Problems

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Total results21,380 problems

Polygon AreaHard8
Geometry, Dynamic programming +2No attempts yetTime limit1sMemory limit1024 MB
Judgeable
Dyson CircleHard8
Graph, Shortest path +1No attempts yetTime limit4sMemory limit1024 MB
Judgeable
Flatland OlympicsHard8
Geometry, Sorting +1No attempts yetTime limit4sMemory limit1024 MB
Judgeable
Burizon FortHard8
Number theory, Math +2No attempts yetTime limit1.4sMemory limit1024 MB
Judgeable
Screamers in the StormHard8
Dynamic programming, Math +2No attempts yetTime limit2sMemory limit1024 MB
Judgeable
Win DieselHard8
Graph, BFS +2No attempts yetTime limit1sMemory limit1024 MB
Judgeable
Finding the K-th Tasty Food 2Hard8
Binary search, Divide and conquer +2No attempts yetTime limit2sMemory limit512 MB
Judgeable
Valid Parenthesis StringHard8
Segment tree, Combinatorics +2No attempts yetTime limit2sMemory limit512 MB
Judgeable
Leaf MatchingHard8
Tree, Greedy +2No attempts yetTime limit1sMemory limit512 MB
Judgeable
Two-Step Shortest Path 3Hard8
Graph, Shortest path +2No attempts yetTime limit6sMemory limit1024 MB
Judgeable
Territory GrabHard8
BFS, Simulation +2No attempts yetTime limit0.5sMemory limit512 MB
Judgeable
Sequence (Hard)Hard8
Dynamic programming, Combinatorics +2No attempts yetTime limit1sMemory limit512 MB
Judgeable
Jegi KickingHard8
Binary search, Prefix sum +2No attempts yetTime limit1sMemory limit512 MB
Judgeable
F1ow3rC0nHard8
Segment tree, Array +2No attempts yetTime limit1sMemory limit512 MB
Judgeable
A Certain Milk Delivery List (Hard)Hard8
Tree, Dynamic programming +2No attempts yetTime limit2sMemory limit512 MB
Judgeable
WombatsHard8
Dynamic programming, Divide and conquer +1No attempts yetTime limit20sMemory limit256 MB
Judgeable
Bazza and ShazzaHard8
Segment tree, Dynamic programming +2No attempts yetTime limit13sMemory limit230 MB
Judgeable
Optimal TruckHard8
Greedy, Sorting +2No attempts yetTime limit2sMemory limit512 MB
Judgeable
Bookshelf SortingHard8
Array, Dynamic programming +2No attempts yetTime limit2sMemory limit512 MB
Judgeable
Garbage RobotHard8
Simulation, Math +1No attempts yetTime limit2sMemory limit512 MB
Judgeable
TicketsHard8
Shortest path, Segment tree +1No attempts yetTime limit2sMemory limit1024 MB
Judgeable
HILOHard8
Combinatorics, Math +2No attempts yetTime limit2sMemory limit1024 MB
Judgeable
HILOHard8
Simulation, Implementation +2No attempts yetTime limit2sMemory limit1024 MB
Judgeable
Closest Cow WinsHard8
Dynamic programming, Sorting +1No attempts yetTime limit2sMemory limit1024 MB
Judgeable
Composite Function and Queries 2Hard8
Graph, Binary search +2No attempts yetTime limit2sMemory limit512 MB
Judgeable
Locked DoorsHard8
Tree, Divide and conquer +2No attempts yetTime limit40sMemory limit1024 MB
Judgeable
Painters' DuelHard8
Game theory, Graph +1No attempts yetTime limit40sMemory limit1024 MB
Judgeable
Diverse SubarrayHard8
Divide and conquer, Array +2No attempts yetTime limit30sMemory limit1024 MB
Judgeable
Scrambled WordsHard8
String matching, Hash map +2No attempts yetTime limitNot setMemory limit1024 MB
Judgeable
Kickstart AlarmHard8
Math, Combinatorics +2No attempts yetTime limit90sMemory limit1024 MB
Judgeable
CandiesHard8
Array, Prefix sum +2No attempts yetTime limit40sMemory limit1024 MB
Judgeable
ParaglidingHard8
Dynamic programming, GeometryNo attempts yetTime limit40sMemory limit1024 MB
Judgeable
Funniest Word SearchHard8
String matching, Trie +2No attempts yetTime limit240sMemory limit1024 MB
Judgeable
Junghoon Wants to Eat Mint Chocolate Jajang RamenHard8
Graph, Shortest path +2No attempts yetTime limit2sMemory limit512 MB
Judgeable
Specializing VillagesHard8
Graph, Minimum spanning tree +2No attempts yetTime limit20sMemory limit1024 MB
Judgeable
Combining ClassesHard8
Binary search, Prefix sum +2No attempts yetTime limit180sMemory limit1024 MB
Judgeable
Let Me Count The WaysHard8
Combinatorics, Dynamic programming +2No attempts yetTime limit40sMemory limit1024 MB
Judgeable
Two CubesHard8
Binary search, Geometry +1No attempts yetTime limit20sMemory limit1024 MB
Judgeable
Tricky TriosHard8
Probability, Greedy +1No attempts yetTime limit20sMemory limit1024 MB
Judgeable
Seating ChartHard8
Combinatorics, Math +2No attempts yetTime limit20sMemory limit1024 MB
Judgeable
Three-Color GraphHard8
Binary search, Shortest path +2No attempts yetTime limit7sMemory limit1024 MB
Judgeable
Funnels and BeakersHard8
Segment tree, Intervals +1No attempts yetTime limit4sMemory limit1024 MB
Judgeable
Introductions OrganizationHard8
Graph, Shortest path +1No attempts yetTime limit40sMemory limit1024 MB
Judgeable
Theater Seat AssignmentHard8
Greedy, Binary search +2No attempts yetTime limit4sMemory limit1024 MB
Judgeable
Algorithm Class - Bubble Sort 6Hard8
Sorting, Simulation +2No attempts yetTime limit3sMemory limit512 MB
Judgeable
XCopyHard8
Bit manipulation, Matrix +1No attempts yetTime limit2sMemory limit1024 MB
Judgeable
DungeonsHard8
Bit manipulation, Graph +2No attempts yetTime limit2sMemory limit1024 MB
Judgeable
JoitterHard8
Graph, Greedy +2No attempts yetTime limit1sMemory limit1024 MB
Judgeable
KeycardsHard8
Combinatorics, Math +1No attempts yetTime limit1sMemory limit1024 MB
Judgeable
ReportHard8
Graph, DFS +2No attempts yetTime limit0.5sMemory limit1024 MB
Judgeable
UFO Airport (UFO) 3Hard8
Backtracking, Brute force +2No attempts yetTime limit1sMemory limit1024 MB
Judgeable
UFO Landing Field (UFO) 5Hard8
Brute force, Greedy +2No attempts yetTime limit1sMemory limit1024 MB
Judgeable
OrienteeringHard8
Dynamic programming, Graph +2No attempts yetTime limit1sMemory limit1024 MB
Judgeable
SengokuHard8
Geometry, Sorting +1No attempts yetTime limit0.75sMemory limit1024 MB
Judgeable
RegionsHard8
Binary search, Tree +2No attempts yetTime limit1sMemory limit1024 MB
Judgeable
Finals Venue (Finals)Hard8
Graph, Minimum spanning tree +2No attempts yetTime limit1sMemory limit1024 MB
Judgeable
PlugsHard8
Graph, Sorting +2No attempts yetTime limit1sMemory limit1024 MB
Judgeable
TerritoryHard8
Geometry, Graph +2No attempts yetTime limit1sMemory limit1024 MB
Judgeable
Starry SkyHard8
Sliding window, Segment tree +1No attempts yetTime limit3sMemory limit1024 MB
Judgeable
Cheating PreventionHard8
Binary search, Greedy +2No attempts yetTime limit1sMemory limit1024 MB
Judgeable
NightmanHard8
Geometry, Graph +2No attempts yetTime limit5sMemory limit1024 MB
Judgeable
Oldest Ruins 2Hard8
Dynamic programming, Geometry +2No attempts yetTime limit1.5sMemory limit1024 MB
Judgeable
ColoringHard8
Combinatorics, Math +2No attempts yetTime limit1sMemory limit512 MB
Judgeable
RotationHard8
Greedy, Array +2No attempts yetTime limit8sMemory limit1024 MB
Judgeable
One is zero, zero is oneHard8
Dynamic programming, String +1No attempts yetTime limit8sMemory limit1024 MB
Judgeable
SkeweringHard8
Geometry, Probability +1No attempts yetTime limit8sMemory limit1024 MB
Judgeable
Mountain RidgeHard8
Dynamic programming, Bit manipulation +1No attempts yetTime limit1sMemory limit1024 MB
Judgeable
Modusign CommuteHard8
Greedy, Intervals +2No attempts yetTime limit1sMemory limit512 MB
Judgeable
One-Dimensional ChessHard8
Trie, Prefix sum +2No attempts yetTime limit1sMemory limit512 MB
Judgeable
1D AnipangHard8
Dynamic programming, Segment tree +2No attempts yetTime limit2sMemory limit1024 MB
Judgeable
BombsHard8
Graph, BFS +2No attempts yetTime limit3sMemory limit1024 MB
Judgeable
MinersHard8
Tree, Dynamic programming +1No attempts yetTime limit1.5sMemory limit1024 MB
Judgeable
NewsHard8
Tree, DFS +2No attempts yetTime limit2sMemory limit1024 MB
Judgeable
LCS HintHard8
Dynamic programming, ImplementationNo attempts yetTime limit2sMemory limit1024 MB
Judgeable
DeliveryHard8
Greedy, Sorting +2No attempts yetTime limit2sMemory limit1024 MB
Judgeable
MonopolyHard8
Graph, Topological sort +2No attempts yetTime limit0.1sMemory limit1024 MB
Judgeable
Mini Bucket ListHard8
Combinatorics, Math +2No attempts yetTime limit1sMemory limit1024 MB
Judgeable
xor²Hard8
Bit manipulation, Segment tree +2No attempts yetTime limit1sMemory limit1024 MB
Judgeable
A Tree With More Root Nodes Is a Better TreeHard8
Tree, DFS +2No attempts yetTime limit2sMemory limit1024 MB
Judgeable
CircleHard8
Graph, Greedy +2No attempts yetTime limit2sMemory limit1024 MB
Judgeable
InfestationHard8
Tree, Segment tree +1No attempts yetTime limit2sMemory limit1024 MB
Judgeable
Music FestivalHard8
Graph, Sorting +1No attempts yetTime limit2.5sMemory limit1024 MB
Judgeable
RainHard8
Greedy, Array +2No attempts yetTime limit2sMemory limit1024 MB
Judgeable
Divide and OwnHard8
Number theory, Math +1No attempts yetTime limit1sMemory limit1024 MB
Judgeable
Most EqualHard8
Dynamic programming, String +2No attempts yetTime limit1sMemory limit1024 MB
Judgeable
PersistenceHard8
Brute force, Greedy +2No attempts yetTime limit1sMemory limit1024 MB
Judgeable
HUNTER×HUNTERHard8
Dynamic programming, GraphNo attempts yetTime limit1.7sMemory limit1024 MB
Judgeable
Matching ColorsHard8
Combinatorics, MathNo attempts yetTime limit0.4sMemory limit1024 MB
Judgeable
BiggestHard8
Sorting, Divide and conquer +1No attempts yetTime limit0.4sMemory limit1024 MB
Judgeable
RainHard8
Array, Sorting +2No attempts yetTime limit1sMemory limit1024 MB
Judgeable
Puang and the StarHard8
Graph, BFS +2No attempts yetTime limit3sMemory limit512 MB
Judgeable
Common FactorsHard8
Number theory, Math +1No attempts yetTime limit1sMemory limit1024 MB
Judgeable
Pizza Party!Hard8
Greedy, Graph +2No attempts yetTime limit3sMemory limit1024 MB
Judgeable
Taxis 2Hard8
Graph, BFS +2No attempts yetTime limit4sMemory limit1024 MB
Judgeable
K-th Shortest PathHard8
Graph, BFS +2No attempts yetTime limit1sMemory limit512 MB
Judgeable
Trade PlanHard8
Graph, Union-find +2No attempts yetTime limit4sMemory limit1024 MB
Judgeable
Caffeine AddictionHard8
Greedy, Sorting +2No attempts yetTime limit1sMemory limit1024 MB
Judgeable
Prison BreakHard8
Geometry, Sorting +2No attempts yetTime limit2sMemory limit512 MB
Judgeable
ŠarenlistHard8
Combinatorics, Tree +2No attempts yetTime limit1sMemory limit512 MB
Judgeable
Self StudyHard8
Binary search, Greedy +2No attempts yetTime limit1sMemory limit512 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Polygon AreaChoose at most K of N given points to form a simple polygon with maximum area, and print the area to one decimal place.	Hard8	GeometryDynamic programming+2	No attempts yet	1s	1024 MB	Judgeable
Dyson CircleGiven n unit-square stars on a grid, find the fewest unit squares forming a corner-connected ring that encloses all stars without edge leaks.	Hard8	GraphShortest path+1	No attempts yet	4s	1024 MB	Judgeable
Flatland OlympicsGiven a track segment and n seat locations, count the ordered pairs of visitors where one seat blocks the other's view of the track.	Hard8	GeometrySorting+1	No attempts yet	4s	1024 MB	Judgeable
Burizon FortA number m is practical when every integer from 1 to m-1 is a sum of distinct divisors of m; decide this for up to 100 values of m up to 10^12.	Hard8	Number theoryMath+2	No attempts yet	1.4s	1024 MB	Judgeable
Screamers in the StormCount sequences of length N with entries in 1..K where every adjacent pair is coprime, modulo 1e9+7, with N up to 1e18.	Hard8	Dynamic programmingMath+2	No attempts yet	2s	1024 MB	Judgeable
Win DieselDig channels in a Mars cave graph by repeatedly visiting the nearest, then safest, room; count the total channel traversals made along the way.	Hard8	GraphBFS+2	No attempts yet	1s	1024 MB	Judgeable
Finding the K-th Tasty Food 2Given three sorted arrays and queries (x, y, z, k), find the k-th smallest value among the first x, y, and z elements and report which array and index it came from.	Hard8	Binary searchDivide and conquer+2	No attempts yet	2s	512 MB	Judgeable
Valid Parenthesis StringA bracket string supports point flips and range queries that count how many ways the characters in [l, r] can be chosen so the whole string becomes a balanced parenthesis sequence.	Hard8	Segment treeCombinatorics+2	No attempts yet	2s	512 MB	Judgeable
Leaf MatchingA weighted tree grows by one leaf per query; after each insertion, report the minimum total distance pairing up all leaves, or -1 when the leaf count is odd.	Hard8	TreeGreedy+2	No attempts yet	1s	512 MB	Judgeable
Two-Step Shortest Path 3Find the shortest path from X to Z in a weighted undirected graph that visits at least three of the P given intermediate vertices.	Hard8	GraphShortest path+2	No attempts yet	6s	1024 MB	Judgeable
Territory GrabStarting from any 'A' cell, a growing rectangle piece can extend and then move each turn, avoiding 'X' cells; mark every cell it can ever cover as 'Y'.	Hard8	BFSSimulation+2	No attempts yet	0.5s	512 MB	Judgeable
Sequence (Hard)Sum the products A[B1]...A[BM] over all increasing index tuples B of length M whose chosen values are pairwise distinct, modulo 1e9+7.	Hard8	Dynamic programmingCombinatorics+2	No attempts yet	1s	512 MB	Judgeable
Jegi KickingChoose the smallest positive integer K so that applying the teacher's add/subtract rules to all scores makes the total at least S, or report -1 if no K works.	Hard8	Binary searchPrefix sum+2	No attempts yet	1s	512 MB	Judgeable
F1ow3rC0nMaintain an array of flower types under point updates and range queries. For each query, find the minimum number of glue bottles needed to attach petals to trees A through B in order, where each bottle covers one color but can be bought and discarded at will.	Hard8	Segment treeArray+2	No attempts yet	1s	512 MB	Judgeable
A Certain Milk Delivery List (Hard)On a tree, each order adds 1, 2, 3, ... along the path from u to v; after each order, report the running total at a queried node.	Hard8	TreeDynamic programming+2	No attempts yet	2s	512 MB	Judgeable
WombatsGiven an R by C grid where road segments hold wombat counts that change over time, find the fewest wombats on a southward path from the top row to a given bottom intersection.	Hard8	Dynamic programmingDivide and conquer+1	No attempts yet	20s	256 MB	Judgeable
Bazza and ShazzaMaintain a huge implicit grid where cells start at 0; support point assignments and range GCD queries over rectangles, with coordinates up to 1e9 and values up to 1e18.	Hard8	Segment treeDynamic programming+2	No attempts yet	13s	230 MB	Judgeable
Optimal TruckEach customer offers contracts pairing a minimum truck capacity with a profit, at most one per customer; for each target profit, find the smallest capacity reaching it.	Hard8	GreedySorting+2	No attempts yet	2s	512 MB	Judgeable
Bookshelf SortingGiven a permutation, repeatedly answer the minimum number of take-and-insert-at-ends moves to sort it, after each of q swaps of two positions.	Hard8	ArrayDynamic programming+2	No attempts yet	2s	512 MB	Judgeable
Garbage RobotGiven a room with one sofa, a robot's start cell and direction, count the cells where the robot leaves garbage before it shuts down, for each of q queries.	Hard8	SimulationMath+1	No attempts yet	2s	512 MB	Judgeable
TicketsFor each starting checkpoint, find the minimum total ticket price needed to reach both checkpoint 1 and checkpoint N, or -1 if impossible.	Hard8	Shortest pathSegment tree+1	No attempts yet	2s	1024 MB	Judgeable
HILOSum, over all permutations Elsie could guess with, the number of times the response string contains the substring HILO.	Hard8	CombinatoricsMath+2	No attempts yet	2s	1024 MB	Judgeable
HILOGiven a permutation Elsie uses to guess, count for every possible hidden integer x how many times the response string contains the substring HILO.	Hard8	SimulationImplementation+2	No attempts yet	2s	1024 MB	Judgeable
Closest Cow WinsGiven Nhoj's cow positions, place N of John's cows (not on Nhoj's cows) to maximize the total tastiness of patches John wins.	Hard8	Dynamic programmingSorting+1	No attempts yet	2s	1024 MB	Judgeable
Composite Function and Queries 2Maintain a function f on {1..N} under updates to f(1) and queries asking for the m-fold iterate f^m(x).	Hard8	GraphBinary search+2	No attempts yet	2s	512 MB	Judgeable
Locked DoorsGiven distinct door difficulties in a row of rooms, determine which room is visited K-th when starting from a given room and always opening the easier available door, for many queries.	Hard8	TreeDivide and conquer+2	No attempts yet	40s	1024 MB	Judgeable
Painters' DuelTwo painters alternate moving through a triangular grid of rooms, avoiding blocked rooms, and the task asks for the best score Alma can guarantee under optimal play.	Hard8	Game theoryGraph+1	No attempts yet	40s	1024 MB	Judgeable
Diverse SubarrayGiven an array of trinket types and a cap S, choose a contiguous interval maximizing the number of elements whose type appears at most S times in that interval.	Hard8	Divide and conquerArray+2	No attempts yet	30s	1024 MB	Judgeable
Scrambled WordsCount dictionary words that appear in a generated string, either as-is or with the middle letters permuted and first and last letters fixed.	Hard8	String matchingHash map+2	No attempts yet	Not set	1024 MB	Judgeable
Kickstart AlarmGiven a generated array and K, sum over i=1..K of the total i-th exponential-power of every contiguous subarray, modulo 1e9+7.	Hard8	MathCombinatorics+2	No attempts yet	90s	1024 MB	Judgeable
CandiesFind the maximum-sum contiguous subarray with at most O odd values and total sum at most D, where the values are generated by a linear recurrence.	Hard8	ArrayPrefix sum+2	No attempts yet	40s	1024 MB	Judgeable
ParaglidingGiven towers on the x-axis and balloons in the plane, find the most balloons Edge can collect by gliding at 45 degrees between towers.	Hard8	Dynamic programmingGeometry	No attempts yet	40s	1024 MB	Judgeable
Funniest Word SearchFind the subgrid of a letter grid that maximizes matched word length divided by width plus height, and count the subgrids that reach that maximum.	Hard8	String matchingTrie+2	No attempts yet	240s	1024 MB	Judgeable
Junghoon Wants to Eat Mint Chocolate Jajang RamenGiven a weighted graph and daily starting stores, follow the unique shortest path home (breaking ties toward larger next stores) and report the first store with stock that can sell one ramen, or -1.	Hard8	GraphShortest path+2	No attempts yet	2s	512 MB	Judgeable
Specializing VillagesAssign each village one of two foods so the average shortest distance to a village of the other food is minimized, and count the optimal assignments.	Hard8	GraphMinimum spanning tree+2	No attempts yet	20s	1024 MB	Judgeable
Combining ClassesGiven N score ranges and Q queries generated by linear recurrences, find the K-th largest score in the merged multiset and output the weighted sum of answers.	Hard8	Binary searchPrefix sum+2	No attempts yet	180s	1024 MB	Judgeable
Let Me Count The WaysCount permutations of 2N distinct people in a row so that none of M specified pairs sit adjacent, modulo 1e9+7.	Hard8	CombinatoricsDynamic programming+2	No attempts yet	40s	1024 MB	Judgeable
Two CubesFind the smallest integer edge length of two axis-parallel cubes so that every sphere lies completely inside at least one of the cubes.	Hard8	Binary searchGeometry+1	No attempts yet	20s	1024 MB	Judgeable
Tricky TriosGiven a face-down deck of 3N cards with three copies each of 1 to N, find the minimum expected number of rounds to remove every trio by flipping cards.	Hard8	ProbabilityGreedy+1	No attempts yet	20s	1024 MB	Judgeable
Seating ChartCount the distinct seating arrangements of N labeled people at K round tables with sizes differing by at most one, where only adjacency matters and table order is irrelevant.	Hard8	CombinatoricsMath+2	No attempts yet	20s	1024 MB	Judgeable
Three-Color GraphGiven a connected weighted graph whose edges are black, red, or blue, add up to X total increments to all red edges and all blue edges to maximize the shortest path from 1 to N.	Hard8	Binary searchShortest path+2	No attempts yet	7s	1024 MB	Judgeable
Funnels and BeakersGiven N stacked funnels that catch water over [L, R] and release it at [M, M+1], find how much water reaches each beaker in Q queries.	Hard8	Segment treeIntervals+1	No attempts yet	4s	1024 MB	Judgeable
Introductions OrganizationGiven which members already know each other, find the fewest minutes until each queried pair can know each other under the session rules, or -1 if it is impossible.	Hard8	GraphShortest path+1	No attempts yet	40s	1024 MB	Judgeable
Theater Seat AssignmentSeat each of the first K customers in a theater of N seats, where each picks the seat farthest from its nearest occupied seat.	Hard8	GreedyBinary search+2	No attempts yet	4s	1024 MB	Judgeable
Algorithm Class - Bubble Sort 6Given arrays A and B, decide whether bubble sort on A produces exactly B at some point within the first K adjacent swaps.	Hard8	SortingSimulation+2	No attempts yet	3s	512 MB	Judgeable
XCopyAssign distinct non-negative integers to each cell of an N by M grid so that neighboring cells differ by exactly one bit, minimizing the largest value used.	Hard8	Bit manipulationMatrix+1	No attempts yet	2s	1024 MB	Judgeable
DungeonsGiven a grid with several possible starting cells and hidden mines, find the most coins a player can guarantee without knowing the start.	Hard8	Bit manipulationGraph+2	No attempts yet	2s	1024 MB	Judgeable
JoitterGiven each user's diary visibility level and pairwise friendship costs, find the minimum number of friendship registrations so everyone can read all diaries, and the minimum cost for that count.	Hard8	GraphGreedy+2	No attempts yet	1s	1024 MB	Judgeable
KeycardsCount the subsets of the 2N possible keys (a nonempty collection) such that exactly K of the N positions are punched in every chosen key, modulo 1e9+7.	Hard8	CombinatoricsMath+1	No attempts yet	1s	1024 MB	Judgeable
ReportEach person reports job i to a fixed target, and the report keeps forwarding until a repeat. For each person, output how many distinct jobs' reports reached them before they start their own job.	Hard8	GraphDFS+2	No attempts yet	0.5s	1024 MB	Judgeable
UFO Airport (UFO) 3Place as many copies of a small B by D UFO shape as possible on a W by H grid so that each copy lies on landable cells and no two copies share an edge.	Hard8	BacktrackingBrute force+2	No attempts yet	1s	1024 MB	Judgeable
UFO Landing Field (UFO) 5Place as many small fixed-shape UFOs as possible in a grid of landable cells, with the twist that no two placed UFOs may share an edge.	Hard8	Brute forceGreedy+2	No attempts yet	1s	1024 MB	Judgeable
OrienteeringGiven a DAG whose edges go from lower to higher altitude, find two paths from 1 to N that together cover every checkpoint, minimizing the total length.	Hard8	Dynamic programmingGraph+2	No attempts yet	1s	1024 MB	Judgeable
SengokuCount the cells of an L by L grid covered by at least one of N diagonal watchmen, where a watchman at (x, y) covers every cell with \|x-i\| = \|y-j\|.	Hard8	GeometrySorting+1	No attempts yet	0.75s	1024 MB	Judgeable
RegionsSplit a weighted tree into M connected regions to minimize the largest region diameter, and output that minimum value.	Hard8	Binary searchTree+2	No attempts yet	1s	1024 MB	Judgeable
Finals Venue (Finals)Choose K cities as finals venues so that every contestant can reach one, minimizing total toll; sharing a road lets travelers split the cost, which reduces to a minimum spanning forest problem.	Hard8	GraphMinimum spanning tree+2	No attempts yet	1s	1024 MB	Judgeable
PlugsEach statement says no plug in index range [C,D] fits any company socket in [A,B]; recover the unique permutation matching plugs to companies.	Hard8	GraphSorting+2	No attempts yet	1s	1024 MB	Judgeable
TerritoryA recorded walk on a grid traces a closed curve; find the largest region enclosed by parts of the path, or 0 if none exists.	Hard8	GeometryGraph+2	No attempts yet	1s	1024 MB	Judgeable
Starry SkyFind the most stars one axis-aligned square can contain, where each star counts only if the square's side is at most that star's L value.	Hard8	Sliding windowSegment tree+1	No attempts yet	3s	1024 MB	Judgeable
Cheating PreventionGiven n adjustable-length devices that can each watch a horizontal or vertical strip with a chosen position p_i and length d_i, assign devices and settings so every applicant is watched both horizontally and vertically while minimizing the largest d_i.	Hard8	Binary searchGreedy+2	No attempts yet	1s	1024 MB	Judgeable
NightmanGiven up to 10 guards, 50 axis-aligned rectangular obstacles, and 10 query points in a rectangle, find the shortest obstacle-avoiding path from each query to its nearest guard and sum the doubled distances.	Hard8	GeometryGraph+2	No attempts yet	5s	1024 MB	Judgeable
Oldest Ruins 2Given N points with no three collinear, find the largest subset that forms a convex polygon and report its vertex count.	Hard8	Dynamic programmingGeometry+2	No attempts yet	1.5s	1024 MB	Judgeable
ColoringCount sequences of N cells where each cell takes one of two distinct color types from chosen bags i and j, summing over all pairs with i different from j.	Hard8	CombinatoricsMath+2	No attempts yet	1s	512 MB	Judgeable
RotationGiven a permutation, repeatedly rotate any contiguous block left or right at a cost equal to the block length; find the minimum total cost to sort it into increasing order.	Hard8	GreedyArray+2	No attempts yet	8s	1024 MB	Judgeable
One is zero, zero is onePick strings from set S to concatenate, then reorder the result into binary string t with the fewest adjacent swaps, ties broken lexicographically.	Hard8	Dynamic programmingString+1	No attempts yet	8s	1024 MB	Judgeable
SkeweringGiven N segments, pick a and b uniformly from (0,1] and find the probability that line ax+by=1 touches exactly i segments, reported as a modular value.	Hard8	GeometryProbability+1	No attempts yet	8s	1024 MB	Judgeable
Mountain RidgeGiven how many lower neighbors each cell has on an n by m grid, find the minimum and maximum height the top-left cell can have.	Hard8	Dynamic programmingBit manipulation+1	No attempts yet	1s	1024 MB	Judgeable
Modusign CommuteGiven intervals (planks) on a line, find the farthest reachable coordinate when each jump distance is bounded by the distance covered since the last landing.	Hard8	GreedyIntervals+2	No attempts yet	1s	512 MB	Judgeable
One-Dimensional ChessGiven N sequences, count for each queried value how often it appears as the last common element before two sequences first differ, over all pairs.	Hard8	TriePrefix sum+2	No attempts yet	1s	512 MB	Judgeable
1D AnipangEach round asks the minimum cost to make an array have no two adjacent equal-sign values, using flips costing R and increments costing C, with point updates across T+1 rounds.	Hard8	Dynamic programmingSegment tree+2	No attempts yet	2s	1024 MB	Judgeable
BombsGiven a multigraph with room 0 as the outside, find the fewest days to route k labeled bombs to their target rooms when each door and each bomb allows one crossing per day.	Hard8	GraphBFS+2	No attempts yet	3s	1024 MB	Judgeable
MinersMiners start at chambers in a rooted tree and walk down to descendants; find the maximum total path score, with each chamber capping the miners ending there.	Hard8	TreeDynamic programming+1	No attempts yet	1.5s	1024 MB	Judgeable
NewsOn a rooted tree, range updates and range count queries target nodes within k levels of a given node; both must be answered online over up to 2*10^5 operations.	Hard8	TreeDFS+2	No attempts yet	2s	1024 MB	Judgeable
LCS HintGiven two integer sequences up to 2 times 10^5 long, find a longest common subsequence while sending a short hint from a slow solver to a fast one.	Hard8	Dynamic programmingImplementation	No attempts yet	2s	1024 MB	Judgeable
DeliveryGiven N deliveries, each at a specific time and house on a line of 10^9 houses, find the minimum number of trucks that can start anywhere and serve all requests, moving at one house per unit time.	Hard8	GreedySorting+2	No attempts yet	2s	1024 MB	Judgeable
MonopolyGiven a directed graph with no 2-cycles or parallel edges, reverse some edges so the resulting graph has no directed cycles.	Hard8	GraphTopological sort+2	No attempts yet	0.1s	1024 MB	Judgeable
Mini Bucket ListCount the ways to place N tasks with given lengths into K unit time slots so that no two overlap, modulo 1e9+7.	Hard8	CombinatoricsMath+2	No attempts yet	1s	1024 MB	Judgeable
xor²Maintain an array under point XOR updates and queries that ask for the XOR of all A_i whose index i satisfies l <= (i xor x) <= r.	Hard8	Bit manipulationSegment tree+2	No attempts yet	1s	1024 MB	Judgeable
A Tree With More Root Nodes Is a Better TreeMaintain a mixed directed/undirected tree under edge-direction updates and after each update report how many nodes can reach all others.	Hard8	TreeDFS+2	No attempts yet	2s	1024 MB	Judgeable
CircleGiven a non-crossing chord set on a circle, color the N houses with the minimum number of colors so no chord has equal endpoints, and output one coloring.	Hard8	GraphGreedy+2	No attempts yet	2s	1024 MB	Judgeable
InfestationProcess infest, ultrasound, and clear events on a rooted tree, and report how many infested nodes lie in the subtree of each queried node.	Hard8	TreeSegment tree+1	No attempts yet	2s	1024 MB	Judgeable
Music FestivalPick one of two intervals for each performer so that no two picked intervals overlap, or report that no such choice exists.	Hard8	GraphSorting+1	No attempts yet	2.5s	1024 MB	Judgeable
RainGiven barrier heights in a box and a set of barriers whose heights may be raised by bounded amounts, find the minimum number of barriers to raise and the maximum water the box can then hold.	Hard8	GreedyArray+2	No attempts yet	2s	1024 MB	Judgeable
Divide and OwnFor each pair (a, b), you may move any prime factor from one number to the other; find the maximum achievable gcd.	Hard8	Number theoryMath+1	No attempts yet	1s	1024 MB	Judgeable
Most EqualGiven N strings over the first M letters, find a K-letter string P (distinct letters, order preserved) that appears as a subsequence in the most strings; report that count, the lexicographically smallest such P, and how many distinct P achieve it.	Hard8	Dynamic programmingString+2	No attempts yet	1s	1024 MB	Judgeable
PersistenceGiven a persistence P, find the smallest non-negative integer whose repeated digit-product process reaches a single digit in exactly P steps.	Hard8	Brute forceGreedy+2	No attempts yet	1s	1024 MB	Judgeable
HUNTER×HUNTERGiven each participant's target T and attachment L, find a badge distribution that maximizes the total attachment of participants who reach at least 2K points.	Hard8	Dynamic programmingGraph	No attempts yet	1.7s	1024 MB	Judgeable
Matching ColorsCount the red and blue fillings of an N by M grid where every cell has a same-colored cell in its row or column, modulo 1000000007.	Hard8	CombinatoricsMath	No attempts yet	0.4s	1024 MB	Judgeable
BiggestInteractive problem: find the positions of the K largest values in an unknown permutation using comparisons, where the first N-1 comparisons are free.	Hard8	SortingDivide and conquer+1	No attempts yet	0.4s	1024 MB	Judgeable
RainGiven the first N drop positions generated by a linear recurrence, find the earliest drop index after which every drop-free subinterval of the pot has length at most D.	Hard8	ArraySorting+2	No attempts yet	1s	1024 MB	Judgeable
Puang and the StarStart with a complete graph on N vertices, delete M given edges, then report the shortest distance from vertex 1 to every other vertex, or -1 if unreachable.	Hard8	GraphBFS+2	No attempts yet	3s	512 MB	Judgeable
Common FactorsGiven n up to 1e18, find the maximum over k in [2,n] of the fraction of integers in [1,k] that share a factor greater than 1 with k, and print it in lowest terms.	Hard8	Number theoryMath+1	No attempts yet	1s	1024 MB	Judgeable
Pizza Party!Given absolute topping requirements and Horn-style implications (conjunctions or disjunctions of toppings implying another), find the minimum number of toppings on a pizza that satisfies every preference.	Hard8	GreedyGraph+2	No attempts yet	3s	1024 MB	Judgeable
Taxis 2For each query town, find the minimum starting money needed to travel from town 1 along red (cost 1) and blue (halve, floor) taxi edges while staying at least 1 yen, or report Large if it exceeds L.	Hard8	GraphBFS+2	No attempts yet	4s	1024 MB	Judgeable
K-th Shortest PathGiven two L-digit numbers, list the K-th lexicographically shortest path between them in a graph where edges connect digits differing by 1 in one place.	Hard8	GraphBFS+2	No attempts yet	1s	512 MB	Judgeable
Trade PlanGiven an undirected graph where each city belongs to a state, answer queries whether two cities can be connected using only cities from the two states containing them.	Hard8	GraphUnion-find+2	No attempts yet	4s	1024 MB	Judgeable
Caffeine AddictionChoose the order to drink N energy drinks, each adding max(0, E_i - accumulated caffeine) awake seconds and C_i caffeine, maximizing total awake time.	Hard8	GreedySorting+2	No attempts yet	1s	1024 MB	Judgeable
Prison BreakGiven a convex polygon and points inside or outside it, count the polygon edges that no outside guard can see, where a guard sees an edge if it subtends a view that reaches the edge.	Hard8	GeometrySorting+2	No attempts yet	2s	512 MB	Judgeable
ŠarenlistCount the ways to color the edges of a tree with k colors so that each of m given paths contains at least two different colors, modulo 1e9+7.	Hard8	CombinatoricsTree+2	No attempts yet	1s	512 MB	Judgeable
Self StudyGiven N courses over M weeks, each class Bitaro either attends (gaining A_i in course i) or self-studies one course (gaining B_i); maximize the minimum final comprehension across all courses.	Hard8	Binary searchGreedy+2	No attempts yet	1s	512 MB	Judgeable