Problems

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Total results29,413 problems

Rock-Scissors-Paper Expression
Hard8
Dynamic programming, Divide and conquer+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Zapina
Hard8
Combinatorics, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Collecting Stamps 3
Hard8
Dynamic programming, Intervals+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Olympic Bus
Hard8
Graph, Shortest path+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Fire
Hard8
Sliding window, Divide and conquer+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
LCS 6
Hard8
String, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
8 MB
Judgeable
LCS 7
Hard8
String, Dynamic programming+2
No attempts yet
Time limit
2s
Memory limit
8 MB
Judgeable
Post Office 1
Hard8
Dynamic programming, Binary search+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Post Office 5
Hard8
Dynamic programming, Divide and conquer+1
No attempts yet
Time limit
10s
Memory limit
1024 MB
Judgeable
Dates
Hard8
Greedy, Segment tree+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Expected Value
Hard8
Graph, Math+1
No attempts yet
Time limit
1.5s
Memory limit
512 MB
Judgeable
Free Edges
Hard8
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Disjoint LIS
Hard8
Dynamic programming, Combinatorics
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Farm of Monsters
Hard8
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Horrible Cycles
Hard8
Graph, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Ignore Submasks
Hard8
Bit manipulation, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Counting Cactus
Hard8
Bit manipulation, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Fast Spanning Tree
Hard8
Union-find, Divide and conquer+1
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Jiry Matchings
Hard8
Tree, Dynamic programming+1
No attempts yet
Time limit
6s
Memory limit
512 MB
Judgeable
K-pop Strings
Hard8
String, Dynamic programming+1
No attempts yet
Time limit
7s
Memory limit
512 MB
Judgeable
Face Recognition Algorithm
Hard8
Geometry, Graph+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Euclid's Algorithm
Hard8
Number theory, Math+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Not Our Problem
Hard8
Dynamic programming, Math
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Bad Doctor
Hard8
Segment tree, Sorting+2
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Tree of Charge
Hard8
Tree, Math+1
No attempts yet
Time limit
4s
Memory limit
512 MB
Judgeable
Program
Hard8
Graph, Shortest path+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Pick Your Own Nim
Hard8
Bit manipulation, Math+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Planar Max Cut
Hard8
Graph, Dynamic programming+1
No attempts yet
Time limit
7s
Memory limit
512 MB
Judgeable
Battle Royale
Hard8
Probability, Math+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Bomas
Hard8
Geometry, Tree+1
No attempts yet
Time limit
6s
Memory limit
512 MB
Judgeable
All Kill
Hard8
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
ICPC Camp
Hard8
Binary search, Greedy+2
No attempts yet
Time limit
4s
Memory limit
512 MB
Judgeable
Scored Nim
Hard8
Game theory, Dynamic programming+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Incomparable Pairs
Hard8
String, Tree+1
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
The Zong of the Zee
Hard8
String, Combinatorics+1
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Expected Value
Hard8
Dynamic programming, Probability+2
No attempts yet
Time limit
3s
Memory limit
16 MB
Judgeable
Game X
Hard8
Math, Greedy+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
5-Path
Hard8
Graph, Binary search+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Count the Sequences
Hard8
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Always Online
Hard8
Graph, Tree+2
No attempts yet
Time limit
4s
Memory limit
512 MB
Judgeable
Daylight
Hard8
Tree, Divide and conquer+1
No attempts yet
Time limit
13s
Memory limit
512 MB
Judgeable
Fireflies
Hard8
Combinatorics, Math+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Glad You Came
Hard8
Segment tree, Implementation+2
No attempts yet
Time limit
4s
Memory limit
512 MB
Judgeable
Hills And Valleys
Hard8
Dynamic programming, String+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Innocence
Hard8
Bit manipulation, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Bus Stop
Hard8
Probability, Math+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Calculating Average
Hard8
Prefix sum, Geometry+1
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Fractional XOR Maximization
Hard8
Bit manipulation, Greedy+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Jimp Numbers
Hard8
Number theory, Math
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
K-Triangles
Hard8
Dynamic programming, Prefix sum+1
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Cake Distribution
Hard8
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Nonsense Time
Hard8
Dynamic programming, Binary search+2
No attempts yet
Time limit
12s
Memory limit
512 MB
Judgeable
Snowy Smile
Hard8
Dynamic programming, Sorting+2
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Support or Not
Hard8
Geometry, Binary search+1
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Game Prediction
Hard8
Dynamic programming, Game theory+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Minimum Spanning Trees
Hard8
Dynamic programming, Probability+2
No attempts yet
Time limit
4s
Memory limit
512 MB
Judgeable
Block Breaker
Hard8
Union-find, Simulation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Square Root Partitioning
Hard8
Brute force, Math+2
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Alakazam
Hard8
Math, Probability+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Dedenne
Hard8
Tree, Dynamic programming+1
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Kecleon
Hard8
String, String matching
No attempts yet
Time limit
4s
Memory limit
512 MB
Judgeable
Restoring a Permutation
Hard8
Greedy, Sorting+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
The Older We Are, The Worse It Hurts
Hard8
Tree, DFS+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Challenge
Hard8
Tree, Greedy+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Graph Measurement
Hard8
Probability, Math
No attempts yet
Time limit
30s
Memory limit
512 MB
Judgeable
Spaceship
Hard8
Geometry, Math+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Erase Nodes
Hard8
Probability, Graph+2
No attempts yet
Time limit
7s
Memory limit
512 MB
Judgeable
Honeycomb
Hard8
Graph, Shortest path+1
No attempts yet
Time limit
6s
Memory limit
512 MB
Judgeable
Power of Function
Hard8
Math, Number theory+1
No attempts yet
Time limit
4s
Memory limit
512 MB
Judgeable
Quicksort
Hard8
Combinatorics, Probability+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Routes
Hard8
Shortest path, Bit manipulation+1
No attempts yet
Time limit
4s
Memory limit
512 MB
Judgeable
Square Substrings
Hard8
String, String matching+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Pyramid
Hard8
Math, Number theory+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Minimums on the Edges
Hard8
Brute force, Bit manipulation+1
No attempts yet
Time limit
4s
Memory limit
512 MB
Judgeable
Find the Vertex
Hard8
Graph, BFS+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Yet Another Mex Problem
Hard8
Dynamic programming, Array+1
No attempts yet
Time limit
4s
Memory limit
512 MB
Judgeable
Road Network
Hard8
Tree, DFS+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Valar Morghulis
Hard8
Graph, Union-find+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Andorra
Hard8
Array, Hash map+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Baklawa
Hard8
Game theory, Geometry+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Crazy LCP
Hard8
String, Trie+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
This Means War
Hard8
Dynamic programming, Geometry
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Awesome Shawarma
Hard8
Tree, DFS+2
No attempts yet
Time limit
14s
Memory limit
512 MB
Judgeable
Dull Chocolates
Hard8
Prefix sum, Sorting+2
No attempts yet
Time limit
9s
Memory limit
512 MB
Judgeable
Exciting Menus
Hard8
Trie, String+2
No attempts yet
Time limit
4s
Memory limit
512 MB
Judgeable
Khoshaf
Hard8
Dynamic programming, Combinatorics+2
No attempts yet
Time limit
12s
Memory limit
512 MB
Judgeable
Contamination
Hard8
Union-find, Geometry+1
No attempts yet
Time limit
10s
Memory limit
512 MB
Judgeable
Invited Speakers
Hard8
Geometry, Greedy+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Space Gophers
Hard8
Union-find, Segment tree+1
No attempts yet
Time limit
20s
Memory limit
512 MB
Judgeable
Balls
Hard8
Array, Math+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Bin
Hard8
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
15s
Memory limit
512 MB
Judgeable
Exp
Hard8
Probability, Dynamic programming+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Flip
Hard8
Combinatorics, Math+1
No attempts yet
Time limit
10s
Memory limit
512 MB
Judgeable
Joy
Hard8
Divide and conquer, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Fast as Ryser
Hard8
Graph, Bit manipulation+2
No attempts yet
Time limit
4s
Memory limit
512 MB
Judgeable
Help Yourself (Gold)
Hard8
Combinatorics, Sorting+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Delegation (Gold)
Hard8
Tree, Dynamic programming+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Bridge Construction
Hard8
Combinatorics, Dynamic programming+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Quarantine
Hard8
Tree, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Tree and Easy Queries
Hard8
Tree, Segment tree+1
No attempts yet
Time limit
2.5s
Memory limit
1024 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Rock-Scissors-Paper ExpressionCount the assignments of R, S, P to the ? symbols in a fixed arithmetic expression, under rock-scissors-paper defined operators, so that evaluation gives A.	Hard8	Dynamic programmingDivide and conquer+2	No attempts yet	2s	512 MB	Judgeable
ZapinaCount the ways to assign N distinct tasks to N programmers so that at least one programmer i receives exactly i tasks, modulo 1e9+7.	Hard8	CombinatoricsDynamic programming+2	No attempts yet	1s	512 MB	Judgeable
Collecting Stamps 3On a circular lake, N stamps sit at given positions with individual collection deadlines; find the maximum number of stamps JOI-kun can collect starting from position 0.	Hard8	Dynamic programmingIntervals+2	No attempts yet	2s	512 MB	Judgeable
Olympic BusChoose at most one directed bus edge to reverse, paying its reversal cost, so that a round trip from city 1 to N and back exists, minimizing total fare plus reversal cost.	Hard8	GraphShortest path+2	No attempts yet	2s	512 MB	Judgeable
FireGiven fire strengths that spread downwind over T steps, answer Q queries for the total fire strength in a range [L, R] at time T.	Hard8	Sliding windowDivide and conquer+1	No attempts yet	2s	512 MB	Judgeable
LCS 6Given two uppercase strings of up to 50000 characters, print the length of their longest common subsequence.	Hard8	StringDynamic programming+1	No attempts yet	1s	8 MB	Judgeable
LCS 7Given two strings of length up to 50000, find the length of their longest common subsequence and print one such subsequence.	Hard8	StringDynamic programming+2	No attempts yet	2s	8 MB	Judgeable
Post Office 1Place P post offices among V villages on a circular road of circumference L to minimize the total distance from every village to its nearest office, and output both the cost and chosen positions.	Hard8	Dynamic programmingBinary search+2	No attempts yet	1s	1024 MB	Judgeable
Post Office 5Choose P of V village positions on a circular road of length L for post offices, minimizing the total distance from each village to its nearest office.	Hard8	Dynamic programmingDivide and conquer+1	No attempts yet	10s	1024 MB	Judgeable
DatesChoose girls and assign each chosen girl a day in her interval, with day x used at most a_x times, to maximize total pleasure.	Hard8	GreedySegment tree+2	No attempts yet	2s	512 MB	Judgeable
Expected ValueGiven a connected plane straight-line graph, find the expected first hitting time of vertex n from vertex 1 in a random walk, modulo 998244353.	Hard8	GraphMath+1	No attempts yet	1.5s	512 MB	Judgeable
Free EdgesGiven an undirected graph, find the minimum number of edges to paint black so that repeatedly blackening a white edge incident to a vertex with exactly one white edge turns every edge black.	Hard8	GraphDFS+2	No attempts yet	1s	512 MB	Judgeable
Disjoint LISCount the permutations of n elements that contain two disjoint increasing subsequences, each as long as the LIS, modulo 998244353.	Hard8	Dynamic programmingCombinatorics	No attempts yet	2s	512 MB	Judgeable
Farm of MonstersYou and a fixed greedy opponent alternate attacking monsters; you choose targets to maximize the number of monsters you personally kill.	Hard8	GreedySorting+2	No attempts yet	1s	512 MB	Judgeable
Horrible CyclesCount the simple cycles in a bipartite graph where each left vertex i connects to the right prefix 1 to a_i, modulo 998244353, with n up to 5000.	Hard8	GraphCombinatorics+1	No attempts yet	2s	512 MB	Judgeable
Ignore SubmasksFor each k-bit mask x, find the first array element that does not contain x as a submask, and sum these indices modulo 998244353.	Hard8	Bit manipulationDynamic programming+2	No attempts yet	1s	512 MB	Judgeable
Counting CactusCount the edge subsets of a graph with at most 13 vertices that form a connected cactus, modulo 998244353.	Hard8	Bit manipulationDynamic programming+1	No attempts yet	2s	512 MB	Judgeable
Fast Spanning TreeGiven weighted vertices and m conditional edges (a, b, s), find the indices of the edges added in order, where an edge is added if it joins two components whose total weight is at least s.	Hard8	Union-findDivide and conquer+1	No attempts yet	5s	512 MB	Judgeable
Jiry MatchingsGiven a weighted tree, find the maximum total weight of a matching with k edges for each k from 1 to n-1, or print ? if none exists.	Hard8	TreeDynamic programming+1	No attempts yet	6s	512 MB	Judgeable
K-pop StringsCount strings of length n over 35 characters that contain no tandem repeat of length n-k or more, modulo 998244353.	Hard8	StringDynamic programming+1	No attempts yet	7s	512 MB	Judgeable
Face Recognition AlgorithmGiven a planar straight-line embedding of a connected graph, decide whether every face, including the outer one, is bounded by exactly three edges.	Hard8	GeometryGraph+2	No attempts yet	2s	512 MB	Judgeable
Euclid's AlgorithmGiven d and k, find the largest integer that divides (a+d)^k - a^k for every positive integer a.	Hard8	Number theoryMath+2	No attempts yet	1s	512 MB	Judgeable
Not Our ProblemCount the ways to fill the -1 entries so every adjacent pair satisfies a_i * a_{i+1} * min(a_i, a_{i+1}) <= C, or print -1 if there are infinitely many.	Hard8	Dynamic programmingMath	No attempts yet	2s	512 MB	Judgeable
Bad DoctorEach doctor prescribes a set of medicines over a day interval; ignoring one doctor, compute the total cost of distinct medicines needed per day summed over all days.	Hard8	Segment treeSorting+2	No attempts yet	3s	512 MB	Judgeable
Tree of ChargeCharges on a rooted tree move up to parents, split down equally among children, or get added at a vertex. Print each final charge modulo 1e9+7.	Hard8	TreeMath+1	No attempts yet	4s	512 MB	Judgeable
ProgramGiven a sequence of assignment and conditional assignment instructions starting from X=1, delete the fewest instructions so the final value is k, for every k.	Hard8	GraphShortest path+2	No attempts yet	2s	512 MB	Judgeable
Pick Your Own NimBob picks one heap from each of his boxes so that he wins for every nonempty subset Alice can choose from her heaps, or the task reports that he cannot.	Hard8	Bit manipulationMath+1	No attempts yet	2s	512 MB	Judgeable
Planar Max CutGiven a planar graph with a fixed straight-line embedding and edge costs, split the vertices into two sets so the total cost of edges crossing between them is maximized.	Hard8	GraphDynamic programming+1	No attempts yet	7s	512 MB	Judgeable
Battle RoyaleGiven house positions x_i and survival times a_i, find each player's probability of being the last survivor when the final safe point M is random in [L, R].	Hard8	ProbabilityMath+2	No attempts yet	2s	512 MB	Judgeable
BomasGiven non-touching circular fences that may nest, find how many animal types fit in each query boma when adjacent areas cannot both hold animals.	Hard8	GeometryTree+1	No attempts yet	6s	512 MB	Judgeable
All KillGiven n coding times and a contest of t minutes, find p times t^n mod 998244353, where p is the chance that all problems are coded in full, each as one contiguous block, before the end.	Hard8	Dynamic programmingCombinatorics+1	No attempts yet	1s	512 MB	Judgeable
ICPC CampGiven n days, p classical and q creative problems with difficulty values, pair one of each per day so every pair sums to at most s, minimizing the largest within-pair difference; output -1 if impossible.	Hard8	Binary searchGreedy+2	No attempts yet	4s	512 MB	Judgeable
Scored NimPlayers alternately split a heap into two colored heaps until all heaps are size one; find Alice's optimal final white-stone count.	Hard8	Game theoryDynamic programming+2	No attempts yet	2s	512 MB	Judgeable
Incomparable PairsCount unordered pairs of substrings of a string s where neither substring is contained in the other.	Hard8	StringTree+1	No attempts yet	3s	512 MB	Judgeable
The Zong of the ZeeGiven m lines of length n with at most one unknown letter per line, count the permutations that turn each line into the next one, modulo 1e9+7.	Hard8	StringCombinatorics+1	No attempts yet	3s	512 MB	Judgeable
Expected ValueRepeatedly pick a random adjacent pair, replace the left value by its difference with the right, drop the right. Find the expected final value modulo 1e9+7.	Hard8	Dynamic programmingProbability+2	No attempts yet	3s	16 MB	Judgeable
Game XGiven n and k, decide whether exactly k pairs of nonzero, distinct-magnitude integers can have positive sum, and if so maximize the number of pairs whose product is positive.	Hard8	MathGreedy+2	No attempts yet	1s	512 MB	Judgeable
5-PathGiven an edge list, find the shortest prefix that creates a simple path of exactly 5 edges between nodes a and b, or report -1.	Hard8	GraphBinary search+1	No attempts yet	2s	512 MB	Judgeable
Count the SequencesCount sequences x_1 to x_m where each 0 <= x_i <= b^i - c and the sum is below n, modulo 998244353.	Hard8	Dynamic programmingCombinatorics+1	No attempts yet	1s	512 MB	Judgeable
Always OnlineSum s xor t xor flow(s, t) over all vertex pairs in a connected graph where every pair has at most two edge-disjoint paths.	Hard8	GraphTree+2	No attempts yet	4s	512 MB	Judgeable
DaylightGiven an unrooted tree and online daily queries (u, v, w), count the vertices within w edges of u or v, with each query decoded from the previous answer.	Hard8	TreeDivide and conquer+1	No attempts yet	13s	512 MB	Judgeable
FirefliesFind the fewest fireflies needed to cover every unit of an n-dimensional box, where each firefly moves one unit step at a time, printed mod 1e9+7.	Hard8	CombinatoricsMath+1	No attempts yet	2s	512 MB	Judgeable
Glad You CameApply m range-max updates (a_j = max(a_j, v_i)) to a zero array, where each l, r, v comes from a fixed 32-bit RNG, then output the XOR of i*a_i.	Hard8	Segment treeImplementation+2	No attempts yet	4s	512 MB	Judgeable
Hills And ValleysGiven a sequence of digits, find the interval to reverse so that the longest non-decreasing subsequence is as long as possible, and report that length with the interval.	Hard8	Dynamic programmingString+1	No attempts yet	2s	512 MB	Judgeable
InnocenceCount arrays of length N with every element in [L, R] whose XOR equals K, modulo 1e9+7, for several K values per test case.	Hard8	Bit manipulationDynamic programming+1	No attempts yet	1s	512 MB	Judgeable
Bus StopEach of n bus routes has independent waiting time uniform on [0, di]; find the expected minimum, output as a fraction modulo 998244353.	Hard8	ProbabilityMath+2	No attempts yet	2s	512 MB	Judgeable
Calculating AverageFor each index k, find the maximum average of a consecutive segment that contains position k.	Hard8	Prefix sumGeometry+1	No attempts yet	5s	512 MB	Judgeable
Fractional XOR MaximizationGiven rational intervals [a, b] and [c, d], find the supremum of the XOR of binary expansions of one number from each interval.	Hard8	Bit manipulationGreedy+1	No attempts yet	2s	512 MB	Judgeable
Jimp NumbersCount the jimp numbers k up to n, where exactly one arithmetic triple (a, b, c) satisfies a^2 + b^2 + k = c^2.	Hard8	Number theoryMath	No attempts yet	2s	512 MB	Judgeable
K-TrianglesGiven an n by m integer matrix and k, find the maximum total sum of two non-overlapping k-triangles.	Hard8	Dynamic programmingPrefix sum+1	No attempts yet	3s	512 MB	Judgeable
Cake DistributionChoose up to 5000 positive integer cake pieces so that for each of A, B, C guests they can be split evenly, labeling each piece with its recipient for each case.	Hard8	MathNumber theory+2	No attempts yet	1s	512 MB	Judgeable
Nonsense TimeElements of a random permutation are unfrozen one at a time; after each unfreeze report the longest increasing subsequence length among the currently available elements.	Hard8	Dynamic programmingBinary search+2	No attempts yet	12s	512 MB	Judgeable
Snowy SmileGiven up to 2000 weighted points, find an axis-aligned rectangle maximizing the sum of weights of points inside or on its border, allowing an empty rectangle for zero.	Hard8	Dynamic programmingSorting+2	No attempts yet	3s	512 MB	Judgeable
Support or NotGiven n spheres in 3D, find the k smallest gap distances between pairs of spheres and print each one rounded up.	Hard8	GeometryBinary search+1	No attempts yet	8s	512 MB	Judgeable
Game PredictionFor each subarray query, compute both players' final scores when they alternately take the leftmost or rightmost element, playing optimally.	Hard8	Dynamic programmingGame theory+2	No attempts yet	1s	512 MB	Judgeable
Minimum Spanning TreesGiven a random graph where each edge has weight 0 to k or is absent, find for each s the probability that the graph is connected with MST weight s, modulo 1e9+7.	Hard8	Dynamic programmingProbability+2	No attempts yet	4s	512 MB	Judgeable
Block BreakerBlocks drop in a grid when a knocked block has a dropped left/right neighbor and a dropped front/back neighbor; after each of q moves, report how many blocks fall.	Hard8	Union-findSimulation+2	No attempts yet	2s	512 MB	Judgeable
Square Root PartitioningGiven n numbers (n up to 36) with values up to 10^100000, count the sign choices + or - that make the signed sum of their square roots equal zero.	Hard8	Brute forceMath+2	No attempts yet	3s	512 MB	Judgeable
AlakazamGiven an array and range shuffle operations that permute a segment uniformly at random, answer point queries for the expected value at a position.	Hard8	MathProbability+2	No attempts yet	2s	512 MB	Judgeable
DedenneFind the minimum memorization cost of n prefix-free binary codewords with no two adjacent 0s, where each prefix's cost depends on how many codewords it covers.	Hard8	TreeDynamic programming+1	No attempts yet	5s	512 MB	Judgeable
KecleonColors join a line one at a time, and each query counts how many length-k windows equal the first k colors of the line.	Hard8	StringString matching	No attempts yet	4s	512 MB	Judgeable
Restoring a PermutationGiven arrays a and b, construct a permutation p where a[i] is the LIS ending at i and b[i] is the longest decreasing subsequence starting at i.	Hard8	GreedySorting+2	No attempts yet	2s	512 MB	Judgeable
The Older We Are, The Worse It HurtsRoot the tree anywhere and order each node's children so that the weighted sum of DFS discovery times is minimized; output that minimum.	Hard8	TreeDFS+2	No attempts yet	2s	512 MB	Judgeable
ChallengeConstruct a tree with at most n vertices whose recursive center-removal decomposition puts some vertex in at least floor(sqrt(n)) different pieces.	Hard8	TreeGreedy+2	No attempts yet	2s	512 MB	Judgeable
Graph MeasurementGiven k random black/white colorings of an unknown graph's edges, recover the graph from the per-vertex counts of black edges.	Hard8	ProbabilityMath	No attempts yet	30s	512 MB	Judgeable
SpaceshipGiven a start point and direction and a target point and direction in 3D, build a path of lines and circular arcs with radius at least r0 that joins them with matching tangent directions.	Hard8	GeometryMath+1	No attempts yet	2s	512 MB	Judgeable
Erase NodesNodes of a connected graph with n nodes and n edges are removed in random order; find the expected number of BFS updates, modulo 998244353.	Hard8	ProbabilityGraph+2	No attempts yet	7s	512 MB	Judgeable
HoneycombGiven a honeycomb block with some traversable edges, find the minimum number of edges to cut between every pair of marked cells and output the sum.	Hard8	GraphShortest path+1	No attempts yet	6s	512 MB	Judgeable
Power of FunctionFind the largest m such that f^m(n) = 1 for some n in [l, r], plus the smallest and largest such n for that m.	Hard8	MathNumber theory+1	No attempts yet	4s	512 MB	Judgeable
QuicksortGiven a flawed quicksort with recursion depth limit k, find the expected number of inversions after running it on a uniformly random permutation of size n, times n! modulo 998244353.	Hard8	CombinatoricsProbability+2	No attempts yet	2s	512 MB	Judgeable
RoutesGiven railway routes and district labels for each city, find the sum of shortest travel times over all city pairs, where each balloon or rail move takes one hour.	Hard8	Shortest pathBit manipulation+1	No attempts yet	4s	512 MB	Judgeable
Square SubstringsGiven a lowercase string and range queries, count the square substrings (even-length strings tt) fully inside each query range.	Hard8	StringString matching+2	No attempts yet	8s	512 MB	Judgeable
PyramidCount the ways to pick three vertices forming an equilateral triangle among the pyramid vertices on levels l to r, for up to 300000 queries.	Hard8	MathNumber theory+2	No attempts yet	2s	512 MB	Judgeable
Minimums on the EdgesGiven a graph with up to 18 vertices and s tokens, place the tokens on vertices to maximize the sum of min(a_u, a_v) over all edges, and print the counts.	Hard8	Brute forceBit manipulation+1	No attempts yet	4s	512 MB	Judgeable
Find the VertexGiven a connected graph and the shortest-path distances from an unknown vertex s to all vertices modulo 3, find s.	Hard8	GraphBFS+2	No attempts yet	1s	512 MB	Judgeable
Yet Another Mex ProblemSplit an array into contiguous pieces of length at most k to maximize the sum of each piece's elements times its mex, and print the total.	Hard8	Dynamic programmingArray+1	No attempts yet	4s	512 MB	Judgeable
Road NetworkGiven a tree, add one edge so that the number of bridges in the resulting graph is minimized, and report that minimum count.	Hard8	TreeDFS+2	No attempts yet	2s	512 MB	Judgeable
Valar MorghulisGiven a graph of rivalries, for each query interval of edges decide whether the graph using only those edges is bipartite, and if so output the maximum possible size of one wing.	Hard8	GraphUnion-find+2	No attempts yet	2s	512 MB	Judgeable
AndorraProcess investors in order; for each, count contiguous intervals containing at least one free block of their type, then remove all free blocks of that type and report the remaining number of intervals.	Hard8	ArrayHash map+2	No attempts yet	2s	512 MB	Judgeable
BaklawaGiven a huge cuboid with up to 100 poisonous unit cells, players alternate cutting off a safe cuboid half; decide who wins under optimal play.	Hard8	Game theoryGeometry+2	No attempts yet	2s	512 MB	Judgeable
Crazy LCPGiven N strings and Q range queries, for each range [L, R] report the maximum longest common prefix over all pairs of distinct strings in that range.	Hard8	StringTrie+2	No attempts yet	2s	512 MB	Judgeable
This Means WarSplit sorted soldiers into contiguous groups to maximize the sum of f_a(x_b) over each group, where a is the group's leftmost and b its rightmost soldier.	Hard8	Dynamic programmingGeometry	No attempts yet	2s	512 MB	Judgeable
Awesome ShawarmaGiven a tree, count the unordered pairs of nodes whose added edge leaves the number of bridges in [L, R].	Hard8	TreeDFS+2	No attempts yet	14s	512 MB	Judgeable
Dull ChocolatesCount prefix rectangles of a huge grid whose parity of white cells is odd versus even, given at most 1000 white cells.	Hard8	Prefix sumSorting+2	No attempts yet	9s	512 MB	Judgeable
Exciting MenusGiven N strings with a joy value per position, maximize over all substrings the product of its length, the joy at its end, and the number of strings having it as a prefix.	Hard8	TrieString+2	No attempts yet	4s	512 MB	Judgeable
KhoshafCount arrays of length N with entries in [L, R] that have exactly K contiguous subarrays whose sum is divisible by 3, modulo 1e9+7.	Hard8	Dynamic programmingCombinatorics+2	No attempts yet	12s	512 MB	Judgeable
ContaminationGiven disjoint contaminated circles, answer for each query whether two points can be connected without entering any circle while staying within a horizontal latitude band.	Hard8	Union-findGeometry+1	No attempts yet	10s	512 MB	Judgeable
Invited SpeakersGiven n red and n blue points in the plane with distinct x and y coordinates and no three collinear, draw n disjoint polygonal chains pairing each red point with a blue point.	Hard8	GeometryGreedy+2	No attempts yet	2s	512 MB	Judgeable
Space GophersGiven tunnels that each remove a full axis-parallel line from a cube, answer whether two empty cells are connected through empty cells.	Hard8	Union-findSegment tree+1	No attempts yet	20s	512 MB	Judgeable
BallsGiven a row of colored balls, repeatedly pick a consecutive segment with a strict majority color and delete all other balls in it; count which colors can remain at the end.	Hard8	ArrayMath+2	No attempts yet	1s	512 MB	Judgeable
BinCount full binary trees with n leaves where each node's left leaf count exceeds its right leaf count by at most k, modulo 998244353.	Hard8	Dynamic programmingCombinatorics+1	No attempts yet	15s	512 MB	Judgeable
ExpEach of n independent monsters grants i experience (0 to k) with probability p_i, totals are capped at x, and the expected capped total must be computed modulo 998244353.	Hard8	ProbabilityDynamic programming+2	No attempts yet	5s	512 MB	Judgeable
FlipGiven sets of people numbered 1 to 2n, find for each set the probability that all its members land on the same team under the coin-flip assignment, modulo 998244353.	Hard8	CombinatoricsMath+1	No attempts yet	10s	512 MB	Judgeable
JoyGiven a queue of n-1 players and your skill x, find for each of the n insertion positions the probability that you win the knockout tournament.	Hard8	Divide and conquerDynamic programming+1	No attempts yet	2s	512 MB	Judgeable
Fast as RyserSum c^\|S\| over all matchings S (edge sets with no shared vertex) in a graph with up to 36 vertices, modulo 1e9+7.	Hard8	GraphBit manipulation+2	No attempts yet	4s	512 MB	Judgeable
Help Yourself (Gold)Sum the number of connected regions in the union of segments over all 2^N subsets, modulo 1e9+7.	Hard8	CombinatoricsSorting+2	No attempts yet	2s	512 MB	Judgeable
Delegation (Gold)Given a tree with N pastures, decide for each K from 1 to N-1 whether its edges can be split into paths that each have exactly K edges.	Hard8	TreeDynamic programming+2	No attempts yet	2s	512 MB	Judgeable
Bridge ConstructionCount unlabeled connected graphs on N vertices with maximum degree at most 4, modulo a prime X.	Hard8	CombinatoricsDynamic programming+2	No attempts yet	2s	256 MB	Judgeable
QuarantineCount the sets of cities to lock on a tree so that no simple path with at least K roads joins two unlocked cities, modulo 10^9+7.	Hard8	TreeDynamic programming+1	No attempts yet	2s	256 MB	Judgeable
Tree and Easy QueriesGiven a weighted tree whose edge lengths change, report the longest simple path through a queried vertex after each update.	Hard8	TreeSegment tree+1	No attempts yet	2.5s	1024 MB	Judgeable