Problems

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Total results29,295 problems

Nightman
Hard8
Geometry, Graph+2
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Oldest Ruins 2
Hard8
Dynamic programming, Geometry+2
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Coloring
Hard8
Combinatorics, Math+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Rotation
Hard8
Greedy, Array+2
No attempts yet
Time limit
8s
Memory limit
1024 MB
Judgeable
One is zero, zero is one
Hard8
Dynamic programming, String+1
No attempts yet
Time limit
8s
Memory limit
1024 MB
Judgeable
Skewering
Hard8
Geometry, Probability+1
No attempts yet
Time limit
8s
Memory limit
1024 MB
Judgeable
Mountain Ridge
Hard8
Dynamic programming, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Modusign Commute
Hard8
Greedy, Intervals+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
One-Dimensional Chess
Hard8
Trie, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
1D Anipang
Hard8
Dynamic programming, Segment tree+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Bombs
Hard8
Graph, BFS+2
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Miners
Hard8
Tree, Dynamic programming+1
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
News
Hard8
Tree, DFS+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
LCS Hint
Hard8
Dynamic programming, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Delivery
Hard8
Greedy, Sorting+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Monopoly
Hard8
Graph, Topological sort+2
No attempts yet
Time limit
0.1s
Memory limit
1024 MB
Judgeable
Mini Bucket List
Hard8
Combinatorics, Math+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
xor²
Hard8
Bit manipulation, Segment tree+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
A Tree With More Root Nodes Is a Better Tree
Hard8
Tree, DFS+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Circle
Hard8
Graph, Greedy+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Infestation
Hard8
Tree, Segment tree+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Music Festival
Hard8
Graph, Sorting+1
No attempts yet
Time limit
2.5s
Memory limit
1024 MB
Judgeable
Rain
Hard8
Greedy, Array+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Divide and Own
Hard8
Number theory, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Most Equal
Hard8
Dynamic programming, String+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Persistence
Hard8
Brute force, Greedy+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
HUNTER×HUNTER
Hard8
Dynamic programming, Graph
No attempts yet
Time limit
1.7s
Memory limit
1024 MB
Judgeable
Matching Colors
Hard8
Combinatorics, Math
No attempts yet
Time limit
0.4s
Memory limit
1024 MB
Judgeable
Biggest
Hard8
Sorting, Divide and conquer+1
No attempts yet
Time limit
0.4s
Memory limit
1024 MB
Judgeable
Rain
Hard8
Array, Sorting+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Puang and the Star
Hard8
Graph, BFS+2
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Common Factors
Hard8
Number theory, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Pizza Party!
Hard8
Greedy, Graph+2
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Taxis 2
Hard8
Graph, BFS+2
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
K-th Shortest Path
Hard8
Graph, BFS+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Trade Plan
Hard8
Graph, Union-find+2
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Caffeine Addiction
Hard8
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Prison Break
Hard8
Geometry, Sorting+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Šarenlist
Hard8
Combinatorics, Tree+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Self Study
Hard8
Binary search, Greedy+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Counting Haybales
Hard8
Dynamic programming, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Multiple Choice Test
Hard8
Geometry, Greedy+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Drought
Hard8
Dynamic programming, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Farm Updates
Hard8
Union-find, Graph+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Sequence Reconstruction
Hard8
Graph, Union-find+2
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
blobblush
Hard8
Bit manipulation, Greedy+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
blobfearful
Hard8
Number theory, Math+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
blobcry
Hard8
Graph, Math+2
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
blobpopcorn
Hard8
Segment tree, Combinatorics+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Hehe, You Can't Go
Hard8
Graph, Union-find+2
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Computing a Well-Known Sum
Hard8
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Meet In The Middle
Hard8
Tree, Graph+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Number of Words
Hard8
Dynamic programming, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Shooting Game
Hard8
Simulation, Sorting+2
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Tree and XOR Queries
Hard8
Tree, Bit manipulation+2
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Garden
Hard8
Greedy, Binary search+1
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Perimeter Trail
Hard8
Geometry, Brute force+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Block Arrangement
Hard8
Binary search, Greedy+2
No attempts yet
Time limit
4s
Memory limit
512 MB
Judgeable
The cactus is growing fast
Hard8
Graph, Tree+2
No attempts yet
Time limit
1.3s
Memory limit
1024 MB
Judgeable
Y
Hard8
Tree, DFS+2
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Queries on This Wonderful Sequence!
Hard8
Math, Segment tree+2
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Palindrome Game
Hard8
Game theory, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Gambling Game
Hard8
Combinatorics, Probability+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Statues
Hard8
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Tomb Hater
Hard8
Dynamic programming, Graph+2
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Good Triplets
Hard8
Combinatorics, Two pointers+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Subprime
Hard8
String matching, Math+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Tree Number Generator
Hard8
Tree, DFS+2
No attempts yet
Time limit
13s
Memory limit
1024 MB
Judgeable
Circle Bounce
Hard8
Math, Geometry+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Shortest Missing Subsequences
Hard8
String, Greedy+2
No attempts yet
Time limit
10s
Memory limit
1024 MB
Judgeable
XOR Island
Hard8
Bit manipulation, Hash map+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Rise and Fall
Hard8
Greedy, String+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Redistributing Gifts
Hard8
Dynamic programming, Bit manipulation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Robot Instructions
Hard8
Divide and conquer, Hash map+2
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Substrings and Subsequences
Hard8
String, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
If We Add Them Up...
Hard8
Math, Number theory+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
City Development
Hard8
Tree, Shortest path+1
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Cactus Eater
Hard8
Graph, DFS+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Journey in Fog
Hard8
Probability, Greedy+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Destructive Game
Hard8
Game theory, Math+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Game with Balls and Boxes
Hard8
Graph, Greedy+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Items and Heroes
Hard8
Tree, Greedy+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Lion and Zebra
Hard8
Tree, DFS+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Math String
Hard8
Dynamic programming, Math+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Two Trees
Hard8
Tree, Divide and conquer+1
No attempts yet
Time limit
8s
Memory limit
256 MB
Judgeable
Box Packing
Hard8
Dynamic programming, Sorting+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Fancy Arrays
Hard8
Dynamic programming, Number theory+2
No attempts yet
Time limit
2.5s
Memory limit
256 MB
Judgeable
Restricted Arrays
Hard8
Graph, Union-find+2
No attempts yet
Time limit
4s
Memory limit
256 MB
Judgeable
Stone Pile Game 1
Hard8
Game theory, Math+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Pentagons Filling the Plane
Hard8
Math, Number theory+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Browsing the Collection
Hard8
Shortest path, Graph+1
No attempts yet
Time limit
4s
Memory limit
512 MB
Judgeable
Escaped from NEF
Hard8
Graph, DFS+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Gross LCS
Hard8
Dynamic programming, Hash map+1
No attempts yet
Time limit
10s
Memory limit
16 MB
Judgeable
Ants
Hard8
Tree, DFS+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Interesting Subsegments
Hard8
Prefix sum, Math+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Lucky Tickets
Hard8
Dynamic programming, Number theory+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Disbalance
Hard8
Probability, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Gachapon
Hard8
Dynamic programming, Probability+1
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Station
Hard8
Union-find, Tree+2
No attempts yet
Time limit
4.5s
Memory limit
1024 MB
Judgeable
Build a City
Hard8
Geometry, Greedy+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
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
Counting HaybalesGiven stacks of haybales, a move transfers a top haybale between adjacent stacks whose heights differ by one. Count the reachable configurations modulo 1e9+7.	Hard8	Dynamic programmingSorting+1	No attempts yet	1s	1024 MB	Judgeable
Multiple Choice TestPick one vector from each of N groups so the squared distance of the total sum from the origin is maximized.	Hard8	GeometryGreedy+2	No attempts yet	1s	1024 MB	Judgeable
DroughtCount N-tuples of hunger levels within given upper bounds for which adjacent-pair feedings can make all cows equal, modulo 1e9+7.	Hard8	Dynamic programmingCombinatorics+2	No attempts yet	1s	1024 MB	Judgeable
Farm UpdatesProcess deactivations, road additions, and road removals over time, then report for each farm the last update index at which it was still relevant.	Hard8	Union-findGraph+2	No attempts yet	1s	1024 MB	Judgeable
Sequence ReconstructionGiven M equations of the form a_i + a_j = k, reconstruct the integer sequence a_1..a_N or report ERROR when more than one solution exists.	Hard8	GraphUnion-find+2	No attempts yet	3s	256 MB	Judgeable
blobblushChoose a subset of {1,...,N} whose XOR is maximum, then among those use the fewest cards, then the lexicographically smallest set, and output it sorted.	Hard8	Bit manipulationGreedy+2	No attempts yet	1s	1024 MB	Judgeable
blobfearfulFor each starting blob count A, find the smallest day i such that the running product A23...i is a multiple of K.	Hard8	Number theoryMath+2	No attempts yet	2s	1024 MB	Judgeable
blobcryGiven a connected simple graph, repeatedly delete any two edges incident to one vertex; list all edges that can be the last remaining edge.	Hard8	GraphMath+2	No attempts yet	3s	1024 MB	Judgeable
blobpopcornGiven distinct heights in a line, count pairs whose interior blobs are all shorter than both endpoints, under point updates to heights.	Hard8	Segment treeCombinatorics+2	No attempts yet	2s	1024 MB	Judgeable
Hehe, You Can't GoGiven an N by N grid of lettered regions with Romeo at the top-left and Juliet at the bottom-right, find the minimum total cells to buy so no 4-directional path connects them.	Hard8	GraphUnion-find+2	No attempts yet	1.5s	1024 MB	Judgeable
Computing a Well-Known SumSum f(i)*g(i) for i from 1 to N, where f(i)=N div i and g(i)=i mod M, with N and M up to 1e9, modulo 1e9+7.	Hard8	MathNumber theory+2	No attempts yet	1s	1024 MB	Judgeable
Meet In The MiddleGiven a weighted tree and K queries each naming two villages, find the village where the two distances are equal, breaking ties by the smallest total distance, or -1.	Hard8	TreeGraph+2	No attempts yet	1s	1024 MB	Judgeable
Number of WordsGiven a run-length compressed string, count the number of distinct subsequences of the fully expanded string, modulo 998244353.	Hard8	Dynamic programmingCombinatorics+2	No attempts yet	1s	1024 MB	Judgeable
Shooting GameSimulate lasers moving upward that destroy horizontal walls, where each wall bends the laser's path by its eigenvalue, and report which walls each shot destroys.	Hard8	SimulationSorting+2	No attempts yet	1.5s	1024 MB	Judgeable
Tree and XOR QueriesMaintain a rooted weighted tree under edge-weight updates; for each query, output the sum of path xors d(a,b) over all a in subtree(x) and b in subtree(y).	Hard8	TreeBit manipulation+2	No attempts yet	4s	1024 MB	Judgeable
GardenGiven sorted tree heights, each day the leftmost tree with the smallest positive gap to its right grows by 1. For each K, find the tallest minus shortest height after K days.	Hard8	GreedyBinary search+1	No attempts yet	3s	512 MB	Judgeable
Perimeter TrailGiven up to 500 distinct integer points, find the largest number of points that can lie on the perimeter of an axis-parallel rectangle.	Hard8	GeometryBrute force+2	No attempts yet	2s	512 MB	Judgeable
Block ArrangementGiven a sequence of N block heights, delete blocks so at least X remain and the largest gap between adjacent kept blocks is minimized; output that smallest possible maximum gap.	Hard8	Binary searchGreedy+2	No attempts yet	4s	512 MB	Judgeable
The cactus is growing fastGiven a colored cactus graph and daily watering of stems, decide whether each color can reach its target flower count on a distinct day.	Hard8	GraphTree+2	No attempts yet	1.3s	1024 MB	Judgeable
YFrom a given tree, delete any vertices to leave the largest subtree shaped like a Y: three leaf paths meeting at one center, with no vertex of degree 4 or more.	Hard8	TreeDFS+2	No attempts yet	1.5s	1024 MB	Judgeable
Queries on This Wonderful Sequence!After each update that pins a Fibonacci-indexed segment to a new value, report the current value at segment N, all modulo 1e9+7.	Hard8	MathSegment tree+2	No attempts yet	4s	1024 MB	Judgeable
Palindrome GameWith a pile of N stones, players alternately remove a palindromic number of stones; determine whether the first player wins.	Hard8	Game theoryDynamic programming+2	No attempts yet	1s	1024 MB	Judgeable
Gambling GameGiven m, n, and p, compute the probability that a card's n disjoint pairs are all covered exactly on the p-th of m balls drawn without replacement, as a reduced fraction.	Hard8	CombinatoricsProbability+2	No attempts yet	1s	1024 MB	Judgeable
StatuesGiven a grid of statues and water cells, choose a corner and an ordering of statues along diagonals from that corner so as to minimize how many statues must move.	Hard8	GreedySorting+2	No attempts yet	1s	1024 MB	Judgeable
Tomb HaterFind a shortest north-to-south path on a grid that spells a concatenation of given words, moving only south, west, or east without revisiting tiles.	Hard8	Dynamic programmingGraph+2	No attempts yet	4s	1024 MB	Judgeable
Good TripletsCount index triplets whose three points on a circle of integer circumference C contain the origin strictly inside their triangle.	Hard8	CombinatoricsTwo pointers+2	No attempts yet	1s	1024 MB	Judgeable
SubprimeCount primes among the lth through hth smallest primes whose decimal representation contains the given digit string p, counting each prime once.	Hard8	String matchingMath+2	No attempts yet	2s	1024 MB	Judgeable
Tree Number GeneratorGiven a tree whose nodes hold digits, answer queries that read the digit string along the path from a to b and return its value modulo m.	Hard8	TreeDFS+2	No attempts yet	13s	1024 MB	Judgeable
Circle BounceA ball thrown from (-1,0) with rational slope a/b bounces perfectly inside a unit circle n times; output the x-coordinate of the n-th impact point modulo 1e9+7.	Hard8	MathGeometry+2	No attempts yet	1s	1024 MB	Judgeable
Shortest Missing SubsequencesGiven a target string and queries over an alphabet, decide for each query whether it is a shortest string that is not a subsequence of the target.	Hard8	StringGreedy+2	No attempts yet	10s	1024 MB	Judgeable
XOR IslandGiven n hat values, find the day on which the first islander can deduce that their hat belongs to an XOR triple (a XOR b = c).	Hard8	Bit manipulationHash map+1	No attempts yet	3s	1024 MB	Judgeable
Rise and FallGiven a huge decimal string, find the largest number no greater than it whose digits split into a nondecreasing prefix and a nonincreasing suffix.	Hard8	GreedyString+2	No attempts yet	1s	1024 MB	Judgeable
Redistributing GiftsGiven each cow's preference permutation and breed strings, count the gift reassignments per string where every cow keeps her gift or gets a preferred one within her breed.	Hard8	Dynamic programmingBit manipulation+1	No attempts yet	2s	1024 MB	Judgeable
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
City DevelopmentAfter repeatedly copying subtrees of a rooted tree and attaching each copy to an existing square, the task answers shortest-path distance queries between squares.	Hard8	TreeShortest path+1	No attempts yet	3s	512 MB	Judgeable
Cactus EaterGiven a cactus, find the expected total energy released when a random vertex is repeatedly eaten and each remaining component is processed, modulo 998244353.	Hard8	GraphDFS+2	No attempts yet	2s	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
Lion and ZebraOn a tree, for each query find the time the lion needs to catch the zebra when the zebra plays optimally from vertex v with the lion at distance d.	Hard8	TreeDFS+1	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
Two TreesGiven two trees on the same n vertices, compute the sum over all vertex pairs of the squared sum of their distances in both trees, modulo 2^32.	Hard8	TreeDivide and conquer+1	No attempts yet	8s	256 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