Problems

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Total results29,185 problems

Binary Search Heap Construction
Medium7
Tree, Stack+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sinks of a Graph
Medium7
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Balanced Food
Medium7
Brute force, Geometry+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hall of Fountains
Medium7
BFS, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Counting Distinct Bracelets
Medium7
Combinatorics, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Phylogenetic Trees Inherited
Medium7
Dynamic programming, Tree+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
New Fruit
Medium7
Dynamic programming, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Euro Cup 2000
Medium7
Brute force, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Settlers of Catan
Medium7
Graph, DFS+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Charlie the Cockchafer
Medium7
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Analog Clock Display
Medium7
Geometry, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Invasion
Medium7
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Arbitrage?
Medium7
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bus Schedules
Medium7
Implementation, Simulation+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Bus Clock Display
Medium7
Dynamic programming, Bit manipulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Measuring Problem Difficulty
Medium7
Sorting, Divide and conquer+2
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Hack around the Lock
Medium7
Graph, Math+2
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
Odd Opportunities
Medium7
Graph, Union-find+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Wooden Fence
Medium7
Geometry, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Safe Gambling
Medium7
Array, Sliding window+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Government Help
Medium7
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Geometric Shapes
Medium7
Geometry, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Corporate Identity
Medium7
String, String matching+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hypertheseus
Medium7
BFS, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Divisors of a Binomial Coefficient
Medium7
Number theory, Math+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
IVXLCDM
Medium7
Greedy, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Firepersons
Medium7
Math, Matrix+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Japan Plotter Driver
Medium7
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hexagonal Routes
Medium7
Geometry, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Traffic Jam
Medium7
BFS, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Defragmentation
Medium7
Graph, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Formatting Text
Medium7
Dynamic programming, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hole Cutter
Medium7
Geometry, Union-find+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Mysterious Villa
Medium7
BFS, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
S-Nim
Medium7
Game theory, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sylvester construction
Medium7
Divide and conquer, Recursion+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Lazy and Strict Evaluation
Medium7
Implementation, Recursion+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tourist
Medium7
Dynamic programming, Matrix+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Mailbox Manufacturers Problem
Medium7
Dynamic programming, Binary search+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Simplified λ-evaluations
Medium7
Implementation, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Connecting Islands
Medium7
Geometry, Minimum spanning tree+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bridge Placements
Medium7
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
A Fair Jury
Medium7
Dynamic programming, Array+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Radio Direction Finder
Medium7
Geometry, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Co-workers from Hell
Medium7
Dynamic programming, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Odd Loving Bakers
Medium7
Bit manipulation, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Factor Solitaire
Medium7
Dynamic programming, Number theory+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tourney
Medium7
Tree, Segment tree+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
LHC
Medium7
Tree, DFS+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Repetitivity
Medium7
String, Dynamic programming+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Mhocskian Languages
Medium7
Dynamic programming, String+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Editor Distance
Medium7
Graph, Shortest path+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Biggest (Zero Carbon) Footprint
Medium7
Geometry, Sorting+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Firehose
Medium7
Binary search, Greedy+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Animal Farm
Medium7
Graph, Minimum spanning tree+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Wowow
Medium7
Segment tree, Binary search+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Wireless
Medium7
Geometry, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Dinner
Medium7
Dynamic programming, Intervals+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Parade
Medium7
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
King & Weber
Medium7
Graph, Union-find+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Mobile
Medium7
Tree, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bowling for Numbers++
Medium7
Dynamic programming, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Road Construction
Medium7
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
CN Tower 2
Medium7
Sorting, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Paint by Numbers
Medium7
Backtracking, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pyramid Message Scheme
Medium7
Tree, Stack+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Great Spamway Strike
Medium7
Tree, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Segments
Medium7
Dynamic programming, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hockey Scores
Medium7
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
S and K
Medium7
Implementation, Simulation+2
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Substrings
Medium7
String, Trie+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cheap Gas
Medium7
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pit Stop Strategy
Medium7
Dynamic programming, Math
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Strategic Bombing
Medium7
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Coke or Chocolate Milk
Medium7
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Millikan's Oil Drop Experiment
Medium7
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
A Knightly Pursuit
Medium7
BFS, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Letter Arithmetic
Medium7
Backtracking, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hoppers
Medium7
BFS, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Guessing Game II
Medium7
Brute force, Hash map+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Ent Numbers
Medium7
Implementation, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Poly-polygonal Numbers
Medium7
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
BSP Trees
Medium7
Geometry, Tree+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Snowball Fight
Medium7
Game theory, Probability+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Walking on Thin Ice
Medium7
Geometry, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Biased Dice
Medium7
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Patisserie ACM
Medium7
Dynamic programming, Matrix+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Packing Rectangles
Medium7
Brute force, Geometry+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Shopping Offers
Medium7
Dynamic programming, Array+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Hidden Codes
Medium7
Dynamic programming, String matching+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Walk the Talk
Medium7
Dynamic programming, Trie+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cow Patterns
Medium7
String matching, Sliding window+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Barn Expansion
Medium7
Geometry, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Feeding Time
Medium7
Shortest path, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Trips
Medium7
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Puzzle
Medium7
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Two Sawmills
Medium7
Dynamic programming, Divide and conquer+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Shift Register
Medium7
Math, Bit manipulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Trip
Medium7
Dynamic programming, Backtracking+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
A Highway and the Seven Dwarfs
Medium7
Geometry, Divide and conquer+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Binary Search Heap ConstructionGiven label/priority pairs, build the unique treap (a binary search tree on labels and a max-heap on priorities) and print it in nested parenthesized form.	Medium7	TreeStack+2	No attempts yet	1s	128 MB	Judgeable
Sinks of a GraphIn each directed graph, list every node v such that every node reachable from v can reach v back.	Medium7	GraphDFS+2	No attempts yet	1s	128 MB	Judgeable
Balanced FoodGiven a pizza of n slices and a sector-shaped table, find the lexicographically smallest order of eating slices so the remaining slices' center of gravity always stays over the table.	Medium7	Brute forceGeometry+2	No attempts yet	1s	128 MB	Judgeable
Hall of FountainsGiven n fountains inside n rooms, each periodically on/off with period 2p and offset q, find the earliest time to walk from before room 1 to past room n using one-second steps, entering a room only while its fountain is off.	Medium7	BFSGraph+2	No attempts yet	1s	128 MB	Judgeable
Counting Distinct BraceletsCount distinct colorings of a bracelet with c colors and s beads up to rotation and reflection, using the dihedral group acting on the ring.	Medium7	CombinatoricsMath+1	No attempts yet	1s	128 MB	Judgeable
Phylogenetic Trees InheritedGiven leaf sequences of a complete binary tree, label internal nodes to minimize the sum of Hamming distances along edges, and output the lexicographically smallest optimal root sequence with its cost.	Medium7	Dynamic programmingTree+2	No attempts yet	1s	128 MB	Judgeable
New FruitFor each pair of strings, output the shortest common supersequence, breaking ties by choosing the lexicographically smallest one.	Medium7	Dynamic programmingString+2	No attempts yet	1s	128 MB	Judgeable
Euro Cup 2000Given partial soccer standings and at most ten remaining games, find each team's best and worst possible final rank under the points and tiebreak rules.	Medium7	Brute forceImplementation+2	No attempts yet	1s	128 MB	Judgeable
The Settlers of CatanGiven an undirected graph where nodes have degree at most three, find the longest path that uses no edge more than once.	Medium7	GraphDFS+1	No attempts yet	1s	128 MB	Judgeable
Charlie the CockchaferFind the fastest route on a 3D segment network where cost combines travel distance and turn angles between consecutive segments.	Medium7	GraphShortest path+2	No attempts yet	1s	128 MB	Judgeable
Analog Clock DisplayGiven times in HH:MM form, draw fixed-size ASCII analog clock faces with the hour and minute hands rasterized as line segments, following exact character rules.	Medium7	GeometrySimulation+2	No attempts yet	1s	128 MB	Judgeable
InvasionFor each prefix of alien bases, count towns whose shortest-path distance to every base built so far is at least K.	Medium7	GraphShortest path+2	No attempts yet	1s	128 MB	Judgeable
Arbitrage?Given exchange rates between currencies, decide whether any sequence of trades returns a strictly larger amount of the starting currency (arbitrage).	Medium7	GraphShortest path+2	No attempts yet	1s	128 MB	Judgeable
Bus SchedulesFor each test case, count the days of a given year that satisfy at least one weekday/holiday specifier and also fall inside a comma-separated list of dates and date ranges.	Medium7	ImplementationSimulation+2	No attempts yet	2s	128 MB	Judgeable
Bus Clock DisplayGiven up to 100 partial 7-segment clock readings with min and max elapsed minutes between consecutive readings, determine the time at each reading or report how many possibilities remain.	Medium7	Dynamic programmingBit manipulation+2	No attempts yet	1s	128 MB	Judgeable
Measuring Problem DifficultyGiven three permutations of the numbers 1 to N, count pairs whose relative order is identical in all three orderings.	Medium7	SortingDivide and conquer+2	No attempts yet	3s	128 MB	Judgeable
Hack around the LockStarting from a given K-digit lock setting, find the minimum number of single-wheel rotations needed to visit every other K-digit setting at least once.	Medium7	GraphMath+2	No attempts yet	5s	256 MB	Judgeable
Odd OpportunitiesGiven a graph and a parity requirement (odd or even degree) for every vertex, decide whether some subset of edges can be kept so each vertex meets its required degree parity.	Medium7	GraphUnion-find+2	No attempts yet	1s	128 MB	Judgeable
Wooden FenceGiven up to 16 trees with coordinates, values, and wood lengths, choose trees to cut so their total wood covers the convex hull perimeter of the rest, minimizing lost value.	Medium7	GeometryBrute force+2	No attempts yet	1s	128 MB	Judgeable
Safe GamblingOn an odd circular wheel of N = 2K+1 priced pockets, choose three arcs of K consecutive pockets covering every pocket, minimizing the total sum of the arcs.	Medium7	ArraySliding window+2	No attempts yet	1s	128 MB	Judgeable
Government HelpAssign each package to one of two banks in some order so that the largest absolute running difference between the two totals is minimized; print that minimum.	Medium7	GreedySorting+2	No attempts yet	1s	128 MB	Judgeable
Geometric ShapesGiven up to 26 shapes (squares, rectangles, segments, triangles, polygons), report for each shape every other shape whose boundary it touches or crosses.	Medium7	GeometryImplementation+2	No attempts yet	1s	128 MB	Judgeable
Corporate IdentityGiven up to 4000 short lowercase strings, find the longest string that occurs as a contiguous substring of every one, breaking ties by lexicographic order.	Medium7	StringString matching+2	No attempts yet	1s	128 MB	Judgeable
HypertheseusGiven a recursive d-dimensional grid with walls and single T, S, M cells, find the shortest walk T to S to M to T, never touching M before the sword is taken.	Medium7	BFSGraph+2	No attempts yet	1s	128 MB	Judgeable
Divisors of a Binomial CoefficientFor each pair n and k, count the distinct divisors of the binomial coefficient C(n, k), where n is at most 431.	Medium7	Number theoryMath+2	No attempts yet	1s	256 MB	Judgeable
IVXLCDMGiven a lowercase inscription line, find the largest value of a valid Roman numeral readable as a subsequence of its letters, or 0 if none.	Medium7	GreedyString+2	No attempts yet	1s	128 MB	Judgeable
FirepersonsGiven the first k terms and multipliers of a linear recurrence modulo 10000, return the i-th term for i up to 10^9.	Medium7	MathMatrix+2	No attempts yet	1s	128 MB	Judgeable
Japan Plotter DriverEmulate a plotter's POINT, TEXT, LINE, CLEAR, and PRINT commands on an ASCII grid, merging overlapping characters by fixed rules, and frame each finished picture.	Medium7	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
Hexagonal RoutesOn a hexagonal grid numbered in a spiral, for each pair of cells find the shortest path length and the number of distinct shortest paths.	Medium7	GeometryMath+2	No attempts yet	1s	128 MB	Judgeable
Traffic JamOn a 6x6 grid of sliding cars and trucks, find the minimum number of slides to drive vehicle x off the right edge, or report that it is impossible.	Medium7	BFSSimulation+2	No attempts yet	1s	128 MB	Judgeable
DefragmentationGiven K files scattered across N disk clusters, find the minimum number of cluster moves to pack them consecutively in file order.	Medium7	GraphSimulation+1	No attempts yet	1s	128 MB	Judgeable
Formatting TextGiven words and a target width, break the text into lines to minimize total gap badness, with a penalty of 500 for any line holding one word.	Medium7	Dynamic programmingGreedy+1	No attempts yet	1s	128 MB	Judgeable
Hole CutterGiven axis-parallel cuts strictly inside a sheet, count how many distinct holes the cuts create.	Medium7	GeometryUnion-find+1	No attempts yet	1s	128 MB	Judgeable
Mysterious VillaGiven up to 10 rooms with doors and switches that may control other rooms' lights, find the minimum number of moves and toggles to reach the bedroom with only its light on.	Medium7	BFSGraph+2	No attempts yet	1s	128 MB	Judgeable
S-NimGiven a move set S, decide for each position whether the S-Nim game is a win or a loss by computing Grundy numbers and XORing them over the heaps.	Medium7	Game theoryDynamic programming+2	No attempts yet	1s	128 MB	Judgeable
Sylvester constructionGiven a Hadamard matrix built by the Sylvester doubling rule, print a small rectangular sub-matrix specified by its top-left corner.	Medium7	Divide and conquerRecursion+2	No attempts yet	1s	128 MB	Judgeable
Lazy and Strict EvaluationGiven function definitions in a small Lisp-like language, count how many times each arithmetic operation runs under lazy (memoized) versus strict evaluation, skipping non-terminating tests.	Medium7	ImplementationRecursion+2	No attempts yet	1s	128 MB	Judgeable
TouristOn a grid with blocked cells, find two monotone paths (down-right then up-left) maximizing the number of distinct interesting cells visited.	Medium7	Dynamic programmingMatrix+2	No attempts yet	1s	128 MB	Judgeable
The Mailbox Manufacturers ProblemWith k identical mailboxes usable up to m firecrackers, find the minimum worst-case cost in firecrackers to pin down exactly how many each can survive.	Medium7	Dynamic programmingBinary search+2	No attempts yet	1s	128 MB	Judgeable
Simplified λ-evaluationsEvaluate simplified lambda-calculus expressions by substitution, stopping after 1000 applications and printing unterminated if it does not finish.	Medium7	ImplementationSimulation+2	No attempts yet	1s	128 MB	Judgeable
Connecting IslandsConnect all island polygons with bridges between vertices, each bridge crossing only water, minimizing the total length of the bridges.	Medium7	GeometryMinimum spanning tree+2	No attempts yet	1s	128 MB	Judgeable
Bridge PlacementsPlace k horizontal bridges between two skyscrapers of given heights to minimize total stairs over all ordered floor pairs, breaking ties with the lowest placement.	Medium7	Dynamic programmingGreedy+2	No attempts yet	1s	128 MB	Judgeable
A Fair JuryPick exactly m candidates from a pool, minimizing \|total defense minus total prosecution\|, then maximizing the combined total among those juries.	Medium7	Dynamic programmingArray+2	No attempts yet	1s	128 MB	Judgeable
Radio Direction FinderGiven beacon positions and two timestamped relative bearings plus the boat's course and speed, find the boat's position at the second reading or report that it is ambiguous.	Medium7	GeometryMath+1	No attempts yet	1s	128 MB	Judgeable
Co-workers from HellPlace tricks in chambers so the watchman's walk, where each trick is used once to change dwell time and jump target, maximizes total time before he normally finishes chamber n.	Medium7	Dynamic programmingGraph+2	No attempts yet	1s	128 MB	Judgeable
Odd Loving BakersSimulate monthly celebrations where bakers with an odd chalk count win and add marks to their favorite bakers; find the number of winners at celebration t up to 1e9.	Medium7	Bit manipulationMath+2	No attempts yet	1s	128 MB	Judgeable
Factor SolitaireStarting from 1, repeatedly replace c by c + a where a divides c and b = c/a, paying b; find the minimum total cost to reach N.	Medium7	Dynamic programmingNumber theory+2	No attempts yet	1s	128 MB	Judgeable
TourneyMaintain a single-elimination bracket of 2^N players under point updates, and answer queries about the winner's position and how many rounds a given player wins.	Medium7	TreeSegment tree+2	No attempts yet	2s	512 MB	Judgeable
LHCGiven a tree, find the maximum cycle length obtainable by adding one edge, and count the vertex pairs that achieve it.	Medium7	TreeDFS+2	No attempts yet	2s	512 MB	Judgeable
RepetitivityCompute the sum of squared occurrence counts over all distinct subsequences of a string, modulo M.	Medium7	StringDynamic programming+2	No attempts yet	2s	512 MB	Judgeable
Mhocskian LanguagesGiven a context-free grammar in Chomsky normal form and a list of words, decide for each word whether the start variable can derive it.	Medium7	Dynamic programmingString+2	No attempts yet	2s	512 MB	Judgeable
Editor DistanceGiven the character counts of N lines up to 80 wide, find the fewest arrow-key presses to move a cursor from a start position to a finish position, where vertical moves clamp to each line's end.	Medium7	GraphShortest path+2	No attempts yet	2s	512 MB	Judgeable
Biggest (Zero Carbon) FootprintGiven tree points in an n by m forest, find the largest axis-aligned rectangle with no tree strictly in its interior.	Medium7	GeometrySorting+2	No attempts yet	2s	512 MB	Judgeable
FirehosePlace k hydrants on a circle of circumference 1000000 so the largest arc-distance from any of H houses to its nearest hydrant is minimized, and report that distance.	Medium7	Binary searchGreedy+2	No attempts yet	2s	512 MB	Judgeable
Animal FarmGiven M pens sharing walls, find the minimum total wall-removal cost so that all animals gather in one connected region, inside one pen or outside all pens.	Medium7	GraphMinimum spanning tree+2	No attempts yet	2s	512 MB	Judgeable
WowowMaintain a dynamic set of (id, rating) friends under insertions, rating updates, and queries for the id holding the K-th highest rating.	Medium7	Segment treeBinary search+2	No attempts yet	2s	512 MB	Judgeable
WirelessGiven K circles with integer centers and integer radii on a grid of intersections, compute the maximum total bitrate sum any intersection receives and how many intersections achieve it.	Medium7	GeometryImplementation+2	No attempts yet	1s	128 MB	Judgeable
DinnerGiven a line of G and H programmers, repeatedly remove a run of at least K equal letters; find the minimum number of removals to clear the line, or -1.	Medium7	Dynamic programmingIntervals+2	No attempts yet	1s	128 MB	Judgeable
ParadeMaintain a list of N perimeter-rotation commands on a 4x4 grid under Q cumulative point updates, printing the resulting grid after each update.	Medium7	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
King & WeberGiven parallel/intersect observations between streets, check consistency and answer for each query whether two streets must be parallel, must intersect, or could be either.	Medium7	GraphUnion-find+2	No attempts yet	1s	128 MB	Judgeable
MobileDecide whether two mobiles, given as rooted binary structures with negated weight labels, can be rotated to look identical.	Medium7	TreeDFS+2	No attempts yet	1s	128 MB	Judgeable
Bowling for Numbers++Choose at most k windows of length w, possibly overlapping beyond the row ends, so the sum of the covered pins is as large as possible.	Medium7	Dynamic programmingPrefix sum+2	No attempts yet	1s	128 MB	Judgeable
Road ConstructionGiven a connected undirected graph, add the fewest edges so that deleting any single edge still leaves the graph connected.	Medium7	GraphDFS+2	No attempts yet	1s	128 MB	Judgeable
CN Tower 2Choose a starting camera orientation so a rotating restaurant brings every landmark's bearing past the camera; minimize total time including flash recharge and the final recharge.	Medium7	SortingGreedy+2	No attempts yet	1s	128 MB	Judgeable
Paint by NumbersGiven the run lengths of stars in every row and column of an n x m grid, reconstruct the lexicographically smallest grid of dots and stars.	Medium7	BacktrackingImplementation+2	No attempts yet	1s	128 MB	Judgeable
Pyramid Message SchemeGiven a chronological list of message recipients from a sequential tree traversal, reconstruct the tree and compute the time saved by a parallel traversal.	Medium7	TreeStack+2	No attempts yet	1s	128 MB	Judgeable
The Great Spamway StrikeChoose a rooted tree over zombies with allowed bidirectional links, minimizing the round-trip time for a gather broadcast that includes each node's per-message read lag.	Medium7	TreeDynamic programming+2	No attempts yet	1s	128 MB	Judgeable
SegmentsOn each row of an n by n grid you must walk the whole interval [L(i), R(i)], moving only left, right, or down; find the shortest path from (1,1) to (n,n).	Medium7	Dynamic programmingGreedy+1	No attempts yet	1s	128 MB	Judgeable
Hockey ScoresGiven unordered score pairs x-y, find the fewest monotone lattice paths from (0,0) that pass through all of them, since each hockey game is such a path.	Medium7	Dynamic programmingGreedy+2	No attempts yet	1s	128 MB	Judgeable
S and KGiven binary trees written with S and K, repeatedly apply the two rewrite rules until no rule fires, then print the final tree string.	Medium7	ImplementationSimulation+2	No attempts yet	3s	128 MB	Judgeable
SubstringsCount the distinct substrings of a string, including the empty string and the whole string, for up to 5000 characters per test case.	Medium7	StringTrie+2	No attempts yet	1s	128 MB	Judgeable
Cheap GasOn an m by n grid with a fuel tank of capacity f, find the cheapest way to buy gas at priced stations while driving from (1,1) to (m,n), or report that the trip is impossible.	Medium7	GraphShortest path+2	No attempts yet	1s	128 MB	Judgeable
Pit Stop StrategyGiven lap and fuel burn formulas plus pit-stop costs, find the minimum race time for L laps without running out of fuel.	Medium7	Dynamic programmingMath	No attempts yet	1s	128 MB	Judgeable
Strategic BombingGiven an undirected graph of at most 26 points, find every edge whose removal disconnects A from B, listing them in input order.	Medium7	GraphDFS+2	No attempts yet	1s	128 MB	Judgeable
Coke or Chocolate MilkAssign each person one of two drinks so that desire, hatred, sameness, difference, and conditional requests all hold, printing the alphabetically earliest Coke-preferring satisfying assignment or reporting failure.	Medium7	GraphDFS+2	No attempts yet	1s	128 MB	Judgeable
Millikan's Oil Drop ExperimentGiven up to 100 measured charges each accurate within 1 percent, find the largest value e such that every measurement can be nudged into an integer multiple of e.	Medium7	MathNumber theory+2	No attempts yet	1s	128 MB	Judgeable
A Knightly PursuitGiven board size and starting squares for a pawn and a knight, decide whether the knight can win, force a stalemate, or loses, and report the minimum knight moves.	Medium7	BFSSimulation+2	No attempts yet	1s	128 MB	Judgeable
Letter ArithmeticAssign distinct digits to letters so that each given letter word plus a second equals a third, then print the three numeric values.	Medium7	BacktrackingMath+2	No attempts yet	1s	128 MB	Judgeable
HoppersFind the minimum number of hops from S to F on a grid, where each hop changes the velocity by at most 1 per component and lands only on empty squares.	Medium7	BFSGraph+2	No attempts yet	1s	128 MB	Judgeable
Guessing Game IIGiven up to 8 guess/response pairs, decide whether the 4-digit secret is already unique, find the smallest next guess that identifies it, or report that none can.	Medium7	Brute forceHash map+2	No attempts yet	2s	128 MB	Judgeable
Ent NumbersSimulate a Goodstein-like sequence where each step subtracts one, then raises the base while keeping digits, and report the base where the term first hits 0 or that it exceeds 2^60.	Medium7	ImplementationMath+1	No attempts yet	1s	128 MB	Judgeable
Poly-polygonal NumbersGiven a set of polygonal indices and a start s, print the next five numbers that are polygonal for at least two of those indices. Input continues until n = 0.	Medium7	MathNumber theory+2	No attempts yet	1s	128 MB	Judgeable
BSP TreesBuild a BSP tree by inserting p slanted planes into the xz-plane, assign n polygons to leaf regions, then print objects in the drawing order the tree induces.	Medium7	GeometryTree+2	No attempts yet	1s	128 MB	Judgeable
Snowball FightGiven fixed alternating throwing order and hit probabilities, players choose targets to maximize their team's win chance; compute win and draw probabilities under optimal play.	Medium7	Game theoryProbability+2	No attempts yet	1s	128 MB	Judgeable
Walking on Thin IceFind the shortest path from y=0 to y=W where only the given safe polygons cost nothing and all other river points cost their length.	Medium7	GeometryGraph+1	No attempts yet	1s	128 MB	Judgeable
Biased DiceSimulate dropping biased dice one by one onto a grid and count which numbers show on the top faces of the final pile.	Medium7	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
Patisserie ACMGiven a hole-free connected polyomino of # cells, find the minimum number of axis-aligned rectangles whose union is exactly the shape, cutting only along grid lines.	Medium7	Dynamic programmingMatrix+2	No attempts yet	1s	128 MB	Judgeable
Packing RectanglesGiven four rectangles, find every smallest enclosing axis-parallel rectangle that fits all four without overlap, using the six basic layouts.	Medium7	Brute forceGeometry+2	No attempts yet	1s	512 MB	Judgeable
Shopping OffersGiven regular item prices and bundle offers, find the minimum cost to buy exactly the listed quantities without buying extras.	Medium7	Dynamic programmingArray+2	No attempts yet	1s	512 MB	Judgeable
Hidden CodesGiven code words and a long text, choose non-overlapping covering sequences, each at most 1000 long, maximizing the total length of the code words used.	Medium7	Dynamic programmingString matching+2	No attempts yet	1s	128 MB	Judgeable
Walk the TalkCount the number of distinct monotone paths (only right and/or up hops) through an H by W letter grid whose visited letters spell one of N given words.	Medium7	Dynamic programmingTrie+2	No attempts yet	1s	128 MB	Judgeable
Cow PatternsFind every length-K window of a spot-count sequence whose relative order matches a given rank pattern.	Medium7	String matchingSliding window+1	No attempts yet	1s	128 MB	Judgeable
Barn ExpansionGiven up to 25000 non-overlapping axis-aligned rectangles, count how many touch no other rectangle at any corner or along any wall.	Medium7	GeometrySorting+1	No attempts yet	1s	128 MB	Judgeable
Feeding TimeGiven N cows in a fixed order with upper and lower bound distance constraints, find the maximum possible distance between cow 1 and cow N, or report impossibility or unboundedness.	Medium7	Shortest pathGraph+2	No attempts yet	1s	128 MB	Judgeable
TripsMatch group sizes to trip intervals so that each interval gets at most one group and the number of matched intervals is maximized.	Medium7	GreedySorting+2	No attempts yet	1s	128 MB	Judgeable
PuzzleGiven an n by n permutation board, decide whether row and column cyclic shifts can turn it into the target board where cell (i,j) holds (i-1)*n+j.	Medium7	MathImplementation+2	No attempts yet	1s	128 MB	Judgeable
Two SawmillsPlace two extra sawmills along a road so that every tree's downhill haul to the first mill at or below it is minimized.	Medium7	Dynamic programmingDivide and conquer+2	No attempts yet	1s	128 MB	Judgeable
Shift RegisterGiven the first 2N output bits of a linear feedback shift register, recover the N switch values, choosing the lexicographically smallest valid setting or reporting -1.	Medium7	MathBit manipulation+2	No attempts yet	1s	128 MB	Judgeable
TripGiven two strings, print all longest common subsequences in lexicographic order without duplicates.	Medium7	Dynamic programmingBacktracking+2	No attempts yet	1s	128 MB	Judgeable
A Highway and the Seven DwarfsGiven N points and many query lines, report for each line whether all points fall strictly on one side or the line splits them into two groups.	Medium7	GeometryDivide and conquer+2	No attempts yet	1s	128 MB	Judgeable