation+2	No attempts yet	1s	512 MB	Judgeable
MajaMaja makes exactly K moves on a grid, starting and ending at the hive, to maximize flowers pollinated, where each cell regrows its flowers after she leaves.	Medium6	MatrixDynamic programming+1	No attempts yet	2s	512 MB	Judgeable
Circle Cross StampsGiven a row of O and X marks printed by single circles, single crosses, and two-mark circle-cross stamps in either orientation, find the largest possible count of circle-cross stamps.	Medium6	Dynamic programmingGreedy+1	No attempts yet	2s	512 MB	Judgeable
XylophoneFind the pitch of each of N bars by querying the max-min difference over contiguous bar ranges, using at most 10000 strikes.	Medium6	ArrayMath+1	No attempts yet	2s	512 MB	Judgeable
Marching CourseFind a closed walk from checkpoint 1 of at most P minutes that maximizes the sum of time times audience divided by road length.	Medium6	GraphShortest path+1	No attempts yet	5s	512 MB	Judgeable
Route CalculatorPick a right/down path through a grid of digits and operators to maximize the expression value, printing -1 if it exceeds 10^15.	Medium6	Dynamic programmingString+1	No attempts yet	2s	512 MB	Judgeable
Tiny RoomGiven N points and an H by W room, check whether the points can be rotated and moved to fit inside the room shrunk by R on every side.	Medium6	GeometrySorting	No attempts yet	2s	512 MB	Judgeable
Colorful DrinkGiven colored liquids with densities and a top-to-bottom list of requested color layers, decide whether one liquid per layer has strictly decreasing densities.	Medium6	GreedyBinary search+2	No attempts yet	2s	512 MB	Judgeable
DictionaryCount the ways to replace each ? in n sorted words with lowercase letters so the words stay in strictly increasing lexicographic order, modulo 1,000,000,007.	Medium6	Dynamic programmingString+1	No attempts yet	4s	512 MB	Judgeable
CrazinessGiven a symmetric matrix of pairwise and individual craziness values for n up to 20 relatives, find the non-empty subset whose invited pairs plus individual terms sum to the maximum.	Medium6	Brute forceBit manipulation+2	No attempts yet	2s	512 MB	Judgeable
Maximum Matching of a CactusGiven a cactus graph as a list of edge sets (cycles or paths), find the size of its maximum matching. Each edge set is a chain of vertices.	Medium6	TreeDynamic programming+1	No attempts yet	0.3s	1024 MB	Judgeable
Pizza CuttingGiven a circle of radius r cut by a grid of vertical and horizontal lines spaced dx and dy apart, count the pieces whose area is less than p times the largest piece.	Medium6	GeometryMath+1	No attempts yet	2s	512 MB	Judgeable
Roman HolidaysGiven integers up to 10^9, output each one's position in the ordering of their Roman numeral forms, as a negative number when counted from the end.	Medium6	StringMath+1	No attempts yet	2s	512 MB	Judgeable
Watch Where You StepFind the maximum number of new one-way sidewalks you can add to a zoo graph without creating any new reachability between attractions.	Medium6	GraphBFS+2	No attempts yet	2s	512 MB	Judgeable
PalaceCount ways to place N non-attacking palace pieces (rook plus king moves) on an N by N board, modulo 1,000,000,007, for up to 1,000,000 test cases with N up to 10,000,000.	Medium6	MathCombinatorics+2	No attempts yet	2s	512 MB	Judgeable
Hotel ManagementEach room belongs to exactly two switches; find whether pressing some subset of switches turns every room's lock state to open.	Medium6	GraphDFS+2	No attempts yet	2s	512 MB	Judgeable
Finding CrossesGiven a grid of stars and dots, decide whether it can be covered exactly by overlapping plus-shaped crosses, and if so output which crosses to draw.	Medium6	ImplementationBrute force+2	No attempts yet	2s	512 MB	Judgeable
Making a ShapeIn a grid of 0s and 1s, find the largest connected group of 1s obtainable by flipping exactly one 0 cell to 1.	Medium6	GraphDFS+2	No attempts yet	2s	512 MB	Judgeable
Digit RearrangementGiven A and B, rearrange the digits of A (no leading zero) to build the largest permutation that is still strictly less than B, or print -1.	Medium6	BacktrackingGreedy+2	No attempts yet	2s	512 MB	Judgeable
Breaking a Wall and Moving 4For each wall cell in an N by M binary grid, break it and print the size of the reachable open region modulo 10, leaving empty cells as 0.	Medium6	GraphBFS+2	No attempts yet	2s	512 MB	Judgeable
Seoul Subway Line 2Given a connected graph with N vertices and N edges (exactly one cycle), find each vertex's distance to the unique cycle.	Medium6	GraphBFS+2	No attempts yet	2s	512 MB	Judgeable
A → BUsing the operations double a number or append a digit 1, find the minimum number of steps to turn A into B, or report that it is impossible.	Medium6	GreedyBFS+2	No attempts yet	2s	512 MB	Judgeable
Ball on a ChessboardEach cell of an R by C board holds a distinct number; every ball rolls to the smallest neighbor until it reaches a local minimum, and we must count how many balls stop on each cell.	Medium6	GraphDynamic programming+2	No attempts yet	2s	512 MB	Judgeable
TeleportGiven N cities with coordinates, some special, travel costs Manhattan distance; special cities also connect by teleport costing T. Answer M shortest-path queries.	Medium6	GraphShortest path+2	No attempts yet	2s	512 MB	Judgeable
DFS Special JudgeGiven a tree and a permutation of its vertices, decide whether that permutation can be the DFS visit order starting from vertex 1.	Medium6	DFSTree+2	No attempts yet	2s	512 MB	Judgeable
Rectangle EscapeA rectangle slides on a grid with walls; find the shortest sequence of unit moves taking its top-left cell from start to finish.	Medium6	BFSPrefix sum+2	No attempts yet	2s	512 MB	Judgeable
Minhyuk's Game PartyGiven people with game choices and cables added one at a time, report after which cable each game's buyers all become connected, or 0 or -1.	Medium6	Union-findGraph+2	No attempts yet	2s	512 MB	Judgeable
Bitaro the BraveCount quadruples (i, j, k, l) with i<k and j<l such that grid cells (i,j)='J', (i,l)='O', (k,j)='I'. H, W up to 3000.	Medium6	Prefix sumArray+1	No attempts yet	1s	512 MB	Judgeable
Insiders' Rock-Paper-ScissorsWith a fixed gesture matchup table and each player's throw sequence, decide whether Jiwoo can win while never repeating a gesture, given match order Jiwoo, Kyunghee, Minho and ties favoring the later player.	Medium6	SimulationImplementation+2	No attempts yet	2s	512 MB	Judgeable
Baaaaaaaaaduk2 (Easy)Place exactly two own stones on empty cells of a board to maximize the number of opponent stones that become completely surrounded and captured.	Medium6	Brute forceSimulation+2	No attempts yet	2s	512 MB	Judgeable
Magic BarrierFor each fired shell, walk through N layers where layer i repeats a binary pattern; the shell at position P shifts by D per layer and survives only if every visited cell is 1. Count survivors.	Medium6	MathImplementation+2	No attempts yet	1s	512 MB	Judgeable
Traveling Salesman 3Find the minimum-length round trip that visits all N cities exactly once and returns to the start, where N is at most 16.	Medium6	Dynamic programmingBit manipulation+2	No attempts yet	1s	512 MB	Judgeable
Busy BoardGiven a start grid and a target grid of up and down pegs, decide whether the target is reachable when hammering a peg lowers it and raises every other peg in its row and column.	Medium6	MatrixGreedy+1	No attempts yet	2s	512 MB	Judgeable
Cost of LivingGiven some yearly inflation rates and commodity prices, use relationships between consecutive years to deduce unknown values and answer price queries.	Medium6	GraphUnion-find+2	No attempts yet	2s	512 MB	Judgeable
Cow PoetryCount the ways to fill M lines of exactly K syllables with given words, where equal rhyme-scheme letters must share a rhyme class, modulo 1e9+7.	Medium6	Dynamic programmingCombinatorics+1	No attempts yet	2s	512 MB	Judgeable
Sleepy Cow SortingFind the minimum number of moves to sort a permutation, where each move takes the front element and inserts it k positions later, and output the move sizes.	Medium6	ArrayGreedy+2	No attempts yet	2s	512 MB	Judgeable
Guess the AnimalGiven N animals and their traits, find the maximum number of yes answers Elsie can hear before her questions pin down exactly one animal.	Medium6	ImplementationGreedy+2	No attempts yet	2s	512 MB	Judgeable
DishwashingGiven a dish order, find the longest prefix that Bessie can soap through counter stacks so Elsie rinses the plates in increasing order.	Medium6	StackGreedy+1	No attempts yet	2s	512 MB	Judgeable
Sleepy Cow Herding (Silver)Find the minimum and maximum moves to make N cows on a number line occupy consecutive integers, moving only the leftmost or rightmost cow each turn.	Medium6	SortingSliding window+1	No attempts yet	2s	512 MB	Judgeable
Painting the Barn (Silver)Given N axis-aligned rectangles with coordinates in 0..1000, find the total area covered by exactly K of them.	Medium6	Prefix sumArray+2	No attempts yet	2s	512 MB	Judgeable
The Great Revegetation (Silver)Count the binary assignments of grass types to N pastures that satisfy M same-or-different constraints on pairs, and print the count in binary.	Medium6	Union-findGraph+2	No attempts yet	2s	512 MB	Judgeable
ParametriziranCount pairs of equal-length words over lowercase letters and question marks that can be made identical by filling the question marks.	Medium6	Bit manipulationHash map+2	No attempts yet	3s	512 MB	Judgeable
Horse DrawingGiven axis-aligned segments and a point T, keep every segment connected to a segment through T, then print the minimal bounding grid marking drawn points with '#'.	Medium6	GraphBFS+2	No attempts yet	2s	512 MB	Judgeable
SličiceGiven current counts of unique cards per team and a nondecreasing points array, choose K additional cards to maximize total points.	Medium6	Dynamic programmingGreedy	No attempts yet	1s	512 MB	Judgeable
MobitelCount the right-or-down paths from the top-left to the bottom-right cell of an R by S grid whose cell product is at least N, modulo 1000000007.	Medium6	Dynamic programmingMatrix	No attempts yet	6s	512 MB	Judgeable
Alice in the Digital WorldFind the maximum sum over subarrays whose minimum element equals m, given that the array and m are bounded by 26.	Medium6	ArrayDivide and conquer+2	No attempts yet	1s	512 MB	Judgeable
Moving a Pipe 1Count the ways to push a two-cell pipe (horizontal, vertical, or diagonal) across an N by N grid of walls until one end reaches (N, N).	Medium6	Dynamic programmingSimulation+2	No attempts yet	1s	512 MB	Judgeable
Coloring PracticeCount how many 3x3 subgrids contain exactly i black cells for each i from 0 to 9, given up to 1e5 black cells on a huge grid.	Medium6	Prefix sumHash map+2	No attempts yet	1s	512 MB	Judgeable
Hyper TomatoGiven an 11-dimensional grid of ripe, unripe, and empty cells, find the minimum days until every unripe tomato ripens, or -1 if some never do.	Medium6	BFSGraph+2	No attempts yet	1s	512 MB	Judgeable
Why the Cows Climbed onto the Information IslandOn a circle of N values, each query flips one value's sign; after every query print the sum of products over all N windows of four consecutive cows.	Medium6	ImplementationMath+2	No attempts yet	2s	256 MB	Judgeable
Why the Fox Climbed Information IslandCount triples of stars (s,t,u) with s.x < t.x < u.x and s.y > t.y < u.y, output the count modulo 1e9+7.	Medium6	SortingBinary search+2	No attempts yet	1s	256 MB	Judgeable
Lemoine's ConjectureCount, for each odd N up to 10^6, the representations N = p + s where p is an odd prime and s is an even semiprime (product of two primes).	Medium6	Number theoryPrefix sum+2	No attempts yet	2s	512 MB	Judgeable
Candy GameCount the number of nondecreasing sequences of length n where the i-th value is at most x[i], multiply by n, and report the result modulo 1e9+7.	Medium6	Dynamic programmingCombinatorics+2	No attempts yet	2s	512 MB	Judgeable
2D Array and OperationsSimulate up to 100 seconds of row-sorting or column-sorting on a 3x3 grid, where each sort replaces values by (value, frequency) pairs, and report when A[r][c] becomes k.	Medium6	SimulationImplementation+2	No attempts yet	0.5s	512 MB	Judgeable
Fishing KingA fisherman sweeps columns left to right, catching the lowest shark in each column while the rest slide and bounce vertically or horizontally, merging sharks that collide.	Medium6	SimulationImplementation+2	No attempts yet	1s	512 MB	Judgeable
Hobson's TrainsEach station has exactly one outgoing edge, and for every station the task asks how many stations can reach it in at most k steps along these edges.	Medium6	GraphDFS+2	No attempts yet	5s	512 MB	Judgeable
Karel the RobotSimulate Karel's moves and turns on a grid for each program, printing the final position and heading, or inf if the program never stops.	Medium6	SimulationRecursion+1	No attempts yet	10s	512 MB	Judgeable
Miniature GolfEach player picks the cap l that gives them the best rank, where each hole score is capped at l and rank counts players with a total at most theirs.	Medium6	SortingPrefix sum+1	No attempts yet	6s	512 MB	Judgeable
Rainbow BeadsFind the longest contiguous substring of a string over R, B, V that has no equal adjacent pair under any of the three color-blind views.	Medium6	Two pointersSliding window+2	No attempts yet	1s	1024 MB	Judgeable
Voronoi Diagram AgainGiven N distinct integer points, count the Voronoi regions under Manhattan distance that are unbounded, where ties belong to every nearest point.	Medium6	GeometrySorting	No attempts yet	5s	1024 MB	Judgeable
A Plus Equals BGiven A and B up to 10^18, output at most 5000 operations of the form A+=A, A+=B, B+=A, or B+=B that make A and B equal.	Medium6	Number theoryMath+1	No attempts yet	1s	1024 MB	Judgeable
Jealous TeachersEach of N-1 students must send exactly N-1 flowers to teachers they learned from, and every teacher must receive exactly N-1 flowers in total, or report that no such assignment exists.	Medium6	GraphImplementation+2	No attempts yet	3s	1024 MB	Judgeable
Cake CuttingGiven cut positions on a roll cake and several target piece counts, find the largest possible minimum piece length for each count.	Medium6	Binary searchGreedy+2	No attempts yet	1s	512 MB	Judgeable
Comparing StringsGiven two lowercase strings, align them by repeating characters of either string, keeping order, and minimize the sum of absolute alphabet-position differences over aligned pairs.	Medium6	Dynamic programmingString+2	No attempts yet	1s	512 MB	Judgeable
Hangul Shortest Word on a GridFind the length of the shortest valid Hangul word spelled along a path from (1, 1) to (N, M) on the grid, or report BAD if no such word exists.	Medium6	BFSMatrix+1	No attempts yet	1s	512 MB	Judgeable
Space ProbeGiven travel times between N planets and a start planet, find the shortest route that visits every planet, with no need to return to the start.	Medium6	Dynamic programmingBit manipulation+2	No attempts yet	1s	512 MB	Judgeable
NautilusGiven an R by C water and island grid plus M move signals with wildcards, count how many cells can be the submarine's current position if it never enters an island.	Medium6	ImplementationSimulation+2	No attempts yet	2s	512 MB	Judgeable
SnakesSplit the sequence into K+1 contiguous segments, set each segment's net size to its maximum, and minimize the total sum of segment maxima minus the sum of all group sizes.	Medium6	Dynamic programmingArray+2	No attempts yet	2s	512 MB	Judgeable
In-jae, did you catch Mushmom?Given In-jae's health A and attack B and Mushmom's health X and attack Y, find the fewest actions In-jae needs to defeat Mushmom.	Medium6	SimulationShortest path	No attempts yet	1s	256 MB	Judgeable
Life GameSimulate Conway-style life on an N x M board for T steps using a (2K+1) square neighborhood with thresholds a and b, then print the final board.	Medium6	SimulationImplementation+2	No attempts yet	2s	512 MB	Judgeable
Scoring HackStarting from 0, each turn adds a or b points or doubles the total, and the game must end with score below n+a while using at most 10% doublings. Find the minimum number of turns.	Medium6	Dynamic programmingGreedy+2	No attempts yet	1s	256 MB	Judgeable
Team SelectionPick five of n candidates and assign each a distinct role among A to E so the total skill summed over roles is as large as possible.	Medium6	Dynamic programmingBit manipulation+1	No attempts yet	1s	256 MB	Judgeable