Problems

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Total results21,331 problems

Robot InstructionsHard8
Divide and conquer, Hash map +2No attempts yetTime limit4sMemory limit1024 MB
Judgeable
Substrings and SubsequencesHard8
String, Combinatorics +2No attempts yetTime limit1sMemory limit512 MB
Judgeable
If We Add Them Up...Hard8
Math, Number theory +1No attempts yetTime limit1sMemory limit512 MB
Judgeable
Journey in FogHard8
Probability, Greedy +1No attempts yetTime limit2sMemory limit512 MB
Judgeable
Destructive GameHard8
Game theory, Math +2No attempts yetTime limit2sMemory limit1024 MB
Judgeable
Game with Balls and BoxesHard8
Graph, Greedy +2No attempts yetTime limit2sMemory limit1024 MB
Judgeable
Items and HeroesHard8
Tree, Greedy +2No attempts yetTime limit2sMemory limit1024 MB
Judgeable
Math StringHard8
Dynamic programming, Math +2No attempts yetTime limit2sMemory limit1024 MB
Judgeable
Box PackingHard8
Dynamic programming, Sorting +2No attempts yetTime limit1sMemory limit256 MB
Judgeable
Fancy ArraysHard8
Dynamic programming, Number theory +2No attempts yetTime limit2.5sMemory limit256 MB
Judgeable
Restricted ArraysHard8
Graph, Union-find +2No attempts yetTime limit4sMemory limit256 MB
Judgeable
Stone Pile Game 1Hard8
Game theory, Math +2No attempts yetTime limit1sMemory limit1024 MB
Judgeable
Pentagons Filling the PlaneHard8
Math, Number theory +1No attempts yetTime limit2sMemory limit1024 MB
Judgeable
Browsing the CollectionHard8
Shortest path, Graph +1No attempts yetTime limit4sMemory limit512 MB
Judgeable
Escaped from NEFHard8
Graph, DFS +2No attempts yetTime limit2sMemory limit512 MB
Judgeable
Gross LCSHard8
Dynamic programming, Hash map +1No attempts yetTime limit10sMemory limit16 MB
Judgeable
AntsHard8
Tree, DFS +1No attempts yetTime limit1sMemory limit512 MB
Judgeable
Interesting SubsegmentsHard8
Prefix sum, Math +2No attempts yetTime limit1sMemory limit512 MB
Judgeable
Lucky TicketsHard8
Dynamic programming, Number theory +2No attempts yetTime limit2sMemory limit512 MB
Judgeable
DisbalanceHard8
Probability, Dynamic programming +1No attempts yetTime limit1sMemory limit512 MB
Judgeable
GachaponHard8
Dynamic programming, Probability +1No attempts yetTime limit5sMemory limit512 MB
Judgeable
StationHard8
Union-find, Tree +2No attempts yetTime limit4.5sMemory limit1024 MB
Judgeable
Build a CityHard8
Geometry, Greedy +1No attempts yetTime limit3sMemory limit1024 MB
Judgeable
RadioHard8
Segment tree, Number theory +1No attempts yetTime limit1.5sMemory limit512 MB
Judgeable
Pancake-Flavored CookieHard8
Dynamic programming, Simulation +1No attempts yetTime limit1sMemory limit1024 MB
Judgeable
XOR-ABCHard8
Bit manipulation, Combinatorics +1No attempts yetTime limit1sMemory limit1024 MB
Judgeable
Three Spheres and a TetrahedronHard8
Geometry, Math +1No attempts yetTime limit1sMemory limit1024 MB
Judgeable
Yurik and Woodwork LessonHard8
Math, CombinatoricsNo attempts yetTime limit1sMemory limit512 MB
Judgeable
BirthdayHard8
Prefix sum, Stack +2No attempts yetTime limit2sMemory limit512 MB
Judgeable
A+BHard8
Dynamic programming, Combinatorics +1No attempts yetTime limit1sMemory limit512 MB
Judgeable
Sorting FractionsHard8
Binary search, Sorting +2No attempts yetTime limit1sMemory limit512 MB
Judgeable
Optical Communication ChannelsHard8
Tree, Dynamic programming +1No attempts yetTime limit1sMemory limit512 MB
Judgeable
Castle DefenseHard8
Greedy, Binary search +1No attempts yetTime limit2sMemory limit1024 MB
Judgeable
Leblanc's Tree TraversalHard8
Tree, DFS +1No attempts yetTime limit2sMemory limit1024 MB
Judgeable
Forest GameHard8
Tree, Game theory +2No attempts yetTime limit2sMemory limit1024 MB
Judgeable
Balanced DevelopmentHard8
Tree, Simulation +2No attempts yetTime limit5sMemory limit512 MB
Judgeable
Inventor OutlastingHard8
Game theory, Simulation +1No attempts yetTime limit40sMemory limit1024 MB
Judgeable
Broken Device 2Hard8
Math, Bit manipulation +1No attempts yetTime limit2sMemory limit512 MB
Judgeable
SprinklerHard8
Tree, DFS +2No attempts yetTime limit4sMemory limit1024 MB
Judgeable
Fish 2Hard8
Divide and conquer, Greedy +1No attempts yetTime limit4sMemory limit1024 MB
Judgeable
Reconstruction ProjectHard8
Graph, Minimum spanning tree +1No attempts yetTime limit5sMemory limit1024 MB
Judgeable
Reversible CompressionHard8
Dynamic programming, String +1No attempts yetTime limit2sMemory limit1024 MB
Judgeable
Planning Railroad DiscontinuationHard8
Minimum spanning tree, Graph +1No attempts yetTime limit5sMemory limit1024 MB
Judgeable
Genealogy of PuppetsHard8
Dynamic programming, Tree +1No attempts yetTime limit2sMemory limit1024 MB
Judgeable
262144 RevisitedHard8
Divide and conquer, Dynamic programming +1No attempts yetTime limit2sMemory limit1024 MB
Judgeable
Hoof and BrainHard8
Graph, BFSNo attempts yetTime limit4sMemory limit1024 MB
Judgeable
Up Down SubsequenceHard8
Dynamic programming, Segment tree +1No attempts yetTime limit2sMemory limit1024 MB
Judgeable
Pair ProgrammingHard8
Dynamic programming, Combinatorics +1No attempts yetTime limit2sMemory limit1024 MB
Judgeable
Fields DivisionHard8
Graph, DFS +2No attempts yetTime limit0.3sMemory limit1024 MB
Judgeable
Punch ThroughHard8
Dynamic programming, Segment tree +1No attempts yetTime limit5sMemory limit1024 MB
Judgeable
HistogramHard8
Stack, Dynamic programming +1No attempts yetTime limit4sMemory limit1024 MB
Judgeable
Colorful Bracket SequencesHard8
Dynamic programming, StringNo attempts yetTime limit2sMemory limit1024 MB
Judgeable
Joyful KMPHard8
String matching, Combinatorics +1No attempts yetTime limit1sMemory limit1024 MB
Judgeable
Drone PhotoHard8
Matrix, Sorting +1No attempts yetTime limit2sMemory limit2048 MB
Judgeable
Gastronomic EventHard8
Tree, Dynamic programming +1No attempts yetTime limit2sMemory limit2048 MB
Judgeable
CelebrationHard8
Graph, Topological sort +1No attempts yetTime limit2sMemory limit1024 MB
Judgeable
Quantum CommunicationHard8
Hash map, Bit manipulation +1No attempts yetTime limit3sMemory limit1024 MB
Judgeable
The Locked BoxHard8
Segment tree, Matrix +1No attempts yetTime limit3sMemory limit1024 MB
Judgeable
Robot GameHard8
Bit manipulation, Dynamic programming +1No attempts yetTime limit10sMemory limit1024 MB
Judgeable
DelicacyHard8
Matrix, Dynamic programming +1No attempts yetTime limit2sMemory limit1024 MB
Judgeable
DestinyHard8
Tree, Dynamic programming +1No attempts yetTime limit2sMemory limit1024 MB
Judgeable
SurrealHard8
Tree, Recursion +1No attempts yetTime limit1sMemory limit1024 MB
Judgeable
RoadHard8
Graph, Shortest path +1No attempts yetTime limit6sMemory limit1024 MB
Judgeable
RadarHard8
Geometry, Sorting +1No attempts yetTime limit2sMemory limit256 MB
Judgeable
RepetitionsHard8
String matching, Divide and conquer +1No attempts yetTime limit10sMemory limit512 MB
Judgeable
Systematic salesmanHard8
Divide and conquer, Dynamic programming +1No attempts yetTime limit6sMemory limit256 MB
Judgeable
Counting RectanglesHard8
Segment tree, StackNo attempts yetTime limit5sMemory limit1024 MB
Judgeable
Strange GraphHard8
Minimum spanning tree, Union-find +1No attempts yetTime limit7sMemory limit1024 MB
Judgeable
Integer LinesHard8
Geometry, Math +1No attempts yetTime limit5sMemory limit1024 MB
Judgeable
SurroundedHard8
BFS, Graph +1No attempts yetTime limit1sMemory limit1024 MB
Judgeable
Dawn Detective GameHard8
Game theory, BFS +1No attempts yetTime limit1sMemory limit1024 MB
Judgeable
Cake Slices (Hard)Hard8
Dynamic programming, Combinatorics +1No attempts yetTime limit3sMemory limit1024 MB
Judgeable
Alternating HeightsHard8
Graph, Topological sort +1No attempts yetTime limit2sMemory limit1024 MB
Judgeable
Bi-ing Lottery TreeketsHard8
Tree, Dynamic programming +1No attempts yetTime limit1sMemory limit1024 MB
Judgeable
Triangular LogsHard8
Segment tree, Sorting +1No attempts yetTime limit12sMemory limit1024 MB
Judgeable
Gahee and Sajik StadiumHard8
Graph, Brute forceNo attempts yetTime limit1sMemory limit512 MB
Judgeable
Joined SessionsHard8
Intervals, Greedy +1No attempts yetTime limit2sMemory limit1024 MB
Judgeable
Stranded Far From HomeHard8
Graph, Union-find +2No attempts yetTime limit1sMemory limit512 MB
Judgeable
PermutationHard8
Greedy, Bit manipulation +1No attempts yetTime limit1sMemory limit256 MB
Judgeable
The Great Egg HuntHard8
Tree, Divide and conquer +1No attempts yetTime limit3sMemory limit1024 MB
Judgeable
Oil-Producing CountryHard8
Graph, Shortest path +2No attempts yetTime limit2sMemory limit1024 MB
Judgeable
I Herd You Like Ternary OperatorsHard8
String, Stack +1No attempts yetTime limit1sMemory limit1024 MB
Judgeable
Letter DeliveryHard8
Greedy, Sorting +1No attempts yetTime limit3sMemory limit1024 MB
Judgeable
Merge the Tree and SequenceHard8
Tree, Sorting +1No attempts yetTime limit2sMemory limit1024 MB
Judgeable
Dao and the Triple Mex GameHard8
Array, Greedy +1No attempts yetTime limit1sMemory limit1024 MB
Judgeable
Tree Cutting GameHard8
Tree, DFS +1No attempts yetTime limit1sMemory limit1024 MB
Judgeable
The Flower of the GameHard8
Tree, Dynamic programming +1No attempts yetTime limit6sMemory limit1024 MB
Judgeable
Fancy StackHard8
Dynamic programming, Combinatorics +1No attempts yetTime limit3sMemory limit512 MB
Judgeable
Job LookupHard8
Dynamic programming, Tree +1No attempts yetTime limit3sMemory limit512 MB
Judgeable
Big CityHard8
Graph, Shortest path +1No attempts yetTime limit3sMemory limit1024 MB
Judgeable
Sum of Subarray Sums Under Range Assignment QueriesHard8
Segment tree, Combinatorics +1No attempts yetTime limit4sMemory limit1024 MB
Judgeable
Semiconductor FabricationHard8
Graph, Shortest path +1No attempts yetTime limit4sMemory limit1024 MB
Judgeable
Event HorizonHard8
Graph, Segment tree +1No attempts yetTime limit3sMemory limit1024 MB
Judgeable
Lagrange's Theorem Has Subtraction TooHard8
Number theory, Math +1No attempts yetTime limit1sMemory limit512 MB
Judgeable
Outer Ring RoadHard8
Shortest path, Tree +1No attempts yetTime limit7sMemory limit1024 MB
Judgeable
MeasuresHard8
Binary search, Segment tree +2No attempts yetTime limit1.5sMemory limit512 MB
Judgeable
Split into IntervalsHard8
Dynamic programming, ArrayNo attempts yetTime limit1sMemory limit1024 MB
Judgeable
Catfish FarmHard8
Dynamic programming, Segment treeNo attempts yetTime limit1sMemory limit1024 MB
Judgeable
Prisoners' ChallengeHard8
Math, ImplementationNo attempts yetTime limit1sMemory limit1024 MB
Judgeable
Tipover TransformHard8
Dynamic programming, Greedy +1No attempts yetTime limit1sMemory limit1024 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Robot InstructionsGiven up to 40 vectors, count for each K how many K-subsets sum to a target point, using meet-in-the-middle over the two halves.	Hard8	Divide and conquerHash map+2	No attempts yet	4s	1024 MB	Judgeable
Substrings and SubsequencesCharacterize strings whose distinct substrings equal their distinct subsequences, then print the n-th such string in length-then-lexicographic order for n up to 1e6.	Hard8	StringCombinatorics+2	No attempts yet	1s	512 MB	Judgeable
If We Add Them Up...Given n integers a_i greater than 1, choose positive rational exponents b_i so that the sum of a_i^(b_i) is an integer, and print the smallest such integer.	Hard8	MathNumber theory+1	No attempts yet	1s	512 MB	Judgeable
Journey in FogGiven Jane's equally likely speeds, find the minimum expected time for Julia to meet Jane on a street of length L and return home.	Hard8	ProbabilityGreedy+1	No attempts yet	2s	512 MB	Judgeable
Destructive GameEach pile is an independent subtraction game where you may remove b^k stones; determine the winner of the sum under optimal play.	Hard8	Game theoryMath+2	No attempts yet	2s	1024 MB	Judgeable
Game with Balls and BoxesBoxes hold a permutation of balls; over two rounds you may open boxes at per-round costs and freely permute balls among open boxes, and must reach the identity, minimizing total cost.	Hard8	GraphGreedy+2	No attempts yet	2s	1024 MB	Judgeable
Items and HeroesA rooted tree has items at each vertex and a hero at each vertex who needs a given number of items from her subtree; decide feasibility after point updates to items or demands.	Hard8	TreeGreedy+2	No attempts yet	2s	1024 MB	Judgeable
Math StringSum the values of all length-N strings over digits 1-9 and the operators + and * that form valid expressions, modulo 998244353, with N up to 1e18.	Hard8	Dynamic programmingMath+2	No attempts yet	2s	1024 MB	Judgeable
Box PackingGiven n boxes as ordered pairs, select the most boxes that can be split into at most k chains, where each chain is nondecreasing in both coordinates.	Hard8	Dynamic programmingSorting+2	No attempts yet	1s	256 MB	Judgeable
Fancy ArraysCount length-n arrays whose elements all divide m and whose neighboring elements share a prime factor, modulo 1e9+7, for up to 150 queries.	Hard8	Dynamic programmingNumber theory+2	No attempts yet	2.5s	256 MB	Judgeable
Restricted ArraysCount the moduli M up to n for which some integer array satisfies a[x]+1 = a[y] (mod M) for every given pair, and list them.	Hard8	GraphUnion-find+2	No attempts yet	4s	256 MB	Judgeable
Stone Pile Game 1Three piles; a move takes one stone from two nonempty piles and adds one to the third. The player unable to move wins, so determine the optimal winner with R moving first.	Hard8	Game theoryMath+2	No attempts yet	1s	1024 MB	Judgeable
Pentagons Filling the PlaneGiven the square centers of two pentagons in a plane tiling, find the shortest graph distance between them for up to 100,000 test cases.	Hard8	MathNumber theory+1	No attempts yet	2s	1024 MB	Judgeable
Browsing the CollectionFor every pair of items on a circle, find the fewest clicks and filter changes needed to move the pointer from one to the other.	Hard8	Shortest pathGraph+1	No attempts yet	4s	512 MB	Judgeable
Escaped from NEFGiven a directed graph whose underlying undirected graph is a cactus, count the ordered vertex pairs (x, y) where y is reachable from x.	Hard8	GraphDFS+2	No attempts yet	2s	512 MB	Judgeable
Gross LCSGiven sequences A and B, find the sum of LCS(A + x, B) over every integer shift x, where x is added to every element of A.	Hard8	Dynamic programmingHash map+1	No attempts yet	10s	16 MB	Judgeable
AntsEach query moves every ant one step toward the current position of ant a_j, then reports how many pairs of ants share a vertex.	Hard8	TreeDFS+1	No attempts yet	1s	512 MB	Judgeable
Interesting SubsegmentsGiven n and k, build the lexicographically smallest array of 0, 1, and 2 of length n with exactly k subsegments whose sum is divisible by 3, or print -1.	Hard8	Prefix sumMath+2	No attempts yet	1s	512 MB	Judgeable
Lucky TicketsGiven n, s, and a prime q, find the sum of luckiness over all q-digit base-n tickets whose digit sum plus digit product is s mod n, modulo q.	Hard8	Dynamic programmingNumber theory+2	No attempts yet	2s	512 MB	Judgeable
DisbalanceEach minute one bacterium is picked at random to divide among n dishes; output the expected sum of the imbalance d over k minutes modulo 998244353.	Hard8	ProbabilityDynamic programming+1	No attempts yet	1s	512 MB	Judgeable
GachaponGiven item frequencies and per-level round counts, compute for each star count the expected number of such items in a legal top-level rolling, times its legality probability, modulo 998244353.	Hard8	Dynamic programmingProbability+1	No attempts yet	5s	512 MB	Judgeable
StationGiven stations with importance levels and bus fares, find the cheapest route cost from each tourist's start station to their destination station.	Hard8	Union-findTree+2	No attempts yet	4.5s	1024 MB	Judgeable
Build a CityGiven settlements and a per-move wall budget m, decide whether some order of acquiring them keeps each move's new wall length within m.	Hard8	GeometryGreedy+1	No attempts yet	3s	1024 MB	Judgeable
RadioStations on frequencies 1 to n switch on and off, and each query asks whether two active frequencies in [l, r] share a common factor above 1.	Hard8	Segment treeNumber theory+1	No attempts yet	1.5s	512 MB	Judgeable
Pancake-Flavored CookieGiven a map with a lifting ability and a gauge, the task is to choose when to use the ability so the cookie collects the most jellies, with setters and per-time queries.	Hard8	Dynamic programmingSimulation+1	No attempts yet	1s	1024 MB	Judgeable
XOR-ABCCount triples A < B < C with A xor B = C, all within 1 to 2^K - 1, for K up to 10^18, modulo 1000003.	Hard8	Bit manipulationCombinatorics+1	No attempts yet	1s	1024 MB	Judgeable
Three Spheres and a TetrahedronGiven tetrahedron OABC, find the center and radius of the sphere through A, B, C that touches the inscribed sphere and the four exspheres.	Hard8	GeometryMath+1	No attempts yet	1s	1024 MB	Judgeable
Yurik and Woodwork LessonCount the ways to cut cells from an N by M board so that the top-left and bottom-right cells stay, the rest is connected, and each row and column is one contiguous segment, modulo 998244353.	Hard8	MathCombinatorics	No attempts yet	1s	512 MB	Judgeable
BirthdayGiven n double-sided cards, sum over all segments [l, r] the largest achievable total not divisible by k, modulo 1e9+7.	Hard8	Prefix sumStack+2	No attempts yet	2s	512 MB	Judgeable
A+BCount the column permutations of three n-digit rows that make a+b=c hold with no leading zeros, modulo 10^9+7.	Hard8	Dynamic programmingCombinatorics+1	No attempts yet	1s	512 MB	Judgeable
Sorting FractionsGiven two sets of distinct integers, sort all reduced fractions a_i/b_j and output the c-th fraction in the sorted list for each query.	Hard8	Binary searchSorting+2	No attempts yet	1s	512 MB	Judgeable
Optical Communication ChannelsGiven a rooted tree where each node has at most k chosen edges, pick the maximum number of edges forming a degree-bounded subgraph, and among those the minimum total weight.	Hard8	TreeDynamic programming+1	No attempts yet	1s	512 MB	Judgeable
Castle DefenseGiven enemy counts at each point on a line, choose archer count k and shot interval t so the castle takes under E damage, minimizing ak - bt.	Hard8	GreedyBinary search+1	No attempts yet	2s	1024 MB	Judgeable
Leblanc's Tree TraversalGiven a tree, decide whether Leblanc can visit every edge exactly once from some start vertex, using moves along edges and two teleport checkpoints.	Hard8	TreeDFS+1	No attempts yet	2s	1024 MB	Judgeable
Forest GameCount the non-empty sets of trees where B wins the stone game, with each turn moving a stone 1 to K unused branches, modulo 998244353.	Hard8	TreeGame theory+2	No attempts yet	2s	1024 MB	Judgeable
Balanced DevelopmentGiven a weighted tree and an activation permutation, find when each region activates as ancestor population inflows trigger chain activations.	Hard8	TreeSimulation+2	No attempts yet	5s	512 MB	Judgeable
Inventor OutlastingTwo players take turns building attractions on free X cells, where each build fills diagonal sign runs; count the first moves that let the first player win.	Hard8	Game theorySimulation+1	No attempts yet	40s	1024 MB	Judgeable
Broken Device 2Anna must encode an integer up to 10^18 into 0/1 arrays sent through a riffle-shuffle device so Bruno can recover it exactly.	Hard8	MathBit manipulation+1	No attempts yet	2s	512 MB	Judgeable
SprinklerGiven a tree of lands with millet heights, multiply every height within distance D of a land by W modulo L, and answer height queries for single lands.	Hard8	TreeDFS+2	No attempts yet	4s	1024 MB	Judgeable
Fish 2With point updates to fish sizes, count how many fish in range [L, R] could be the one that eats all the others when the fish are merged left to right.	Hard8	Divide and conquerGreedy+1	No attempts yet	4s	1024 MB	Judgeable
Reconstruction ProjectGiven a connected graph with edge widths, find for each query X the minimum total width change so that a spanning tree has every edge equal to X.	Hard8	GraphMinimum spanning tree+1	No attempts yet	5s	1024 MB	Judgeable
Reversible CompressionFind the shortest code string whose decoding matches the given digits and still matches when the code is reversed. Ties go to the lexicographically smallest.	Hard8	Dynamic programmingString+1	No attempts yet	2s	1024 MB	Judgeable
Planning Railroad DiscontinuationGiven l copies of a subway network arranged in a ring and linked by bullet trains at fixed stations, find the minimum total cost of routes that keeps every station connected.	Hard8	Minimum spanning treeGraph+1	No attempts yet	5s	1024 MB	Judgeable
Genealogy of PuppetsCount the ordered binary trees on n puppets that respect each puppet's child-count limits and require a later-released child under every parent with children, modulo 1e9+7.	Hard8	Dynamic programmingTree+1	No attempts yet	2s	1024 MB	Judgeable
262144 RevisitedMerge adjacent pairs into one more than the larger value, and sum the minimum final number over every contiguous subarray.	Hard8	Divide and conquerDynamic programming+1	No attempts yet	2s	1024 MB	Judgeable
Hoof and BrainGiven a directed graph and two starting tokens, decide for each query whether the brain or the hoof wins the token-moving game.	Hard8	GraphBFS	No attempts yet	4s	1024 MB	Judgeable
Up Down SubsequenceGiven a permutation and a string of U and D letters, find the longest subsequence whose consecutive comparisons match the letters.	Hard8	Dynamic programmingSegment tree+1	No attempts yet	2s	1024 MB	Judgeable
Pair ProgrammingCount the distinct expressions formed by interleaving two programs of N instructions each, modulo 10^9+7.	Hard8	Dynamic programmingCombinatorics+1	No attempts yet	2s	1024 MB	Judgeable
Fields DivisionSplit a connected graph of N fields into two connected parts so that the wheat sums (field i yields 2i kg) are as close as possible.	Hard8	GraphDFS+2	No attempts yet	0.3s	1024 MB	Judgeable
Punch ThroughGiven N membranes in an N by M tunnel, find the minimum cost to pass through when teleporting costs A and passing a membrane costs B, for many (A, B) queries.	Hard8	Dynamic programmingSegment tree+1	No attempts yet	5s	1024 MB	Judgeable
HistogramGiven a histogram of N bars, find the maximum total area of at most K non-overlapping rectangles for K = 1, 2, and 3.	Hard8	StackDynamic programming+1	No attempts yet	4s	1024 MB	Judgeable
Colorful Bracket SequencesCount the distinct colorful bracket subsequences of a colored bracket string, where adjacent and matched brackets must have different colors.	Hard8	Dynamic programmingString	No attempts yet	2s	1024 MB	Judgeable
Joyful KMPCount the lowercase strings that have the same failure function as the given string, and print the K-th one in lexicographic order or OVER.	Hard8	String matchingCombinatorics+1	No attempts yet	1s	1024 MB	Judgeable
Drone PhotoCount the axis-aligned rectangles of contestants where the two youngest corners form one pair of opposite sides and the two oldest form the other pair.	Hard8	MatrixSorting+1	No attempts yet	2s	2048 MB	Judgeable
Gastronomic EventAssign ratings 1 to n to the rooms of a tree so that the number of edge-following paths with increasing ratings is maximized, and print that maximum.	Hard8	TreeDynamic programming+1	No attempts yet	2s	2048 MB	Judgeable
CelebrationFor each parade, count the cities that can lie on some path from s to t after adding up to two temporary one-way roads.	Hard8	GraphTopological sort+1	No attempts yet	2s	1024 MB	Judgeable
Quantum CommunicationFor each online query, decide whether a 256-bit string lies within Hamming distance k (at most 15) of some word in a dictionary of up to 400,000 words.	Hard8	Hash mapBit manipulation+1	No attempts yet	3s	1024 MB	Judgeable
The Locked BoxMaintain the value of a continued fraction built from a W/E operation string under append, flip, and reverse updates, printing it modulo 998244353.	Hard8	Segment treeMatrix+1	No attempts yet	3s	1024 MB	Judgeable
Robot GameCount the input and output tape combinations for which some start square lets every robot finish its operations without exploding and produce its target tape.	Hard8	Bit manipulationDynamic programming+1	No attempts yet	10s	1024 MB	Judgeable
DelicacyFind the maximum happiness from a trip that starts and ends in city 1 on day T, where each city visit adds its value and timed festivals add bonuses, or report -1.	Hard8	MatrixDynamic programming+1	No attempts yet	2s	1024 MB	Judgeable
DestinyCount the 0/1 labelings of tree edges so that every ancestor-descendant pair in Q has at least one edge set to 1 on its path, modulo 998244353.	Hard8	TreeDynamic programming+1	No attempts yet	2s	1024 MB	Judgeable
SurrealGiven a finite set of rooted binary trees, decide whether only finitely many trees cannot be reached from them by repeatedly replacing leaves with trees.	Hard8	TreeRecursion+1	No attempts yet	1s	1024 MB	Judgeable
RoadFind the minimum total length of a route from city s to city t whose roads can be removed while the remaining roads still connect all cities.	Hard8	GraphShortest path+1	No attempts yet	6s	1024 MB	Judgeable
RadarEach radius and ray direction gives one scanned point. For each query point, output the distance to the nearest scanned point.	Hard8	GeometrySorting+1	No attempts yet	2s	256 MB	Judgeable
RepetitionsGiven a lowercase string of up to 10^6 letters and up to 100 range queries, find the longest square tt inside each range and its leftmost start.	Hard8	String matchingDivide and conquer+1	No attempts yet	10s	512 MB	Judgeable
Systematic salesmanFind the shortest path through all cities when the route must alternate left/right and lower/upper splits of the point set, and print the visiting order.	Hard8	Divide and conquerDynamic programming+1	No attempts yet	6s	256 MB	Judgeable
Counting RectanglesArrays A and B grow by appends, and after some appends the task asks for the number of all-black subrectangles of the grid where A_i + B_j is at least 0, modulo 998244353.	Hard8	Segment treeStack	No attempts yet	5s	1024 MB	Judgeable
Strange GraphGiven a complete graph whose edge weights come from entries of a matrix, find the total weight of its minimum spanning forest after removing M specified edges.	Hard8	Minimum spanning treeUnion-find+1	No attempts yet	7s	1024 MB	Judgeable
Integer LinesCount integer lines y = ax + b that split the n peppers into two equal groups without touching any pepper, or print -1 if there are infinitely many.	Hard8	GeometryMath+1	No attempts yet	5s	1024 MB	Judgeable
SurroundedMirko moves his piece on a grid to wall in Slavko's hidden piece before it reaches the border, and the task asks for the fewest wall cells needed.	Hard8	BFSGraph+1	No attempts yet	1s	1024 MB	Judgeable
Dawn Detective GameOn a grid with walls, the detective and thief move in turns, and the task is to find the fewest moves for the detective to lock the thief in prison, or print -1.	Hard8	Game theoryBFS+1	No attempts yet	1s	1024 MB	Judgeable
Cake Slices (Hard)Count the subsets of cake slices, where slice i is 1/c_i of a cake, whose total falls between 0.99 and 1.01 of a whole cake, modulo 10^9+7.	Hard8	Dynamic programmingCombinatorics+1	No attempts yet	3s	1024 MB	Judgeable
Alternating HeightsFor each query range, decide whether distinct heights can make the photo order alternate up and down, meaning the required comparisons contain no cycle.	Hard8	GraphTopological sort+1	No attempts yet	2s	1024 MB	Judgeable
Bi-ing Lottery TreeketsCount the distinct winning tickets produced by dropping K numbered balls into a rooted binary tree of N nodes, modulo 1e9+7.	Hard8	TreeDynamic programming+1	No attempts yet	1s	1024 MB	Judgeable
Triangular LogsFor each rectangle query, decide whether three trees inside it have heights that form a non-degenerate triangle.	Hard8	Segment treeSorting+1	No attempts yet	12s	1024 MB	Judgeable
Gahee and Sajik StadiumPlace N idols on an R by C grid to maximize total charm, counting each cell's charm and the extra charm for adjacent Three Musketeers pairs.	Hard8	GraphBrute force	No attempts yet	1s	512 MB	Judgeable
Joined SessionsGiven n intervals, find the fewest merges of overlapping intervals that lower the minimum number of intervals needed to overlap every other interval, or report impossible.	Hard8	IntervalsGreedy+1	No attempts yet	2s	1024 MB	Judgeable
Stranded Far From HomeGiven village populations and a road map, find every village whose initial tie color could become the final color for all islanders.	Hard8	GraphUnion-find+2	No attempts yet	1s	512 MB	Judgeable
PermutationFor each query k, build a permutation of 0 to n-1 with a small n whose increasing subsequences, including the empty one, number exactly k.	Hard8	GreedyBit manipulation+1	No attempts yet	1s	256 MB	Judgeable
The Great Egg HuntGiven a tree of N rooms, find all starting rooms that minimize the expected time for Egg First Search to find the hidden egg.	Hard8	TreeDivide and conquer+1	No attempts yet	3s	1024 MB	Judgeable
Oil-Producing CountryGiven a tree with N nodes plus M extra edges, pick two edges to toll so the total toll collected over all shortest paths between node pairs is maximized.	Hard8	GraphShortest path+2	No attempts yet	2s	1024 MB	Judgeable
I Herd You Like Ternary OperatorsCount the distinct parse trees of a parenthesis-free ternary expression made of letters, ? and :, modulo 1,000,000,007.	Hard8	StringStack+1	No attempts yet	1s	1024 MB	Judgeable
Letter DeliveryAssign letter requests to couriers on a line so the total round-trip distance is minimized, then print each courier's delivery order.	Hard8	GreedySorting+1	No attempts yet	3s	1024 MB	Judgeable
Merge the Tree and SequenceAssign the sequence B to the tree vertices one-to-one to find the minimum and maximum of the sum over color regions of (sum of A) times (sum of matched B).	Hard8	TreeSorting+1	No attempts yet	2s	1024 MB	Judgeable
Dao and the Triple Mex GameGiven array A, pick subsequences to build array B of mex values, then pick subarrays of B to build C. Find the maximum possible sum of C.	Hard8	ArrayGreedy+1	No attempts yet	1s	1024 MB	Judgeable
Tree Cutting GameGiven a tree with 2^K-1 vertices, find the maximum of (vertices minus edges) GS can reach by removing vertices and re-joining components.	Hard8	TreeDFS+1	No attempts yet	1s	1024 MB	Judgeable
The Flower of the GameGiven a weighted tree, find the longest path whose vertex weights strictly increase, and report that length again after each weight update query.	Hard8	TreeDynamic programming+1	No attempts yet	6s	1024 MB	Judgeable
Fancy StackCount the stacks that use all n blocks in a zigzag order where even positions strictly increase, modulo 998244353.	Hard8	Dynamic programmingCombinatorics+1	No attempts yet	3s	512 MB	Judgeable
Job LookupGiven a symmetric communication matrix, build a binary search tree on keys 1 to n that minimizes the total weighted distance between all pairs and print each node's parent.	Hard8	Dynamic programmingTree+1	No attempts yet	3s	512 MB	Judgeable
Big CityGiven N vertical and M horizontal roads with K officers on some of them, sum the minimum total movement for every pair of officers to meet.	Hard8	GraphShortest path+1	No attempts yet	3s	1024 MB	Judgeable
Sum of Subarray Sums Under Range Assignment QueriesGiven N cells and Q range-assign queries, sum every subarray sum over all query windows [U, D], modulo 998244353.	Hard8	Segment treeCombinatorics+1	No attempts yet	4s	1024 MB	Judgeable
Semiconductor FabricationChoose vertex potentials and edge energies, with E1=1.0 and EN=-1.0 fixed, to minimize total transfer cost, or print HAPPY if the cost can drop below zero.	Hard8	GraphShortest path+1	No attempts yet	4s	1024 MB	Judgeable
Event HorizonEach day every cell takes the maximum over a range of cells, and the task is to find the value each cell shows forever after.	Hard8	GraphSegment tree+1	No attempts yet	3s	1024 MB	Judgeable
Lagrange's Theorem Has Subtraction TooGiven an integer N with \|N\| up to 10^12, find the fewest distinct positive squares whose signed sum equals N and print each signed term.	Hard8	Number theoryMath+1	No attempts yet	1s	512 MB	Judgeable
Outer Ring RoadGiven a weighted tree whose leaves form a ring road, answer Q queries for the shortest travel time between two intersections.	Hard8	Shortest pathTree+1	No attempts yet	7s	1024 MB	Judgeable
MeasuresGiven N people on a line, find the minimum time for them to spread out so every pair is at least D apart, after each of M added people.	Hard8	Binary searchSegment tree+2	No attempts yet	1.5s	512 MB	Judgeable
Split into IntervalsChoose exactly K non-overlapping contiguous intervals to maximize the sum of (max minus min) over each interval, for every K from 1 to R.	Hard8	Dynamic programmingArray	No attempts yet	1s	1024 MB	Judgeable
Catfish FarmChoose a fishing spot length for each column of an N by N grid to maximize the total weight of the catfish that can be caught.	Hard8	Dynamic programmingSegment tree	No attempts yet	1s	1024 MB	Judgeable
Prisoners' ChallengeDesign a prisoner strategy that uses one blackboard integer to pass information, so the group can find the bag with fewer coins when each bag holds at most N coins.	Hard8	MathImplementation	No attempts yet	1s	1024 MB	Judgeable
Tipover TransformGiven a row of cells with standing blocks of various heights, find the fewest 1 cm cube blocks needed so the hero can walk from cell 0 to cell N.	Hard8	Dynamic programmingGreedy+1	No attempts yet	1s	1024 MB	Judgeable