Problems

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Total results29,431 problems

Tour Course
Medium7
Prefix sum, String+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Stone Placement Game
Medium7
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Distance Sum Maximization
Medium7
Tree, Segment tree+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Bamyanggaeng
Medium7
Graph, Matrix+2
No attempts yet
Time limit
2.5s
Memory limit
1024 MB
Judgeable
Reducing Boredom
Medium7
Prefix sum, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Broken Calculator
Medium7
Dynamic programming, String+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Dolphin Photos
Medium7
Graph, Greedy
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
City
Medium7
Graph, Dynamic programming+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Good Grid
Medium7
Matrix, Implementation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
A Tree Using Trees
Medium7
Tree, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Split the SSHS 4
Medium7
Tree, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Grand Operation: Invasion of the Underground Secret Base
Medium7
Union-find, Graph+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Computing the Average
Medium7
Math, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Candy Delivery
Medium7
Dynamic programming, Graph+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Growing Trees
Medium7
Greedy, Math+2
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
POEM
Medium7
Math, Union-find+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Virus
Medium7
Segment tree, String matching
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Cafeteria Serving
Medium7
Dynamic programming, Segment tree+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
The Final Destination of the Graph
Medium7
Graph, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Delicious Ruby Problem
Medium7
Dynamic programming, Matrix+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Water Tank Job (Hard)
Medium7
Tree, Dynamic programming+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Building MATKOR Strings
Medium7
Segment tree, Dynamic programming+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Vault Breaker
Medium7
Math, Number theory
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Super Shy (Hard)
Medium7
Recursion, Divide and conquer+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Drawing Binary Trees
Medium7
Tree, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Treasure Hunt Game
Medium7
Graph, Game theory+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Running Through Time (Rough)
Medium7
BFS, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Build the World
Medium7
Graph, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Make the Minimum Value
Medium7
Bit manipulation, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Espresso Made Your Way
Medium7
Stack, Greedy+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Matching Mentors
Medium7
Binary search, Greedy+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Moving Marbles
Medium7
Graph, Shortest path
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
Tactics
Medium7
Brute force, Sorting+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Paragliding
Medium7
Geometry, Sorting+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Trainee's Letter
Medium7
String matching, Dynamic programming
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Draw A Perfect Circle
Medium7
Sorting, Two pointers+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Growing Hwaetbul
Medium7
Dynamic programming, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Normalizing the Stone Piles
Medium7
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Moving on a Grid
Medium7
Combinatorics, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Ice Mage Dongwoo's Contest Review
Medium7
Hash map, Array+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Make Differences at Least M
Medium7
Dynamic programming, Segment tree+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Keep Differences at Most M
Medium7
Dynamic programming, Math+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Make the Difference M
Medium7
Dynamic programming, Hash map+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Plant Watering
Medium7
Greedy, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Card Flipping 2
Medium7
Segment tree, Simulation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Summer Driving
Medium7
Tree, Game theory+1
No attempts yet
Time limit
6s
Memory limit
1024 MB
Judgeable
Heavy Light Decomposition
Medium7
Dynamic programming, Hash map+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Maxwell's Demon
Medium7
Math, Simulation+1
No attempts yet
Time limit
6s
Memory limit
1024 MB
Judgeable
BipBop 커플
Medium7
String, String matching+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Decrease the Boss Strength
Medium7
Dynamic programming, Bit manipulation+1
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Bike Parking
Medium7
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Light Bulbs
Medium7
Combinatorics, Bit manipulation+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Efficient Slabstones Rearrangement
Medium7
Dynamic programming, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Fibonacci Lucky Numbers
Medium7
Number theory, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Game of Rounding
Medium7
Prefix sum, Divide and conquer+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Construct a Coin Set
Medium7
Greedy, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Graceful Triangles
Medium7
Math, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Hexagonal Tiling
Medium7
Graph, Matrix
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Jenga Game
Medium7
Game theory, Dynamic programming
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Travel
Medium7
Tree, Simulation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Colorful Trees
Medium7
Tree, Hash map+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Genetic Reconstruction
Medium7
Backtracking, Graph
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Repelling Monsters in the Magic Dungeon
Medium7
Greedy, Dynamic programming+1
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
Chance! 2
Medium7
BFS, Graph+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Insane Drift
Medium7
Math, Greedy+1
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
Confusion
Medium7
Graph, Dynamic programming+1
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Chaotic Cables
Medium7
Graph, BFS+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Baseball Court
Medium7
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Elapid Errands
Medium7
Simulation, Implementation+1
No attempts yet
Time limit
11s
Memory limit
1024 MB
Judgeable
Hotfix
Medium7
String, String matching
No attempts yet
Time limit
8s
Memory limit
1024 MB
Judgeable
Cowpproximation
Medium7
Binary search, Geometry+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Reptile Eggs
Medium7
Dynamic programming, String matching+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Fishception
Medium7
Geometry, Sorting
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Hamster
Medium7
Dynamic programming, Matrix+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
P||k Cutting
Medium7
Bit manipulation, Two pointers+1
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Kangaroo Race
Medium7
Math, Number theory
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Disgruntled Diner
Medium7
Graph, String+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Horse Habitat
Medium7
Matrix, Prefix sum+1
No attempts yet
Time limit
25s
Memory limit
2048 MB
Judgeable
GCD and Shortest Path
Medium7
Number theory, Graph+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Mole Hunt
Medium7
Number theory, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
A_i+A_j
Medium7
Graph, Shortest path+2
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Dongggatteungppung Game
Medium7
Tree, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
ZOAC 7
Medium7
Dynamic programming, Matrix
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
IK-WARM Virus
Medium7
Minimum spanning tree, Binary search+2
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Black and White Chef
Medium7
Dynamic programming, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Game of Death (Hard)
Medium7
Game theory, Graph+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Stone Game
Medium7
Game theory, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Red and Blue Points 3
Medium7
Geometry, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Big AND Circuit
Medium7
Tree, Greedy+2
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Rectangle Tiling
Medium7
Greedy, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Space Elevator
Medium7
Dynamic programming, Sorting+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Double Up 2
Medium7
Graph, Dynamic programming+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Wall Game
Medium7
Game theory, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Within Reach
Medium7
Geometry, Binary search+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Dimensional Tree Trip
Medium7
Tree, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Connecting Computers
Medium7
Graph, DFS+1
No attempts yet
Time limit
3s
Memory limit
2048 MB
Judgeable
Exact Change
Medium7
Math, Greedy+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
GCD Pairs
Medium7
Number theory, Math+1
No attempts yet
Time limit
5s
Memory limit
2048 MB
Judgeable
Homework Help
Medium7
Binary search, Divide and conquer+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Rainbow Bowl Ranges
Medium7
Math, Greedy+1
No attempts yet
Time limit
2s
Memory limit
2048 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Tour CourseGiven which tourists on a circular route end with affection at least 1, build a snowfield or desert pattern for the N segments, or report NO if none exists.	Medium7	Prefix sumString+1	No attempts yet	2s	1024 MB	Judgeable
Stone Placement GameOn a circle of valued cells, find each player's optimal score when they alternately place stones next to their own stones.	Medium7	GreedySorting+1	No attempts yet	1s	1024 MB	Judgeable
Distance Sum MaximizationGiven a tree, answer each query (u, v) by finding the maximum of dist(x,u) + dist(x,v) over all vertices x.	Medium7	TreeSegment tree+1	No attempts yet	3s	1024 MB	Judgeable
BamyanggaengFor each i, find the least possible largest grade among i disjoint horizontally or vertically adjacent cell pairs in an N by N grid.	Medium7	GraphMatrix+2	No attempts yet	2.5s	1024 MB	Judgeable
Reducing BoredomGiven a string of N zeros and N ones, find the fewest adjacent swaps so that every segment's count difference between 0s and 1s is at most K.	Medium7	Prefix sumGreedy+1	No attempts yet	1s	1024 MB	Judgeable
Broken CalculatorInsert parentheses into an expression so that a calculator with equal-priority + and * gives the intended value modulo P in every evaluation order.	Medium7	Dynamic programmingString+1	No attempts yet	1s	1024 MB	Judgeable
Dolphin PhotosGiven each dolphin's trick times over K hours, find the most dolphins Seungjin can photograph when each needs a camera installed earlier and each hour allows one action.	Medium7	GraphGreedy	No attempts yet	2s	1024 MB	Judgeable
CityGiven an N by N grid of developed and undeveloped regions with tourism values, pick K undeveloped regions to develop so the total value of the resulting cities is maximized.	Medium7	GraphDynamic programming+1	No attempts yet	4s	1024 MB	Judgeable
Good GridGiven an N by N grid of distinct numbers, find the fewest row and column swaps that make 1 to N*N follow a path of adjacent cells, or report -1.	Medium7	MatrixImplementation+1	No attempts yet	2s	1024 MB	Judgeable
A Tree Using TreesFor each vertex i, cut its subtree from the parent and reattach it to any vertex inside that subtree, then report the largest diameter possible.	Medium7	TreeDynamic programming+1	No attempts yet	2s	1024 MB	Judgeable
Split the SSHS 4For each vertex i, find the fewest bursts needed to clear the tree after a leaf is attached to i. A burst removes a vertex and all its neighbors.	Medium7	TreeDynamic programming+1	No attempts yet	2s	1024 MB	Judgeable
Grand Operation: Invasion of the Underground Secret BaseEach passage opens with any key type in its range [L, R]; for each query, decide whether rooms X and Y are connected using keys U through V.	Medium7	Union-findGraph+1	No attempts yet	3s	1024 MB	Judgeable
Computing the AverageGiven N integers (2 to 10) in registers, output at most 1000 pairwise-averaging operations that leave their mean in R2000 with error at most 1e-9.	Medium7	MathImplementation	No attempts yet	1s	1024 MB	Judgeable
Candy DeliveryFind the least total time for Anz to visit K houses on a down-right grid path, where each extra trip back to (1,1) costs C[N][M].	Medium7	Dynamic programmingGraph+1	No attempts yet	3s	1024 MB	Judgeable
Growing TreesEach day the shortest tree is doubled (leftmost on ties). For up to 10^9 days, find the K-th smallest height modulo 10^9+7.	Medium7	GreedyMath+2	No attempts yet	3s	1024 MB	Judgeable
POEMAssign numbers 1 to N to N positions so each range's product sign and sum parity match its contract, or print 0 if impossible.	Medium7	MathUnion-find+2	No attempts yet	1s	1024 MB	Judgeable
VirusGiven a bit string under range updates that map 0 and 1 to chosen bits, check after each update whether the string matches the regex (1(10)+1*\|0+10)+.	Medium7	Segment treeString matching	No attempts yet	2s	1024 MB	Judgeable
Cafeteria ServingEach student picks some foods from their list, and the next student cannot receive any food the previous one took. Find the maximum total happiness.	Medium7	Dynamic programmingSegment tree+1	No attempts yet	1s	1024 MB	Judgeable
The Final Destination of the GraphGiven a layered graph where each node's pointer rotates through its lower-grade children, find the node where the T-th run from the grade-1 node ends.	Medium7	GraphDynamic programming+1	No attempts yet	2s	1024 MB	Judgeable
Delicious Ruby ProblemChoose at most K cells of an N by M grid, no two sharing a side, to maximize the total value of the chosen cells.	Medium7	Dynamic programmingMatrix+1	No attempts yet	1s	1024 MB	Judgeable
Water Tank Job (Hard)Given a binary tree of water tanks with capacities, find the pump tank for m units of water that leaves the most tanks completely full.	Medium7	TreeDynamic programming+1	No attempts yet	3s	1024 MB	Judgeable
Building MATKOR StringsWith point updates on a string, count the ways to turn a substring into MATKOR using one delete and letter shifts, and print the variance of operation counts.	Medium7	Segment treeDynamic programming+1	No attempts yet	3s	1024 MB	Judgeable
Vault BreakerFind the fewest presses of A (add 1 to the whole number mod B^N) and B (add 1 to each digit mod B) that return the display to S, using both at least once.	Medium7	MathNumber theory	No attempts yet	1s	1024 MB	Judgeable
Super Shy (Hard)Given N empty seats, find the maximum number of people who can sit when each person takes the farthest available seat and the seating choices are made to maximize the count.	Medium7	RecursionDivide and conquer+1	No attempts yet	1s	1024 MB	Judgeable
Drawing Binary TreesCount the x-coordinate assignments for a binary tree's nodes in [1, V] that keep the left-below, right-above ordering and match the fixed values in A, modulo 444449.	Medium7	TreeDynamic programming+1	No attempts yet	1s	512 MB	Judgeable
Treasure Hunt GameFor each start vertex, decide whether Alice can force the token to hit treasure vertices infinitely often in a two-player token game on an undirected graph.	Medium7	GraphGame theory+1	No attempts yet	4s	1024 MB	Judgeable
Running Through Time (Rough)Given G and F, find the fewest moves from time 0 to time G using +1 or doubling, where any time at or above F wraps to its remainder mod F.	Medium7	BFSMath+1	No attempts yet	1s	1024 MB	Judgeable
Build the WorldBuild a simple connected graph on 3N vertices with 3M edges where every vertex has a prime degree, or report NO if impossible.	Medium7	GraphMath+1	No attempts yet	1s	1024 MB	Judgeable
Make the Minimum ValueBuild a permutation of 0 to N-1 that minimizes the sum of adjacent XORs, then minimizes the XOR of the first and last elements.	Medium7	Bit manipulationGreedy+1	No attempts yet	1s	1024 MB	Judgeable
Espresso Made Your WayGiven a customer's accepted range of coffee-to-milk ratios, find the fewest cups of ingredients that must be wasted when mixing half-full cups of pure coffee and pure milk to hit some ratio in that range.	Medium7	StackGreedy+2	No attempts yet	1s	1024 MB	Judgeable
Matching MentorsCount the ways to match students with mentors, each student and mentor used at most once, that maximize the minimum final skill across all students.	Medium7	Binary searchGreedy+2	No attempts yet	1s	1024 MB	Judgeable
Moving MarblesGiven start and target 0/1 grids, find the fewest moves to reach the target by sliding, removing, or placing marbles. Print -1 if impossible.	Medium7	GraphShortest path	No attempts yet	0.5s	1024 MB	Judgeable
TacticsFind the probability and average of X squared when the final score X of N random tactics is positive, and the same when it is negative, modulo 998244353.	Medium7	Brute forceSorting+2	No attempts yet	2s	1024 MB	Judgeable
ParaglidingGiven N paragliders with start points and heights, find the highest flying paraglider's height at each query position p_i to the right of the reference line, or 0 if none is flying.	Medium7	GeometrySorting+1	No attempts yet	3s	1024 MB	Judgeable
Trainee's LetterGiven N letter pages with M pages lost, the task is to find which of K names appear in the letter no matter which M pages are missing.	Medium7	String matchingDynamic programming	No attempts yet	3s	1024 MB	Judgeable
Draw A Perfect CircleGiven N points and a band width K, find the radius R maximizing the number of points whose distance from the origin lies in the band around R, and print the accuracy as a percentage.	Medium7	SortingTwo pointers+2	No attempts yet	1s	1024 MB	Judgeable
Growing HwaetbulGiven N daily foods with values A_i and at most k doublings, find the largest final size from initial size s, printing MEGA above 1e11 or -1 if Hwaetbul must die.	Medium7	Dynamic programmingGreedy+1	No attempts yet	1s	1024 MB	Judgeable
Normalizing the Stone PilesCount the permutations of piles for which the greedy rule (the player with fewer stones takes the next pile) leaves both players with equal totals, modulo 1,000,000,007.	Medium7	Dynamic programmingCombinatorics+1	No attempts yet	1s	1024 MB	Judgeable
Moving on a GridCount the shortest paths from (0,0) to (a,b) on a grid where some cells have diagonal roads of length sqrt(2), modulo 1e9+7.	Medium7	CombinatoricsDynamic programming+1	No attempts yet	1s	1024 MB	Judgeable
Ice Mage Dongwoo's Contest ReviewToggle reviewers in and out of contests, add x pain to every current reviewer of a contest, and report each reviewer's total pain.	Medium7	Hash mapArray+1	No attempts yet	1s	1024 MB	Judgeable
Make Differences at Least MGiven a sequence A and an integer M, find the fewest terms to change so every adjacent difference is at least M, or report -1 if impossible.	Medium7	Dynamic programmingSegment tree+1	No attempts yet	1s	1024 MB	Judgeable
Keep Differences at Most MFind the fewest elements to change so every adjacent pair differs by at most M, where each changed value can be any integer.	Medium7	Dynamic programmingMath+1	No attempts yet	3s	1024 MB	Judgeable
Make the Difference MGiven a sequence, find the fewest elements to change so that every pair of adjacent elements differs by exactly M.	Medium7	Dynamic programmingHash map+1	No attempts yet	3s	1024 MB	Judgeable
Plant WateringGiven N plants that wilt after a_i days without water (each a_i a power of 2), find the minimum number X of plants to water each day so that none wilts forever.	Medium7	GreedyMath+1	No attempts yet	1s	1024 MB	Judgeable
Card Flipping 2Each card i flips every later card j whose top face is smaller than card i's top face. Print the final top face of each card.	Medium7	Segment treeSimulation+1	No attempts yet	2s	1024 MB	Judgeable
Summer DrivingAlice and Bob move on a tree from city R, with Alice taking exactly A unused roads and Bob up to B roads per turn. Find their final city under optimal play.	Medium7	TreeGame theory+1	No attempts yet	6s	1024 MB	Judgeable
Heavy Light DecompositionCount the ways to split an array into contiguous parts where each part alternates between values that appear once and values that appear more than once, modulo 1,000,003.	Medium7	Dynamic programmingHash map+1	No attempts yet	4s	1024 MB	Judgeable
Maxwell's DemonFind the earliest time at which the demon can move all red particles into the left chamber and all blue particles into the right chamber.	Medium7	MathSimulation+1	No attempts yet	6s	1024 MB	Judgeable
BipBop 커플Given N moves, find the expected number of verses two random starts dance in sync before diverging or reaching the end, as a reduced fraction.	Medium7	StringString matching+2	No attempts yet	1s	1024 MB	Judgeable
Decrease the Boss StrengthCount the orderings of spell uses that bring N down to zero, where spell i subtracts a_i and needs N divisible by 2^b_i.	Medium7	Dynamic programmingBit manipulation+1	No attempts yet	1.5s	1024 MB	Judgeable
Bike ParkingAssign each user to one slot so that upvotes minus downvotes is maximized, given the slot count per tier and the user count per subscription level.	Medium7	GreedySorting+1	No attempts yet	1s	1024 MB	Judgeable
Light BulbsFind which N by N lamps to switch on, each lighting a full row or column, so every square is lit, using as few experiments as possible with lit-square counts as feedback.	Medium7	CombinatoricsBit manipulation+1	No attempts yet	4s	1024 MB	Judgeable
Efficient Slabstones RearrangementShift the n slabstones with the least total movement so a new slabstone of length x fits while every pair keeps at least d empty regions between them.	Medium7	Dynamic programmingGreedy+1	No attempts yet	2s	1024 MB	Judgeable
Fibonacci Lucky NumbersGiven n, output the last 10 digits of the Fibonacci number whose index is 7 raised to 7 raised to 7^n, for up to 20 test cases.	Medium7	Number theoryMath+1	No attempts yet	2s	1024 MB	Judgeable
Game of RoundingFor each start level l, find the segment starting at l whose rounded average is maximal, and report the shortest length that reaches it.	Medium7	Prefix sumDivide and conquer+1	No attempts yet	2s	1024 MB	Judgeable
Construct a Coin SetGiven N, build a coin set where greedy change-making is optimal for every amount below N but fails at N, or report -1 if none exists.	Medium7	GreedyDynamic programming+1	No attempts yet	1s	1024 MB	Judgeable
Graceful TrianglesGiven n, assign distinct positive values to the n+2 vertices of a triangle strip so that edge differences cover 1 to 2n+1 exactly once, or report -1.	Medium7	MathImplementation	No attempts yet	2s	1024 MB	Judgeable
Hexagonal TilingGiven a regular hexagon of side N split into unit triangles and a cost for each unit rhombus, find the minimum total cost to tile the hexagon completely.	Medium7	GraphMatrix	No attempts yet	4s	1024 MB	Judgeable
Jenga GameTwo players take turns removing blocks from a Jenga tower while it stays stable, and the player with no legal move loses. Output the winner for each test case.	Medium7	Game theoryDynamic programming	No attempts yet	1s	1024 MB	Judgeable
TravelYan walks a tree by always taking the first road in each city's list and moving that road to the end. Find the earliest day he visits all friends in order.	Medium7	TreeSimulation+1	No attempts yet	1s	1024 MB	Judgeable
Colorful TreesFor each edge of a vertex-colored tree, count the same-color vertex pairs whose connecting path passes through that edge.	Medium7	TreeHash map+1	No attempts yet	1s	1024 MB	Judgeable
Genetic ReconstructionGiven each creature's parents and eye color, find the alphabetically smallest pair of alleles per creature that fits inheritance and eye colors, or report -1.	Medium7	BacktrackingGraph	No attempts yet	4s	1024 MB	Judgeable
Repelling Monsters in the Magic DungeonBert starts at floor 0 and walks up or down to clear monsters, each costing w per hour until cleared; the task is to minimize total drained power over the walk.	Medium7	GreedyDynamic programming+1	No attempts yet	0.5s	1024 MB	Judgeable
Chance! 2Check, for each allowed spell count K, whether complex a can reach complex b using exactly K moves of +1, doubling, or multiplying by i.	Medium7	BFSGraph+1	No attempts yet	2s	1024 MB	Judgeable
Insane DriftGiven a target (X, Y), decide whether a car that doubles its step length on each repeated R or U can reach it in at most 4000 moves, and output a move sequence if so.	Medium7	MathGreedy+1	No attempts yet	0.5s	1024 MB	Judgeable
ConfusionCount the simple cycles in a triangulated convex polygon with N vertices, given its N-3 non-crossing diagonals, modulo 1e9+7.	Medium7	GraphDynamic programming+1	No attempts yet	5s	1024 MB	Judgeable
Chaotic CablesDecide whether a graph with n devices and m wires is a hypercube, where each edge joins two binary addresses that differ in exactly one bit.	Medium7	GraphBFS+1	No attempts yet	1s	1024 MB	Judgeable
Baseball CourtCount the ways to place all N unit tiles in an a by b plot so each outer corner tile lies at the same Manhattan distance from the south-west corner.	Medium7	Dynamic programmingCombinatorics+1	No attempts yet	4s	1024 MB	Judgeable
Elapid ErrandsFind a grid path from (0,0) that visits the N points (N up to 20) in the given order, ends at the last point, and never revisits a cell.	Medium7	SimulationImplementation+1	No attempts yet	11s	1024 MB	Judgeable
HotfixGiven a string of up to 10^6 ASCII letters, count how many times each letter appears in the output that lists every distinct substring with its occurrence count.	Medium7	StringString matching	No attempts yet	8s	1024 MB	Judgeable
CowpproximationGiven N circles that move at speed up to 1, find the earliest time at which all circles share a common point. Binary search on time with a circle intersection check.	Medium7	Binary searchGeometry+1	No attempts yet	4s	1024 MB	Judgeable
Reptile EggsFind the longest subsequence of the egg line that matches a regular expression with ?, *, brackets, and parentheses, or report -1 if none matches.	Medium7	Dynamic programmingString matching+1	No attempts yet	1s	1024 MB	Judgeable
FishceptionGiven N hole coordinates forming N/4 strictly nested rectangles, find the area of the innermost one.	Medium7	GeometrySorting	No attempts yet	1s	1024 MB	Judgeable
HamsterFind the largest total of larvae on a path from the northwest to the southeast corner of an N by M grid that never revisits a cell.	Medium7	Dynamic programmingMatrix+1	No attempts yet	2s	1024 MB	Judgeable
P\|\|k CuttingCount contiguous subarrays whose bitwise OR equals K, given N values up to 4 * 10^5 and K up to 10^9.	Medium7	Bit manipulationTwo pointers+1	No attempts yet	5s	1024 MB	Judgeable
Kangaroo RaceGiven a cyclic track of n segments and a kangaroo at segment x, find the fewest jumps of y(y-1) segments needed to reach segment 1, or report impossible.	Medium7	MathNumber theory	No attempts yet	5s	1024 MB	Judgeable
Disgruntled DinerGiven the order log and partly hidden pinned tickets, decide whether all tickets for table t are item m, or find the fewest tickets to flip to check it.	Medium7	GraphString+1	No attempts yet	2s	1024 MB	Judgeable
Horse HabitatGiven a grid of suitable and unsuitable cells, count how many all-suitable h by w rectangles fit in it, for each query.	Medium7	MatrixPrefix sum+1	No attempts yet	25s	2048 MB	Judgeable
GCD and Shortest PathCount the vertices x from 1 to N whose shortest-path distance to K in the coprime graph equals gcd(x, K).	Medium7	Number theoryGraph+1	No attempts yet	1s	1024 MB	Judgeable
Mole HuntGiven N mole holes with periods A_i and a target pattern B, find the smallest time T from 1 to L where each hole has a mole exactly when B_i is 1.	Medium7	Number theoryMath+1	No attempts yet	2s	1024 MB	Judgeable
A_i+A_jGiven a weighted directed graph, find the minimum A_i + A_j over pairs i < j that both lie on some shortest path from S to T.	Medium7	GraphShortest path+2	No attempts yet	5s	1024 MB	Judgeable
Dongggatteungppung GameFor each start vertex of a tree rooted at 1, decide whether first player Dongwoo wins the piece-moving game, where ties go to Hyukjun.	Medium7	TreeDynamic programming+2	No attempts yet	1s	1024 MB	Judgeable
ZOAC 7Given an N by M grid of Z, O, A, and C, find the maximum count of each letter on a right-or-down path from the top-left to the bottom-right cell that may teleport once.	Medium7	Dynamic programmingMatrix	No attempts yet	2s	1024 MB	Judgeable
IK-WARM VirusGiven a PC network with edge transmission times and per-PC hack costs, find the minimum total cost to infect every PC using at most K direct hacks.	Medium7	Minimum spanning treeBinary search+2	No attempts yet	1.5s	1024 MB	Judgeable
Black and White ChefGiven N steaks with thicknesses up to 25, find the minimum total grilling time so that both sides of every steak are cooked the same number of times and for the same total time.	Medium7	Dynamic programmingGreedy+1	No attempts yet	1s	1024 MB	Judgeable
Game of Death (Hard)Pick K from 10 to 99 so Hyeongjin, who chooses his passes, never ends up holding the turn at K=0 while the others pass at random.	Medium7	Game theoryGraph+1	No attempts yet	1s	1024 MB	Judgeable
Stone GameGiven a 1 by N board of black, white, and empty cells, decide whether the first player (black) wins, loses, or the game is a draw under optimal play.	Medium7	Game theoryGreedy+1	No attempts yet	1s	1024 MB	Judgeable
Red and Blue Points 3Given red and blue points with blue powers, draw a line so all red points lie on one side, and find the maximum total power of blue points on the other side.	Medium7	GeometrySorting+1	No attempts yet	1s	1024 MB	Judgeable
Big AND CircuitGiven N source signals with delays n_i, a gate delay D, and an LED delay L, build a tree of N-1 AND gates that minimizes the worst-case delay to flip the LED.	Medium7	TreeGreedy+2	No attempts yet	3s	1024 MB	Judgeable
Rectangle TilingGiven a W x H rectangle and counts of power-of-two squares, find the fewest squares that tile it exactly, or report -1 if no tiling exists.	Medium7	GreedyBit manipulation+1	No attempts yet	1s	1024 MB	Judgeable
Space ElevatorFind the minimum total distance an elevator starting at height H0 must travel to carry every request from its pickup height u to its drop height v.	Medium7	Dynamic programmingSorting+1	No attempts yet	2s	1024 MB	Judgeable
Double Up 2Each array element can be doubled mod M. Find the largest number of equal values reachable and the fewest doublings needed to make that many equal.	Medium7	GraphDynamic programming+2	No attempts yet	2s	1024 MB	Judgeable
Wall GameGiven N rows and 2 columns, find the number of moves needed to reach row N when one player places walls to delay the other under optimal play.	Medium7	Game theoryGreedy+1	No attempts yet	1s	1024 MB	Judgeable
Within ReachEach rectangle may be rotated around its center, and the task is to count how many can reach within distance R of the origin.	Medium7	GeometryBinary search+1	No attempts yet	1s	1024 MB	Judgeable
Dimensional Tree TripGiven a tree, find the longest sequence of distinct vertices where each step moves to a vertex not adjacent to the current one, counting the start as a warp.	Medium7	TreeDynamic programming+1	No attempts yet	1s	1024 MB	Judgeable
Connecting ComputersGiven a cactus graph of computers with typed cables, find the fewest cable types that keep all computers connected and count the subsets that do.	Medium7	GraphDFS+1	No attempts yet	3s	2048 MB	Judgeable
Exact ChangeGiven binary numbers a and b with up to 10^6 bits, find the fewest powers-of-two coins that let you pay every integer amount from a to b exactly.	Medium7	MathGreedy+1	No attempts yet	1s	2048 MB	Judgeable
GCD PairsCount the pairs of array elements whose gcd is squarefree, meaning not divisible by any x^2 with x greater than 1, where each element is at most 10^12.	Medium7	Number theoryMath+1	No attempts yet	5s	2048 MB	Judgeable
Homework HelpUsing queries that return the inversion count of any subarray of a hidden permutation, find the length of the permutation's longest increasing subsequence.	Medium7	Binary searchDivide and conquer+1	No attempts yet	1s	2048 MB	Judgeable
Rainbow Bowl RangesGiven n bowls in a circle and m colors with c_i balls each, place each color as a contiguous arc to maximize the number of maximal runs where every color appears exactly once.	Medium7	MathGreedy+1	No attempts yet	2s	2048 MB	Judgeable