Problems

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Total results29,214 problems

Acrobat Reader
Medium7
Geometry, Hash map+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Flipping Networks
Medium7
Graph, BFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Mandalas
Medium7
Geometry, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Minotaur
Medium7
BFS, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Mondriaan
Medium7
Geometry, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Nim/3
Medium7
Game theory, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Little Bear and the Honey Pot
Medium7
BFS, Binary search+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Merchant
Medium7
Dynamic programming, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Type Printer
Medium7
Trie, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sails
Medium7
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Miners
Medium7
Dynamic programming, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Valley of Mexico
Medium7
Graph, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
That Nice Euler Circuit
Medium7
Geometry, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hermes
Medium7
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Comparing Code
Medium7
String matching, Hash map+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Utopia Divided
Medium7
Greedy, Backtracking+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Post Office
Medium7
Dynamic programming, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Run, IOI Train
Medium7
Dynamic programming, Two pointers+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Mansion
Medium7
Graph, BFS+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Night Market
Medium7
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Nails
Medium7
Array, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Dungeon
Medium7
Greedy, Math
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Santa Claus and Rudolph
Medium7
Backtracking, DFS+2
No attempts yet
Time limit
12s
Memory limit
128 MB
Judgeable
Shuffle
Medium7
Combinatorics, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Number of Paint Colors
Medium7
Combinatorics, Geometry+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
The Lightest Mobile
Medium7
Tree, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Longest Chain
Medium7
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Apartment Rental
Medium7
Number theory, Math+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Distance Between the Closest Pair of Points
Medium7
Divide and conquer, Sorting+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Pastries
Medium7
Geometry, Binary search+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Probability Through Experiment
Medium7
Geometry, Two pointers+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Optimal Space Way
Medium7
Geometry, Math+2
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Radioactivity
Medium7
Geometry, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Joyful Coloring
Medium7
Backtracking, Game theory+2
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Queen Game
Medium7
Game theory, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Consecutive Sum
Medium7
Number theory, Math+2
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
Airplane Parking
Medium7
Dynamic programming, Intervals+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Your Ways
Medium7
Dynamic programming, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Arranging Heaps
Medium7
Dynamic programming, Divide and conquer+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Electrical Pollution
Medium7
Union-find, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Jupiter Attacks!
Medium7
Segment tree, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cocircular Points
Medium7
Geometry, Hash map+2
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
String Farm
Medium7
String, Dynamic programming+2
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Hyperactive Boy Gangsan
Medium7
Dynamic programming, Intervals+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Ingenious Metro
Medium7
Math, Number theory+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Kids' Wishes
Medium7
Graph, Union-find+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Almost Shortest Path
Medium7
Shortest path, Graph+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Figure Out the Base
Medium7
Math, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Candy Picking Contest
Medium7
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Traveling Shoemaker
Medium7
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Shrinking Inscribed Polygon
Medium7
Number theory, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Acquapia
Medium7
Tree, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Emoticons :-)
Medium7
String matching, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Lazy Jumping Frog
Medium7
Shortest path, Graph+2
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Onion Layers
Medium7
Geometry, Sorting+2
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Turkish Roulette
Medium7
Dynamic programming, Array+2
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
P-Networks
Medium7
Dynamic programming, Greedy+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Land Division Tax
Medium7
Dynamic programming, Intervals+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Two-Stacks Solitaire
Medium7
Dynamic programming, Stack+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
X-Mart
Medium7
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Telecommunication Partners
Medium7
Graph, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Uncle Tom's Inherited Land
Medium7
Graph, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Myth Busters
Medium7
Brute force, Recursion+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Difficult Routes
Medium7
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
RealPhobia
Medium7
Number theory, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Insidious Branding
Medium7
Hash map, String
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Help-or-else
Medium7
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Oil Skimming
Medium7
Graph, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Parachute Rings
Medium7
Graph, Union-find+2
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
The Suffering Dwarves
Medium7
Segment tree, Array+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Rice Hub
Medium7
Two pointers, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
What's Up With Gravity
Medium7
BFS, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Fuel Economy
Medium7
Greedy, Stack+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Blink
Medium7
Matrix, Bit manipulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Photo
Medium7
Greedy, Intervals+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Haywire
Medium7
Backtracking, Brute force+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Cow Run
Medium7
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Necklace
Medium7
Dynamic programming, String matching+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Poker Hands
Medium7
Greedy, Array+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Seating
Medium7
Segment tree, Binary search+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Square Overlap
Medium7
Sorting, Sliding window+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Party Invitations
Medium7
Graph, BFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Mirrors
Medium7
Geometry, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Liars and Truth Tellers
Medium7
Graph, Union-find+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Running Away From the Barn
Medium7
Tree, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Concurrently Balanced Strings
Medium7
Hash map, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bookshelf
Medium7
Dynamic programming, Segment tree+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Running Laps
Medium7
Sorting, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Surveillance Cameras
Medium7
Brute force, Recursion+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Unlocking Blocks
Medium7
BFS, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Haybale Restacking
Medium7
Greedy, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Wrong Directions
Medium7
Simulation, Hash map+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Efficient Cow Buying
Medium7
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Overplanting
Medium7
Geometry, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Relocation
Medium7
Shortest path, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bovine Alliance
Medium7
Graph, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Mountain Climbing
Medium7
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cow Photography
Medium7
Sorting, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cow Photography
Medium7
Sorting, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Binary Sudoku
Medium7
Math, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Acrobat ReaderFor each test case, decide whether two sets of N points match under rotation by a multiple of 90 degrees, translation, and positive uniform scaling, with reflections disallowed.	Medium7	GeometryHash map+2	No attempts yet	1s	128 MB	Judgeable
Flipping NetworksMaintain an undirected graph under edge toggle operations and count, after every flip, how many hosts are reachable from host 1 but only by paths longer than 10 hops.	Medium7	GraphBFS+2	No attempts yet	1s	128 MB	Judgeable
MandalasGiven up to 500 circles, count how many regions the arrangement of circles divides the plane into, handling tangency and duplicate circles exactly.	Medium7	GeometryGraph+2	No attempts yet	1s	128 MB	Judgeable
MinotaurGiven a grid maze, Theseus, and a deterministic twice-as-fast Minotaur, find the minimum number of Theseus turns needed to reach the exit, or 0 if impossible.	Medium7	BFSSimulation+2	No attempts yet	1s	128 MB	Judgeable
MondriaanGiven non-overlapping rectangles that tile a big rectangle, count the 3-colorings of the adjacency graph where orthogonally touching regions differ and white is a fourth free option.	Medium7	GeometryGraph+2	No attempts yet	1s	128 MB	Judgeable
Nim/3Three-player Nim where each player has a preferred winner; find player 1's optimal move with smallest stack then smallest count.	Medium7	Game theoryDynamic programming+2	No attempts yet	1s	128 MB	Judgeable
Little Bear and the Honey PotOn a grid, bees spread one step per minute from hives; find the longest whole number of minutes the bear can eat at the pot before moving up to S cells per minute to reach home without ever sharing a cell with bees.	Medium7	BFSBinary search+1	No attempts yet	1s	128 MB	Judgeable
MerchantChoose a subset of markets to visit in nondecreasing opening-day order along a river, starting and ending at home, to maximize profits minus asymmetric upstream/downstream fuel costs.	Medium7	Dynamic programmingSorting+2	No attempts yet	1s	128 MB	Judgeable
Type PrinterFind the minimum number of add, remove, and print operations to type N distinct words on a printer that keeps a single editable string, with any print order allowed.	Medium7	TrieDFS+2	No attempts yet	1s	128 MB	Judgeable
SailsPlace K sails on each mast (height H) to minimize the total count of same-height sails behind each sail.	Medium7	GreedySorting+1	No attempts yet	1s	128 MB	Judgeable
MinersAssign each of N shipments in order to one of two mines; each shipment scores 1 to 3 based on how many distinct kinds appear among it and the previous two shipments at that mine, and the goal is to maximize the total.	Medium7	Dynamic programmingString+1	No attempts yet	1s	128 MB	Judgeable
The Valley of MexicoGiven a graph on cities placed in convex position, find a crossing-free Hamiltonian path (visiting every vertex once) that is lexicographically smallest, or report none.	Medium7	GraphDynamic programming+2	No attempts yet	1s	128 MB	Judgeable
That Nice Euler CircuitGiven the vertices of a closed polygonal Euler circuit whose segments may cross, count the connected regions the drawing divides the plane into.	Medium7	GeometryGraph+2	No attempts yet	1s	128 MB	Judgeable
HermesHermes walks on an infinite grid and must, in order, reach either the row or the column of each given point, starting at the origin; find the minimum total travel distance.	Medium7	Dynamic programmingGreedy+2	No attempts yet	1s	128 MB	Judgeable
Comparing CodeFind the longest run of HAL's lines that matches a run of RBN's lines up to injective variable renaming and swapping the two right-hand operands.	Medium7	String matchingHash map+1	No attempts yet	1s	128 MB	Judgeable
Utopia DividedAssign 2N distinct numbers into N signed x/y pairs so the teleporter visits the given regions in order, choosing the lexicographically smallest guiding.	Medium7	GreedyBacktracking+2	No attempts yet	1s	128 MB	Judgeable
Post OfficePlace P post offices in some of V villages on a line so that the sum of each village's distance to its nearest post office is minimized.	Medium7	Dynamic programmingPrefix sum+2	No attempts yet	1s	128 MB	Judgeable
Run, IOI TrainDiscard a prefix from each of two I/O strings, then interleave the remaining fronts to build the longest alternating string that starts and ends with I.	Medium7	Dynamic programmingTwo pointers+2	No attempts yet	1s	128 MB	Judgeable
The MansionIn a grid where only vertical doors start open, find the shortest time to go from (1,1) to (M,N), where holding a switch in certain rooms for a minute flips every door's state.	Medium7	GraphBFS+2	No attempts yet	1s	256 MB	Judgeable
Night MarketChoose an increasing-index subset of stalls, each with a non-overlapping integer start time before T, so that no play interval strictly contains time S, maximizing total fun.	Medium7	Dynamic programmingGreedy+2	No attempts yet	1s	128 MB	Judgeable
NailsGiven up to 500000 upward triangles on a triangular grid of N nails per side, count the nails covered by at least one triangle.	Medium7	ArrayPrefix sum+2	No attempts yet	1s	128 MB	Judgeable
DungeonStarting with stamina H on floor 1, repeatedly choose how often to drink each floor's spring while descending N-1 floors, so stamina stays in 1..H; minimize total spring uses.	Medium7	GreedyMath	No attempts yet	1s	128 MB	Judgeable
Santa Claus and RudolphCount the closed tours that start and end at the single church, visiting every house once, where each move is a straight horizontal or vertical glide that may not pass over an already visited house.	Medium7	BacktrackingDFS+2	No attempts yet	12s	128 MB	Judgeable
ShuffleAfter applying m shuffles to an ordered deck of n cards, count how many cards numbered r or less fall in positions p through q. n is up to 1e9, so the huge deck must be tracked implicitly.	Medium7	CombinatoricsMath+2	No attempts yet	1s	128 MB	Judgeable
Number of Paint ColorsCount connected regions of a rectangle cut by up to 1000 axis-aligned masking tape rectangles, where regions sharing only a corner stay separate.	Medium7	CombinatoricsGeometry+1	No attempts yet	2s	128 MB	Judgeable
The Lightest MobileGiven a tree of balanced rods with integer lever ratios, assign positive integer masses to all weights so every rod balances and the total mass is minimized.	Medium7	TreeDFS+2	No attempts yet	1s	128 MB	Judgeable
The Longest ChainGiven n strings, each with labeled rings a and b at its ends, find the number of vertices in the longest trail in the resulting multigraph.	Medium7	GraphDFS+2	No attempts yet	1s	128 MB	Judgeable
Apartment RentalCount how many given numbers up to 2^31-1 cannot be written as 2xy + x + y with positive integers x and y.	Medium7	Number theoryMath+2	No attempts yet	1s	256 MB	Judgeable
Distance Between the Closest Pair of PointsGiven up to 500,000 distinct points, find the two closest and print the square of their distance.	Medium7	Divide and conquerSorting+2	No attempts yet	1s	256 MB	Judgeable
PastriesGiven up to 100,000 triangles with integer vertices and 100,000 axis-aligned lines, count for each line how many triangles it cuts into two positive-area pieces.	Medium7	GeometryBinary search+2	No attempts yet	1s	128 MB	Judgeable
Probability Through ExperimentGiven n points on a circle by angle, count how many triples form an acute triangle.	Medium7	GeometryTwo pointers+2	No attempts yet	2s	128 MB	Judgeable
Optimal Space WayFor each test case, fit a weighted straight line through the plane minimizing the mean squared perpendicular distance from given points, and answer queries that give one point extra weight.	Medium7	GeometryMath+2	No attempts yet	5s	128 MB	Judgeable
RadioactivityFor each pair of radiation radii, count houses not covered by either plant after houses in both zones donate a spare unit.	Medium7	GeometrySorting+2	No attempts yet	1s	128 MB	Judgeable
Joyful ColoringGiven subsets of size at most 3, decide whether every subset can be made non-monochromatic under a 2-coloring.	Medium7	BacktrackingGame theory+2	No attempts yet	3s	128 MB	Judgeable
Queen GameGiven N queens on an R by C board that move up, left, or up-left, decide if the first player wins with optimal play.	Medium7	Game theoryMath+1	No attempts yet	1s	128 MB	Judgeable
Consecutive SumGiven q, count how many p make the sum of p consecutive integers equal the sum of the next q consecutive positive integers. Handle up to 2000 queries with q below 10^14.	Medium7	Number theoryMath+2	No attempts yet	5s	256 MB	Judgeable
Airplane ParkingGiven N time intervals (arrival, departure), find the largest subset that can be scheduled in a stack, so planes leave in last-in first-out order.	Medium7	Dynamic programmingIntervals+2	No attempts yet	1s	128 MB	Judgeable
Your WaysCount monotone lattice paths from (0,0) to (W,H) modulo 2552 for K days, where each day blocks up to 100 unit street/avenue segments with no two blocked segments on a common monotone path.	Medium7	Dynamic programmingCombinatorics+2	No attempts yet	1s	128 MB	Judgeable
Arranging HeapsGiven N heaps at increasing positions with weights, merge them into exactly K heaps where each heap moves only downriver, minimizing total weight times distance moved.	Medium7	Dynamic programmingDivide and conquer+2	No attempts yet	2s	128 MB	Judgeable
Electrical PollutionGiven consistent anomaly measurements at grid points, determine for each queried point whether its anomaly is uniquely forced by propagation along rows and columns of generators on the diagonal line.	Medium7	Union-findGraph+2	No attempts yet	1s	128 MB	Judgeable
Jupiter Attacks!Maintain an array under point updates and queries of a polynomial hash over a subarray modulo a prime, printing each hash result.	Medium7	Segment treePrefix sum+2	No attempts yet	1s	128 MB	Judgeable
Cocircular PointsFor each test case with up to 100 distinct points, find the largest subset that lies on one common circle and print its size.	Medium7	GeometryHash map+2	No attempts yet	5s	128 MB	Judgeable
String FarmGiven up to 10^4 strings, find the longest chain where each string is a contiguous substring of the next, all photos distinct.	Medium7	StringDynamic programming+2	No attempts yet	5s	128 MB	Judgeable
Hyperactive Boy GangsanCount minimal subsets of intervals that cover [0, M] with no redundant interval, modulo 10^8, over multiple test cases.	Medium7	Dynamic programmingIntervals+2	No attempts yet	1s	128 MB	Judgeable
Ingenious MetroGiven teleporter positions, each move reflects the current station across a chosen teleporter; decide for each query whether start can reach destination.	Medium7	MathNumber theory+1	No attempts yet	1s	128 MB	Judgeable
Kids' WishesDecide whether all kids can be seated in a circle so every wish (each kid asks for at most two neighbors) is satisfied.	Medium7	GraphUnion-find+2	No attempts yet	1s	128 MB	Judgeable
Almost Shortest PathRemove every edge that lies on any shortest S to D path, then find the shortest remaining path from S to D, or report -1.	Medium7	Shortest pathGraph+1	No attempts yet	1s	256 MB	Judgeable
Figure Out the BaseGiven an equation with + and * over digit strings, find every base B >= 2 in which both sides evaluate to the same value.	Medium7	MathBrute force+2	No attempts yet	1s	128 MB	Judgeable
Candy Picking ContestChoose boxes in an M by N grid so no two chosen boxes touch vertically or horizontally, maximizing the total candies collected.	Medium7	Dynamic programmingGreedy+2	No attempts yet	1s	256 MB	Judgeable
Traveling ShoemakerCities each belong to one or two color confederations; moving between cities consumes and produces tickets. Decide if a start city exists to visit every city exactly once.	Medium7	GraphDFS+2	No attempts yet	1s	128 MB	Judgeable
Shrinking Inscribed PolygonGiven arc lengths around an inscribed polygon, find the minimum number of vertices to delete so the remaining vertices form a regular polygon, or report -1.	Medium7	Number theoryMath+2	No attempts yet	1s	128 MB	Judgeable
AcquapiaMultiple test cases give several river trees; for each city pair, report whether a route exists and, if so, the unique city where the ship must switch from upstream to downstream.	Medium7	TreeDFS+2	No attempts yet	1s	128 MB	Judgeable
Emoticons :-)Given a set of emoticon strings, replace the fewest characters with spaces across several text lines so that no emoticon appears consecutively in any line.	Medium7	String matchingDynamic programming+2	No attempts yet	1s	128 MB	Judgeable
Lazy Jumping FrogGiven a grid with up to 1000 rectangular water regions, find the minimum energy path between two dry cells using a fixed set of twelve weighted jumps.	Medium7	Shortest pathGraph+2	No attempts yet	3s	128 MB	Judgeable
Onion LayersGiven N points, repeatedly take the convex hull of the remaining points, remove all points on that hull, and report whether the total number of layers removed is odd.	Medium7	GeometrySorting+2	No attempts yet	3s	128 MB	Judgeable
Turkish RoulettePlace B ordered balls into B non-overlapping pairs of adjacent wheel slots to maximize the dealer's profit, where each ball's value is its number times the sum of its two slots.	Medium7	Dynamic programmingArray+2	No attempts yet	3s	128 MB	Judgeable
P-NetworksGiven a permutation of N wires, decide whether a p-network can realize it, and if so report the minimum number of strokes needed.	Medium7	Dynamic programmingGreedy+2	No attempts yet	2s	128 MB	Judgeable
Land Division TaxSplit a ring of N lots one at a time; each split costs F times the larger resulting piece. Find the minimum total tax.	Medium7	Dynamic programmingIntervals+2	No attempts yet	1s	128 MB	Judgeable
Two-Stacks SolitaireGiven a stock pile dealt in order, decide whether the top card can be moved to intermediate pile 1 or 2 or popped to the foundation so all cards end non-decreasing.	Medium7	Dynamic programmingStack+2	No attempts yet	1s	128 MB	Judgeable
X-MartGiven customers who each vote for up to two products to keep and against up to two to drop, decide whether some keep/drop assignment pleases all of them.	Medium7	GraphDFS+2	No attempts yet	1s	128 MB	Judgeable
Telecommunication PartnersGiven an undirected graph and K, find the largest connected vertex set where each vertex has degree at least K inside the set.	Medium7	GraphGreedy+1	No attempts yet	1s	128 MB	Judgeable
Uncle Tom's Inherited LandGiven a grid where at most 50 squares are usable land and the rest are ponds, find the maximum number of 1x2 dominoes that tile the usable squares.	Medium7	GraphDynamic programming+2	No attempts yet	1s	128 MB	Judgeable
Myth BustersFor each city's list of four-digit carriage IDs, decide whether every ID can reach the value 10 by permuting its digits and inserting +, -, *, / with parentheses.	Medium7	Brute forceRecursion+2	No attempts yet	1s	128 MB	Judgeable
Difficult RoutesGiven a 3D road map where each directed edge has a difficulty, find the shortest route from s to t whose maximum edge difficulty equals exactly d.	Medium7	GraphShortest path+2	No attempts yet	1s	128 MB	Judgeable
RealPhobiaFor each fraction A/B, find C/D with D < B that minimizes the error \|A/B - C/D\|, breaking ties by the smallest denominator.	Medium7	Number theoryMath+2	No attempts yet	1s	128 MB	Judgeable
Insidious BrandingCount quadruples of dictionary words A, B, C, D with A+B = C+D and length(A) < length(C).	Medium7	Hash mapString	No attempts yet	2s	128 MB	Judgeable
Help-or-elseChoose an ordered subset of people to help; the finish time of each helper accumulates, and unhelped people add a penalty, so find the largest feasible subset under budget K.	Medium7	Dynamic programmingGreedy+2	No attempts yet	1s	128 MB	Judgeable
Oil SkimmingGiven an N by N grid of oil cells, choose as many non-overlapping horizontal or vertical adjacent pairs of oil cells as possible.	Medium7	GraphDynamic programming+2	No attempts yet	1s	128 MB	Judgeable
Parachute RingsProcess link operations on a growing undirected graph and, after each query, count the vertices whose removal leaves only paths (or nothing).	Medium7	GraphUnion-find+2	No attempts yet	3s	128 MB	Judgeable
The Suffering DwarvesMaintain a permutation under swaps and answer whether the set of heights A through B occupies consecutive positions.	Medium7	Segment treeArray+2	No attempts yet	1s	512 MB	Judgeable
Rice HubGiven sorted field positions on a line and a budget B, choose an integer hub position maximizing how many fields can be reached within total transport cost B.	Medium7	Two pointersPrefix sum+2	No attempts yet	1s	256 MB	Judgeable
What's Up With GravityOn a grid with two gravity directions, find the minimum number of gravity flips to move from C to D, where falling is forced downward and you can step sideways only when blocked below.	Medium7	BFSGraph+2	No attempts yet	1s	128 MB	Judgeable
Fuel EconomyFind the cheapest way to buy fuel along a route with a tank of capacity G, visiting stations with given prices, or report that the trip is impossible.	Medium7	GreedyStack+2	No attempts yet	1s	128 MB	Judgeable
BlinkEach bulb toggles when its left neighbor was on the previous step; given N up to 16 bulbs and a step count B up to 10^15, report the final states.	Medium7	MatrixBit manipulation+2	No attempts yet	1s	128 MB	Judgeable
PhotoGiven N cows in a line and K unfriendly pairs that cannot share a photo, find the minimum number of consecutive-range photos covering every cow.	Medium7	GreedyIntervals+2	No attempts yet	1s	128 MB	Judgeable
HaywireGiven a 3-regular graph on N cows (N at most 12), find the ordering of cows in a row minimizing the sum of pairwise distances between friends.	Medium7	BacktrackingBrute force+1	No attempts yet	1s	128 MB	Judgeable
The Cow RunCows sit at distinct positions on a line; John starts at 0, moves one unit per minute, and each cow costs one dollar per minute until reached. Minimize the sum of arrival times.	Medium7	Dynamic programmingGreedy+2	No attempts yet	1s	128 MB	Judgeable
NecklaceGiven a string and a pattern, delete the fewest characters so the pattern no longer appears as a contiguous substring.	Medium7	Dynamic programmingString matching+2	No attempts yet	1s	128 MB	Judgeable
Poker HandsGiven card counts per rank, find the fewest contiguous-rank straights whose unit cards sum to exactly those counts.	Medium7	GreedyArray+2	No attempts yet	1s	128 MB	Judgeable
SeatingTrack seats in a row under arrivals needing the lowest block of p empty seats and range departures; count the parties turned away.	Medium7	Segment treeBinary search+2	No attempts yet	1s	128 MB	Judgeable
Square OverlapGiven N centers of equal K by K squares, find the single overlapping pair and print its shared area, 0 if none overlap, or -1 if two or more pairs overlap.	Medium7	SortingSliding window+2	No attempts yet	1s	128 MB	Judgeable
Party InvitationsInviting cow 1 forces whole groups once all but one member is in; find the smallest set of cows that must be invited.	Medium7	GraphBFS+2	No attempts yet	1s	128 MB	Judgeable
MirrorsGiven N small mirrors tilted at 45 degrees, find the first mirror whose flip lets a horizontal ray from the origin reflect to reach point (a,b).	Medium7	GeometrySimulation+2	No attempts yet	1s	128 MB	Judgeable
Liars and Truth TellersEach statement says whether one cow calls another honest or a liar; find the largest prefix of statements that admits a consistent truth/lie labeling of all cows.	Medium7	GraphUnion-find+2	No attempts yet	1s	128 MB	Judgeable
Running Away From the BarnFor every node in a weighted tree rooted at node 1, count the descendants within total distance L along the downward path, including the node itself.	Medium7	TreeDFS+2	No attempts yet	1s	128 MB	Judgeable
Concurrently Balanced StringsGiven K parenthesis strings of length N, count index ranges whose substring is balanced in all K strings at once.	Medium7	Hash mapPrefix sum+2	No attempts yet	1s	128 MB	Judgeable
BookshelfPartition the books, in order, into shelves of total width at most L to minimize the sum of each shelf's max height.	Medium7	Dynamic programmingSegment tree+1	No attempts yet	1s	128 MB	Judgeable
Running LapsCount how many times a faster cow overtakes a slower cow, counting ordered pairs, before the fastest cow finishes L laps on a track of length C.	Medium7	SortingMath+2	No attempts yet	1s	128 MB	Judgeable
Surveillance CamerasGiven up to 50,000 distinct grid points, decide whether three axis-parallel lines (full rows or columns) can cover all of them.	Medium7	Brute forceRecursion+2	No attempts yet	1s	128 MB	Judgeable
Unlocking BlocksThree connected polyomino pieces slide one unit at a time on a small grid; decide whether they can be moved so their bounding boxes are pairwise disjoint.	Medium7	BFSSimulation+2	No attempts yet	1s	128 MB	Judgeable
Haybale RestackingGiven N piles in a circle with current and target amounts of hay, move bales at cost equal to circular distance to reach the target with minimum total work.	Medium7	GreedyPrefix sum+2	No attempts yet	1s	128 MB	Judgeable
Wrong DirectionsGiven a command string of F, L, and R, count the distinct final positions reachable by changing exactly one character to a different one.	Medium7	SimulationHash map+2	No attempts yet	1s	128 MB	Judgeable
Efficient Cow BuyingGiven N cows with a full price and a cheaper coupon price, and K coupons plus M dollars, find the maximum number of cows that can be bought.	Medium7	GreedySorting+2	No attempts yet	1s	128 MB	Judgeable
OverplantingGiven up to 1000 axis-aligned rectangles, compute the total area of their union.	Medium7	GeometrySorting+1	No attempts yet	1s	128 MB	Judgeable
RelocationGiven an undirected weighted graph with up to 5 market towns, pick a non-market town as home and an order to visit all markets and return, minimizing total distance.	Medium7	Shortest pathGraph+2	No attempts yet	1s	128 MB	Judgeable
Bovine AllianceCount assignments of each of M trails to one of its two endpoint farms so that no farm builds more than one trail, modulo 1e9+7.	Medium7	GraphCombinatorics+2	No attempts yet	1s	128 MB	Judgeable
Mountain ClimbingTwo farmers each handle one leg of the trip, so at most one cow climbs up and one climbs down at a time. Find the minimum total time with reorderable descent.	Medium7	GreedySorting+2	No attempts yet	1s	128 MB	Judgeable
Cow PhotographyGiven five orderings of N cows where each cow moves in at most one photo, reconstruct the original intended order.	Medium7	SortingImplementation+2	No attempts yet	1s	128 MB	Judgeable
Cow PhotographyGiven five permutations of 1..N, each reachable from an unknown target permutation by at most one element removal-and-reinsertion, recover the target permutation.	Medium7	SortingImplementation+1	No attempts yet	1s	128 MB	Judgeable
Binary SudokuGiven a 9x9 grid of 0s and 1s, find the fewest toggles so that every row, column, and 3x3 block has an even number of 1s.	Medium7	MathBit manipulation+1	No attempts yet	1s	128 MB	Judgeable