Problems

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Total results29,441 problems

Graph Transformation
Medium5
Math, Graph
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Shortest Circuit
Medium5
Shortest path, Graph+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Alley
Medium5
Stack, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Turning Trominos
Medium5
Divide and conquer, Recursion+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
DJ Gigs
Medium5
Dynamic programming, Shortest path+2
No attempts yet
Time limit
8s
Memory limit
1024 MB
Judgeable
Haybale Distribution
Medium5
Sorting, Prefix sum+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Cowntact Tracing 2
Medium5
Greedy, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Rainy Day
Medium5
BFS, Simulation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Single Player Game
Medium5
Implementation, Prefix sum
No attempts yet
Time limit
10s
Memory limit
1024 MB
Judgeable
Namomo Subsequence
Medium5
String, Dynamic programming+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Allin
Medium5
Brute force, Simulation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Liars
Medium5
Array, Prefix sum
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Infection
Medium5
Dynamic programming, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Laser Beam
Medium5
Geometry, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Mirror Brackets
Medium5
Stack, String+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Graph Theory
Medium5
Segment tree, Graph+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Hockey
Medium5
Simulation, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Days of the week
Medium5
Matrix, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Divided Mechanism
Medium5
Simulation, Implementation+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Complete Road
Medium5
Math, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Equipment
Medium5
Greedy, Union-find+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Multiply
Medium5
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Recover the Sequence
Medium5
Graph, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Tourism Product
Medium5
Binary search, Prefix sum
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Keep Climbing
Medium5
Stack, Sliding window+1
No attempts yet
Time limit
0.7s
Memory limit
1024 MB
Judgeable
Mice
Medium5
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
TV Game
Medium5
Dynamic programming, Matrix
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Shooting
Medium5
Sorting, Binary search+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Training
Medium5
Dynamic programming, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Soccer Tournament
Medium5
Dynamic programming, Greedy
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Distinct Digits
Medium5
Dynamic programming, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Toy Dog
Medium5
Math, Hash map+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Compare Continued Fractions
Medium5
Math, Array
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Construction of Chand Baori
Medium5
Dynamic programming, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Devil's Hell deLivery
Medium5
Dynamic programming, Bit manipulation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Composition of Polynomials
Medium5
Math, Bit manipulation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Perfect gift
Medium5
Geometry, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Candies
Medium5
Heap, Simulation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Geometric Progression
Medium5
Number theory, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Lunch
Medium5
Math, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
The Pool for Lucky Ones
Medium5
Greedy, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Bridge Building
Medium5
Binary search, Greedy
No attempts yet
Time limit
5.5s
Memory limit
1024 MB
Judgeable
Maths
Medium5
Number theory, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
History
Medium5
Math, Implementation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Chemistry
Medium5
Implementation, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Urban geography
Medium5
Two pointers, Union-find+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Overload Prevention
Medium5
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Military Enlistment
Medium5
Dynamic programming, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
UFO Invasion
Medium5
Prefix sum, Math+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
String Graph Matching
Medium5
Sliding window, String+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Sinchon Merger Plan
Medium5
Linked list, String+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Carrot Click Game
Medium5
Dynamic programming, Greedy
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Chocolate Flip Game (Bitter)
Medium5
Math, String
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Two-pronged array output
Medium5
Matrix, Simulation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Hair War
Medium5
Tree, DFS+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Card game
Medium5
Dynamic programming, Binary search+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Supporting everyone
Medium5
Graph, BFS
No attempts yet
Time limit
0.25s
Memory limit
1024 MB
Judgeable
Olympic goodies
Medium5
Tree, Greedy+1
No attempts yet
Time limit
0.25s
Memory limit
1024 MB
Judgeable
Multiplication in Base N (tiny)
Medium5
Math, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
DP (Large)
Medium5
Dynamic programming, Binary search
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Item Selection
Medium5
Greedy, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Streets Behind
Medium5
Math, Simulation
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
New AVL Tree
Medium5
Tree, Dynamic programming
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Reluctant to Commute 1
Medium5
Combinatorics, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Reversal of the Discharge
Medium5
Dynamic programming, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Strong and Powerful Morning
Medium5
Graph, Shortest path
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Ransomware and Bitcoin
Medium5
Combinatorics, Implementation
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Wine Tasting
Medium5
Greedy, Sorting
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Forming Groups
Medium5
Array, Prefix sum+1
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Pho Restaurant
Medium5
Greedy, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Eggplant Spirit Sasa
Medium5
Math, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Eggplant Cucumber Carrot
Medium5
Implementation, Brute force+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Lefties vs. Righties
Medium5
Dynamic programming, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Graduation Table
Medium5
Graph, Greedy
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Precarious Stacks
Medium5
Segment tree, Sorting
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Special Student Council President Replacement
Medium5
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Postage Stamps
Medium5
Math, Hash map
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Reserved Seating 1
Medium5
Sorting, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Be Quiet!!
Medium5
Bit manipulation, BFS+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Split the SSHS Bamboo Forest
Medium5
Tree, DFS+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Split the GSHS 2
Medium5
Dynamic programming, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Making PPC
Medium5
Greedy, Two pointers+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
78 stairs descent contest
Medium5
Dynamic programming, Binary search+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Phoenix Locks the Door
Medium5
Greedy, String+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Virus Attack
Medium5
BFS, Simulation+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
RUN Number
Medium5
Math, Implementation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Construct a Graph
Medium5
Graph, Shortest path
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
MR.DR String
Medium5
Combinatorics, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
First Bus
Medium5
Graph, Shortest path
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Item 2
Medium5
Dynamic programming, Prefix sum+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
The Beauty of Fireworks
Medium5
Dynamic programming, Tree+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Count Triangles from Segments
Medium5
Geometry, Sorting+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Inequality Puzzle
Medium5
Graph, Topological sort
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Insung Lake Park
Medium5
Prefix sum, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Simple Permutation Problem
Medium5
Stack, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Snowflake Tanghulu
Medium5
Hash map, Math+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Bubble Bubble
Medium5
Array, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Yeongil Land
Medium5
Dynamic programming, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
EDF
Medium5
Greedy, Heap+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
The K512 Cup Begins!
Medium5
Dynamic programming, Bit manipulation
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Graph TransformationGiven a complete graph with N vertices, find the vertex count after K line-graph transformations, modulo 1000000007.	Medium5	MathGraph	No attempts yet	1s	1024 MB	Judgeable
Shortest CircuitGiven a grid of two-wire and single-wire knobs, find the fewest 90-degree spins that connect the two end knobs.	Medium5	Shortest pathGraph+1	No attempts yet	1s	1024 MB	Judgeable
AlleyGiven floats in street order, decide whether a single dead-end alley used as a stack can sort them by license plate.	Medium5	StackGreedy+1	No attempts yet	1s	1024 MB	Judgeable
Turning TrominosGiven a square (x, y) in the tiled first quadrant, output which of the four L-tromino orientations covers it, using the numbering in Figure 2.	Medium5	Divide and conquerRecursion+1	No attempts yet	3s	1024 MB	Judgeable
DJ GigsDoug starts at venue 1 at time 0 and picks non-overlapping gigs, accounting for road travel times between venues, to maximize total pay.	Medium5	Dynamic programmingShortest path+2	No attempts yet	8s	1024 MB	Judgeable
Haybale DistributionGiven N barn positions and Q pairs (a, b), find for each pair the minimum total haybale waste when choosing a delivery point y in [0, 10^6].	Medium5	SortingPrefix sum+2	No attempts yet	2s	1024 MB	Judgeable
Cowntact Tracing 2Find the fewest starting infected cows that, spreading to adjacent cows each night, produce the given infected bitstring.	Medium5	GreedyDynamic programming+1	No attempts yet	2s	1024 MB	Judgeable
Rainy DayGiven N students, M umbrellas, and a per-umbrella capacity K, find the fewest moves for all students to cross between two halls, or -1 if impossible.	Medium5	BFSSimulation	No attempts yet	1s	1024 MB	Judgeable
Single Player GameInteractive task: find how many times each of 1 to 4 appears in a hidden sequence, using range-count and adjacent-change queries.	Medium5	ImplementationPrefix sum	No attempts yet	10s	1024 MB	Judgeable
Namomo SubsequenceCount the length-6 subsequences of s whose equal-character pattern matches	Medium5	StringDynamic programming+1	No attempts yet	3s	1024 MB	Judgeable
AllinGiven your two hole cards and the three flop cards, decide whether you win the showdown against every possible opponent hand and every possible turn and river.	Medium5	Brute forceSimulation+1	No attempts yet	1s	1024 MB	Judgeable
LiarsGiven N statements that each claim at least k or at most k people are lying, list every number of liars that makes the statements consistent.	Medium5	ArrayPrefix sum	No attempts yet	2s	1024 MB	Judgeable
InfectionGiven timed contacts that spread infection with probability 1/2, find each employee's infection probability, given that employee k ends up infected.	Medium5	Dynamic programmingBit manipulation+1	No attempts yet	1s	1024 MB	Judgeable
Laser BeamGiven mirror angle alpha and beam angle beta, count how many times a laser beam reflects off the two mirrors before it travels off to infinity.	Medium5	GeometryMath	No attempts yet	1s	1024 MB	Judgeable
Mirror BracketsGiven a string of mirror letters and brackets, apply the reflections until no brackets remain and print the final string.	Medium5	StackString+1	No attempts yet	1s	1024 MB	Judgeable
Graph TheoryRemove one edge from an n-cycle so that the largest shortest-path distance over m given vertex pairs is as small as possible.	Medium5	Segment treeGraph+1	No attempts yet	1s	1024 MB	Judgeable
HockeyGiven a timed log of goals and penalties in a hockey match, report each player-count format (AxB) that appeared and how long it lasted.	Medium5	SimulationImplementation	No attempts yet	1s	1024 MB	Judgeable
Days of the weekEach button shifts its linked universes forward one weekday (mod 7). Decide whether every weekday configuration is reachable, and print an unreachable one if not.	Medium5	MatrixMath+1	No attempts yet	1s	1024 MB	Judgeable
Divided MechanismGiven a grid with connected A and B parts and a sequence of moves, determine whether sliding B in some move direction can ever leave it unable to touch A, splitting the parts.	Medium5	SimulationImplementation+1	No attempts yet	3s	1024 MB	Judgeable
Complete RoadGiven hole positions and segment length m, find the fewest damaged segments over all start offsets k from 1 to m, and list every k that reaches it.	Medium5	MathPrefix sum+1	No attempts yet	1s	1024 MB	Judgeable
EquipmentAssign each child a distinct kit from their interval [L_i, R_i], or report NO if no such assignment exists.	Medium5	GreedyUnion-find+1	No attempts yet	1s	1024 MB	Judgeable
MultiplyGiven a sequence a and Q limits K, find the minimum sum of a_i times b_i when no value appears in b more than K times.	Medium5	GreedySorting+1	No attempts yet	1s	1024 MB	Judgeable
Recover the SequenceGiven sums a_i + a_j for some index pairs, recover the hidden positive integer sequence a_0 through a_{n-1}.	Medium5	GraphMath+1	No attempts yet	1s	1024 MB	Judgeable
Tourism ProductGiven N beauty values, find the largest median over all contiguous segments of at least two attractions.	Medium5	Binary searchPrefix sum	No attempts yet	1s	1024 MB	Judgeable
Keep ClimbingGiven a sequence A, find the smallest window size k so that the sliding-window maxima of A form a non-decreasing sequence.	Medium5	StackSliding window+1	No attempts yet	0.7s	1024 MB	Judgeable
MiceGiven mice and cheese positions on a line, find the movement direction and the fewest hungry mice under two eating rules.	Medium5	GreedySorting+1	No attempts yet	1s	1024 MB	Judgeable
TV GameFind the maximum sum of digits a ball collects while falling down a board, along with the starting column and one path that reaches it.	Medium5	Dynamic programmingMatrix	No attempts yet	1s	1024 MB	Judgeable
ShootingFind the smallest starting skill that lets a shooter, hitting the highest reachable target on each of at most M shots, reach a total score of A.	Medium5	SortingBinary search+1	No attempts yet	1s	1024 MB	Judgeable
TrainingPick at least one training from each situation so the total time stays within M hours and is as large as possible. Print -1 if no valid plan exists.	Medium5	Dynamic programmingArray	No attempts yet	1s	1024 MB	Judgeable
Soccer TournamentSelect 11 players, exactly one goalkeeper and at least one each of striker, midfielder, and defender, to maximize the sum of their assigned preference scores.	Medium5	Dynamic programmingGreedy	No attempts yet	1s	1024 MB	Judgeable
Distinct DigitsCount the integers in [A, B], where B can be up to 10^100, whose decimal digits are all distinct and have no leading zeros.	Medium5	Dynamic programmingBit manipulation+1	No attempts yet	1s	1024 MB	Judgeable
Toy DogGiven a move string S repeated K times, decide whether a walk starting at the origin returns to the origin after its first step.	Medium5	MathHash map+1	No attempts yet	1s	1024 MB	Judgeable
Compare Continued FractionsGiven two finite continued fractions, decide whether the rational number x is less than, equal to, or greater than y.	Medium5	MathArray	No attempts yet	2s	1024 MB	Judgeable
Construction of Chand BaoriCount the descent routes along one face of an N-level stepped well and report whether that count is below the pilgrim number M.	Medium5	Dynamic programmingMath	No attempts yet	1s	1024 MB	Judgeable
Devil's Hell deLiveryAssign K items to N trucks over the fewest steps so each truck's load per step stays within its capacity, and print the assignment.	Medium5	Dynamic programmingBit manipulation+1	No attempts yet	2s	1024 MB	Judgeable
Composition of PolynomialsGiven polynomials f, g, and h over Z/2Z, compute f(g(x)) modulo h(x) and print the remainder in the same coefficient format.	Medium5	MathBit manipulation+1	No attempts yet	2s	1024 MB	Judgeable
Perfect giftGiven two stitched cells on an infinite grid, find the fewest new stitches needed to complete a parallelepiped outline whose edges are each at least 3 cells long.	Medium5	GeometryMath+1	No attempts yet	2s	1024 MB	Judgeable
CandiesGiven n counts and a bonus of up to y for bobo 1, find the most candies bobo 1 can hold after m rounds, where each round the minimum (ties to the smallest label) gets x.	Medium5	HeapSimulation+1	No attempts yet	1s	1024 MB	Judgeable
Geometric ProgressionCount index triples i<j<k in a strictly increasing array with values up to 1e6 where a_i times a_k equals a_j squared.	Medium5	Number theoryMath	No attempts yet	1s	1024 MB	Judgeable
LunchGiven n leaves, a start leaf s, and a finish leaf f, find the fewest distance-1 jumps for a path that lands on every leaf exactly once, or report -1.	Medium5	MathGreedy+1	No attempts yet	1s	1024 MB	Judgeable
The Pool for Lucky OnesGiven swimmer counts per lane, move single swimmers to adjacent lanes to minimize how many swimmers remain in the lanes with the maximum count.	Medium5	GreedyArray	No attempts yet	1s	1024 MB	Judgeable
Bridge BuildingGiven x logs of length a and y logs of length b, split them into l rows to maximize the smallest row total.	Medium5	Binary searchGreedy	No attempts yet	5.5s	1024 MB	Judgeable
MathsGiven n, find integers a_1 to a_n, each between 1 and 300, so that every prefix sum for k from 2 to n has exactly a_k divisors, or report Impossible.	Medium5	Number theoryMath+1	No attempts yet	1s	1024 MB	Judgeable
HistoryGiven years A to B in the Gregorian calendar, count for each k from 0 to 12 how many years have exactly k Friday the 13ths.	Medium5	MathImplementation+1	No attempts yet	1s	1024 MB	Judgeable
ChemistryGiven n tubes holding 1 nanoliter each, pour between equal-volume tubes to leave exactly k nanoliters in tube 1, or report -1.	Medium5	ImplementationMath	No attempts yet	1s	1024 MB	Judgeable
Urban geographyPick a set of roads that keeps all districts connected while minimizing the gap between the most expensive and cheapest kept road, then print their numbers.	Medium5	Two pointersUnion-find+2	No attempts yet	2s	1024 MB	Judgeable
Overload PreventionGiven power strips with their socket counts, K wall outlets, and M devices with maximum strip-depth limits, find the most devices that can receive power.	Medium5	GreedySorting+1	No attempts yet	1s	1024 MB	Judgeable
Military EnlistmentGiven daily volunteer points and a blood donation that blocks the next D days, find the fewest donations needed to reach at least M points, or -1 if impossible.	Medium5	Dynamic programmingPrefix sum+1	No attempts yet	1s	1024 MB	Judgeable
UFO InvasionGiven N UFOs that teleport every second for T seconds, answer each query with how many UFOs a horizontal or vertical laser line can hit.	Medium5	Prefix sumMath+1	No attempts yet	3s	1024 MB	Judgeable
String Graph MatchingCount the substrings of T whose set of adjacent letter pairs is exactly the given set of M directed edges.	Medium5	Sliding windowString+1	No attempts yet	2s	1024 MB	Judgeable
Sinchon Merger PlanGiven N strings and the sequence of pairs where one string is appended to another and emptied, output the final merged string.	Medium5	Linked listString+1	No attempts yet	2s	1024 MB	Judgeable
Carrot Click GameGiven N speed effects with costs A_i and speed gains B_i, find the most carrots Eric can hold after K seconds of clicking and buying.	Medium5	Dynamic programmingGreedy	No attempts yet	2s	1024 MB	Judgeable
Chocolate Flip Game (Bitter)Given a row of H, T, and ? marks, count the ways to set each ? to H or T so the chocolate flip game can be won, modulo 1,000,000,007.	Medium5	MathString	No attempts yet	2s	1024 MB	Judgeable
Two-pronged array outputGiven the grid size and a starting side, fill an N by M array with a two-pronged spiral numbering from the side's center outward.	Medium5	MatrixSimulation	No attempts yet	2s	1024 MB	Judgeable
Hair WarGiven a complete binary tree with N broken edges, compare a fork-splitting search against a left-first DFS with return costs, and report which finishes faster.	Medium5	TreeDFS+1	No attempts yet	1s	1024 MB	Judgeable
Card gameFind the fewest single-card moves to group the hand by suit with each suit sorted by number, and put the cyan cards last in increasing order.	Medium5	Dynamic programmingBinary search+1	No attempts yet	1s	1024 MB	Judgeable
Supporting everyoneEach country is either supported with a pin for 1 or has its flag colours bought at 1 per colour; find the minimum total cost.	Medium5	GraphBFS	No attempts yet	0.25s	1024 MB	Judgeable
Olympic goodiesGiven a tree of N nodes and P items to place on its edges, find the smallest possible maximum item count over all paths.	Medium5	TreeGreedy+1	No attempts yet	0.25s	1024 MB	Judgeable
Multiplication in Base N (tiny)Multiply two integers A and B written in base N, where N may be negative, and print the product in base N.	Medium5	MathImplementation	No attempts yet	1s	1024 MB	Judgeable
DP (Large)For each queried problem, find the longest subsequence of problems whose numbers and difficulties both strictly increase and that includes it.	Medium5	Dynamic programmingBinary search	No attempts yet	4s	1024 MB	Judgeable
Item SelectionGiven pages of m items with preselected and wanted items, find the fewest checkbox and button clicks needed to make the selection match the wanted items.	Medium5	GreedyDynamic programming+1	No attempts yet	1s	2048 MB	Judgeable
Streets BehindGiven n serious runners, k casual runners, and threshold a/b, find the fewest training runs that convert every casual runner, or -1 if impossible.	Medium5	MathSimulation	No attempts yet	1s	2048 MB	Judgeable
New AVL TreeGiven a set S of allowed balance values and a height h, count the tree shapes of height h where every non-leaf node has a balance in S, modulo 1e9+7.	Medium5	TreeDynamic programming	No attempts yet	2s	1024 MB	Judgeable
Reluctant to Commute 1Count the attendance patterns for N employees over M hours where at most one employee is absent in any hour, given each employee's hours present, modulo 1e9+7.	Medium5	CombinatoricsMath	No attempts yet	1s	1024 MB	Judgeable
Reversal of the DischargeChoose actions within a slack budget to maximize Yeongdo's discharge lead over Jonghyeon, or minimize his lag if no lead is possible.	Medium5	Dynamic programmingImplementation	No attempts yet	1s	1024 MB	Judgeable
Strong and Powerful MorningGiven a directed weighted graph of N languages, answer each query with the cheapest path from s to e that avoids vertex k, or print No if none exists.	Medium5	GraphShortest path	No attempts yet	1s	1024 MB	Judgeable
Ransomware and BitcoinDistribute 20 file types across 15 computers, storing at most 8 per computer, so that any 10 computers still hold all 20 file types.	Medium5	CombinatoricsImplementation	No attempts yet	1s	512 MB	Judgeable
Wine TastingPick K of N wines and order them so the sum of perceived tastes is maximized, where a step up from a worse wine to a better one counts as the difference.	Medium5	GreedySorting	No attempts yet	1s	512 MB	Judgeable
Forming GroupsChoose where student 1 stands in the line and a divisor k of n (k above 1) so that the largest-to-smallest ratio of round-robin group sums is minimized.	Medium5	ArrayPrefix sum+1	No attempts yet	5s	1024 MB	Judgeable
Pho RestaurantGiven n tables of binary dish orders, find the fewest contestants to move so every table serves one dish type.	Medium5	GreedyImplementation	No attempts yet	2s	1024 MB	Judgeable
Eggplant Spirit SasaGiven a field side length n, print the numbers that sit in the same cell of a row-major table and a diagonal zigzag table, in ascending order.	Medium5	MathImplementation	No attempts yet	2s	1024 MB	Judgeable
Eggplant Cucumber CarrotGiven partly hidden vegetable choices and each bird's reported win, draw, or loss, decide whether a consistent assignment exists and output one if it does.	Medium5	ImplementationBrute force+1	No attempts yet	1s	1024 MB	Judgeable
Lefties vs. RightiesGiven T topics and N experts labeled rightie or leftie, pick at least one expert per topic with equal numbers of each label, minimizing the total interviewed.	Medium5	Dynamic programmingArray	No attempts yet	1s	1024 MB	Judgeable
Graduation TableGiven friend pairs with bribe values at a circular table where each person has at most two friends, choose which pairs to seat together to maximize total bribes.	Medium5	GraphGreedy	No attempts yet	1s	1024 MB	Judgeable
Precarious StacksGiven N squares dropped in order, each landing on the ground or on earlier squares, report the highest y coordinate after each drop.	Medium5	Segment treeSorting	No attempts yet	4s	1024 MB	Judgeable
Special Student Council President ReplacementGiven N groups with vote counts and a total budget M, find the largest budget the Student Council can keep without being impeached.	Medium5	GreedySorting+1	No attempts yet	1s	1024 MB	Judgeable
Postage StampsGiven stamps labeled by city, for each k find the most stamps that can be split into k identical multisets, one per person.	Medium5	MathHash map	No attempts yet	2s	1024 MB	Judgeable
Reserved Seating 1Given the heights of M students who want each of N rows, decide whether every student can sit in a preferred row so that no column's view is blocked.	Medium5	SortingGreedy+1	No attempts yet	1s	1024 MB	Judgeable
Be Quiet!!Find the most mosquitoes one walker can catch within T steps, and the most a single field center can reach with taxicab distance at most P divided by stamina.	Medium5	Bit manipulationBFS+1	No attempts yet	1s	1024 MB	Judgeable
Split the SSHS Bamboo ForestGiven a tree with weighted nodes, cut one edge so the two resulting components have the smallest possible difference in total weight, and print that difference and the edge.	Medium5	TreeDFS+1	No attempts yet	1s	1024 MB	Judgeable
Split the GSHS 2Count the ways to split students 1 to N into consecutive groups, where each group's size is an endpoint leader's A plus 1, modulo 1e9+7.	Medium5	Dynamic programmingArray	No attempts yet	1s	1024 MB	Judgeable
Making PPCGiven a string of C and P characters and at most K swaps, maximize the number of PPC subsequences (P, then P, then C, in order).	Medium5	GreedyTwo pointers+1	No attempts yet	1s	1024 MB	Judgeable
78 stairs descent contestFind the maximum total score of a path from step 1 to step N, where opening chest i needs the previous visited step to be at least H_i+B_i tall.	Medium5	Dynamic programmingBinary search+1	No attempts yet	1s	1024 MB	Judgeable
Phoenix Locks the DoorGiven N dials showing letters, find the lexicographically smallest string after turning single dials exactly K times, with each turn advancing a letter and wrapping Z to A.	Medium5	GreedyString+1	No attempts yet	1s	1024 MB	Judgeable
Virus AttackGiven a grid with virus sources and buildings that hold the virus for a set delay, list the cells that stay safe, or print -1 if none exist.	Medium5	BFSSimulation+1	No attempts yet	3s	1024 MB	Judgeable
RUN NumberGiven an N-digit number K, write K as a sum of at most N+1 RUN numbers (repdigits) and print the terms.	Medium5	MathImplementation+1	No attempts yet	1s	1024 MB	Judgeable
Construct a GraphGiven an N x N distance matrix, build a connected weighted graph whose shortest-path distances match it with minimum total edge weight, or report -1 if none exists.	Medium5	GraphShortest path	No attempts yet	1s	1024 MB	Judgeable
MR.DR StringCount the length-N uppercase strings that contain MRDR as a subsequence, modulo 1,000,000,007.	Medium5	CombinatoricsMath+1	No attempts yet	1s	1024 MB	Judgeable
First BusFind the minimum time to travel from building 1 to building N, where sidewalks work anytime but buses on roads can only be taken from time K onward.	Medium5	GraphShortest path	No attempts yet	2s	1024 MB	Judgeable
Item 2Find the maximum sum of picked values when each interior picked run must span at least K positions, while runs touching either end of the line are exempt.	Medium5	Dynamic programmingPrefix sum+1	No attempts yet	2s	1024 MB	Judgeable
The Beauty of FireworksGiven a tree with weight W_i on each node, pick one node a so that the sum of W_b times the distance from a to every other node b is maximized.	Medium5	Dynamic programmingTree+1	No attempts yet	3s	1024 MB	Judgeable
Count Triangles from SegmentsGiven N points on a circle and M disjoint chords, count the triples of chords that all cross each other pairwise, forming triangles.	Medium5	GeometrySorting+1	No attempts yet	2s	1024 MB	Judgeable
Inequality PuzzleFill an N by N grid with each integer from 1 to N^2 once so that every adjacent pair satisfies its given < or > sign.	Medium5	GraphTopological sort	No attempts yet	2s	1024 MB	Judgeable
Insung Lake ParkGiven a ring of fork paths a_i and gate spurs b_i, find the longest walk between two different gates that never reuses a path.	Medium5	Prefix sumArray	No attempts yet	1s	1024 MB	Judgeable
Simple Permutation ProblemCount position pairs i < j in a permutation where both values are larger than every element strictly between them.	Medium5	StackArray	No attempts yet	1s	1024 MB	Judgeable
Snowflake TanghuluGiven fruit positions and candidate endpoints, find the most fruits one skewer from (0, 0) to a candidate endpoint can pierce.	Medium5	Hash mapMath+2	No attempts yet	2s	512 MB	Judgeable
Bubble BubbleGiven distinct integers, find the fewest operations to sort them using adjacent swaps, where one whole-array reversal (allowed once) also counts as one operation.	Medium5	ArraySorting+1	No attempts yet	1s	1024 MB	Judgeable
Yeongil LandFind the longest directed route from the gate that rides each of N rides (N up to 9) exactly once and returns to the gate.	Medium5	Dynamic programmingBit manipulation+1	No attempts yet	1s	1024 MB	Judgeable
EDFGiven N existing jobs and M jobs arriving later, simulate earliest-deadline-first scheduling with preemption and report whether all jobs finish, and the finish time if they do.	Medium5	GreedyHeap+1	No attempts yet	1s	1024 MB	Judgeable
The K512 Cup Begins!Starting from 0, use all N add-scrolls and M multiply-scrolls in some order to find the maximum final luck value.	Medium5	Dynamic programmingBit manipulation	No attempts yet	1s	512 MB	Judgeable