Problems

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Total results29,441 problems

Socks Tycoon Dongwoo and Kind Haneul
Medium7
Probability, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Good Subset
Medium7
Number theory, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Strange Game on a Graph
Medium7
Graph, Game theory+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Lazy Woodcutters
Medium7
Hash map, Prefix sum+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Genius Walk
Medium7
Shortest path, Graph+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Sam and the Warehouse
Medium7
Array, Stack+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Escape from the Mountain Base
Medium7
Greedy, Tree+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Jerry and Tasks
Medium7
Dynamic programming, Bit manipulation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Mysterious Device
Medium7
String matching, Trie+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Battle Droids
Medium7
Math, Hash map+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Combination Lock
Medium7
Graph, Matrix+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Society Reception
Medium7
Geometry, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
The Great Battle
Medium7
Segment tree, Simulation
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Ancient Greek Isomorphism
Medium7
Graph, BFS+1
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Good Dreams
Medium7
Implementation, Greedy
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Viking Village
Medium7
Graph, Topological sort+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Island Travel
Medium7
Shortest path, Geometry
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Orderings
Medium7
Tree, Dynamic programming+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Doomsday Protocol
Medium7
Tree, Graph+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Morty Buys Groceries
Medium7
Math, Prefix sum+1
No attempts yet
Time limit
6s
Memory limit
1024 MB
Judgeable
Autocomplete
Medium7
Dynamic programming, Trie+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
The Trial
Medium7
Bit manipulation, Array+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Murder Investigation
Medium7
Math, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
IPvX
Medium7
Implementation, Hash map+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Energy
Medium7
Dynamic programming, Tree+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Equality
Medium7
Dynamic programming, Number theory+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Arithmetic Lesson
Medium7
Bit manipulation, Trie
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Mario and the Parallel World
Medium7
Dynamic programming, Matrix+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Mario's Vegetable Garden
Medium7
Geometry, Binary search+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Finding the Ship
Medium7
BFS, Graph+2
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Max and Distances
Medium7
Sorting, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Restoring the array
Medium7
Dynamic programming, String+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Sale!
Medium7
Sorting, Greedy+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Doctor Strange and the Exhibition
Medium7
Bit manipulation, Combinatorics
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Ring Roads
Medium7
Geometry, Binary search+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Restoring the Number
Medium7
Brute force, Sorting+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Factory
Medium7
Array, Segment tree+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Prison for Zedd
Medium7
Graph, Sorting+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Frogs in a Well
Medium7
Sorting, BFS+1
No attempts yet
Time limit
8s
Memory limit
1024 MB
Judgeable
Let's go to the movies
Medium7
Sorting, Greedy+1
No attempts yet
Time limit
8s
Memory limit
1024 MB
Judgeable
Tree
Medium7
Tree, Union-find+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Counterfeit Coin
Medium7
Math, Divide and conquer+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Standoff
Medium7
Sorting, Two pointers+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Stacks
Medium7
Segment tree, Stack+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Race
Medium7
Shortest path, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Triangles
Medium7
Geometry, Sorting+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Sequences
Medium7
Math, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
New Entertainment
Medium7
Game theory, Number theory+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Messages
Medium7
Graph, Binary search+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Volleyball
Medium7
Divide and conquer, Array+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Jump if you can!
Medium7
Geometry, Binary search+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Digital Twin
Medium7
Dynamic programming, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Sea Urchin Field
Medium7
Graph, BFS+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
x
Medium7
Game theory, String matching
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Big Number Game
Medium7
Number theory, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Tree and K
Medium7
Tree, Divide and conquer+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Arctic Fox Flips the Brackets
Medium7
Segment tree, String+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Mr. Bean and the Newspaper
Medium7
Matrix, Simulation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Spider Web Production
Medium7
Dynamic programming, String matching+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Fun Game
Medium7
Game theory, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Krabsburgers
Medium7
Dynamic programming, Bit manipulation+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
President Election
Medium7
Dynamic programming, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Uncle Scrooge's Accounts
Medium7
Math, Number theory+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Reduce the Number of Problems
Medium7
Dynamic programming, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
KSA Hide and Seek
Medium7
Tree, BFS+1
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Beetle Sandwiches
Medium7
Dynamic programming, Sorting+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Bella's Best Friends
Medium7
Prefix sum, Hash map+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Journey
Medium7
Graph, Shortest path
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Tickets to Provall
Medium7
Bit manipulation, Dynamic programming
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Hercules
Medium7
Tree, Graph+1
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Inversions in a Range
Medium7
Array, Segment tree+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Chairs
Medium7
Binary search, Two pointers+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
History
Medium7
Minimum spanning tree, Graph+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
List
Medium7
Trie, String+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Nano's clock hands
Medium7
Number theory, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Counting primes on a board
Medium7
Math, Number theory+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Hyper Dice Rolling
Medium7
Simulation, Math+1
No attempts yet
Time limit
2.5s
Memory limit
1024 MB
Judgeable
Delaunay
Medium7
Geometry, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Start of the End
Medium7
Array, Hash map+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Sightseeing Drive
Medium7
Divide and conquer, Tree+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Powerful Explosion
Medium7
Math, Number theory
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Melman
Medium7
String matching, String
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Jam
Medium7
Binary search, Segment tree
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Highway
Medium7
Geometry, Simulation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Plague
Medium7
Dynamic programming, Shortest path
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Round Table
Medium7
Dynamic programming, Combinatorics
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
One Walk
Medium7
Graph, DFS
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Wolhyang, Takeoff
Medium7
Greedy, Heap+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Painting the Fence
Medium7
Intervals, Segment tree+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Bet
Medium7
Dynamic programming, String matching+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Pizza Marathon
Medium7
Trie, Tree+2
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Secret Laboratory
Medium7
Combinatorics, Dynamic programming+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Greedy
Medium7
Greedy, Segment tree
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Restoring a Permutation
Medium7
Greedy, Sorting+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Sawmill
Medium7
Dynamic programming, Prefix sum+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Where am I?
Medium7
Matrix, Graph+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Game
Medium7
String, Union-find+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Sentries
Medium7
Divide and conquer, Sorting+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Cards
Medium7
Dynamic programming, String matching+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Ancient Calendar
Medium7
Dynamic programming, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Socks Tycoon Dongwoo and Kind HaneulGiven n sock types and m random draws, find the mean and variance of the number of socks left on the floor, modulo 1e9+7.	Medium7	ProbabilityMath+1	No attempts yet	1s	1024 MB	Judgeable
Good SubsetGiven n natural numbers up to 10^18, find the size of the largest subset whose GCD is greater than one.	Medium7	Number theoryMath+1	No attempts yet	2s	1024 MB	Judgeable
Strange Game on a GraphTwo players alternately erase edges, each new edge must share a vertex with the previous one. Determine whether the first player can force a win on a given graph.	Medium7	GraphGame theory+1	No attempts yet	2s	1024 MB	Judgeable
Lazy WoodcuttersCount the pairs (a, b) where hiring woodcutters a through b changes the wall height by a whole number of meters at every point.	Medium7	Hash mapPrefix sum+1	No attempts yet	2s	1024 MB	Judgeable
Genius WalkFind the earliest time Sam can reach city t from s when each road has periodic rain and he cannot stop midway along a road.	Medium7	Shortest pathGraph+1	No attempts yet	2s	1024 MB	Judgeable
Sam and the WarehouseTwo players alternately break any prefix of a row of constructors, then take the next one. Find the optimal difference Sam's total minus Lovets's total.	Medium7	ArrayStack+1	No attempts yet	2s	1024 MB	Judgeable
Escape from the Mountain BaseGiven a rooted tree of n clearings, place k helicopters to maximize the number of clearings that have a helicopter somewhere in their subtree.	Medium7	GreedyTree+1	No attempts yet	2s	1024 MB	Judgeable
Jerry and TasksFind the least starting money so that Jerry's balance never goes negative in any valid task order, where each dependency spans at most 10 indices.	Medium7	Dynamic programmingBit manipulation+1	No attempts yet	2s	1024 MB	Judgeable
Mysterious DeviceGiven buttons that append fixed strings or delete a set number of characters, decide for each query string whether the screen can end up showing it.	Medium7	String matchingTrie+1	No attempts yet	2s	1024 MB	Judgeable
Battle DroidsCount contiguous segments where the sum of 2^a_i over the segment is a power of two, since equal AIQ values merge like binary addition.	Medium7	MathHash map+1	No attempts yet	2s	1024 MB	Judgeable
Combination LockChoose which rows of an n by m table to reverse (each at most once) so that every column has distinct values, or report that it is impossible.	Medium7	GraphMatrix+1	No attempts yet	2s	1024 MB	Judgeable
Society ReceptionGiven speeds q and p, build a route of lattice points from (0, 0) whose travel time at speed p equals Bough's straight-line time at speed q.	Medium7	GeometryMath+1	No attempts yet	2s	1024 MB	Judgeable
The Great BattleGiven gods with strengths, handle range decrements and, for each query, find which god in a range first drives Kratos's power to zero.	Medium7	Segment treeSimulation	No attempts yet	5s	1024 MB	Judgeable
Ancient Greek IsomorphismGiven a graph with the same vertex and edge counts as an n by m grid, decide whether it is isomorphic to the grid graph.	Medium7	GraphBFS+1	No attempts yet	5s	1024 MB	Judgeable
Good DreamsPlace n nuhls on an n by n grid so each family forms one connected region of its size, and no family's straight digging paths reach another family's cells.	Medium7	ImplementationGreedy	No attempts yet	2s	1024 MB	Judgeable
Viking VillageGiven a directed graph, decide whether a rooted tree has the same reachable set for every node, and print its parent array if one exists.	Medium7	GraphTopological sort+1	No attempts yet	2s	1024 MB	Judgeable
Island TravelFind the minimum flying distance from island a to island b, where Hiccup can walk freely across each convex polygon island.	Medium7	Shortest pathGeometry	No attempts yet	2s	1024 MB	Judgeable
OrderingsCount the room orders where every oriented passage in a tree points from an earlier room to a later one, modulo 998244353.	Medium7	TreeDynamic programming+1	No attempts yet	3s	1024 MB	Judgeable
Doomsday ProtocolFor each start station and tunnel budget, find the station nearest the shop that the agents can reach using at most k tunnels.	Medium7	TreeGraph+2	No attempts yet	2s	1024 MB	Judgeable
Morty Buys GroceriesGiven n product costs, count ordered sequences of k products whose total cost lies between l and r for each query, modulo 786433.	Medium7	MathPrefix sum+1	No attempts yet	6s	1024 MB	Judgeable
AutocompleteCount the ways to type word s using at most k actions, where each action types a letter, deletes a letter, or accepts one of the top three autocomplete suggestions, modulo 1e9+7.	Medium7	Dynamic programmingTrie+1	No attempts yet	2s	1024 MB	Judgeable
The TrialAfter each OR or AND operation on the whole array, report the minimum number of non-decreasing contiguous segments the array can be split into.	Medium7	Bit manipulationArray+1	No attempts yet	2s	1024 MB	Judgeable
Murder InvestigationFor each query (n, k), compute the cunning value beta(n, k) from the prefix-sum recurrence, modulo 998244353.	Medium7	MathCombinatorics+1	No attempts yet	2s	1024 MB	Judgeable
IPvXGiven taken IPvX addresses and starting addresses a < b, find the fewest addresses to occupy so the two assigned addresses become adjacent, or -1.	Medium7	ImplementationHash map+1	No attempts yet	2s	1024 MB	Judgeable
EnergyChoose exactly k vertex-disjoint paths in a tree to maximize the total energy of the rooms they cover.	Medium7	Dynamic programmingTree+1	No attempts yet	1s	1024 MB	Judgeable
EqualityInsert exactly k equality signs and plus (or multiply) signs into a digit string so every block has the same remainder modulo m.	Medium7	Dynamic programmingNumber theory+1	No attempts yet	3s	1024 MB	Judgeable
Arithmetic LessonApply xor or and with a value to every element of a sequence in order, and count the elements in the range [l, r] after each query.	Medium7	Bit manipulationTrie	No attempts yet	2s	1024 MB	Judgeable
Mario and the Parallel WorldGiven a grid of positive integers, find the best right-or-down path sum from top-left to bottom-right when an adversary blocks one cell to minimize that best sum.	Medium7	Dynamic programmingMatrix+1	No attempts yet	3s	1024 MB	Judgeable
Mario's Vegetable GardenGiven n seed cells on an r by c grid, find the number of seconds until every cell is infected when infection spreads to side-adjacent cells each second.	Medium7	GeometryBinary search+1	No attempts yet	2s	1024 MB	Judgeable
Finding the ShipGiven a graph and queries (v, k), find the single point the ship must occupy after k steps on a shortest path from s to v, or report impossible or ambiguous.	Medium7	BFSGraph+2	No attempts yet	3s	1024 MB	Judgeable
Max and DistancesGiven an n by n distance matrix, restore a sorted point array x and permutations a and b that generate it, or report that none exist.	Medium7	SortingGreedy+1	No attempts yet	2s	1024 MB	Judgeable
Restoring the arrayDelete the fewest digits from each number so the array becomes non-decreasing, or print -1 if no deletion works.	Medium7	Dynamic programmingString+1	No attempts yet	2s	1024 MB	Judgeable
Sale!Given n book prices, a delivery fee e, and w free books per qualifying order, find the minimum total cost to buy all books for each q from 1 to n.	Medium7	SortingGreedy+2	No attempts yet	2s	1024 MB	Judgeable
Doctor Strange and the ExhibitionGiven n numbers below 4096, decide whether some k of them have a bitwise AND equal to zero.	Medium7	Bit manipulationCombinatorics	No attempts yet	1s	1024 MB	Judgeable
Ring RoadsFor each query, find the shortest distance from an inner-ring point at angle a to an outer-ring point at angle b, using one-way connecting roads.	Medium7	GeometryBinary search+1	No attempts yet	2s	1024 MB	Judgeable
Restoring the NumberFill the ? digits of a string n (no leading zero) so that n mod m is as small as possible, and print that remainder.	Medium7	Brute forceSorting+2	No attempts yet	2s	1024 MB	Judgeable
FactoryProcess swap queries on conveyors at given stages, and for each lookup report where the item starting on conveyor r ends up after stage x.	Medium7	ArraySegment tree+1	No attempts yet	2s	1024 MB	Judgeable
Prison for ZeddPick six of the given rectangles to form the three face pairs of a box and report the largest possible volume, or -1 if no box can be built.	Medium7	GraphSorting+1	No attempts yet	2s	1024 MB	Judgeable
Frogs in a WellFor each distance d from 1 to h+w-2, count the frogs with no strictly stronger frog within Manhattan distance d on an h by w grid.	Medium7	SortingBFS+1	No attempts yet	8s	1024 MB	Judgeable
Let's go to the moviesGiven N movies that repeat daily on a T-hour cycle, find the earliest time all N can be watched once each without overlap.	Medium7	SortingGreedy+1	No attempts yet	8s	1024 MB	Judgeable
TreeFind the maximum over all vertex pairs of the path length times the smaller of the two endpoint values in a tree.	Medium7	TreeUnion-find+1	No attempts yet	2s	1024 MB	Judgeable
Counterfeit CoinFind the single fake coin among 2a+1 coins, where gold and silver counts are a and a+1 in some order, using at most t balance weighings.	Medium7	MathDivide and conquer+1	No attempts yet	2s	1024 MB	Judgeable
StandoffFind the integer shift of the soldier segments, all moved together within [l, r], that minimizes their total overlap with the hedgehog segments.	Medium7	SortingTwo pointers+1	No attempts yet	2s	1024 MB	Judgeable
StacksGiven n stacks and m requests that push a value onto a range, cancel an earlier push, or query a stack's top, print the top value for each query.	Medium7	Segment treeStack+1	No attempts yet	2s	1024 MB	Judgeable
RaceGiven a weighted undirected graph, find the minimum total length of a route of k checkpoints where each consecutive pair is joined by an edge, with repeats allowed.	Medium7	Shortest pathDynamic programming+1	No attempts yet	2s	1024 MB	Judgeable
TrianglesCount the triangles formed by mutant triples that strictly contain the point Cerebro, given n points up to 10^5 and coordinates up to 10^9.	Medium7	GeometrySorting+2	No attempts yet	2s	1024 MB	Judgeable
SequencesChoose 2n fighters from two copies of each strength 1 to n+1 so that each chosen strength's copies sit x apart, or report -1.	Medium7	MathImplementation	No attempts yet	2s	1024 MB	Judgeable
New EntertainmentTwo players alternately divide one of two numbers by a divisor greater than one, or divide both by a common one. Decide whether the first player can force a win.	Medium7	Game theoryNumber theory+1	No attempts yet	2s	1024 MB	Judgeable
MessagesFind the minimum time for k messages from vertex 1 to reach k distinct targets, when each edge carries one message per second.	Medium7	GraphBinary search+1	No attempts yet	4s	1024 MB	Judgeable
VolleyballGiven n pole heights and m intervals, find for each interval the longest distance between two poles of equal height with no taller pole between them.	Medium7	Divide and conquerArray+1	No attempts yet	2s	1024 MB	Judgeable
Jump if you can!Find the shortest rope length that lets you jump from the first iceberg to the last, where a rope may not cross any iceberg between them.	Medium7	GeometryBinary search+1	No attempts yet	2s	1024 MB	Judgeable
Digital TwinFind the shortest belt path from (1,1) to (N,N) that moves only left, right, or down and covers every machine cell, or report -1.	Medium7	Dynamic programmingImplementation	No attempts yet	1s	1024 MB	Judgeable
Sea Urchin FieldGiven a sea urchin field graph, find the maximum number of urchins that can be gathered so that no two adjacent urchins are both picked.	Medium7	GraphBFS+1	No attempts yet	1s	1024 MB	Judgeable
xGiven a score and a melody, color every occurrence of the melody's suffixes in the score, then decide which player wins the turn-based game on the colored notes.	Medium7	Game theoryString matching	No attempts yet	1s	1024 MB	Judgeable
Big Number GameGiven N up to 10^12, find the sum of the largest numbers the two players can form from the prime factors of N and of a chosen M less than N.	Medium7	Number theorySorting+1	No attempts yet	1s	1024 MB	Judgeable
Tree and KGiven a weighted tree, answer each query with the XOR of all vertex numbers whose distance from vertex x is exactly d.	Medium7	TreeDivide and conquer+1	No attempts yet	3s	1024 MB	Judgeable
Arctic Fox Flips the BracketsApply flip, reverse, and rotate updates to a bracket string, then report the maximum number of removable () pairs in each queried range.	Medium7	Segment treeString+1	No attempts yet	3s	1024 MB	Judgeable
Mr. Bean and the NewspaperApply k queries that each add row y to row x of an n by m table, then print the final table modulo 1000000007.	Medium7	MatrixSimulation+1	No attempts yet	2s	1024 MB	Judgeable
Spider Web ProductionFind the minimum cost to build a given string from empty using letter append, self-duplication, and last-letter deletion operations.	Medium7	Dynamic programmingString matching+1	No attempts yet	2s	1024 MB	Judgeable
Fun GamePlayers start at 1 and double the number or add 1 without exceeding n; count the winning values of n in [l, r] for the first player.	Medium7	Game theoryMath+1	No attempts yet	2s	1024 MB	Judgeable
KrabsburgersCount the ways to cut n ingredients into k consecutive nonempty groups whose XORs fall in the given per-customer ranges, modulo 1e9+7.	Medium7	Dynamic programmingBit manipulation+1	No attempts yet	3s	1024 MB	Judgeable
President ElectionGiven how many votes each member received, decide whether members can be split into two factions where everyone voted across, and print one valid split.	Medium7	Dynamic programmingMath+1	No attempts yet	2s	1024 MB	Judgeable
Uncle Scrooge's AccountsEach hint gives balances of some accounts on one unknown day. Find positive integer daily amounts b_i that fit every hint, or report NO.	Medium7	MathNumber theory+1	No attempts yet	3s	1024 MB	Judgeable
Reduce the Number of ProblemsSplit an array into contiguous segments whose adjacent lengths differ, maximizing the sum of each segment's XOR.	Medium7	Dynamic programmingBit manipulation+1	No attempts yet	1s	1024 MB	Judgeable
KSA Hide and SeekGiven a tree, find the fewest distance queries needed to identify the hidden building in the worst case.	Medium7	TreeBFS+1	No attempts yet	1.5s	1024 MB	Judgeable
Beetle SandwichesGiven n beetles with satisfaction values a_i and k bread slices, build sandwiches that use every beetle and slice to maximize total satisfaction.	Medium7	Dynamic programmingSorting+1	No attempts yet	2s	1024 MB	Judgeable
Bella's Best FriendsFor each guessed set of consonants, find the longest substring where every listed letter appears the same number of times.	Medium7	Prefix sumHash map+1	No attempts yet	2s	1024 MB	Judgeable
JourneyGiven a weighted railway graph with fare limits A and B, find the minimum amount Korejko spends on a trip from station s to station t.	Medium7	GraphShortest path	No attempts yet	2s	1024 MB	Judgeable
Tickets to ProvallPick two ticket numbers i and j with i AND j equal to 0 that maximize x[i] + y[j], where there are 2^n tickets and n is at most 20.	Medium7	Bit manipulationDynamic programming	No attempts yet	2s	1024 MB	Judgeable
HerculesOstap must reach a hidden person in a tree of rooms by choosing corridors, learning only whether each move brought him closer or farther.	Medium7	TreeGraph+1	No attempts yet	5s	1024 MB	Judgeable
Inversions in a RangeCount the inversions inside each query segment of a permutation, where every query's bounds are shifted by the previous answer.	Medium7	ArraySegment tree+1	No attempts yet	4s	1024 MB	Judgeable
ChairsGiven two rows of jewel values, find the largest sum of one chair from each row that no non-crossing guard set can cover, with 0 if none exists.	Medium7	Binary searchTwo pointers+1	No attempts yet	2s	1024 MB	Judgeable
HistoryBuild a connected simple graph with N vertices, M edges, and weights from 1 to R whose minimum spanning tree weight is exactly S, or print -1 if impossible.	Medium7	Minimum spanning treeGraph+1	No attempts yet	2s	1024 MB	Judgeable
ListGiven n names, count for each length x the pairs whose length-x prefixes and length-x suffixes are both equal.	Medium7	TrieString+1	No attempts yet	2s	1024 MB	Judgeable
Nano's clock handsTwo clocks with N and M ticks have hands moving in opposite directions, and the task asks for the first positive second when both hands point to the same number.	Medium7	Number theoryMath	No attempts yet	1s	1024 MB	Judgeable
Counting primes on a boardStarting from a prime P, a prime q with q-1 = p1 + p2 is replaced by p1 and p2 repeatedly; find the maximum count of primes ever written on the board.	Medium7	MathNumber theory+1	No attempts yet	1s	1024 MB	Judgeable
Hyper Dice RollingTrack the die center through M rolls on an N-dimensional die and print its squared distance from the origin.	Medium7	SimulationMath+1	No attempts yet	2.5s	1024 MB	Judgeable
DelaunayFor each given triangle of levers, check whether its circumscribed circle strictly contains any other lever point.	Medium7	GeometryMath	No attempts yet	2s	1024 MB	Judgeable
Start of the EndGiven an original array and its result after reversing every length-k window from left to right, list all k that could produce the result.	Medium7	ArrayHash map+1	No attempts yet	2s	1024 MB	Judgeable
Sightseeing DriveGiven a weighted tree, find a path with exactly K vertices and total edge weight T, and print its two endpoints in ascending order, or 0 0 if none exists.	Medium7	Divide and conquerTree+1	No attempts yet	2s	1024 MB	Judgeable
Powerful ExplosionCount the distinct values of x / c^y over integers x from 1 to a and y from 0 to b, given a, b, and c.	Medium7	MathNumber theory	No attempts yet	2s	1024 MB	Judgeable
MelmanFind every length-n substring of s that differs from t only at two positions exactly k apart, and print the count and start indices.	Medium7	String matchingString	No attempts yet	2s	1024 MB	Judgeable
JamEach stage adds an arithmetic progression to a range of jars. For each jar, find the first stage where it reaches its required amount, or -1.	Medium7	Binary searchSegment tree	No attempts yet	2s	1024 MB	Judgeable
HighwayDecide whether a person can walk straight up from the corner of a highway with wrapping moving cars without touching a car interior, and if so, find a valid start time.	Medium7	GeometrySimulation+1	No attempts yet	2s	1024 MB	Judgeable
PlagueFind the earliest minute House can reach the city by riding village convoys from village 1 at minute 1, and the fewest transfers that achieve it.	Medium7	Dynamic programmingShortest path	No attempts yet	2s	1024 MB	Judgeable
Round TableCount the ways to seat n economist-politician pairs around a round table of 2n colored chairs so that no three consecutive seats share a field.	Medium7	Dynamic programmingCombinatorics	No attempts yet	2s	1024 MB	Judgeable
One WalkOrient each edge of an undirected graph so that exactly one walk goes from S to E, or print -1 if that is impossible.	Medium7	GraphDFS	No attempts yet	1s	1024 MB	Judgeable
Wolhyang, TakeoffEach staff member adds their ability on a chosen day exactly once, and cumulative sums must meet every deadline. Find the maximum total by the last deadline.	Medium7	GreedyHeap+1	No attempts yet	1s	1024 MB	Judgeable
Painting the FenceAfter each prefix of n painted segments, report the largest visible color, where overlapping segments merge into groups colored by their mean.	Medium7	IntervalsSegment tree+1	No attempts yet	2s	1024 MB	Judgeable
BetGiven two strings of letters and digits, decide whether both could come from one original string by replacing some Roman numeral substrings with Arabic numbers.	Medium7	Dynamic programmingString matching+1	No attempts yet	2s	1024 MB	Judgeable
Pizza MarathonAnswer sums of prices over pizzas whose names start with pizza i's name and have length at least k, with point price updates.	Medium7	TrieTree+2	No attempts yet	5s	1024 MB	Judgeable
Secret LaboratoryCount the labeled directed acyclic graphs on n rooms, modulo 1e9+7, for n up to 6500.	Medium7	CombinatoricsDynamic programming+1	No attempts yet	3s	1024 MB	Judgeable
GreedySplit a digit string into the fewest substrings, each forming a number at most x, and report the minimum after each single-digit update.	Medium7	GreedySegment tree	No attempts yet	2s	1024 MB	Judgeable
Restoring a PermutationGiven a transformed permutation, construct a Robin permutation of 1 to 2n that maps to it, or report -1 if none exists.	Medium7	GreedySorting+1	No attempts yet	2s	1024 MB	Judgeable
SawmillGiven saw positions on a ruler and a trunk of length l, find a left-end placement so every log length is between a and b, or report that none exists.	Medium7	Dynamic programmingPrefix sum+1	No attempts yet	2s	1024 MB	Judgeable
Where am I?Given an undirected friendship graph of n houses, list every house reachable from house 1 by a walk of exactly k edges.	Medium7	MatrixGraph+1	No attempts yet	2s	1024 MB	Judgeable
GameGiven n, the length of a hidden palindrome, and m logged appends, decide whether the word is unique, ambiguous, or impossible.	Medium7	StringUnion-find+1	No attempts yet	2s	1024 MB	Judgeable
SentriesFor each sentry, count the other sentries inside the 90-degree cone that its flashlight lights in its fixed direction (N, E, S, or W).	Medium7	Divide and conquerSorting+1	No attempts yet	2s	1024 MB	Judgeable
CardsGiven word t and cards where no card is a suffix of another, find the fewest cards, copies allowed, whose row contains t, and print that row.	Medium7	Dynamic programmingString matching+1	No attempts yet	2s	1024 MB	Judgeable
Ancient CalendarGiven N up to 10^18, count the adjacent zero pairs in the concatenated Zeckendorf representations of 1, 2, 3, ... within the first N characters.	Medium7	Dynamic programmingMath+1	No attempts yet	2s	1024 MB	Judgeable