Problems

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Total results29,262 problems

Piling Papers
Hard8
Dynamic programming, String
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Bakery
Hard8
Math, Geometry+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Three Similar Chocolates
Hard8
Geometry, Number theory+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Singularity of the Nim
Hard8
Game theory, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Square Deck 2
Hard8
Math, Number theory+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Permutation Cycles and Queries
Hard8
Number theory, Array+1
No attempts yet
Time limit
7s
Memory limit
512 MB
Judgeable
Yoon stole something huge
Hard8
Game theory, Graph+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Three People on a Tree
Hard8
Tree, Dynamic programming+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
낱말 퍼즐
Hard8
Simulation, Implementation+1
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Purification Tanks
Hard8
Tree, DFS+2
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Belt Conveyor
Hard8
Tree, Bit manipulation+1
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Tourism
Hard8
Tree, Sliding window+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Pareidolia
Hard8
Segment tree, Dynamic programming+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Good Bitstrings
Hard8
Number theory, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Triples of Cows
Hard8
Union-find, Tree+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Tree Merging
Hard8
Tree, DFS+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Monochrome Tree
Hard8
Tree, Dynamic programming
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Binary Sequence and Queries
Hard8
Segment tree, String+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Tsunami
Hard8
Dynamic programming, Segment tree+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Triangle Adventure
Hard8
Shortest path, Union-find+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Shuffled Stones
Hard8
Combinatorics, Math
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Splitting Pairs
Hard8
Game theory, Math+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Lucky Stars Management
Hard8
Tree, DFS+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Optimal Quadratic Function
Hard8
Math, Binary search+1
No attempts yet
Time limit
10s
Memory limit
1024 MB
Judgeable
Cooperation Game
Hard8
Dynamic programming, Greedy+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Shortest Path Query
Hard8
Shortest path, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Banshee
Hard8
Greedy, Binary search+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Courses
Hard8
Dynamic programming, Combinatorics
No attempts yet
Time limit
15s
Memory limit
1024 MB
Judgeable
Sets May Be Good
Hard8
Math, Matrix+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
LCSLCSLCS
Hard8
Dynamic programming, String
No attempts yet
Time limit
10s
Memory limit
1024 MB
Judgeable
Record Parity
Hard8
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
5
Hard8
Dynamic programming, Math
No attempts yet
Time limit
5s
Memory limit
555 MB
Judgeable
Classical Counting Problem
Hard8
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Classical FFT Problem
Hard8
Combinatorics, Math
No attempts yet
Time limit
10s
Memory limit
1024 MB
Judgeable
Cyberland
Hard8
Shortest path, Dynamic programming+2
No attempts yet
Time limit
7s
Memory limit
1024 MB
Judgeable
Dominoes
Hard8
Stack, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Ammunition Storage
Hard8
Matrix, Linked list+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Network Topology in Hezardastan
Hard8
Graph, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Stone Taking Game
Hard8
Game theory, Graph+1
No attempts yet
Time limit
0.5s
Memory limit
256 MB
Judgeable
Tree and Flags
Hard8
Tree, DFS+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Colored-Dealt
Hard8
Implementation, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Estimated-Floccinaucinihilipilificated
Hard8
Game theory, Binary search+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Starred-Transferred
Hard8
Graph, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Inversion Number Squared
Hard8
Probability, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Galaxy Online Marketing Project
Hard8
Sorting, Two pointers+2
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
The Five Heroes' Swords
Hard8
Dynamic programming, Game theory+1
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Triangle Collection
Hard8
Greedy, Segment tree+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Zigzag
Hard8
Segment tree, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Foolish Lock
Hard8
Dynamic programming, Segment tree+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Link Cut Tomato
Hard8
Graph, Union-find+2
No attempts yet
Time limit
3.5s
Memory limit
1024 MB
Judgeable
ChatNOI
Hard8
Graph, Hash map+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Recurrence and Period
Hard8
Number theory, Matrix+1
No attempts yet
Time limit
0.5s
Memory limit
512 MB
Judgeable
Distance Code
Hard8
Tree, Implementation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Sum of five squares
Hard8
Math, Number theory
No attempts yet
Time limit
5.555s
Memory limit
555 MB
Judgeable
Instability
Hard8
Tree, Dynamic programming
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Similarity
Hard8
Sliding window, Segment tree+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Fibonacci Half Sequence
Hard8
Math, Recursion+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Scallion, Not Eggplant
Hard8
Game theory, Graph+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
An Ordinary String Problem
Hard8
Combinatorics, Graph+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Video Surveillance
Hard8
Sorting, Two pointers+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Trade Route
Hard8
Tree, DFS+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Moving Stones
Hard8
Game theory, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Records and anti-records
Hard8
Dynamic programming, Segment tree+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Garden
Hard8
Two pointers, Segment tree+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Divide
Hard8
Number theory, Math
No attempts yet
Time limit
1.8s
Memory limit
1024 MB
Judgeable
Fork
Hard8
Dynamic programming, Probability
No attempts yet
Time limit
0.15s
Memory limit
1024 MB
Judgeable
Lifts
Hard8
Graph, Greedy+1
No attempts yet
Time limit
2.5s
Memory limit
64 MB
Judgeable
Sorting
Hard8
Number theory, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Dolls
Hard8
Dynamic programming, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Inspections
Hard8
Intervals, Sorting+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Apples into Baskets
Hard8
Sorting, Prefix sum+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Missing Trash
Hard8
Segment tree, Bit manipulation
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Artifacts
Hard8
Tree, Dynamic programming+2
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Pumpkin Placement
Hard8
Dynamic programming, Divide and conquer+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Encrypted Message
Hard8
String matching, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Raid on the Transporter
Hard8
Dynamic programming, Sorting+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Fast Interpreter
Hard8
Bit manipulation, Array+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Costume Problems
Hard8
Combinatorics, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Gigaskeletons
Hard8
Dynamic programming, Number theory+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Perfect Triangle Covering
Hard8
Greedy, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Suspicious Reports
Hard8
String matching, Array+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Zoo
Hard8
Tree, Sliding window+1
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Chain Reaction
Hard8
Shortest path, Graph+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Trains in Zaun
Hard8
Union-find, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Magical clock
Hard8
Number theory, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Blowing Up the Windmill
Hard8
Dynamic programming, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Quest Log
Hard8
Queue, Heap+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Chain Repair
Hard8
Graph, Bit manipulation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
x
Hard8
Tree, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Tree House
Hard8
Math, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Escape from the Building
Hard8
Dynamic programming, Greedy
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Decreasing Growth Rate Tragedy 2
Hard8
Geometry, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Hyeoncheol's Blind Date
Hard8
Dynamic programming, Probability+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Socks Pairing Probability for Dongwoo and Tsundere Jaewoo
Hard8
Probability, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Streaks and Queries
Hard8
Segment tree, Hash map+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Protective Barrier
Hard8
Dynamic programming, Bit manipulation+1
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Unified Network
Hard8
Dynamic programming, Graph+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Delivery Robot
Hard8
Number theory, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Mail Delivery
Hard8
Dynamic programming, Tree+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Mousetraps
Hard8
Geometry, Divide and conquer+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Piling PapersFor each query range of digits, count the ways to add each digit to the top, the bottom, or skip it so the final number lies in [A, B], modulo 1e9+7.	Hard8	Dynamic programmingString	No attempts yet	2s	1024 MB	Judgeable
BakeryGiven friends' orders and waiting limits, find the fewest oven upgrades that cut cookie and muffin times so every friend is served before leaving.	Hard8	MathGeometry+1	No attempts yet	2s	1024 MB	Judgeable
Three Similar ChocolatesCount integer tuples (a,b,c,d) with b+d < N for which some integer point P on segment AC makes triangles ABP, BDP, and DCP pairwise similar.	Hard8	GeometryNumber theory+1	No attempts yet	3s	1024 MB	Judgeable
Singularity of the NimGiven a staircase game where taking x coins from a step adds x^j coins to each lower step j, decide whether the first or second player wins.	Hard8	Game theoryMath+1	No attempts yet	2s	1024 MB	Judgeable
Square Deck 2Merge N single-card decks so each merge pairs cards with a perfect-square sum, minimizing the product of recorded differences modulo 998244353.	Hard8	MathNumber theory+1	No attempts yet	2s	512 MB	Judgeable
Permutation Cycles and QueriesGiven a permutation A and a huge exponent m, answer queries that swap two entries of A and print the sum of S^m(i) times i.	Hard8	Number theoryArray+1	No attempts yet	7s	512 MB	Judgeable
Yoon stole something hugeGiven a tree with Yoon at vertex a and the two officers at b and c, decide whether Yoon can reach a leaf without being caught.	Hard8	Game theoryGraph+2	No attempts yet	1s	1024 MB	Judgeable
Three People on a TreeCount triples of people on three distinct vertices whose pairwise LCA D is not one of them and whose distances to D sum to K, modulo 998244353.	Hard8	TreeDynamic programming+1	No attempts yet	4s	1024 MB	Judgeable
낱말 퍼즐Given an N by M letter grid, apply up to a million cut-and-rotate queries and print the grid each time a type 2 query appears.	Hard8	SimulationImplementation+1	No attempts yet	3s	512 MB	Judgeable
Purification TanksFor each query, find the minimum purification cost to get water of grade K or lower at tank X, using only the source-to-X path of a tree.	Hard8	TreeDFS+2	No attempts yet	3s	512 MB	Judgeable
Belt ConveyorGiven a tree of N tables, recover the original direction of every conveyor using at most 30 product-placement queries.	Hard8	TreeBit manipulation+1	No attempts yet	5s	1024 MB	Judgeable
TourismGiven a tree of islands and a range of spots, find the fewest islands that form a connected subtree containing every spot's island in the range.	Hard8	TreeSliding window+1	No attempts yet	4s	1024 MB	Judgeable
PareidoliaSum B(s) over all substrings of t, where B(s) is the most copies of "bessie" that can be picked as subsequences of s, after each single-character update.	Hard8	Segment treeDynamic programming+1	No attempts yet	4s	1024 MB	Judgeable
Good BitstringsGiven A and B, count the prefixes of gen_string(A, B) that also equal gen_string(x, y) for some positive integers x and y.	Hard8	Number theoryMath+1	No attempts yet	2s	1024 MB	Judgeable
Triples of CowsGiven a tree of N cows, each cow leaves in order and its remaining friends become a clique. Output the count of ordered friend triples before each departure.	Hard8	Union-findTree+1	No attempts yet	2s	1024 MB	Judgeable
Tree MergingGiven an initial rooted tree and a final tree, output a sequence of sibling merge operations that turns the first tree into the second.	Hard8	TreeDFS+1	No attempts yet	2s	1024 MB	Judgeable
Monochrome TreeFor each k from 0 to n, find the fewest ancestor-descendant pairs of black vertices when exactly k vertices of a rooted tree are colored black.	Hard8	TreeDynamic programming	No attempts yet	2s	1024 MB	Judgeable
Binary Sequence and QueriesGiven a binary array with point updates, each range query asks for a subsegment whose longest run of 0s is x and longest run of 1s is y, or -1 if none exists.	Hard8	Segment treeString+1	No attempts yet	3s	1024 MB	Judgeable
TsunamiGiven evacuation spots, obstacle segments with crossing costs, and nondecreasing sideways costs, find the minimum time to reach y=Y from each x from 1 to X.	Hard8	Dynamic programmingSegment tree+1	No attempts yet	4s	1024 MB	Judgeable
Triangle AdventureGiven an N by M grid split by diagonal walls into triangles, answer up to 300,000 queries for the fewest moves between two triangles, or -1 if unreachable.	Hard8	Shortest pathUnion-find+1	No attempts yet	2s	1024 MB	Judgeable
Shuffled StonesGiven N and a pair X, Y, count the sequences of 2N stones with longest decreasing subsequence 2 in which X and Y are a pair, modulo 998244353.	Hard8	CombinatoricsMath	No attempts yet	3s	1024 MB	Judgeable
Splitting PairsGiven piles of stones, decide whether Alice wins a Nim variant where each turn removes k piles and splits k others, with k at most half the piles.	Hard8	Game theoryMath+1	No attempts yet	1s	2048 MB	Judgeable
Lucky Stars ManagementGiven a company tree and expected fines E_i, decide whether the values are consistent and, if so, find Bill's minimum possible annual salary.	Hard8	TreeDFS+2	No attempts yet	2s	1024 MB	Judgeable
Optimal Quadratic FunctionGiven N points (x_i, y_i), find the quadratic ax^2+bx+c that minimizes the maximum squared vertical error over all points and print that minimum.	Hard8	MathBinary search+1	No attempts yet	10s	1024 MB	Judgeable
Cooperation GameGiven a line of class numbers, remove same-class pairs in some order to maximize the sum of their current position distances.	Hard8	Dynamic programmingGreedy+1	No attempts yet	3s	1024 MB	Judgeable
Shortest Path QueryGiven a DAG whose edges are black or white, answer queries for the shortest distance from vertex 1 to x when black edges cost a and white edges cost b.	Hard8	Shortest pathDynamic programming+1	No attempts yet	2s	1024 MB	Judgeable
BansheeGiven buildings on a line with hitpoints and shields, find the minimum time for m banshees to destroy all of them.	Hard8	GreedyBinary search+1	No attempts yet	1s	1024 MB	Judgeable
CoursesCount the course sequences with total cost exactly t and total IQ change at least k, for each t from 1 to n, modulo 998244353.	Hard8	Dynamic programmingCombinatorics	No attempts yet	15s	1024 MB	Judgeable
Sets May Be GoodCount the vertex subsets whose induced edge count is even, for a graph with up to 1000 vertices, modulo 998244353.	Hard8	MathMatrix+1	No attempts yet	2s	1024 MB	Judgeable
LCSLCSLCSGiven strings A and B and repeat counts n and m (up to 10^15), find the LCS length of A repeated n times and B repeated m times.	Hard8	Dynamic programmingString	No attempts yet	10s	1024 MB	Judgeable
Record ParityGiven a permutation, find the sum of (-1)^len over all subsequences with exactly k records (left-to-right maxima), modulo 998244353.	Hard8	Dynamic programmingCombinatorics+1	No attempts yet	1s	1024 MB	Judgeable
5Given an array of non-negative integers with sum S and at least S/5 ones, count the pairs (k, T) where some subsequence of length k sums to T.	Hard8	Dynamic programmingMath	No attempts yet	5s	555 MB	Judgeable
Classical Counting ProblemCount the distinct sets of p problems that can end up as the top p after m judges each vote for v problems, modulo 998244353.	Hard8	Dynamic programmingCombinatorics+1	No attempts yet	2s	1024 MB	Judgeable
Classical FFT ProblemGiven a Young diagram with nondecreasing row widths, find the fewest rooks that cover every cell and count the ways to place them.	Hard8	CombinatoricsMath	No attempts yet	10s	1024 MB	Judgeable
CyberlandFind the minimum time from country 0 to country H when some countries zero the passing time or halve it, with at most K halvings.	Hard8	Shortest pathDynamic programming+2	No attempts yet	7s	1024 MB	Judgeable
DominoesGiven n dominoes that fall left with heights l_i, find for each starting domino the area of the union of quarter circles that topple.	Hard8	StackDynamic programming+1	No attempts yet	2s	1024 MB	Judgeable
Ammunition StorageCount the sub-rectangles of at least 2 by 2 whose four corner cells are taller than every other cell inside the rectangle.	Hard8	MatrixLinked list+1	No attempts yet	2s	1024 MB	Judgeable
Network Topology in HezardastanDecide whether every m-subset of servers can be perfectly matched to the m terminals, and output a failing subset if one cannot.	Hard8	GraphGreedy+1	No attempts yet	2s	1024 MB	Judgeable
Stone Taking GameGiven a cycle whose edges hold stones, find for each i the fewest extra stones Jeonghu must add so he wins from at least i starting vertices.	Hard8	Game theoryGraph+1	No attempts yet	0.5s	256 MB	Judgeable
Tree and FlagsFor each edge of a tree with flagged vertices, count the flag choices where one new edge between the two split parts reconnects them into a tree.	Hard8	TreeDFS+1	No attempts yet	2s	1024 MB	Judgeable
Colored-DealtUsing at most N wreath attempts and only the maximum photo value r + 2g + 3b over rotations, infer the color order of the N flowers Jay places.	Hard8	ImplementationMath+1	No attempts yet	1s	1024 MB	Judgeable
Estimated-FloccinaucinihilipilificatedFind Heeseung's full priority order over N gift candidates by playing the alternating pick game with him, using at most 2048 queries.	Hard8	Game theoryBinary search+1	No attempts yet	1s	1024 MB	Judgeable
Starred-TransferredGiven a network of degree-3 beacons and terminal planets, decide whether some routing policy lets terminal letter counts reveal each beacon's dark matter state.	Hard8	GraphImplementation	No attempts yet	2s	1024 MB	Judgeable
Inversion Number SquaredGiven a_i copies of each value i from 1 to n, find the expected square of the inversion count of a uniformly random arrangement, modulo 998244353.	Hard8	ProbabilityCombinatorics+1	No attempts yet	2s	1024 MB	Judgeable
Galaxy Online Marketing ProjectFor each target P, pick one city per country and optionally add up to C users to one pick, so the total reaches P with the smallest max-min gap.	Hard8	SortingTwo pointers+2	No attempts yet	5s	1024 MB	Judgeable
The Five Heroes' SwordsGiven five disjoint sets of possible attack powers, find the fewest hardness tests needed in the worst case to identify the strongest sword.	Hard8	Dynamic programmingGame theory+1	No attempts yet	5s	1024 MB	Judgeable
Triangle CollectionAfter each update to the stick counts, the task asks for the maximum number of isosceles triangles that can be built from the remaining sticks.	Hard8	GreedySegment tree+1	No attempts yet	4s	1024 MB	Judgeable
ZigzagFor each x, the task sums the longest zigzag subsequence over all subarrays, using only values at most x in a permutation.	Hard8	Segment treeGreedy+1	No attempts yet	2s	1024 MB	Judgeable
Foolish LockGiven a lowercase string with point updates, find the fewest single-letter steps needed to make the string non-decreasing, after each update.	Hard8	Dynamic programmingSegment tree+1	No attempts yet	2s	1024 MB	Judgeable
Link Cut TomatoGiven a graph whose edges form or break on given days, find the earliest day each tomato ripens when ripeness spreads across connected edges.	Hard8	GraphUnion-find+2	No attempts yet	3.5s	1024 MB	Judgeable
ChatNOIGiven a training text and a k-word prefix, append m words so that the minimum follow-count along the sentence is as large as possible.	Hard8	GraphHash map+1	No attempts yet	4s	1024 MB	Judgeable
Recurrence and PeriodGiven a prime p and the recurrence x_n = ax_{n-1} + bx_{n-2} mod p, find the lexicographically smallest (S, T) where the sequence becomes periodic with period T from index S.	Hard8	Number theoryMatrix+1	No attempts yet	0.5s	512 MB	Judgeable
Distance CodeWrite an encoder that orders the removal of tree leaves, and a decoder that rebuilds an isomorphic tree from the distances between successive removed nodes.	Hard8	TreeImplementation+1	No attempts yet	1s	1024 MB	Judgeable
Sum of five squaresGiven n up to 10^10, count the signed integer 4-tuples and 5-tuples whose squares sum to n.	Hard8	MathNumber theory	No attempts yet	5.555s	555 MB	Judgeable
InstabilityCut edges of a rooted tree so each piece is k-good for some k, minimizing the total of f(k) over all pieces.	Hard8	TreeDynamic programming	No attempts yet	1.5s	1024 MB	Judgeable
SimilarityFind the max intersection size of a length-K window of p and a length-K window of q, and count the window pairs achieving it, after each adjacent swap in p.	Hard8	Sliding windowSegment tree+1	No attempts yet	3s	1024 MB	Judgeable
Fibonacci Half SequenceFor n up to 10^18, find the lexicographically smallest sequence a with a[a[n]] = f[n], where f is 1, 2, 3, 5, ...; print -1 if a[n] exceeds 10^18.	Hard8	MathRecursion+1	No attempts yet	2s	1024 MB	Judgeable
Scallion, Not EggplantGiven a grid of 가, 지, 대, 파, and ☆ tiles, decide whether Scallion, Aubergine, or neither wins the alternating move game under optimal play.	Hard8	Game theoryGraph+1	No attempts yet	2s	1024 MB	Judgeable
An Ordinary String ProblemFor each string, count the non-empty strings over a, b, c that have the same number of every length-2 substring, modulo 10^9 + 7.	Hard8	CombinatoricsGraph+1	No attempts yet	2s	1024 MB	Judgeable
Video SurveillanceGiven k image cells on a grid that wraps around in both directions, find the smallest bounding box reachable by cyclic shifts and the fewest button presses needed to reach it.	Hard8	SortingTwo pointers+1	No attempts yet	1s	1024 MB	Judgeable
Trade RouteGiven a tree with a profit on each node, find the maximum-sum simple path that contains all listed countries in each query, or No if none exists.	Hard8	TreeDFS+1	No attempts yet	4s	1024 MB	Judgeable
Moving StonesGiven a row of white stones, black stones, and empty cells, decide which team wins when each turn moves one of its stones forward one cell under optimal play.	Hard8	Game theoryMath	No attempts yet	2s	1024 MB	Judgeable
Records and anti-recordsSplit a permutation into two non-empty subsequences to maximize the records in the first plus the anti-records in the second.	Hard8	Dynamic programmingSegment tree+1	No attempts yet	3s	1024 MB	Judgeable
GardenFind the smallest axis-aligned rectangle that contains at least one artwork of each kind, where type A repeats with period D in both directions and type B in one.	Hard8	Two pointersSegment tree+2	No attempts yet	2s	1024 MB	Judgeable
DivideCount pairs (a, b) with a up to p and b up to q where a*b/(a+b) is an integer between 1 and n.	Hard8	Number theoryMath	No attempts yet	1.8s	1024 MB	Judgeable
ForkGiven P, N, L, and R, find the minimum expected number of key presses to finish typing a fixed N-character string into two random shells.	Hard8	Dynamic programmingProbability	No attempts yet	0.15s	1024 MB	Judgeable
LiftsGiven k lifts with free starting floors and n ordered requests (l, r), find the minimum total floors the lifts travel empty between requests.	Hard8	GraphGreedy+1	No attempts yet	2.5s	64 MB	Judgeable
SortingRecover a hidden permutation of 1 to N using as few position comparisons as possible, with unlimited checks of whether a difference is divisible by any d.	Hard8	Number theorySorting+1	No attempts yet	1s	1024 MB	Judgeable
DollsAfter each doll is added, find the largest stack where every doll is at least 2 bigger than the doll inside it.	Hard8	Dynamic programmingSorting+1	No attempts yet	1s	1024 MB	Judgeable
InspectionsGiven m tasks that each run a range of n machines in order, count the inspections needed for each safety value s in a list.	Hard8	IntervalsSorting+2	No attempts yet	2s	1024 MB	Judgeable
Apples into BasketsFor each query, decide whether every pair (x, y) with x<=a and y<=b can be split between two baskets using apples of weight at most k.	Hard8	SortingPrefix sum+1	No attempts yet	2s	1024 MB	Judgeable
Missing TrashGiven an array with range assign and range AND, OR, or XOR updates, print the sum of a_i XOR i over each type 1 query range.	Hard8	Segment treeBit manipulation	No attempts yet	5s	1024 MB	Judgeable
ArtifactsFind the minimum walk on a weighted tree that visits sites holding all k artifact kinds, where the start and end points cost nothing.	Hard8	TreeDynamic programming+2	No attempts yet	1.5s	1024 MB	Judgeable
Pumpkin PlacementPick fence positions, always including the first and last, to maximize total gap satisfaction minus the chosen discontentment costs.	Hard8	Dynamic programmingDivide and conquer+2	No attempts yet	2s	1024 MB	Judgeable
Encrypted MessageSplit the string t into words so that t is w1 to wn followed by wn to w1, with the maximum possible number of words, then print them.	Hard8	String matchingDynamic programming+1	No attempts yet	1s	1024 MB	Judgeable
Raid on the TransporterFind the longest line of members with nondecreasing strength and speed where each speed step is at most x, then pick one extra member's strength and speed to make it longer.	Hard8	Dynamic programmingSorting+2	No attempts yet	1s	1024 MB	Judgeable
Fast InterpreterGiven array a and a copy b, repeat a program of m shift-then-xor/and/or steps p times (p up to 1e9) and print the final b.	Hard8	Bit manipulationArray+1	No attempts yet	3s	1024 MB	Judgeable
Costume ProblemsGiven n limb types, m head types, and random orders of a limbs and b heads, find the expected number of distinct costumes modulo 1073676287.	Hard8	CombinatoricsMath+1	No attempts yet	1s	1024 MB	Judgeable
GigaskeletonsSplit n skeletons with bone counts up to 2e5 into LCM-wide groups so the sum of each group's LCM is minimal, then print the groups.	Hard8	Dynamic programmingNumber theory+1	No attempts yet	1s	1024 MB	Judgeable
Perfect Triangle CoveringGiven triangle tiles with legs 2^a_i, for each plaza side 2^b find the largest tile size that can cover it exactly, or -1 if impossible.	Hard8	GreedyMath+1	No attempts yet	2s	1024 MB	Judgeable
Suspicious ReportsGiven a full histogram s and a sequence t, decide whether some cut height h makes t equal the heights above h, and if so, output the matching column indices.	Hard8	String matchingArray+1	No attempts yet	1s	1024 MB	Judgeable
ZooGiven a tree of enclosures labeled with species, answer each query with the highest count of one species on the path between two enclosures.	Hard8	TreeSliding window+1	No attempts yet	5s	1024 MB	Judgeable
Chain ReactionFind the minimum time for energy sent from node u at time t0 to reach node v, where some links pass energy only during given time windows.	Hard8	Shortest pathGraph+2	No attempts yet	2s	1024 MB	Judgeable
Trains in ZaunGiven n railway lines opened one by one with train counts and crossings, find the depots of minimum total capacity that fit all trains at every moment.	Hard8	Union-findGreedy+1	No attempts yet	2s	1024 MB	Judgeable
Magical clockGiven a clock with 720t divisions whose minute hand resets when it catches the hour hand, find the fewest ticks between two hand states for each query, or -1.	Hard8	Number theoryMath+1	No attempts yet	2s	1024 MB	Judgeable
Blowing Up the WindmillEach component can be disabled once stability is at least a_i, and it shifts stability by b_i. Find the lowest reachable stability and an order of components that reaches it.	Hard8	Dynamic programmingGreedy+1	No attempts yet	1s	1024 MB	Judgeable
Quest LogProcess a queue of quests with priorities, delete unimportant ones when a product condition holds, and print the id of each quest completed next.	Hard8	QueueHeap+1	No attempts yet	2s	1024 MB	Judgeable
Chain RepairFind the fewest open and solder actions needed to turn the tangled chain into a path where only links i and i+1 are interlocked.	Hard8	GraphBit manipulation+1	No attempts yet	2s	1024 MB	Judgeable
xCount the connected vertex subsets of a tree that contain at least one vertex of each of the m skill colors, modulo 998244353.	Hard8	TreeDynamic programming+1	No attempts yet	2s	1024 MB	Judgeable
Tree HouseGiven n floors of cross-shaped 5-room layouts and m staircases between adjacent floors, find the minimum total distance over all pairs of rooms.	Hard8	MathGreedy+1	No attempts yet	2s	1024 MB	Judgeable
Escape from the BuildingFind the minimum total energy the robber spends on chip uses while climbing an n-floor building to reach the roof before the police.	Hard8	Dynamic programmingGreedy	No attempts yet	2s	1024 MB	Judgeable
Decreasing Growth Rate Tragedy 2Given N daily growth readings rounded to 0.001 cm, find the largest constant growth rate that can produce them, or report Impossible.	Hard8	GeometryPrefix sum+1	No attempts yet	1s	1024 MB	Judgeable
Hyeoncheol's Blind DateSplit n consecutive laundry items into baskets to minimize the expected washing time, where a basket of total weight g takes g^2 and each extra basket adds c.	Hard8	Dynamic programmingProbability+1	No attempts yet	1s	1024 MB	Judgeable
Socks Pairing Probability for Dongwoo and Tsundere JaewooGiven n sock types and m random draws, find the probability that the floor sock count after m trials equals the count at the start.	Hard8	ProbabilityMath+1	No attempts yet	2s	1024 MB	Judgeable
Streaks and QueriesGiven submissions, verdict flips, and day advances, print the longest streak of the user whose streak ranks k-th largest.	Hard8	Segment treeHash map+1	No attempts yet	1s	1024 MB	Judgeable
Protective BarrierFor each attempt, find the spell order that maximizes the sum of range maxima over q given intervals, with n up to 30 and m up to 1000.	Hard8	Dynamic programmingBit manipulation+1	No attempts yet	5s	1024 MB	Judgeable
Unified NetworkGiven a connected edge cactus of cities, assign one of three transmitter types to each city so adjacent cities differ, using as few type-three transmitters as possible.	Hard8	Dynamic programmingGraph+1	No attempts yet	2s	1024 MB	Judgeable
Delivery RobotGiven a start point and a target point, build a sequence of at most 10^6 rotation commands around two towers, or report -1 if none exists.	Hard8	Number theoryMath+1	No attempts yet	2s	1024 MB	Judgeable
Mail DeliveryCount the DFS visiting orders from the capital where every parcel's source city is visited before its destination city, modulo 1e9+7.	Hard8	Dynamic programmingTree+1	No attempts yet	2s	1024 MB	Judgeable
MousetrapsGiven n points, remove one so the convex hull of the remaining points has minimum area, and print twice that area.	Hard8	GeometryDivide and conquer+1	No attempts yet	2s	1024 MB	Judgeable