Problems

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Total results29,275 problems

Warehouse Polygon
Medium7
Stack, Geometry+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Otherworld Game
Medium7
BFS, Brute force+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Turning Off Streetlights
Medium7
Dynamic programming, Greedy+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
City Round Trips 2
Medium7
Graph, Shortest path+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Binary Matrix
Medium7
Graph, BFS+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Symmetric Picture 2
Medium7
Geometry, Math+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Escape
Medium7
Graph, Shortest path+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Binary Tree Drawing
Medium7
Dynamic programming, Tree+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Counting Submatrices with Divisible Sums
Medium7
Prefix sum, Hash map+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Unnecessary Numbers
Medium7
Math, Number theory+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Compare Tree Traversal Paths
Medium7
Tree, String+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Three-Way Call
Medium7
Graph, Shortest path+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Maximum String Pasting
Medium7
String matching, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Unit Fraction Decomposition
Medium7
Backtracking, Number theory+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Stable Network
Medium7
Union-find, Minimum spanning tree+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Covering Holes in a Board
Medium7
Graph, Bit manipulation+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Rectangle
Medium7
Geometry, Hash map+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Department Assignment
Medium7
Union-find, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tree Path Partition
Medium7
Tree, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Paving Blocks
Medium7
Graph, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bookshelf
Medium7
Binary search, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Mobile Binary Number
Medium7
Dynamic programming, Recursion+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Crossing Segments
Medium7
Dynamic programming, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Number Dial Alignment
Medium7
Greedy, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Monkeys
Medium7
Graph, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Heewon's New York Life
Medium7
Geometry, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
High-Speed Railway
Medium7
Intervals, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Grid Board
Medium7
Binary search, Greedy
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Rotating Square Tiles
Medium7
BFS, Brute force+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Magic Colored Paper
Medium7
Simulation, Binary search+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Car Race
Medium7
Graph, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Mischievous Frogs
Medium7
Greedy, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
DNA Similarity
Medium7
Dynamic programming, String
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Gene
Medium7
String matching, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cube Net
Medium7
Simulation, Geometry+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Connecting Black and White Points
Medium7
Greedy, Stack+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Emergency Contact Network
Medium7
Tree, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Connecting Rectangles
Medium7
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
I²C
Medium7
Simulation, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
How Was Typesetting Done in the Past?
Medium7
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Reading UPC Barcodes
Medium7
String matching, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Optimizing Mobile Phone Text Entry
Medium7
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Fibonacci Number 3
Medium7
Math, Matrix+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Magician Hyunwoo
Medium7
Combinatorics, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Completely Diversified Sequence
Medium7
Combinatorics, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Secret Words
Medium7
Dynamic programming, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Romantic King
Medium7
BFS, Dynamic programming+1
No attempts yet
Time limit
10s
Memory limit
128 MB
Judgeable
Restore the Sequence
Medium7
Greedy, Backtracking+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
F7 Championship Candidates
Medium7
Greedy, Binary search+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Business Expansion
Medium7
Shortest path, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Meetings
Medium7
Geometry, Binary search+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Trampoline
Medium7
Graph, DFS+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cake Cuts
Medium7
Math, Geometry+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Crayons
Medium7
Binary search, Brute force+2
No attempts yet
Time limit
5s
Memory limit
160 MB
Judgeable
Stacking Books
Medium7
Greedy, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
ASCII Street
Medium7
String matching, Trie+1
No attempts yet
Time limit
4s
Memory limit
512 MB
Judgeable
Sangbeom's Melancholy
Medium7
Intervals, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Attractive Fence
Medium7
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Function Return Value
Medium7
Dynamic programming, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Descending-Run Sorting
Medium7
Array, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Alien Guitar Performance
Medium7
Stack, Greedy+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Tap Dance
Medium7
Segment tree, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Minimum Number of Ships
Medium7
Greedy, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Donggyu's Keyboard Paint Program
Medium7
Simulation, Implementation+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Candy Candy
Medium7
Binary search, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Walking Trail
Medium7
Prefix sum, Binary search+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Prime Cycle
Medium7
Simulation, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Gremlins
Medium7
Dynamic programming, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Clearing the Beads
Medium7
Dynamic programming, Stack+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Explosion-Safe Folding
Medium7
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Call Reconstruction
Medium7
Greedy, Intervals+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Donghyuk Astronomical Observatory
Medium7
Math, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sorting with Restricted Swaps
Medium7
BFS, Brute force+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Clothesline
Medium7
Prefix sum, Geometry+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Mineral Clusters
Medium7
Simulation, Matrix+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
LRH Plants
Medium7
Segment tree, Geometry+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Aladdin and the Lamp
Medium7
Simulation, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Strange Painter
Medium7
Divide and conquer, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Symmetric Matrix
Medium7
Greedy, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Zoo Expansion
Medium7
Binary search, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Greco-Roman Architecture
Medium7
Brute force, Geometry+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Donghyuk, King of the Board Game
Medium7
Math, Bit manipulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Messengers
Medium7
Binary search, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Playlist Display Intervals
Medium7
Greedy, Intervals+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Self Product
Medium7
Math, Number theory+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Bomb Production
Medium7
Binary search, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
A=S
Medium7
Dynamic programming, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The King's Visit
Medium7
Shortest path, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Median of a Contiguous Subsequence
Medium7
Prefix sum, Hash map+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Closest Permutation Numbers
Medium7
Greedy, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Victory
Medium7
Dynamic programming, Game theory+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Longest Repeated Substring
Medium7
String, Binary search+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Housewarming
Medium7
Dynamic programming, Stack+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Minimize the Difference
Medium7
Binary search, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cookies
Medium7
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Salary Increase
Medium7
Tree, Binary search+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bakery
Medium7
Graph, Greedy+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Fence
Medium7
Sorting, Stack+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Gamers' Arrogance
Medium7
Binary search, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Lake
Medium7
Graph, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Warehouse PolygonGiven pillar positions and heights, compute the minimum area of a roof polygon that covers all pillars while forming a shape without concave water-collecting dips, using a monotonic stack over the skyline.	Medium7	StackGeometry+1	No attempts yet	2s	128 MB	Judgeable
Otherworld GameFind the minimum adjacent swaps on a 4x4 grid to transform a current P/L pattern into a target pattern.	Medium7	BFSBrute force+1	No attempts yet	2s	128 MB	Judgeable
Turning Off StreetlightsFind the optimal order to switch off all streetlights on a line, starting from a given position, minimizing sum of power times shutoff time, a classic interval DP problem.	Medium7	Dynamic programmingGreedy+1	No attempts yet	2s	128 MB	Judgeable
City Round Trips 2Given a graph, find the maximum number of vertex-disjoint (except endpoints 1 and 2) paths between cities 1 and 2, essentially a max-flow problem with vertex capacities.	Medium7	GraphShortest path+1	No attempts yet	2s	128 MB	Judgeable
Binary MatrixGiven a binary matrix, find and output the minimum sequence of flood-fill region flips that makes the whole matrix uniform.	Medium7	GraphBFS+1	No attempts yet	2s	128 MB	Judgeable
Symmetric Picture 2Given up to 700 points, decide whether a mirror line exists so the point set is exactly symmetric about it, with no point on the line.	Medium7	GeometryMath+1	No attempts yet	2s	128 MB	Judgeable
EscapeGiven a grid with prisoners and exits, find the minimum number of empty cells to block (as vertex cut) so no prisoner reaches any exit, within a limit K, using max-flow min-cut with vertex splitting.	Medium7	GraphShortest path+1	No attempts yet	2s	128 MB	Judgeable
Binary Tree DrawingGiven a binary tree reconstructed from preorder and inorder traversals, compute the minimum area of a grid drawing where each right child extends the row and each down child extends the column.	Medium7	Dynamic programmingTree+1	No attempts yet	2s	128 MB	Judgeable
Counting Submatrices with Divisible SumsCount contiguous submatrices of an N by M matrix (N,M up to 256) whose sum is divisible by K, requiring an efficient prefix-sum plus hashing technique.	Medium7	Prefix sumHash map+1	No attempts yet	1s	128 MB	Judgeable
Unnecessary NumbersGiven N and M, determine which indices in a length-N sequence have coefficient divisible by M in the final repeated-adjacent-sum value modulo M, using binomial coefficient properties.	Medium7	MathNumber theory+1	No attempts yet	2s	128 MB	Judgeable
Compare Tree Traversal PathsGiven two 0/1 Euler-tour strings from DFS traversals of a tree rooted at the same vertex, decide whether both could come from the same underlying tree.	Medium7	TreeString+1	No attempts yet	2s	128 MB	Judgeable
Three-Way CallFind a minimum-cost subtree (Steiner tree) connecting three given switches in a weighted graph and output the cost and chosen edges.	Medium7	GraphShortest path+1	No attempts yet	2s	128 MB	Judgeable
Maximum String PastingGiven a long string and up to 500 short patterns, find all their occurrences and select non-overlapping intervals to maximize total covered length via DP.	Medium7	String matchingDynamic programming+1	No attempts yet	1s	128 MB	Judgeable
Unit Fraction DecompositionCount ways to write p/q as a sum of at most n unit fractions (order ignored) whose denominators multiply to at most a.	Medium7	BacktrackingNumber theory+2	No attempts yet	2s	128 MB	Judgeable
Stable NetworkGiven a star network from a hub plus some existing branch edges, add minimum-cost edges among branches so the whole network stays connected after any single edge or node fails (2-connectivity via biconnected components and MST on component graph).	Medium7	Union-findMinimum spanning tree+1	No attempts yet	2s	128 MB	Judgeable
Covering Holes in a BoardGiven a grid of holes, find the minimum number of horizontal or vertical tape strips (which may overlap on hole cells but never cover a non-hole cell) needed to cover every hole.	Medium7	GraphBit manipulation+2	No attempts yet	2s	128 MB	Judgeable
RectangleGiven up to 1500 points, find the maximum area rectangle (not necessarily axis-aligned) whose four vertices are among the points.	Medium7	GeometryHash map+1	No attempts yet	2s	1024 MB	Judgeable
Department AssignmentGiven friend/rival constraints among N employees, decide via union-find with parity whether a bipartition exists and, if so, find the split minimizing the size difference between two groups using a subset-sum style DP over component sizes.	Medium7	Union-findDynamic programming+1	No attempts yet	1s	128 MB	Judgeable
Tree Path PartitionGiven a tree and integer K, find the minimum number of vertex-disjoint paths of length at most K that cover all vertices.	Medium7	TreeGreedy+1	No attempts yet	1s	128 MB	Judgeable
Paving BlocksGiven an M×N grid of split rectangular tiles, find a Hamiltonian cycle visiting the maximum number of tiles and print the visiting order.	Medium7	GraphImplementation+1	No attempts yet	1s	128 MB	Judgeable
BookshelfPartition an ordered sequence of books into contiguous shelves to minimize the max of total shelf-height sum and the largest shelf-width, using binary search plus greedy/DP feasibility check.	Medium7	Binary searchGreedy+1	No attempts yet	1s	128 MB	Judgeable
Mobile Binary NumberGiven a nested-bar mobile whose bars may each be flipped independently, find the K-th lexicographically smallest distinct binary string obtainable across all flip combinations.	Medium7	Dynamic programmingRecursion+2	No attempts yet	1s	128 MB	Judgeable
Crossing SegmentsGiven segments between two parallel lines that are 2-colorable by non-crossing constraint, find the longest chain where consecutive segments cross.	Medium7	Dynamic programmingSorting+1	No attempts yet	1s	128 MB	Judgeable
Number Dial AlignmentDetermine the minimum-step sequence of left (chained) and right (single) dial rotations to transform one digit string into another for up to 10,000 connected rotary dials.	Medium7	GreedySimulation+1	No attempts yet	1s	128 MB	Judgeable
MonkeysGiven a graph with max degree 3, split vertices into two nonempty groups so each vertex has at most one same-group neighbor that dislikes it.	Medium7	GraphGreedy+1	No attempts yet	1s	128 MB	Judgeable
Heewon's New York LifeGiven points A and B on a grid plus a diagonal Broadway line, compute the shortest travel distance using horizontal, vertical, and the diagonal road, allowed to switch roads only at intersections.	Medium7	GeometryMath+1	No attempts yet	1s	128 MB	Judgeable
High-Speed RailwayCount subsets of interval-graph vertices forming a vertex cover of the interval overlap graph, modulo a given number.	Medium7	IntervalsDynamic programming+1	No attempts yet	1s	128 MB	Judgeable
Grid BoardChoose K rows and columns to delete from a grid so the maximum value among the remaining cells is minimized, then output the selected rows and columns.	Medium7	Binary searchGreedy	No attempts yet	1s	128 MB	Judgeable
Rotating Square TilesFind the minimum sequence of cyclic row/column rotations (up to 7 moves) that sorts a 4x4 tile board into ascending order.	Medium7	BFSBrute force+1	No attempts yet	1s	128 MB	Judgeable
Magic Colored PaperSimulate recursive cutting of a sheet into black/white pieces by successive points, tracking each piece's rectangle, and report the largest and smallest resulting areas.	Medium7	SimulationBinary search+2	No attempts yet	1s	128 MB	Judgeable
Car RaceGiven a directed graph with no cycles avoiding vertex 1, find the maximum-score simple route from checkpoint 1 back to checkpoint 1 and print it.	Medium7	GraphDynamic programming+1	No attempts yet	1s	128 MB	Judgeable
Mischievous FrogsGiven how many frogs stepped on each of N field positions, reconstruct the minimum number of frogs, each following an arithmetic-progression path with step size at most 6, that reproduces the counts.	Medium7	GreedySimulation+1	No attempts yet	1s	128 MB	Judgeable
DNA SimilarityFind the lexicographically smallest longest common subsequence of two DNA strings where adjacent picked characters in each string must be within index-distance K.	Medium7	Dynamic programmingString	No attempts yet	1s	128 MB	Judgeable
GeneReconstruct a unique circular-free DNA sequence from overlapping fragments (usable forward or reversed) split across k identical copies, then print the lexicographically smaller of it and its reverse.	Medium7	String matchingGraph+1	No attempts yet	1s	128 MB	Judgeable
Cube NetGiven a hexomino net on a 6x6 grid with faces numbered 1 to 6, determine if it folds into a valid cube and if so output the face opposite face 1, otherwise output 0.	Medium7	SimulationGeometry+1	No attempts yet	1s	128 MB	Judgeable
Connecting Black and White PointsPair n black and n white points on a line with non-crossing arcs of chosen height, minimizing total arc length, and output the pairing.	Medium7	GreedyStack+2	No attempts yet	1s	128 MB	Judgeable
Emergency Contact NetworkDesign a fastest call schedule so a class leader's contact network reaches every student, respecting call directions and one-call-per-student, minimizing total minutes.	Medium7	TreeGreedy+1	No attempts yet	1s	128 MB	Judgeable
Connecting RectanglesGiven N candidate axis-aligned rectangles with weights equal to their index, select a maximum-weight subset of pairwise non-overlapping and non-touching rectangles.	Medium7	Dynamic programmingGreedy+2	No attempts yet	1s	128 MB	Judgeable
I²CParse raw I2C SCL/SDA bit-sample sequences to decode start/stop bits, address, direction, ACKs, and data bytes, reporting the transaction or the first protocol error.	Medium7	SimulationString+2	No attempts yet	1s	128 MB	Judgeable
How Was Typesetting Done in the Past?Simulate historical typesetting rules by replacing letter combinations with ligature codes and correctly choosing long s versus short s per word based on multiple context-dependent rules.	Medium7	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
Reading UPC BarcodesGiven a 95-bit UPC-A barcode string with unknown bits and possible reversal, enumerate all valid 12-digit UPC codes matching the pattern and checksum.	Medium7	String matchingBrute force+2	No attempts yet	1s	128 MB	Judgeable
Optimizing Mobile Phone Text EntryPartition the 26 letters into K ordered contiguous groups (max 8 each) to minimize frequency-weighted key presses, breaking ties by lexicographically smallest concatenated output.	Medium7	Dynamic programmingGreedy+2	No attempts yet	1s	128 MB	Judgeable
Fibonacci Number 3Compute the nth Fibonacci number modulo 1,000,000 for n up to 10^18, requiring fast matrix or fast-doubling exponentiation.	Medium7	MathMatrix+1	No attempts yet	1s	128 MB	Judgeable
Magician HyunwooGiven 5 chosen cards, output the hidden card and reorder the remaining 4 so a specific decoding rule recovers it correctly.	Medium7	CombinatoricsMath+1	No attempts yet	1s	128 MB	Judgeable
Completely Diversified SequenceGiven n, construct a minimum-length sequence of even-size subsets of {1,...,n} where each element m appears in exactly m subsets, or report impossibility.	Medium7	CombinatoricsGreedy+2	No attempts yet	1s	128 MB	Judgeable
Secret WordsGiven secret words and a target string, find minimum total rearrangement cost to build the target by concatenating (possibly rearranged) copies of the words, or -1 if impossible.	Medium7	Dynamic programmingString+1	No attempts yet	1s	128 MB	Judgeable
Romantic KingGiven a grid with a start, an end, and up to 16 gift trees where movement speed decreases with carried gifts, find the maximum number of gifts deliverable within a time limit.	Medium7	BFSDynamic programming+1	No attempts yet	10s	128 MB	Judgeable
Restore the SequenceReconstruct a permutation of 1..N that satisfies M range max/min constraints, or report impossibility.	Medium7	GreedyBacktracking+1	No attempts yet	1s	128 MB	Judgeable
F7 Championship CandidatesGiven pre-race scores of N drivers and knowing final-race points are a permutation of 1..N, count how many drivers can end up tied for the maximum total score for some assignment of final ranks.	Medium7	GreedyBinary search+1	No attempts yet	1s	128 MB	Judgeable
Business ExpansionGiven a directed graph, find a walk from city 1 to city 2 and back to city 1 that minimizes the number of distinct visited cities.	Medium7	Shortest pathGraph+1	No attempts yet	1s	128 MB	Judgeable
MeetingsGiven N meeting points each a Chebyshev-distance disk around a home, find the minimum total Chebyshev-distance path visiting the disks in given order, with free start and end.	Medium7	GeometryBinary search+2	No attempts yet	1s	128 MB	Judgeable
TrampolineGiven building heights, adjacency-based jump rules, and trampolines that allow teleporting anywhere, find the maximum number of distinct buildings reachable starting from building K.	Medium7	GraphDFS+1	No attempts yet	1s	128 MB	Judgeable
Cake CutsGiven K, find the minimum number of straight full-square chord cuts needed so the cake splits into at least K pieces, and output coordinates for such cuts.	Medium7	MathGeometry+1	No attempts yet	1s	128 MB	Judgeable
CrayonsGiven N RGB-colored crayons, choose K of them minimizing the maximum pairwise Chebyshev distance and output that minimum along with a valid selection.	Medium7	Binary searchBrute force+2	No attempts yet	5s	160 MB	Judgeable
Stacking BooksGiven masses of stacked unit-length rectangles placed in fixed order, maximize the rightmost x-coordinate while keeping every prefix's center of mass within distance 1 of the block beneath it.	Medium7	GreedyMath+1	No attempts yet	1s	128 MB	Judgeable
ASCII StreetGiven a street string and multiple pattern tiles, count how many street positions are never covered by any occurrence of any pattern, requiring efficient multi-pattern matching like Aho-Corasick.	Medium7	String matchingTrie+1	No attempts yet	4s	512 MB	Judgeable
Sangbeom's MelancholyGiven daily moods, compute flower-giving intervals before each depressed run (2T days, or 3T for one chosen longest run) and find the maximum count of distinct covered days by optimally picking which longest run gets the 3T rule.	Medium7	IntervalsGreedy+1	No attempts yet	1s	128 MB	Judgeable
Attractive FenceArrange purchased plank heights to match a given up/down pattern while maximizing the sum of absolute differences between adjacent planks.	Medium7	GreedySorting+1	No attempts yet	1s	128 MB	Judgeable
Function Return ValueGiven N nested loops whose bounds are either fixed integers or an outer loop variable, compute the total iteration count modulo 1e9+7.	Medium7	Dynamic programmingCombinatorics+2	No attempts yet	1s	128 MB	Judgeable
Descending-Run SortingGiven a permutation whose minimal slope decomposition always has even-length decreasing runs, simulate/derive how many reversal operations the described repeated slope-reversal sort performs until the array is sorted.	Medium7	ArraySimulation+1	No attempts yet	1s	128 MB	Judgeable
Alien Guitar PerformanceSimulate finger presses and releases on a 6-string guitar to play a melody in order with minimum total finger movements, keeping only pressed frets that could still be the highest useful one.	Medium7	StackGreedy+1	No attempts yet	1s	256 MB	Judgeable
Tap DanceMaintain, after each single-character flip in a binary string, the length of the longest alternating (no two equal adjacent) substring, supporting online point updates.	Medium7	Segment treeString+1	No attempts yet	1s	128 MB	Judgeable
Minimum Number of ShipsGiven the sorted list of days on which at least one periodic ship arrived, find the minimum number of periodic ships (each starting day 1) that can generate exactly that set of days.	Medium7	GreedyMath+1	No attempts yet	1s	128 MB	Judgeable
Donggyu's Keyboard Paint ProgramSimulate up to 100000 paint, save, and load commands on an N by N grid with checkerboard rectangle fills and version rollback, then output the final grid.	Medium7	SimulationImplementation+1	No attempts yet	2s	128 MB	Judgeable
Candy CandyDistribute M candies among N friends to minimize the sum of squared shortages, using a binary-search-on-marginal-cost style allocation strategy.	Medium7	Binary searchGreedy+1	No attempts yet	1s	128 MB	Judgeable
Walking TrailFor up to 100,000 rectangle queries over 300,000 points, count how many points lie exactly on the boundary of each axis-aligned rectangle.	Medium7	Prefix sumBinary search+1	No attempts yet	1s	128 MB	Judgeable
Prime CycleSimulate a circle of N people where the square-chair holder repeatedly swaps rightward by successive prime counts over K rounds, then report the neighbours of person A, with N up to 5,000,000 and K up to 500,000 requiring an efficient model of the swapping process rather than direct simulation.	Medium7	SimulationMath+1	No attempts yet	1s	128 MB	Judgeable
GremlinsGiven a graph of gremlin reproduction with hatching and growth delays over T years (T up to 10^15), compute the maximum number of ancestors any gremlin has.	Medium7	Dynamic programmingGraph+1	No attempts yet	1s	128 MB	Judgeable
Clearing the BeadsFind the minimum number of beads to insert between colored beads so every bead can eventually be cleared by removing runs of length at least K.	Medium7	Dynamic programmingStack+1	No attempts yet	1s	128 MB	Judgeable
Explosion-Safe FoldingCount ways to fold N tape pieces at seams (straight or 180 degree) so coated faces never touch, given coating patterns from both ends, modulo 10301.	Medium7	Dynamic programmingCombinatorics+1	No attempts yet	1s	128 MB	Judgeable
Call ReconstructionGiven detector counts of calls crossing certain positions along a line of houses, find the minimum number of calls consistent with all counts (interval covering via greedy/sweep with counts as constraints).	Medium7	GreedyIntervals+1	No attempts yet	1s	128 MB	Judgeable
Donghyuk Astronomical ObservatoryGiven observation windows spanning possibly multiple years and event type counts per telescope, determine a consistent duration (1 to 365 days) for each of the M event types satisfying all telescopes' total observed days, or report -1.	Medium7	MathSimulation+1	No attempts yet	1s	128 MB	Judgeable
Sorting with Restricted SwapsFind the minimum number of allowed position-swaps needed to sort a permutation of up to 12 elements, using BFS over permutation states.	Medium7	BFSBrute force+1	No attempts yet	1s	128 MB	Judgeable
ClotheslineFor each query time, compute the total overlapping area of given rectangles covered by an expanding Chebyshev-distance square of oil centered at the origin.	Medium7	Prefix sumGeometry+2	No attempts yet	2s	128 MB	Judgeable
Mineral ClustersSimulate sticks destroying minerals in a grid cave, splitting and dropping clusters under gravity after each hit, and print the final grid.	Medium7	SimulationMatrix+1	No attempts yet	1s	128 MB	Judgeable
LRH PlantsGiven plants added over time with increasing heights, count for each new plant how many crossing points appear where its stems cross earlier plants' horizontal segments or vice versa, avoiding duplicate points.	Medium7	Segment treeGeometry+2	No attempts yet	1s	128 MB	Judgeable
Aladdin and the LampSimulate a grid walker whose turns depend on cell wizards and day of week, and find the day count when exactly K direction changes have occurred, using cycle detection since K can reach one billion.	Medium7	SimulationMath+1	No attempts yet	1s	128 MB	Judgeable
Strange PainterReconstruct a picture painted by a recursive quadrant-coloring process closest (in Hamming distance) to a given N x N binary target, then output that minimal difference and the picture.	Medium7	Divide and conquerDynamic programming+1	No attempts yet	1s	128 MB	Judgeable
Symmetric MatrixConstruct the lexicographically smallest symmetric NxN matrix from given character counts and output selected columns, or report impossibility.	Medium7	GreedyMath+2	No attempts yet	1s	128 MB	Judgeable
Zoo ExpansionFind the switch time X within [0,T] so the total coconuts picked by monkeys of the first kind by time X matches what the second kind can open in the remaining T-X seconds, using binary search over count-producing step functions.	Medium7	Binary searchMath+1	No attempts yet	1s	128 MB	Judgeable
Greco-Roman ArchitectureGiven a grid marked with traces of two overlapping axis-aligned square floor plans, find the top-left corner and size of each of the two squares whose union equals the marked cells.	Medium7	Brute forceGeometry+1	No attempts yet	1s	128 MB	Judgeable
Donghyuk, King of the Board GameGiven a board colored by AND of bit patterns of row and column indices, count gray cells visited in the first K steps of a zigzag diagonal traversal of an R x C grid.	Medium7	MathBit manipulation+2	No attempts yet	1s	128 MB	Judgeable
MessengersFind the minimum time for a spreading news to reach all messengers on a line, where informed messengers can move up to speed 1 and hear within distance K, typically via binary search plus greedy feasibility check.	Medium7	Binary searchGreedy+1	No attempts yet	1s	128 MB	Judgeable
Playlist Display IntervalsGiven a sequence of distinct requested songs, choose a length-K window covering each request to minimize the total number of distinct songs ever shown across all windows.	Medium7	GreedyIntervals+1	No attempts yet	1s	128 MB	Judgeable
Self ProductCount positive integers N whose self product (N times the product of its decimal digits) lies within a given range [A,B] with B up to 10^18.	Medium7	MathNumber theory+1	No attempts yet	3s	256 MB	Judgeable
Bomb ProductionGiven N components with warehouse stock and two purchasable package sizes/prices under a budget M, determine the maximum number of bombs buildable by binary searching on the answer and solving the per-component minimum cost via bounded package combination.	Medium7	Binary searchGreedy+1	No attempts yet	1s	128 MB	Judgeable
A=SInsert plus signs between digits of a huge number A so the resulting sum equals a small target S, using as few plus signs as possible.	Medium7	Dynamic programmingString+1	No attempts yet	1s	128 MB	Judgeable
The King's VisitCompute the delivery vehicle's shortest travel time from A to B given that certain roads are temporarily closed during time windows determined by the king's earlier route.	Medium7	Shortest pathGraph+1	No attempts yet	1s	128 MB	Judgeable
Median of a Contiguous SubsequenceCount odd-length contiguous subarrays of a permutation of 1..N whose median equals a given value B.	Medium7	Prefix sumHash map+1	No attempts yet	1s	128 MB	Judgeable
Closest Permutation NumbersGiven digit string a and a multiset of digits from b, find the smallest permutation of b's digits that is >= a and the largest that is < a, with no leading zero.	Medium7	GreedyString+1	No attempts yet	1s	128 MB	Judgeable
VictoryCount first moves in a circular pick-up game with adjacency constraints that force a win for the first player against an optimal second player counting odd numbers picked.	Medium7	Dynamic programmingGame theory+1	No attempts yet	1s	128 MB	Judgeable
Longest Repeated SubstringGiven a lowercase string of up to 200000 characters, compute the length of the longest substring that occurs at least twice, allowing overlaps.	Medium7	StringBinary search+1	No attempts yet	1s	256 MB	Judgeable
HousewarmingGiven a grid with blocked cells, find the maximum rectangle of empty cells and output twice its width plus height (the perimeter).	Medium7	Dynamic programmingStack+1	No attempts yet	1s	128 MB	Judgeable
Minimize the DifferenceGiven an array with a budget of T total decrements (each element bounded below by 1), reduce elements to minimize the maximum adjacent absolute difference and output the resulting array.	Medium7	Binary searchGreedy+1	No attempts yet	1s	128 MB	Judgeable
CookiesCount, modulo 10007, the number of orders of choosing cookies on a circle so that each chosen cookie's two current neighbors always match in flavor, until 1 or 2 remain.	Medium7	Dynamic programmingCombinatorics+1	No attempts yet	5s	128 MB	Judgeable
Salary IncreaseFor each new employee added to a hierarchy tree, count how many ancestors get their salary raised to match the new hire's salary until the chain stabilizes.	Medium7	TreeBinary search+1	No attempts yet	1s	128 MB	Judgeable
BakeryGiven a grid where pipelines move from the first column to the last column stepping right, diagonal-up-right or diagonal-down-right without sharing cells, find the maximum number of vertex-disjoint such paths.	Medium7	GraphGreedy+1	No attempts yet	1s	256 MB	Judgeable
FenceGiven overlapping rectangular planks forming a skyline, select the minimum subset of planks that reproduces the exact same skyline.	Medium7	SortingStack+2	No attempts yet	1s	128 MB	Judgeable
Gamers' ArroganceReconstruct one valid sequence of graphics card memory sizes given each new gamer's arrogance score, which sums floor divisions against everyone already in line.	Medium7	Binary searchGreedy+1	No attempts yet	1s	128 MB	Judgeable
LakeCount simple cycles in a fixed circular ladder graph with some edges removed, given three binary strings of usable inner, outer, and bridge edges, modulo 1e9+7.	Medium7	GraphDynamic programming+1	No attempts yet	1s	128 MB	Judgeable