Problems

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Total results29,384 problems

Linked Triangles
Medium6
Geometry, Brute force+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Special Large Fountain
Medium6
Bit manipulation, Hash map+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Special Homework Reordering
Medium6
Array, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Hat Puzzle
Medium6
Simulation, Bit manipulation+1
No attempts yet
Time limit
10s
Memory limit
1024 MB
Judgeable
Slastičarnica
Medium6
Dynamic programming, Array+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Quartet
Medium6
Graph, Sorting+1
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Cherry Blossom Ending
Medium6
Segment tree, Sorting+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Demon Realm Anam
Medium6
Shortest path, Graph+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Yonsei-Korea Derby
Medium6
Graph, BFS
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Simple Query Problem
Medium6
Array, Segment tree+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Eggplant Breeding
Medium6
Math, Greedy
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Eggplant Landslide
Medium6
Binary search, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Harvesting the Eggplant Farm
Medium6
Tree, Dynamic programming
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Alien Molecule
Medium6
Segment tree, String matching+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Anti-Cheating Seating
Medium6
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Ribbon (Hard)
Medium6
Intervals, Sorting
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
LaLa and Lamp
Medium6
Implementation, Math+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Sanjini's Travel Plan
Medium6
Minimum spanning tree, Union-find+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Teleporter
Medium6
Shortest path, Graph
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
White Light
Medium6
Dynamic programming, Segment tree+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
FEB
Medium6
String, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Favorite Tree
Medium6
Tree, DFS+1
No attempts yet
Time limit
0.1s
Memory limit
1024 MB
Judgeable
Merging Branches
Medium6
Array, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Gravity Queue
Medium6
Queue, Simulation+1
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
Mechanical Duck Research
Medium6
Dynamic programming, Bit manipulation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Spy
Medium6
Dynamic programming, Matrix+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Surviving the Explosions
Medium6
Geometry, Sorting
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Flat Earth
Medium6
Hash map, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Prize Selection for the Contest
Medium6
Greedy, Two pointers+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Tree Climbing (Hard)
Medium6
Dynamic programming, Tree+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Walks and Queries
Medium6
Union-find, Graph
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Items
Medium6
Bit manipulation, Trie+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Schnitzel Chicken Rendezvous
Medium6
BFS, Simulation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Ant mansion collapse
Medium6
Minimum spanning tree, Graph+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
A Tree and Two Edges
Medium6
Graph, Tree+1
No attempts yet
Time limit
3s
Memory limit
2048 MB
Judgeable
First Last
Medium6
Game theory, Graph
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Frequent Flier
Medium6
Dynamic programming, Sliding window+1
No attempts yet
Time limit
2s
Memory limit
2048 MB
Judgeable
Pibonacci 2
Medium6
Dynamic programming, Math
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
One, Two, Three
Medium6
Greedy, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Beautiful Sequence
Medium6
Sorting, Greedy+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
TreeScript
Medium6
Tree, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Two Missing Numbers
Medium6
Bit manipulation, Math+1
No attempts yet
Time limit
1s
Memory limit
64 MB
Judgeable
Kth Lex Min Min Min Subpalindromes
Medium6
Greedy, Combinatorics+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Counting K4 Subgraphs
Medium6
Graph, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Classical Scheduling Problem
Medium6
Sorting, Binary search+1
No attempts yet
Time limit
6s
Memory limit
1024 MB
Judgeable
Block Stacking
Medium6
Dynamic programming, Prefix sum
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Simplification
Medium6
Dynamic programming, Geometry
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Group Work
Medium6
Combinatorics, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Count the Integers
Medium6
Dynamic programming, String matching
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Interfered-Jumped
Medium6
Tree, DFS+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Kneaded-Loosened
Medium6
Math, Number theory+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Wiped-Xeroxed
Medium6
Matrix, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Unite to Survive
Medium6
Hash map, Union-find+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Split Surveillance Zones
Medium6
Binary search, Greedy+1
No attempts yet
Time limit
1.5s
Memory limit
512 MB
Judgeable
Minimum Cost Roads
Medium6
Shortest path, Graph+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Line Town
Medium6
Sorting, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Skate Practice
Medium6
Greedy, Stack+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Meat Party
Medium6
Segment tree, Intervals+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Ant Nests on the Lawn
Medium6
Tree, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Run Run Run
Medium6
Shortest path, BFS+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Jaeha's Toy
Medium6
Geometry, Graph+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Jubeat
Medium6
Math, Number theory+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Olympics
Medium6
Greedy, Sorting+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Clear Sky Project
Medium6
Dynamic programming, Intervals+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Talk jail
Medium6
Sorting, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
N-beat
Medium6
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
GGGCCCDDD
Medium6
Number theory, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Island Alliances
Medium6
Union-find, Hash map
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Thieves and Prisons
Medium6
Simulation, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Balloon Darts
Medium6
Geometry, Brute force+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Freestyle Masonry
Medium6
Sorting, Array+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Animosity
Medium6
Dynamic programming, Tree
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
HODOŠAN
Medium6
Segment tree, Array+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
JETPACK
Medium6
Graph, BFS+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Graph
Medium6
Graph, Recursion+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Average
Medium6
Number theory, Greedy
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Revolving Sushi
Medium6
Simulation, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Sloth
Medium6
Tree, Recursion+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Gerrymandering
Medium6
Dynamic programming, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Mosquito Killer
Medium6
Dynamic programming, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Lead or Butterfly
Medium6
Graph, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Polarizers
Medium6
Segment tree, Bit manipulation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Nabiya Nabiya
Medium6
Combinatorics, Geometry+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Ones
Medium6
Array, Binary search+1
No attempts yet
Time limit
2.5s
Memory limit
1024 MB
Judgeable
Heavy coins
Medium6
Bit manipulation, Divide and conquer+1
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
Sequence
Medium6
Hash map, Sliding window+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Pleasant Playlist
Medium6
Binary search, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Autumn Megapalindrome
Medium6
Math, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Subway Priority Seating
Medium6
Simulation, Number theory+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Autumn Novella
Medium6
String, Hash map+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Exhibit Placement
Medium6
Sorting, Segment tree+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Alien Squids
Medium6
Stack, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Escape from the Space Prison
Medium6
Array, Implementation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Switchman
Medium6
BFS, Simulation+2
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Monsters and Humans
Medium6
Dynamic programming, Graph+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Investigating the Evidence
Medium6
Stack, Tree
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Criminal Network
Medium6
Tree, DFS+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Marker in the Library
Medium6
String, Divide and conquer+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Defense Plan
Medium6
Dynamic programming, Sliding window+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Payakan in Trouble
Medium6
BFS, Simulation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Linked TrianglesGiven six points in 3D space, list every split into two triangles where one triangle is linked to the other by piercing.	Medium6	GeometryBrute force+1	No attempts yet	2s	1024 MB	Judgeable
Special Large FountainGiven a starting fountain height x0, apply the XOR-based update rule N times and print the height at time N, with x0 and N up to 10^18.	Medium6	Bit manipulationHash map+1	No attempts yet	1s	512 MB	Judgeable
Special Homework ReorderingDecide whether a permutation can be turned into a target permutation by repeatedly sorting any three adjacent elements in ascending or descending order.	Medium6	ArrayMath	No attempts yet	1s	1024 MB	Judgeable
Hat PuzzleGiven who can see whose hat, simulate rounds of public yes/no answers over all hat configurations and output each asked setter's answer.	Medium6	SimulationBit manipulation+1	No attempts yet	10s	1024 MB	Judgeable
SlastičarnicaCustomers arrive in order, each taking d cakes from one end of a row with all sweetness at least s. Find the maximum number of customers that can be served.	Medium6	Dynamic programmingArray+1	No attempts yet	2s	1024 MB	Judgeable
QuartetChoose four students and seat them in a line to maximize the sum of synergy weights between adjacent seats in a weighted graph.	Medium6	GraphSorting+1	No attempts yet	1.5s	1024 MB	Judgeable
Cherry Blossom EndingGiven N cherry trees with bloom periods over M days, find the longest run of adjacent trees blooming together on any day and how many days reach that length.	Medium6	Segment treeSorting+1	No attempts yet	3s	1024 MB	Judgeable
Demon Realm AnamFor each building, count the minimum-cost paths from building 1, printing -1 when a zero-cost cycle makes the count infinite.	Medium6	Shortest pathGraph+2	No attempts yet	2s	1024 MB	Judgeable
Yonsei-Korea DerbyPick at least one Korea player to maximize the number of ambushing Korea players minus the Yonsei players they eliminate.	Medium6	GraphBFS	No attempts yet	2s	1024 MB	Judgeable
Simple Query ProblemGiven a permutation and range queries, compute the sum of \|a_i - a_j\| over all pairs i <= j inside each query range.	Medium6	ArraySegment tree+1	No attempts yet	3s	1024 MB	Judgeable
Eggplant BreedingGiven eggplant varieties and each assistant's set, decide whether some cross order lets Kiwi finish with a white eggplant, printing W or P.	Medium6	MathGreedy	No attempts yet	1s	1024 MB	Judgeable
Eggplant LandslideRains add water to floors one at a time; find the first rain after which some floor collapses and name one such floor, or report -1.	Medium6	Binary searchPrefix sum+1	No attempts yet	1s	1024 MB	Judgeable
Harvesting the Eggplant FarmGiven a tree rooted at plot 1, find the minimum total walking distance to collect every leaf while carrying at most 3 eggplants per trip back to the root.	Medium6	TreeDynamic programming	No attempts yet	2s	1024 MB	Judgeable
Alien MoleculeGiven a string S with range-overwrite updates, the task answers whether each substring S[l..r] equals one of N given patterns.	Medium6	Segment treeString matching+1	No attempts yet	3s	1024 MB	Judgeable
Anti-Cheating SeatingArrange students of N classes in one row so the minimum gap between two students from the same class is as large as possible, then print the class sequence.	Medium6	GreedySorting+1	No attempts yet	1s	1024 MB	Judgeable
Ribbon (Hard)Given N ribbons with positions, lengths, and colors, find two ribbons of different colors whose reach intervals overlap, or report that none exist.	Medium6	IntervalsSorting	No attempts yet	1s	1024 MB	Judgeable
LaLa and LampGiven a triangular grid of bulbs, decide whether flipping whole rows in any of the three directions can turn every bulb off.	Medium6	ImplementationMath+1	No attempts yet	3s	1024 MB	Judgeable
Sanjini's Travel PlanGiven a weighted connected graph, pick N-1 roads with maximum total length, then find the shortest walk from the start city that visits every city.	Medium6	Minimum spanning treeUnion-find+1	No attempts yet	1s	512 MB	Judgeable
TeleporterFind the round when Bi Taro minimizes and Biba Ko maximizes the time to reach room N from room 1, or -1 if the game never ends.	Medium6	Shortest pathGraph	No attempts yet	2s	1024 MB	Judgeable
White LightTurn off runs of up to K consecutive lights so the lights left on read as RGB repeated; find the minimum number of operations.	Medium6	Dynamic programmingSegment tree+1	No attempts yet	2s	1024 MB	Judgeable
FEBGiven a string of B, E, and unknown F characters, list every possible count of adjacent equal pairs (BB or EE) after each F is filled with B or E.	Medium6	StringGreedy+1	No attempts yet	2s	1024 MB	Judgeable
Favorite TreeGiven two trees T1 and T2, decide whether T1 contains a connected subtree that is isomorphic to T2.	Medium6	TreeDFS+1	No attempts yet	0.1s	1024 MB	Judgeable
Merging BranchesGiven N sorted sales territories, answer Q queries for the minimum widening K that merges branches s through e into one.	Medium6	ArrayGreedy+1	No attempts yet	2s	1024 MB	Judgeable
Gravity QueueProcess Q queries on a queue that rotates, where balls fall out below the lowest shield when vertical, and print the ball and shield counts.	Medium6	QueueSimulation+1	No attempts yet	0.5s	1024 MB	Judgeable
Mechanical Duck ResearchGiven N battery powers and a limit K, count the distinct sums made from 1 to K batteries and print them in ascending order.	Medium6	Dynamic programmingBit manipulation	No attempts yet	1s	1024 MB	Judgeable
SpyCount the N-day mission plans whose total progress reaches at least M, where a repeated place halves that day's progress.	Medium6	Dynamic programmingMatrix+1	No attempts yet	2s	1024 MB	Judgeable
Surviving the ExplosionsGiven N explosion points, decide whether a person at the origin moving at speed 1 can avoid all expanding blast circles forever.	Medium6	GeometrySorting	No attempts yet	2s	1024 MB	Judgeable
Flat EarthChoose nonzero row and column multipliers that make every cell of an N x N grid equal, minimizing the number of distinct multiplier values.	Medium6	Hash mapMath+1	No attempts yet	2s	1024 MB	Judgeable
Prize Selection for the ContestGiven a budget and sorted prices, find how many of each prize to buy so each place gets the priciest prize the remaining participants can still afford.	Medium6	GreedyTwo pointers+1	No attempts yet	1s	1024 MB	Judgeable
Tree Climbing (Hard)Count the root-to-leaf chains where each jump goes down 1 to A_i levels to a descendant, with N up to 10^6.	Medium6	Dynamic programmingTree+1	No attempts yet	2s	1024 MB	Judgeable
Walks and QueriesAfter each path is added, count the rooms whose connected component contains an odd cycle, since those rooms can walk every long enough length.	Medium6	Union-findGraph	No attempts yet	3s	1024 MB	Judgeable
ItemsGiven item positions on a number line, find the most items Juwon can pick up when each pickup doubles the length of his moves.	Medium6	Bit manipulationTrie+1	No attempts yet	3s	1024 MB	Judgeable
Schnitzel Chicken RendezvousFind the earliest minute Sang-hyuk can stand on the same cell as Seon-woo, who circles the grid edge one cell per minute, or report -1.	Medium6	BFSSimulation+1	No attempts yet	1s	1024 MB	Judgeable
Ant mansion collapseFind the minimum total risk of paths linking nests 1 to N to nest 0, then the least stamina among those, or -1 if some nest is unreachable.	Medium6	Minimum spanning treeGraph+1	No attempts yet	2s	1024 MB	Judgeable
A Tree and Two EdgesGiven a connected graph with n nodes and n+1 edges, count the simple paths between each queried pair of nodes.	Medium6	GraphTree+1	No attempts yet	3s	2048 MB	Judgeable
First LastTreat each word as an edge from its first letter to its last letter, then count the words that let Alice force a win when she picks them first in the chain game.	Medium6	Game theoryGraph	No attempts yet	1s	2048 MB	Judgeable
Frequent FlierGiven monthly flight counts, find the fewest flights you must pay for when every m consecutive months requires at least k paid flights or all flights in that span.	Medium6	Dynamic programmingSliding window+1	No attempts yet	2s	2048 MB	Judgeable
Pibonacci 2Given n, compute P[n] where P[n] = P[n-1] + P[n-π] for n above π, and print it modulo 10^18.	Medium6	Dynamic programmingMath	No attempts yet	2s	128 MB	Judgeable
One, Two, ThreeGiven a sequence of 1s, 2s, and 3s, pick the maximum number of disjoint index triples forming the pattern 1-2-3 or 3-2-1 and print them.	Medium6	GreedyImplementation	No attempts yet	2s	1024 MB	Judgeable
Beautiful SequenceRearrange N integers to maximize the number of members that are not less than their neighbors, and print that maximum beauty.	Medium6	SortingGreedy+1	No attempts yet	3s	1024 MB	Judgeable
TreeScriptFind the fewest registers needed to build a rooted tree from its parent array, where a parent must stay in a register until its children are created.	Medium6	TreeDynamic programming+1	No attempts yet	1s	1024 MB	Judgeable
Two Missing NumbersFind the two integers that appear once in a stream where every other value appears twice, reading the stream in two runs that pass two 64-bit numbers forward.	Medium6	Bit manipulationMath+1	No attempts yet	1s	64 MB	Judgeable
Kth Lex Min Min Min SubpalindromesFind the k-th lexicographically smallest length-n array over 1 to m that has the fewest palindromic subarrays, or print -1 if there are fewer than k such arrays.	Medium6	GreedyCombinatorics+1	No attempts yet	3s	1024 MB	Judgeable
Counting K4 SubgraphsCount the 4-vertex subsets of a simple undirected graph (n, m up to 100,000) in which all six edges between them exist.	Medium6	GraphSorting+1	No attempts yet	1s	1024 MB	Judgeable
Classical Scheduling ProblemGiven topics with learning times a_i and confidence thresholds b_i, choose a subset within time t that maximizes the number of confident topics and print it.	Medium6	SortingBinary search+1	No attempts yet	6s	1024 MB	Judgeable
Block StackingGiven N cells with block counts, move blocks between adjacent cells so every count lies in [L, R] and never decreases left to right, minimizing total moves.	Medium6	Dynamic programmingPrefix sum	No attempts yet	2s	1024 MB	Judgeable
SimplificationFind the fewest points to keep from a price history so that every removed point stays within vertical distance delta of the simplified line.	Medium6	Dynamic programmingGeometry	No attempts yet	2s	1024 MB	Judgeable
Group WorkFind the sum, over all permutations of 1 to n, of the ways to split the line into segments whose length equals each segment's minimum, modulo 1e9+7.	Medium6	CombinatoricsDynamic programming+1	No attempts yet	1s	1024 MB	Judgeable
Count the IntegersCount integers in [L, R] whose decimal form contains X as a substring, modulo 998244353, where R can have up to 100000 digits.	Medium6	Dynamic programmingString matching	No attempts yet	5s	1024 MB	Judgeable
Interfered-JumpedIn a tree of N zones, place hurdles so no two adjacent zones both have one, then predict from nearby hurdle counts how many zones lie on some longest path.	Medium6	TreeDFS+1	No attempts yet	3s	1024 MB	Judgeable
Kneaded-LoosenedGiven foot powers L and R and N spots needing exact forces S_i, find foot placements and repeat counts that hit every spot exactly, or report -1.	Medium6	MathNumber theory+1	No attempts yet	1s	1024 MB	Judgeable
Wiped-XeroxedGiven an M by N black-and-white image with dust, restore the original blueprint by wiping at most C full rows or columns, using the fact that dust never sits on two adjacent pixels.	Medium6	MatrixGreedy+1	No attempts yet	2s	1024 MB	Judgeable
Unite to SurviveGiven N sets, process commands that merge set b into set a and empty set b, and print the size of a queried set.	Medium6	Hash mapUnion-find+1	No attempts yet	2s	1024 MB	Judgeable
Split Surveillance ZonesSplit N rooms on a corridor into M consecutive zones so that the largest total pairwise distance within any zone is as small as possible.	Medium6	Binary searchGreedy+1	No attempts yet	1.5s	512 MB	Judgeable
Minimum Cost RoadsGiven a weighted undirected road graph, keep a subset of roads with minimum total cost so every pair's shortest distance stays unchanged.	Medium6	Shortest pathGraph+1	No attempts yet	2s	1024 MB	Judgeable
Line TownGiven N happiness values, find the fewest adjacent swaps that sort them, where each swap negates both swapped values, or report -1 if impossible.	Medium6	SortingGreedy+1	No attempts yet	2s	1024 MB	Judgeable
Skate PracticeGiven N speed limits, find the maximum sum of speeds when speed can rise freely but drops by at most 1 between consecutive points.	Medium6	GreedyStack+1	No attempts yet	2s	1024 MB	Judgeable
Meat PartyGiven meat pieces as intervals with tastiness and skewer pairs, output for each person the total tastiness of pieces both skewers pierce and no earlier person removed.	Medium6	Segment treeIntervals+1	No attempts yet	3s	1024 MB	Judgeable
Ant Nests on the LawnGiven a tree of N rooms, count the room pairs where adding one tunnel between them keeps the maximum set of non-adjacent ants the same size.	Medium6	TreeDynamic programming+1	No attempts yet	2s	1024 MB	Judgeable
Run Run RunFind the minimum number of days for a knight to reach a rook on an N by N board, where carrot cells give the knight extra moves on the day it eats them.	Medium6	Shortest pathBFS+1	No attempts yet	3s	1024 MB	Judgeable
Jaeha's ToyGiven a closed polyline whose segments may cross each other, count the bounded regions with positive area that it forms.	Medium6	GeometryGraph+1	No attempts yet	1s	1024 MB	Judgeable
JubeatGiven a score S and a range [a, b] for the note count N, sum every N in the range whose possible scores include S.	Medium6	MathNumber theory+1	No attempts yet	4s	1024 MB	Judgeable
OlympicsFor each country, find its best possible rank under two ranking methods after K more events, each awarding one gold, silver, and bronze to different countries.	Medium6	GreedySorting+1	No attempts yet	2s	1024 MB	Judgeable
Clear Sky ProjectGiven N horizontal cloud segments and at most K laser shots, find the minimum total cost, where a shot at x costs x times the number of clouds it removes.	Medium6	Dynamic programmingIntervals+1	No attempts yet	1s	1024 MB	Judgeable
Talk jailFor each of M timed messages with a sender and an unread count, find how many people certainly have not read that message.	Medium6	SortingGreedy+1	No attempts yet	1s	1024 MB	Judgeable
N-beatCount the B-screen sequences on an x by y grid where lit-button totals stay within p1 per screen, p2 per two screens, and p3 per three screens, mod 1e9+7.	Medium6	Dynamic programmingCombinatorics+1	No attempts yet	3s	1024 MB	Judgeable
GGGCCCDDDGiven N and M, compute the sum of gcd(a1, ..., aM) over all M-tuples of integers from 1 to N, modulo 1,000,000,007.	Medium6	Number theoryMath	No attempts yet	1s	1024 MB	Judgeable
Island AlliancesGiven n islands, m enemy pairs, and q merge requests, report for each request whether merging the two states keeps every enemy pair apart.	Medium6	Union-findHash map	No attempts yet	5s	1024 MB	Judgeable
Thieves and PrisonsGiven a log of catch and gate-opening events for thieves across k prisons, assign each event a prison consistent with the log, or report that none exists.	Medium6	SimulationGreedy+1	No attempts yet	1s	1024 MB	Judgeable
Balloon DartsGiven n points in the plane, decide whether three straight lines can together pass through every point.	Medium6	GeometryBrute force+1	No attempts yet	1s	1024 MB	Judgeable
Freestyle MasonryGiven the current column heights of a w by h wall, decide whether the empty cells can be filled exactly with 2x1 bricks.	Medium6	SortingArray+1	No attempts yet	2s	1024 MB	Judgeable
AnimositySwap children at any node of a complete binary tree to reorder the leaves, minimizing the total animosity between adjacent guests at the table.	Medium6	Dynamic programmingTree	No attempts yet	1.5s	1024 MB	Judgeable
HODOŠANGiven two dancers' known genres and a song sequence, find the longest run of songs both can dance to, both before and after one dancer learns a new genre.	Medium6	Segment treeArray+1	No attempts yet	1s	1024 MB	Judgeable
JETPACKGiven fuel costs for each jetpack move and refueling at every station, find which stations Maroje can reach from the first station.	Medium6	GraphBFS+1	No attempts yet	2s	1024 MB	Judgeable
GraphGiven a graph, decide whether it can be built by recursively joining three smaller copies with three new edges at each level.	Medium6	GraphRecursion+1	No attempts yet	2s	1024 MB	Judgeable
AverageGiven N integers, repeatedly replace two numbers with an even sum by their mean. Decide whether one number can remain and output a valid sequence of operations.	Medium6	Number theoryGreedy	No attempts yet	3s	1024 MB	Judgeable
Revolving SushiGiven N setters with sushi counts and N+1 rotating cooks, find the minute when every setter has eaten all leftover sushi in sets of K, or -1 if never.	Medium6	SimulationMath+1	No attempts yet	2s	1024 MB	Judgeable
SlothGiven the preorder and postorder traversals of a binary tree, count the binary trees that produce both, modulo 998244353.	Medium6	TreeRecursion+1	No attempts yet	2s	1024 MB	Judgeable
GerrymanderingSplit the array into contiguous segments so that positive-sum segments outnumber negative-sum segments. Zero-sum segments do not count either way.	Medium6	Dynamic programmingPrefix sum+1	No attempts yet	1s	1024 MB	Judgeable
Mosquito KillerFind the minimum time for Hayak-i to walk from building R at position 0 to building T at position L while spraying mosquitoes that approach from ahead.	Medium6	Dynamic programmingGreedy+1	No attempts yet	1s	1024 MB	Judgeable
Lead or ButterflyCount the distinct butterfly subgraphs in a given graph, where a butterfly is a center vertex with two disjoint triangles and two pendant neighbors.	Medium6	GraphCombinatorics+1	No attempts yet	1s	1024 MB	Judgeable
PolarizersGiven a row of polarizers with angle updates, answer whether light entering one polarizer can pass through another polarizer further down the row.	Medium6	Segment treeBit manipulation	No attempts yet	1s	1024 MB	Judgeable
Nabiya NabiyaGiven N points with no three collinear, count the 4-point cycles whose two opposite sides cross, with each segment set counted once.	Medium6	CombinatoricsGeometry+1	No attempts yet	2s	1024 MB	Judgeable
OnesFind where the longest run of 1s sits in a hidden bit array, using as few flip-and-query rounds as possible, where each query returns only the new longest run length.	Medium6	ArrayBinary search+1	No attempts yet	2.5s	1024 MB	Judgeable
Heavy coinsUsing a scale that compares two equal-size sets of coins, find how many of the 2^K coins are heavy and return the number of one heavy coin.	Medium6	Bit manipulationDivide and conquer+1	No attempts yet	0.5s	1024 MB	Judgeable
SequenceCount the subarrays whose values form a permutation of 1 to the subarray length, given a sequence of N natural numbers.	Medium6	Hash mapSliding window+1	No attempts yet	1s	1024 MB	Judgeable
Pleasant PlaylistGiven songs whose enjoyment drops with each consecutive repeat, find the total enjoyment of a k-song playlist built by always picking the currently best song.	Medium6	Binary searchSorting+1	No attempts yet	1s	1024 MB	Judgeable
Autumn MegapalindromeGiven an n by m grid of letters, decide whether reordering rows and columns can make every row and every column a palindrome.	Medium6	MathCombinatorics+1	No attempts yet	1s	1024 MB	Judgeable
Subway Priority SeatingGiven regular passengers who check their phones every a_i minutes and priority passengers boarding at times b_i, find when each priority passenger gets a seat.	Medium6	SimulationNumber theory+1	No attempts yet	1s	1024 MB	Judgeable
Autumn NovellaGiven a cyclic keyboard of n letters and a string s, determine whether s can be typed by stepping to the next key or jumping between keys with the same letter.	Medium6	StringHash map+1	No attempts yet	1s	1024 MB	Judgeable
Exhibit PlacementCount the distinct sets of exactly n exhibits that equal all exhibits with height at most H and width at most W for some H and W.	Medium6	SortingSegment tree+1	No attempts yet	1s	1024 MB	Judgeable
Alien SquidsGiven n columns of squids, find the minimum number of operations that remove x squids from a run of equal-height adjacent columns until all columns are empty.	Medium6	StackImplementation	No attempts yet	1s	1024 MB	Judgeable
Escape from the Space PrisonGiven a sorted array and a permutation, find the number of applications of the permutation needed until every value a_i can be seen at position i in some state.	Medium6	ArrayImplementation+1	No attempts yet	1s	1024 MB	Judgeable
SwitchmanFind the fewest seconds to walk from a start cell to a target cell in a grid where arrows rotate 45 degrees each second, or report -1 if impossible.	Medium6	BFSSimulation+2	No attempts yet	3s	1024 MB	Judgeable
Monsters and HumansGiven each player's accusation target, find the largest set of monsters where no monster accuses another monster.	Medium6	Dynamic programmingGraph+1	No attempts yet	1s	1024 MB	Judgeable
Investigating the EvidenceFor each start clue, find where the leftward walk stops when it moves only over clues of weight at most the current one and at most k equal-weight moves.	Medium6	StackTree	No attempts yet	2s	1024 MB	Judgeable
Criminal NetworkPick one member to call so that the most people, counting members and their foot soldiers, receive the message within T minutes.	Medium6	TreeDFS+2	No attempts yet	2s	1024 MB	Judgeable
Marker in the LibraryGiven a string s, repeatedly write one character and split on it, recursing on both sides. Find the lexicographically smallest string this process can produce.	Medium6	StringDivide and conquer+2	No attempts yet	1s	1024 MB	Judgeable
Defense PlanFind the fewest shelter windows of exactly x consecutive attacks that cover every attack stronger than m, with each window starting no later than attack n-x+1.	Medium6	Dynamic programmingSliding window+1	No attempts yet	1s	1024 MB	Judgeable
Payakan in TroubleFind the minimum number of moves and turns for a length-k snake to move its head from the top-left start to the bottom-right cell of a grid with reefs.	Medium6	BFSSimulation+1	No attempts yet	1s	1024 MB	Judgeable