Problems

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Total results29,414 problems

Map Reduce (Small)
Hard8
BFS, Simulation+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Radioactive Islands (Small)
Hard8
Geometry, Math+2
No attempts yet
Time limit
30s
Memory limit
512 MB
Judgeable
Rebel Against the Empire (Large)
Hard8
Graph, Binary search+2
No attempts yet
Time limit
30s
Memory limit
512 MB
Judgeable
Go++ (Large)
Hard8
Implementation, Simulation+1
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
The Gardener of Seville (Small)
Hard8
Backtracking, Brute force+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Freeform Factory (Large)
Hard8
Graph, Greedy+1
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
String Table
Hard8
Dynamic programming, String+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
The Unscrupulous Kingdom
Hard8
Minimum spanning tree, Union-find+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Fleet
Hard8
Binary search, Graph+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Poklon
Hard8
Prefix sum, Hash map+1
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Strelice
Hard8
Graph, Greedy+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Parallelograms
Hard8
Geometry, Implementation+2
No attempts yet
Time limit
1s
Memory limit
64 MB
Judgeable
Piano
Hard8
String matching, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
64 MB
Judgeable
Palindromes and Queries 2
Hard8
String, String matching+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Semiexpress
Hard8
Greedy, Binary search+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Soccer
Hard8
Graph, Shortest path+2
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Wells
Hard8
Tree, Dynamic programming+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Rides 1
Hard8
Sorting, Binary search+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
People You May Know
Hard8
Graph, BFS+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Counting Cycles
Hard8
Graph, Matrix+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Cutting the Cake(?)
Hard8
Math, Greedy+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Subsequence Reversal
Hard8
Dynamic programming, Array+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Why Did the Cow Cross the Road 11
Hard8
Dynamic programming, Divide and conquer+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Tidying the Plush Toys
Hard8
Dynamic programming, Bit manipulation+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Sequence and Queries 18
Hard8
Segment tree, Sorting+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Pieces of Parentheses
Hard8
Dynamic programming, Greedy+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Stars in a Can
Hard8
Geometry, Brute force+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Stretching Streamers
Hard8
Dynamic programming, Combinatorics+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Blazing New Trails
Hard8
Minimum spanning tree, Graph+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Ski Resort
Hard8
Tree, Dynamic programming+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Raspad
Hard8
Dynamic programming, Divide and conquer+2
No attempts yet
Time limit
6s
Memory limit
1024 MB
Judgeable
Modern Art (Platinum)
Hard8
Implementation, Prefix sum+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
COWBASIC
Hard8
Implementation, Simulation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
The Rabbit's Escape Route
Hard8
Dynamic programming, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Taking Balls from Three Baskets
Hard8
Game theory, Combinatorics+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Balance Scale
Hard8
Combinatorics, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Too Many Traps
Hard8
Prefix sum, Array+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Protocol
Hard8
Math, Divide and conquer+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Communism
Hard8
Math, Backtracking+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Study Group
Hard8
Bit manipulation, Sliding window+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Heaven's Kitchen
Hard8
Minimum spanning tree, Union-find+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Scoreboard Tampering
Hard8
Greedy, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Weather Forecast
Hard8
Segment tree, Binary search+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Toppling Dominoes (Small)
Hard8
Dynamic programming, Sorting+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Dominoes (Large)
Hard8
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Segment Friends (Large)
Hard8
Graph, BFS+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
AI Tetris (Large)
Hard8
BFS, Simulation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Over Fitting (Large)
Hard8
Geometry, Sorting+2
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Monday Blues
Hard8
Graph, Minimum spanning tree+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Space Exploration
Hard8
Geometry, Sorting+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
The 3rd IUPC
Hard8
Number theory, Hash map+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Airport Construction
Hard8
Geometry, Brute force+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Get a Clue!
Hard8
Greedy, Simulation+1
No attempts yet
Time limit
4s
Memory limit
512 MB
Judgeable
Money for Nothing
Hard8
Divide and conquer, Geometry+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Flubber and Water Pipe Network
Hard8
Graph, Shortest path+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Visual Python++
Hard8
Sorting, Stack+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Yeongjeong's Big Cleanup
Hard8
Math, Implementation+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Yunho the Potion Thief
Hard8
Number theory, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Yeongseon takes the bait
Hard8
Tree, DFS+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Minimum Cost Flow
Hard8
Minimum spanning tree, Graph+2
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
RMT Subway Load Test
Hard8
Segment tree, Prefix sum+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Cartesian Conquest
Hard8
Math, Number theory+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Vera and Modern Art
Hard8
Math, Bit manipulation+2
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Nemmo Nemmo (Hard)
Hard8
Dynamic programming, Bit manipulation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Electronic devices
Hard8
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Tile Flipping (Hard)
Hard8
Math, Greedy+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Aztec Diamond
Hard8
Greedy, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Break Oven, Run Cookie!
Hard8
BFS, Binary search+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
God Game
Hard8
BFS, Graph+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Strange Solutions at Jeong Lab
Hard8
Geometry, Binary search+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Jerry and Tom
Hard8
Geometry, Graph+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Leftmost Segment
Hard8
Sorting, Binary search+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Map Labeling
Hard8
Dynamic programming, Sorting+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Studying for Exams
Hard8
Math, Greedy+2
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Two-Headed Cows
Hard8
Graph, Union-find+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Stable Neighbors
Hard8
Greedy, Implementation+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Pony Express (Large)
Hard8
Shortest path, Graph+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Core Training (Small2)
Hard8
Dynamic programming, Greedy+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Beaming With Joy
Hard8
Simulation, Implementation+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Shoot the Turrets (Small)
Hard8
BFS, Graph+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Shoot the Turrets (Large)
Hard8
BFS, Graph+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Good News and Bad News (Large)
Hard8
Graph, DFS+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Mountain Tour (Large)
Hard8
Graph, Dynamic programming+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Operation (Small)
Hard8
Brute force, Backtracking+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Card Operation (Large)
Hard8
Greedy, Sorting+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Smallest Graph with K Spanning Trees
Hard8
Graph, Dynamic programming+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Omnicircumnavigation (Small)
Hard8
Geometry, Math+1
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Stack Management (Large)
Hard8
Graph, Topological sort+2
No attempts yet
Time limit
20s
Memory limit
512 MB
Judgeable
Cups and Marbles
Hard8
Binary search, Sorting+2
No attempts yet
Time limit
4s
Memory limit
256 MB
Judgeable
Coin Combinations and Queries
Hard8
Dynamic programming, Combinatorics+2
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
doju
Hard8
Math, Number theory+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Binomial coefficient 6
Hard8
Number theory, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Grid paper and triangles
Hard8
Combinatorics, Math+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
GCD table and a contiguous subsequence
Hard8
Number theory, Math+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Product of GCDs
Hard8
Number theory, Math+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Sum of least common multiples
Hard8
Number theory, Math+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Standing in line
Hard8
Topological sort, Sorting+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
The Restless Cat
Hard8
Graph, DFS+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Gathering clams
Hard8
Dynamic programming, Prefix sum+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Horse tied outside the castle
Hard8
Geometry, Math+1
No attempts yet
Time limit
0.1s
Memory limit
16 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Map Reduce (Small)Given a walled grid with a start and finish, decide whether removing walls can make the shortest path exactly D, and if so output the map built by a fixed greedy removal procedure.	Hard8	BFSSimulation+2	No attempts yet	5s	512 MB	Judgeable
Radioactive Islands (Small)Find the minimum radiation dose for a boat crossing from (-10, A) to (10, B) at speed 1, given 1 unit/hour plus 1/D^2 per island at (0, C_i).	Hard8	GeometryMath+2	No attempts yet	30s	512 MB	Judgeable
Rebel Against the Empire (Large)Given moving asteroids, minimize the maximum jump distance so that no gap between jumps exceeds S seconds.	Hard8	GraphBinary search+2	No attempts yet	30s	512 MB	Judgeable
Go++ (Large)Decide whether two bounded Go++ programs can jointly print every good string while never printing the bad string, and construct them by the given rule.	Hard8	ImplementationSimulation+1	No attempts yet	5s	512 MB	Judgeable
The Gardener of Seville (Small)Fill an R by C grid with / and \ hedges so that each given pair of border courtiers is connected by a wall-free path, choosing the lexicographically smallest grid.	Hard8	BacktrackingBrute force+2	No attempts yet	5s	512 MB	Judgeable
Freeform Factory (Large)Given who can operate which machine, find the minimum number of single skill lessons so every machine always gets an operator for any arrival order and choice.	Hard8	GraphGreedy+1	No attempts yet	5s	512 MB	Judgeable
String TableBuild a table whose cells are huge concatenated strings defined by comparing neighbors, then print 50 characters from a given position of the final cell.	Hard8	Dynamic programmingString+2	No attempts yet	2s	512 MB	Judgeable
The Unscrupulous KingdomWith n points in the plane and m existing edges, add the fewest edges (segments that avoid other points) so the graph is connected while maximizing the sum of squared lengths.	Hard8	Minimum spanning treeUnion-find+2	No attempts yet	2s	512 MB	Judgeable
FleetFind the minimum thickness so that k ships can all travel from island 1 to island n within time T, where each waterway has a height limit and carries one ship per time unit.	Hard8	Binary searchGraph+2	No attempts yet	2s	512 MB	Judgeable
PoklonFor each query interval, count distinct values that occur exactly twice within it. N and Q go up to 500,000.	Hard8	Prefix sumHash map+1	No attempts yet	5s	512 MB	Judgeable
StreliceOn an arrow board, choose K non-last-column cells so that a robot starting anywhere in column 1 passes through exactly one of them or loops forever.	Hard8	GraphGreedy+1	No attempts yet	1s	512 MB	Judgeable
ParallelogramsGiven N points, produce a sequence of moves that translates one point to A+B-C each time, following a fixed published rule to bring every point into the first quadrant or report impossibility when all points are collinear.	Hard8	GeometryImplementation+2	No attempts yet	1s	64 MB	Judgeable
PianoGiven N equally likely piano tones, find the expected number of presses until a fixed M-tone sequence appears, for every prefix of it.	Hard8	String matchingDynamic programming+2	No attempts yet	1s	64 MB	Judgeable
Palindromes and Queries 2Given a string and queries, each query asks how many palindromic substrings start at a given index with length at least a given value.	Hard8	StringString matching+2	No attempts yet	2s	512 MB	Judgeable
SemiexpressChoose exactly K stops for a new train so that the number of stations reachable from station 1 within T minutes is maximized.	Hard8	GreedyBinary search+1	No attempts yet	1s	256 MB	Judgeable
SoccerFind the minimum total fatigue for moving a soccer ball from player 1 to player N using kicks, walks, and player handoffs.	Hard8	GraphShortest path+2	No attempts yet	3s	256 MB	Judgeable
WellsOn a tree where placing wells at a vertex counts for it and its direct neighbors, find the minimum number of wells so every village's demand is met.	Hard8	TreeDynamic programming+2	No attempts yet	2s	256 MB	Judgeable
Rides 1Each day one child grows by 1 cm; after each growth, count how many of Q given pairs (i,j) can ride their specified ride, where the pair's combined height meets the ride's limit.	Hard8	SortingBinary search+2	No attempts yet	2s	256 MB	Judgeable
People You May KnowGiven a friendship graph, find the minimum number of vertices to delete so that A and B are no longer 3-friends under the given n-friend definition.	Hard8	GraphBFS+2	No attempts yet	2s	512 MB	Judgeable
Counting CyclesCount all closed walks (cycles) of length less than K in a directed graph, where rotations count separately, modulo M.	Hard8	GraphMatrix+2	No attempts yet	2s	512 MB	Judgeable
Cutting the Cake(?)Find the minimum number of straight parallel-plane cuts needed so N people can each receive equal bread and equal cream from a square-topped rectangular loaf.	Hard8	MathGreedy+1	No attempts yet	2s	512 MB	Judgeable
Subsequence ReversalReverse one subsequence of a length-N array, then find the longest non-decreasing subsequence length achievable.	Hard8	Dynamic programmingArray+2	No attempts yet	2s	512 MB	Judgeable
Why Did the Cow Cross the Road 11Given a permutation of breeds on each side of a road, connect pairs whose breed numbers differ by at most 4 using non-crossing edges, maximizing the count.	Hard8	Dynamic programmingDivide and conquer+2	No attempts yet	2s	512 MB	Judgeable
Tidying the Plush ToysGiven a row of N toys of M types, find the fewest toys to remove so that after reinserting them all toys of each type form one contiguous block.	Hard8	Dynamic programmingBit manipulation+1	No attempts yet	2s	512 MB	Judgeable
Sequence and Queries 18Maintain an array under point updates and answer range queries counting elements greater than k.	Hard8	Segment treeSorting+2	No attempts yet	2s	512 MB	Judgeable
Pieces of ParenthesesGiven n pieces of parentheses, choose and order some pieces to build the longest balanced parenthesis string.	Hard8	Dynamic programmingGreedy+1	No attempts yet	2s	512 MB	Judgeable
Stars in a CanPlace all n points in 3D inside one cylinder of any orientation, with at least three stars on one base, and print the minimum possible volume.	Hard8	GeometryBrute force+2	No attempts yet	2s	512 MB	Judgeable
Stretching StreamersCount ways to draw non-crossing chords among n points on a circle so the graph is a tree, edges only between numbers sharing a factor.	Hard8	Dynamic programmingCombinatorics+2	No attempts yet	2s	512 MB	Judgeable
Blazing New TrailsChoose a spanning tree of a graph whose edges each join a marked or unmarked vertex, with exactly w marked-unmarked edges, minimizing total cost.	Hard8	Minimum spanning treeGraph+2	No attempts yet	2s	512 MB	Judgeable
Ski ResortFor each query, count the size-k sets of areas such that every favorite area has exactly one stocked area lying on every path from the top, and all chosen areas lie on paths to favorite areas.	Hard8	TreeDynamic programming+2	No attempts yet	2s	512 MB	Judgeable
RaspadSum the number of connected components of 1-cells over every contiguous band of rows in an n by m grid, with m at most 50 and n up to 100000.	Hard8	Dynamic programmingDivide and conquer+2	No attempts yet	6s	1024 MB	Judgeable
Modern Art (Platinum)Given the final N x N canvas painted by N^2 nested rectangles, count how many colors could have been painted first.	Hard8	ImplementationPrefix sum+1	No attempts yet	2s	512 MB	Judgeable
COWBASICInterpret a tiny language of assignments, nested fixed-count MOO loops, and one RETURN, all additions taken modulo 10^9+7, and print the returned value.	Hard8	ImplementationSimulation+2	No attempts yet	2s	512 MB	Judgeable
The Rabbit's Escape RouteCount self-avoiding walks on a 3 by N grid from the top left cell to the bottom right cell, modulo 1e9+9.	Hard8	Dynamic programmingCombinatorics+2	No attempts yet	1s	256 MB	Judgeable
Taking Balls from Three BasketsCount triples of baskets (chosen from N) where the second player wins the subtraction game on three piles with move limit M.	Hard8	Game theoryCombinatorics+2	No attempts yet	2s	256 MB	Judgeable
Balance ScaleCount the orders and pan choices for placing weights 2^1 through 2^N so the left pan never outweighs the right, modulo 1e9+9.	Hard8	CombinatoricsDynamic programming+2	No attempts yet	1s	256 MB	Judgeable
Too Many TrapsGiven N shoe propulsions and M futon positions on a line, find an order of all shoes whose prefix sums avoid every futon, or report -1.	Hard8	Prefix sumArray+1	No attempts yet	1s	256 MB	Judgeable
ProtocolStarting from one wire of capacity N, each year every wire splits into two wires transformed by two quadratic polynomials, and after M years we need the sum of 112345 raised to each wire's capacity, mod 1e9+9.	Hard8	MathDivide and conquer+2	No attempts yet	2s	256 MB	Judgeable
CommunismAssign each of N jobs to one of three people so that Ad's total and Larry's total differ by at most D, and count the assignments.	Hard8	MathBacktracking+2	No attempts yet	1s	512 MB	Judgeable
Study GroupGiven students with skill values and sets of known algorithms, pick a group whose skill range is at most D to maximize (union size minus intersection size) times group size.	Hard8	Bit manipulationSliding window+2	No attempts yet	2s	128 MB	Judgeable
Heaven's KitchenChoose match order and winners so a knockout tournament maximizes summed floor((Ci+Cj)/\|Pi-Pj\|), then output the unique bracket fixed by the stated tie-breaking rules.	Hard8	Minimum spanning treeUnion-find+2	No attempts yet	1s	128 MB	Judgeable
Scoreboard TamperingGiven the frozen scoreboard and all remaining submission logs, decide whether B can share or reassign them to end strictly ahead of A, and output the lexicographically smallest plan.	Hard8	GreedyImplementation+2	No attempts yet	1s	128 MB	Judgeable
Weather ForecastMaintain N snow depths under point increments and decrements, then answer range-count queries (depth between L and R) and T-th largest value queries online.	Hard8	Segment treeBinary search+2	No attempts yet	2s	128 MB	Judgeable
Toppling Dominoes (Small)Sort the dominoes by position and find the minimum number of manual pushes so that chains topple every domino.	Hard8	Dynamic programmingSorting+1	No attempts yet	1s	512 MB	Judgeable
Dominoes (Large)Find the fewest pushes (each a domino plus a direction) needed to topple every domino through chain reactions.	Hard8	GreedySorting+2	No attempts yet	1s	512 MB	Judgeable
Segment Friends (Large)Given N segments on a line, build the intersection graph and answer Q shortest-path queries between segment pairs, or report -1.	Hard8	GraphBFS+2	No attempts yet	2s	256 MB	Judgeable
AI Tetris (Large)Given a fixed 20 by 10 board, find the most rows a single auto-placed tetromino can clear, allowing it to slide sideways and tuck under overhangs before it settles.	Hard8	BFSSimulation+2	No attempts yet	1s	512 MB	Judgeable
Over Fitting (Large)Given N labeled points in the plane, find a line whose positive half-plane contains only LOVELYZ points and maximizes how many LOVELYZ points it captures.	Hard8	GeometrySorting+2	No attempts yet	3s	512 MB	Judgeable
Monday BluesGiven an N by M grid with costly buildable cells and blocked or unbuildable cells, find the minimum total cost to cut every path from (1,1) to (N,M), or report that no placement can do it.	Hard8	GraphMinimum spanning tree+2	No attempts yet	1s	512 MB	Judgeable
Space ExplorationGiven N segment obstacles in the first quadrant and M rays from the origin, count how many segments no ray intersects, including exact endpoint touches.	Hard8	GeometrySorting+1	No attempts yet	2s	256 MB	Judgeable
The 3rd IUPCCount how many distinct values appear among all A_i times B_i^p for p = 0..C_i, across N lines with huge exponents.	Hard8	Number theoryHash map+2	No attempts yet	2s	256 MB	Judgeable
Airport ConstructionGiven a simple polygon with up to 200 vertices, find the longest line segment that lies entirely inside it.	Hard8	GeometryBrute force+1	No attempts yet	2s	512 MB	Judgeable
Get a Clue!Given your Cluedo hand and a log of suggestions with evidence responses, deduce which of the murderer, weapon, and room cards you can be certain of.	Hard8	GreedySimulation+1	No attempts yet	4s	512 MB	Judgeable
Money for NothingPick one producer and one consumer to maximize (q-p)(e-d) over pairs where q>p and e>d, with up to 500000 of each.	Hard8	Divide and conquerGeometry+2	No attempts yet	5s	512 MB	Judgeable
Flubber and Water Pipe NetworkSend two viscous liquids through one shared bidirectional network with a linear capacity constraint and maximize F^a W^(1-a) at the destination.	Hard8	GraphShortest path+2	No attempts yet	5s	512 MB	Judgeable
Visual Python++Match n top-left corners to n bottom-right corners so the rectangles form properly nested or disjoint blocks, or report a syntax error.	Hard8	SortingStack+2	No attempts yet	5s	512 MB	Judgeable
Yeongjeong's Big CleanupMold spreads diagonally every hour on an N x M grid, moving to the four diagonal neighbors and leaving its old cell; decide whether it ever covers the entire floor.	Hard8	MathImplementation+1	No attempts yet	1s	512 MB	Judgeable
Yunho the Potion ThiefEach bought potion yields at most one divisor, and divisors chosen across potions must share no prime factor; maximize how many such divisors can be extracted.	Hard8	Number theoryDynamic programming+2	No attempts yet	1s	512 MB	Judgeable
Yeongseon takes the baitOn a tree, count alternating left/right paths from a fixed start where each vertex is used once; report the maximum over all starting vertices.	Hard8	TreeDFS+2	No attempts yet	1s	512 MB	Judgeable
Minimum Cost FlowGiven a spanning tree and extra edges, with a one-pipe discount available, find the minimum number of edge swaps to reach a minimum-cost spanning tree.	Hard8	Minimum spanning treeGraph+2	No attempts yet	3s	512 MB	Judgeable
RMT Subway Load TestEach subway line is a cycle of stations; line operations rotate passenger counts around the cycle, and range-sum surveys must be answered online.	Hard8	Segment treePrefix sum+2	No attempts yet	5s	512 MB	Judgeable
Cartesian ConquestA rectangle N by M must be tiled by rectangles with side ratio 2:1, added one at a time so the union stays a rectangle; find the min and max tile counts.	Hard8	MathNumber theory+2	No attempts yet	2s	512 MB	Judgeable
Vera and Modern ArtEach of N paint drops covers a lattice of points with power-of-two steps; answer Q queries for the total colour sum at a given point.	Hard8	MathBit manipulation+2	No attempts yet	4s	1024 MB	Judgeable
Nemmo Nemmo (Hard)Count subsets of occupied cells in an N by M grid (N times M at most 300) that contain no full 2 by 2 square, modulo 1e9+7.	Hard8	Dynamic programmingBit manipulation+2	No attempts yet	2s	512 MB	Judgeable
Electronic devicesAssign distinct power supplies to components so every device i gets at least Y_i working components, with a supply's chosen power matching the component's exact requirement, and output the lexicographically smallest connection list.	Hard8	GreedySorting+2	No attempts yet	1s	512 MB	Judgeable
Tile Flipping (Hard)Fill the free tiles so that flipping every black tile once leaves the whole board white, choosing the lexicographically smallest result or reporting impossibility.	Hard8	MathGreedy+2	No attempts yet	1s	512 MB	Judgeable
Aztec DiamondGiven a domino tiling of an Aztec diamond, find the shortest sequence of 2x2 rotations that turns all bricks vertical, lexicographically smallest.	Hard8	GreedySimulation+2	No attempts yet	1s	128 MB	Judgeable
Break Oven, Run Cookie!Cookies on a grid move simultaneously, each at most one cell per second, and each must reach a distinct weak cell that then becomes a permanent obstacle; find the minimum escape time.	Hard8	BFSBinary search+2	No attempts yet	1s	256 MB	Judgeable
God GameFind the minimum time for a ball on an N by M grid to reach the goal while dodging obstacles that loop clockwise around small squares forever.	Hard8	BFSGraph+2	No attempts yet	1s	512 MB	Judgeable
Strange Solutions at Jeong LabGiven a growing set of (A,B) pairs, decide each day whether the new pair is dominated by or lies on the segment between two existing points.	Hard8	GeometryBinary search+2	No attempts yet	1s	512 MB	Judgeable
Jerry and TomDecide whether every mouse can be assigned to a visible hole on the polygon boundary, with each hole holding at most k mice.	Hard8	GeometryGraph+2	No attempts yet	1s	512 MB	Judgeable
Leftmost SegmentGiven n segments spanning two horizontal lines, answer m queries asking which segment meets a horizontal line at the leftmost point, breaking ties by the upper endpoint.	Hard8	SortingBinary search+2	No attempts yet	1s	512 MB	Judgeable
Map LabelingPlace disjoint unit-height labels on a line above given points and count the minimum number of connectors that cannot run straight down to their own label.	Hard8	Dynamic programmingSorting+2	No attempts yet	1s	512 MB	Judgeable
Studying for ExamsDistribute up to T hours among N subjects to maximize the average of concave quadratic grade functions, with continuous time and exact rounding.	Hard8	MathGreedy+2	No attempts yet	3s	512 MB	Judgeable
Two-Headed CowsN cows each have two heads, and M dislike pairs require that those heads face opposite troughs. Split the cows into the fewest consecutive blocks that each admit a valid orientation.	Hard8	GraphUnion-find+1	No attempts yet	2s	512 MB	Judgeable
Stable NeighborsPlace given counts of six mane colors around a ring so that no two neighbors share a base hair color, and output the lexicographically smallest valid arrangement.	Hard8	GreedyImplementation+2	No attempts yet	5s	512 MB	Judgeable
Pony Express (Large)For each of Q deliveries, find the minimum travel time using horses of limited endurance, allowing instant horse swaps at cities.	Hard8	Shortest pathGraph+2	No attempts yet	5s	512 MB	Judgeable
Core Training (Small2)Distribute U training units among N cores, each unit adding 1 to a core's success probability (capped at 1), to maximize the chance that at least K cores succeed.	Hard8	Dynamic programmingGreedy+2	No attempts yet	5s	512 MB	Judgeable
Beaming With JoyDecide which beam shooters to rotate 90 degrees so every empty cell is lit and no shooter is destroyed, outputting the lexicographically smallest valid grid.	Hard8	SimulationImplementation+2	No attempts yet	5s	512 MB	Judgeable
Shoot the Turrets (Small)With each soldier walking at most M steps on a grid with walls, find the maximum number of turrets that can be destroyed, given line-of-sight firing rules and turret-firing-on-exit timing.	Hard8	BFSGraph+2	No attempts yet	5s	512 MB	Judgeable
Shoot the Turrets (Large)Soldiers on a grid with buildings each get one bullet and a move budget; find the maximum number of turrets that can be destroyed, accounting for turrets that block cells until destroyed.	Hard8	BFSGraph+2	No attempts yet	5s	512 MB	Judgeable
Good News and Bad News (Large)Assign a nonzero integer to each directed edge so every vertex's outgoing sum equals its incoming sum, exactly as built by a prescribed DFS cycle-circulation procedure.	Hard8	GraphDFS+2	No attempts yet	5s	512 MB	Judgeable
Mountain Tour (Large)Given a directed graph where each camp has exactly two departing and two arriving tours with daily departure hours and durations, find the fastest route that uses every tour once and returns to camp 1.	Hard8	GraphDynamic programming+2	No attempts yet	5s	512 MB	Judgeable
Operation (Small)Given a start value S and up to 15 operation cards, order all cards to maximize the final rational result, printed as an irreducible fraction with positive denominator.	Hard8	Brute forceBacktracking+2	No attempts yet	5s	512 MB	Judgeable
Card Operation (Large)Order a set of arithmetic cards applied to a starting value to maximize the final rational result, printed as a reduced fraction.	Hard8	GreedySorting+2	No attempts yet	5s	512 MB	Judgeable
Smallest Graph with K Spanning TreesFind the smallest node count of a graph built by the move/attach process whose spanning tree count equals K, for K up to 10000.	Hard8	GraphDynamic programming+2	No attempts yet	5s	512 MB	Judgeable
Omnicircumnavigation (Small)Given points on a sphere visited in order, decide whether the closed path along shortest arcs meets every great circle (every hemisphere) on the sphere.	Hard8	GeometryMath+1	No attempts yet	5s	512 MB	Judgeable
Stack Management (Large)Given several stacks of cards, decide whether a sequence of suit-based removals and moves to empty stacks can reduce every stack to at most one card.	Hard8	GraphTopological sort+2	No attempts yet	20s	512 MB	Judgeable
Cups and MarblesAfter m range-sort spells (ascending or descending) on a permutation, report the marble in the middle cup.	Hard8	Binary searchSorting+2	No attempts yet	4s	256 MB	Judgeable
Coin Combinations and QueriesFor each query, count the multisets of at most d_i coins of denomination c_i (i=1..4) that sum to exactly v; answers fit in 64-bit.	Hard8	Dynamic programmingCombinatorics+2	No attempts yet	3s	512 MB	Judgeable
dojuCount increasing sequences of distinct integers within bounds for which both wrong formulas a_n/g and a_n-n give the wrong parity, modulo q.	Hard8	MathNumber theory+2	No attempts yet	2s	512 MB	Judgeable
Binomial coefficient 6For up to 100,000 queries, compute the binomial coefficient C(N,K) modulo 142857 where N goes up to 1e9.	Hard8	Number theoryCombinatorics+1	No attempts yet	2s	512 MB	Judgeable
Grid paper and trianglesCount ordered triples of lattice points in a (w+1) by (h+1) grid whose triangle has positive integer area, modulo 1e9+7.	Hard8	CombinatoricsMath+2	No attempts yet	2s	512 MB	Judgeable
GCD table and a contiguous subsequenceGiven n, m, k and a sequence a, decide whether some row i of the GCD matrix G[i][j] = gcd(i, j) contains a as a contiguous run of columns.	Hard8	Number theoryMath+2	No attempts yet	2s	512 MB	Judgeable
Product of GCDsCompute the product of gcd(i, j) over all pairs 1<=i<=N, 1<=j<=M, modulo 1e9+7, with N and M up to 15 million.	Hard8	Number theoryMath+2	No attempts yet	5s	512 MB	Judgeable
Sum of least common multiplesSum lcm(x, y) over all pairs 1<=x<=n, 1<=y<=m that share no squared prime factor.	Hard8	Number theoryMath+2	No attempts yet	2s	512 MB	Judgeable
Standing in lineGiven a partial order of comparisons between students in line, recover a card permutation consistent with all pairs or print -1.	Hard8	Topological sortSorting+2	No attempts yet	2s	512 MB	Judgeable
The Restless CatIn a connected, planar, simple graph with a guaranteed cycle, find rooms whose single-vertex deletion leaves the graph acyclic (a forest), summing their indices.	Hard8	GraphDFS+1	No attempts yet	2s	512 MB	Judgeable
Gathering clamsGiven an N by N grid of clam limits, compute after each of N single-cell +1/-1 updates the sum over all cells of the maximum-weight monotone staircase path to the top-left.	Hard8	Dynamic programmingPrefix sum+1	No attempts yet	2s	512 MB	Judgeable
Horse tied outside the castleGiven a convex polygon and an exterior point with rope length L, compute the area reachable when the rope bends around polygon vertices and the two wrapping directions do not overlap.	Hard8	GeometryMath+1	No attempts yet	0.1s	16 MB	Judgeable