Problems

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Total results29,429 problems

Challenge 24
Medium6
Brute force, Recursion+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cover Up
Medium6
Probability, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Decompressing in a GIF
Medium6
String, Hash map+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Flood
Medium6
Graph, Union-find+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Jack of All Trades
Medium6
Graph, DFS+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tanks a Lot
Medium6
Prefix sum, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
A Puzzling Problem
Medium6
Graph, BFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pizza Delivery Minimum Time
Medium6
Shortest path, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Game of Efil
Medium6
Bit manipulation, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Swamp Things
Medium6
Geometry, Hash map+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Two Ends
Medium6
Dynamic programming, Game theory+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sunday Drive
Medium6
Dynamic programming, Geometry
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Data Recovery
Medium6
Graph, Prefix sum+2
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Roller Coaster
Medium6
Dynamic programming
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Ninja Way
Medium6
Dynamic programming, Array
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Robot Challenge
Medium6
Dynamic programming, Geometry+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Mosaic
Medium6
Dynamic programming, Bit manipulation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Series / Parallel Resistor Circuits
Medium6
Graph, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
A Walk in the Park
Medium6
Sorting, Hash map+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Secret Polynomial
Medium6
Math, Brute force+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Class Schedule
Medium6
Dynamic programming, Sorting
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Compound Words
Medium6
Trie, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Driving Range
Medium6
Graph, Union-find+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Paintball
Medium6
Geometry, Union-find+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
HST
Medium6
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pick up sticks
Medium6
Topological sort, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tic-Tac-Toe
Medium6
Implementation, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Fire!
Medium6
BFS, Graph+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Cranes
Medium6
Brute force, Geometry+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
WiFi
Medium6
Binary search, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Friend Network
Medium6
Union-find, Hash map+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Train Sorting
Medium6
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Balance
Medium6
Geometry, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tournament
Medium6
Dynamic programming, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Exchange Rates
Medium6
Dynamic programming, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Security Company
Medium6
Dynamic programming, Greedy+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Translations
Medium6
Graph, Hash map+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
EKG Sequence
Medium6
Number theory, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Water Main Break, Fixed
Medium6
Brute force, Greedy+2
No attempts yet
Time limit
8s
Memory limit
128 MB
Judgeable
Pushing Boxes
Medium6
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Knockout Tournament
Medium6
Tree, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
One Person “The Price is Right”
Medium6
Dynamic programming, Game theory
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Slots of Fun
Medium6
Geometry, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Semi-prime H-numbers
Medium6
Number theory, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Trip (2007)
Medium6
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
WFF 'N PROOF
Medium6
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Card Hands
Medium6
Trie, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
When Does C Pass M?
Medium6
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
A Walk Through the Forest
Medium6
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Ultra-QuickSort
Medium6
Divide and conquer, Sorting+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Up the Ante
Medium6
Probability, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Mint
Medium6
Number theory, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Expanding Rods
Medium6
Binary search, Geometry+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Powers of Three
Medium6
Math, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Work Reduction
Medium6
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Marbles on a Tree
Medium6
Tree, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
A Flea on a Chessboard
Medium6
Math, Number theory+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Dead Fraction
Medium6
Number theory, Math
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Biometrics
Medium6
Geometry, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Russian Dolls
Medium6
Sorting, Greedy
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Persistent Numbers
Medium6
Greedy, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Based Integer Constants
Medium6
String, Recursion+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Euclid's Game
Medium6
Game theory, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Build a Square from Sticks
Medium6
Backtracking, Recursion+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
A Star, Not a Tree?
Medium6
Geometry, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Adventures in Moving - Part IV
Medium6
Greedy, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pairsumonious Numbers
Medium6
Sorting, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
No Tipping
Medium6
Backtracking, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sum Set
Medium6
Hash map, Brute force+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Gopher II
Medium6
Graph, Union-find+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Dividing
Medium6
Number theory, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bridge Crossing
Medium6
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Saskatchewan
Medium6
Geometry, Math
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Demerit Points
Medium6
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Snakes
Medium6
Geometry, Union-find+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Choose and Divide
Medium6
Math, Number theory+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Billiard
Medium6
Math, Geometry+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Brick Stops Here
Medium6
Dynamic programming, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Watching Watches
Medium6
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Dick and Jane
Medium6
Math, Brute force+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Stupendous Man
Medium6
Stack, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sang-geun's Lock
Medium6
Dynamic programming, Recursion+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Fibonacci Number Analysis
Medium6
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pride and Prejudice and Zombies
Medium6
Brute force, Backtracking+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
George Lucas and 1138
Medium6
Divide and conquer, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pebbles
Medium6
Dynamic programming, Bit manipulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
All Your Base
Medium6
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Words and the Periodic Table
Medium6
Dynamic programming, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Neptune Adventure
Medium6
Shortest path, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Phil in the Blanks
Medium6
Brute force, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
I'm Attacking the Darkness!
Medium6
Dynamic programming, Probability+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Like Water for Clay
Medium6
Simulation, BFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cables ... in Spaaace!
Medium6
Graph, Minimum spanning tree+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
No Wormholes Were Harmed...
Medium6
Graph, Shortest path+2
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Another Brick in the Wall
Medium6
Graph, Shortest path+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Schottkey 7th Path
Medium6
String, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Final Countdown
Medium6
Implementation, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Children of the Candy Corn
Medium6
BFS, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Janken Tactics
Medium6
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bingo!
Medium6
Brute force, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Challenge 24From four distinct positive integers, enumerate every value reachable using each number once with +, -, *, and even-only division, then report the longest run of consecutive integers, choosing the largest start on ties.	Medium6	Brute forceRecursion+2	No attempts yet	1s	128 MB	Judgeable
Cover UpGiven per-digit candidate lists with known-candidate probabilities, compute the win probability when the contestant plays optimally.	Medium6	ProbabilityDynamic programming+2	No attempts yet	1s	128 MB	Judgeable
Decompressing in a GIFDecode a digit string compressed with a simplified GIF LZW scheme, rebuilding the dictionary and tracking when the encoding width grows.	Medium6	StringHash map+2	No attempts yet	1s	128 MB	Judgeable
The FloodGiven a grid of altitudes, find the lowest water level at which the dry land splits into two or more connected pieces, where water floods inward from outside.	Medium6	GraphUnion-find+2	No attempts yet	1s	128 MB	Judgeable
Jack of All TradesGiven directed trades between items, find the minimum exchange ratio from one item to another using at most 9 trades, and count the chains achieving it.	Medium6	GraphDFS+1	No attempts yet	1s	128 MB	Judgeable
Tanks a LotGiven gas stations on a circular track whose fuel exactly covers one lap, list every station and direction from which a full lap can be completed.	Medium6	Prefix sumGreedy+1	No attempts yet	1s	128 MB	Judgeable
A Puzzling ProblemGiven a word search grid and word list, decide whether removing any single word ever disconnects the remaining words from one another.	Medium6	GraphBFS+2	No attempts yet	1s	128 MB	Judgeable
Pizza Delivery Minimum TimeGiven directed travel times between a pizzeria and up to 10 stops, find the shortest round trip from the pizzeria visiting every stop.	Medium6	Shortest pathDynamic programming+2	No attempts yet	1s	128 MB	Judgeable
The Game of EfilCount how many predecessor configurations on a torus could evolve into a given Game of Life state.	Medium6	Bit manipulationBrute force+2	No attempts yet	1s	128 MB	Judgeable
Swamp ThingsFor each test case, count how many of up to 1000 points lie on a single line chosen as the one containing the most points, but only if that maximum count is at least four.	Medium6	GeometryHash map+2	No attempts yet	1s	128 MB	Judgeable
Two EndsFor each even-length row of cards, find the best score margin the first player can get when the second player always takes the larger end.	Medium6	Dynamic programmingGame theory+1	No attempts yet	1s	128 MB	Judgeable
Sunday DriveGiven a sequence of straight and 90-degree curved highway sections with M lanes, find the shortest path including lane changes, which take 100 feet per lane.	Medium6	Dynamic programmingGeometry	No attempts yet	1s	128 MB	Judgeable
Data RecoveryGiven a grid with some unknown cells plus all row and column sums, print each unknown cell's forced value, or -1 if several values fit.	Medium6	GraphPrefix sum+2	No attempts yet	5s	128 MB	Judgeable
Roller CoasterEach section of a roller coaster either adds fun and dizziness or reduces dizziness by K; find the maximum fun keeping dizziness at or below L at all times.	Medium6	Dynamic programming	No attempts yet	1s	128 MB	Judgeable
The Ninja WayGiven trees in fixed left-to-right order with distinct heights, place them on integer positions so each jump to the next taller tree spans at most D, maximizing the span from shortest to tallest.	Medium6	Dynamic programmingArray	No attempts yet	1s	128 MB	Judgeable
Robot ChallengeThe robot starts at (0,0), must visit targets in order, and may skip any target by paying its penalty. Find the minimum total time plus penalties to reach (100,100).	Medium6	Dynamic programmingGeometry+2	No attempts yet	1s	128 MB	Judgeable
MosaicCount the tilings of an N x M grid with 2 x 2 squares and L-trominoes, modulo 1,000,000.	Medium6	Dynamic programmingBit manipulation	No attempts yet	1s	128 MB	Judgeable
Series / Parallel Resistor CircuitsRepeatedly merge series and parallel resistor pairs in a given circuit, then report the equivalent resistance between A and Z or -1.000 if it fails.	Medium6	GraphSimulation+1	No attempts yet	1s	128 MB	Judgeable
A Walk in the ParkGiven points for trees and infinite horizontal or vertical paths that avoid all trees, count trees visible along a perpendicular direction with no other tree blocking the sight line.	Medium6	SortingHash map+2	No attempts yet	2s	128 MB	Judgeable
Secret PolynomialGiven f(1) and f(f(1)) for an unknown polynomial with non-negative integer coefficients, recover it or report IMPOSSIBLE or AMBIGUOUS.	Medium6	MathBrute force+1	No attempts yet	1s	128 MB	Judgeable
Class ScheduleChoose one class per category to minimize class costs plus total travel from position 0 through the chosen rooms to position L.	Medium6	Dynamic programmingSorting	No attempts yet	1s	128 MB	Judgeable
Compound WordsGiven a dictionary of up to 120,000 sorted lowercase words, list every word that can be split into two shorter dictionary words.	Medium6	TrieString+2	No attempts yet	1s	128 MB	Judgeable
Driving RangeGiven a weighted undirected graph, find the smallest range R such that using only edges of length at most R keeps the whole graph connected, or report IMPOSSIBLE.	Medium6	GraphUnion-find+2	No attempts yet	1s	128 MB	Judgeable
PaintballDecide whether a path can cross a 1000x1000 field from west edge to east edge while avoiding circular firing ranges, and give the northernmost entry and exit points.	Medium6	GeometryUnion-find+2	No attempts yet	1s	128 MB	Judgeable
HSTGiven tax rate categories and monthly purchases, compute the difference between total HST paid and total PST plus GST paid, with each tax rounded per item.	Medium6	MathImplementation+2	No attempts yet	1s	128 MB	Judgeable
Pick up sticksGiven a set of on-top-of relations between sticks, output the lexicographically smallest removal order, or IMPOSSIBLE if a cycle exists.	Medium6	Topological sortGraph+2	No attempts yet	1s	128 MB	Judgeable
Tic-Tac-ToeGiven an n by n tic-tac-toe board with win length m, decide if the state is in progress, finished (X, O, or draw), or impossible.	Medium6	ImplementationSimulation+2	No attempts yet	1s	128 MB	Judgeable
Fire!Given a grid with walls, one starting cell, and burning cells, find the earliest minute Jihoon can step off the edge, given the fire spreads one cell per minute.	Medium6	BFSGraph+2	No attempts yet	1s	256 MB	Judgeable
CranesChoose a subset of at most 15 crane locations, each with a radius, so that every pair's distance exceeds the sum of radii, maximizing the total squared radius.	Medium6	Brute forceGeometry+2	No attempts yet	1s	128 MB	Judgeable
WiFiGiven house positions on a line and a budget of n access points, place them to minimize the maximum distance from any house to its nearest access point.	Medium6	Binary searchGreedy+2	No attempts yet	1s	128 MB	Judgeable
Friend NetworkProcess friendships one by one and after each union print the size of the merged friend network containing the two users.	Medium6	Union-findHash map+1	No attempts yet	3s	256 MB	Judgeable
Train SortingCars arrive in a fixed order; each can be attached to the front, the back, or skipped, keeping weights strictly decreasing front to back. Find the longest train.	Medium6	Dynamic programmingGreedy+2	No attempts yet	1s	128 MB	Judgeable
BalanceGiven the polygon outline of a boat's side view, compute the centroid above and below the waterline and report whether the Center of Effort is forward, aft, or balanced, with the difference rounded to two decimals.	Medium6	GeometryMath+2	No attempts yet	1s	128 MB	Judgeable
TournamentGiven k knights with abilities, choose 2^e - k of them to sit out the first round and pair the rest to minimize the sum of squared ability differences.	Medium6	Dynamic programmingSorting+2	No attempts yet	1s	128 MB	Judgeable
Exchange RatesWith a daily CAD/USD rate and a 3% commission per conversion, find the maximum final amount of Canadian dollars you can hold after the last day.	Medium6	Dynamic programmingGreedy+1	No attempts yet	1s	128 MB	Judgeable
Security CompanyPoints lie on a line with travel times between neighbors; starting from point a and visiting every point, minimize the total first-arrival time over all points.	Medium6	Dynamic programmingGreedy+2	No attempts yet	2s	128 MB	Judgeable
TranslationsGiven two alphabetically sorted lists of two-word phrases in two languages, reconstruct the unknown one-to-one word translation mapping. Print each source word with its translation, sorted.	Medium6	GraphHash map+2	No attempts yet	1s	128 MB	Judgeable
EKG SequenceBuild the EKG sequence up to position 1000000 and report the 1-based position where each queried integer n first appears.	Medium6	Number theoryBrute force+2	No attempts yet	1s	128 MB	Judgeable
Water Main Break, FixedA crew starts at the origin and must visit up to 10 breaks in some order; pick the order that minimizes total water lost, where each break waits until its start time.	Medium6	Brute forceGreedy+2	No attempts yet	8s	128 MB	Judgeable
Pushing BoxesSimulate pushes of the four walls on unit boxes, stopping each wall when boxes are packed against the opposite wall, and report final positions sorted top-to-bottom, left-to-right.	Medium6	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
Knockout TournamentGiven knockout tournament results, find the best and worst possible rank each queried player could hold under a transitive beat relation.	Medium6	TreeDFS+2	No attempts yet	1s	128 MB	Judgeable
One Person “The Price is Right”Given G guesses and L lifelines, find the largest N such that a strategy guarantees a win for any price from 1 to N.	Medium6	Dynamic programmingGame theory	No attempts yet	1s	128 MB	Judgeable
Slots of FunGiven letters on a triangular lattice, find every letter whose three positions form an equilateral triangle.	Medium6	GeometryBrute force+2	No attempts yet	1s	128 MB	Judgeable
Semi-prime H-numbersFor each H-number h, count H-semi-primes up to h, where H-primes are irreducible among numbers of the form 4n+1.	Medium6	Number theoryMath+2	No attempts yet	1s	128 MB	Judgeable
The Trip (2007)Given n bag sizes where a strictly smaller bag fits inside a larger one, find the minimum number of outermost pieces and then the smallest possible size of the largest nested piece.	Medium6	GreedySorting+2	No attempts yet	1s	128 MB	Judgeable
WFF 'N PROOFGiven counts of logic symbols, find the maximum length of a well-formed formula that can be built from a subset of them.	Medium6	Dynamic programmingGreedy+2	No attempts yet	1s	128 MB	Judgeable
Card HandsGiven several ordered card hands, merge lists that share a common suffix and report the total number of linked list nodes needed.	Medium6	TrieString+1	No attempts yet	1s	128 MB	Judgeable
When Does C Pass M?Given five observed meeting times along a highway, find the exact moment when car C passes car M.	Medium6	MathImplementation+2	No attempts yet	1s	128 MB	Judgeable
A Walk Through the ForestCount the number of routes from intersection 1 to 2 in an undirected weighted graph where each step strictly decreases the shortest distance to intersection 2.	Medium6	GraphShortest path+2	No attempts yet	1s	128 MB	Judgeable
Ultra-QuickSortGiven a sequence of distinct integers, count the minimum number of adjacent swaps needed to sort it, which is the number of inversions.	Medium6	Divide and conquerSorting+2	No attempts yet	1s	256 MB	Judgeable
Up the AnteGiven per-round win probabilities, find the chance a capped martingale strategy shows a positive balance at some round from k through m.	Medium6	ProbabilityDynamic programming+2	No attempts yet	1s	128 MB	Judgeable
MintGiven coin thicknesses, a length is constructible when at least four distinct thicknesses divide it; for each query height, report the nearest constructible length at or below it and the nearest at or above it.	Medium6	Number theoryBrute force+2	No attempts yet	1s	128 MB	Judgeable
Expanding RodsGiven a heated rod fixed at both ends, compute how far its midpoint bows out, using the circular-segment geometry and binary search.	Medium6	Binary searchGeometry+1	No attempts yet	1s	128 MB	Judgeable
Powers of ThreeGiven n, list the elements of the n-th smallest subset of powers of 3 when subsets are ordered by their sums.	Medium6	MathCombinatorics+2	No attempts yet	1s	128 MB	Judgeable
Work ReductionFor each agency with per-unit cost A and halving cost B, find the minimum cost to cut N units of paperwork down to exactly M.	Medium6	Dynamic programmingGreedy+2	No attempts yet	1s	128 MB	Judgeable
Marbles on a TreeGiven a rooted tree where each vertex has a box and the total marbles equal the number of vertices, find the minimum number of moves (along edges) so every box holds exactly one marble.	Medium6	TreeDFS+2	No attempts yet	1s	128 MB	Judgeable
A Flea on a ChessboardThe flea jumps by (dx, dy) from (x, y) on a grid of square size S; find the first jump landing strictly inside a white square, or report that none exists.	Medium6	MathNumber theory+1	No attempts yet	1s	128 MB	Judgeable
Dead FractionGiven a truncated decimal with a repeating tail, find the fraction with the smallest denominator that produces the recorded digits.	Medium6	Number theoryMath	No attempts yet	1s	128 MB	Judgeable
BiometricsGiven two polygons with vertices in matching feature order, decide whether one maps onto the other by translation, rotation, and uniform scaling without reflection.	Medium6	GeometryMath+1	No attempts yet	1s	128 MB	Judgeable
Russian DollsGiven 2n dolls with height, diameter, and wall thickness, decide whether they can be split into two chains of n that each nest perfectly.	Medium6	SortingGreedy	No attempts yet	1s	128 MB	Judgeable
Persistent NumbersFor each big integer N, find the smallest multi-digit number whose digits multiply to N, or report that none exists.	Medium6	GreedyMath+2	No attempts yet	1s	128 MB	Judgeable
Based Integer ConstantsFor each string, decide whether it is a valid Ada integer constant, which may nest a based integer as the base of another based integer.	Medium6	StringRecursion+1	No attempts yet	1s	128 MB	Judgeable
Euclid's GameGiven two starting numbers, decide who wins the subtraction game Euclid's Game under optimal play, for each pair until the terminating 0 0 line.	Medium6	Game theoryMath+2	No attempts yet	1s	128 MB	Judgeable
Build a Square from SticksGiven up to 20 stick lengths, decide whether all sticks can be split into four groups of equal total length.	Medium6	BacktrackingRecursion+2	No attempts yet	1s	128 MB	Judgeable
A Star, Not a Tree?Given up to 100 points in the plane, pick one hub location that minimizes the sum of Euclidean distances to all points, and report the rounded minimum.	Medium6	GeometryMath+2	No attempts yet	1s	128 MB	Judgeable
Adventures in Moving - Part IVGiven a route with up to 100 gas stations, each with a price per litre, find the cheapest way to fuel a truck with a 200-litre tank that starts and ends half full.	Medium6	GreedyDynamic programming+2	No attempts yet	1s	128 MB	Judgeable
Pairsumonious NumbersGiven all pairwise sums of N numbers, recover the N numbers in non-descending order, choosing the lexicographically smallest set or reporting Impossible.	Medium6	SortingMath+2	No attempts yet	1s	128 MB	Judgeable
No TippingCount the orders in which n packages can be removed from a lever on two fulcrums so the board never tips.	Medium6	BacktrackingBit manipulation+1	No attempts yet	1s	128 MB	Judgeable
Sum SetGiven a set of distinct integers, find the largest element d that equals the sum of three other distinct elements.	Medium6	Hash mapBrute force+1	No attempts yet	1s	128 MB	Judgeable
Gopher IIEach gopher escapes if some hole within s*v metres is assigned to it, one gopher per hole; minimize the number of gophers left out by finding a maximum matching.	Medium6	GraphUnion-find+2	No attempts yet	1s	128 MB	Judgeable
DividingFor each case with t, a, b, decide whether (t^a-1)/(t^b-1) is an integer below 100 digits, and print it or a fixed message.	Medium6	Number theoryMath+2	No attempts yet	1s	128 MB	Judgeable
Bridge CrossingGiven n people's crossing times and one flashlight, find the minimum total time to move everyone across when at most two cross together.	Medium6	GreedySorting+2	No attempts yet	1s	128 MB	Judgeable
SaskatchewanGiven a polygon with integer vertices, count how many unit grid squares lie entirely inside the polygon.	Medium6	GeometryMath	No attempts yet	1s	128 MB	Judgeable
Demerit PointsSimulate a driver's demerit and merit points over time, applying offense, merit award, and yearly reduction rules, and print each change.	Medium6	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
SnakesDecide whether a path exists from the west edge to the east edge of a 1000 by 1000 square while staying at distance at least r from every snake.	Medium6	GeometryUnion-find+1	No attempts yet	1s	128 MB	Judgeable
Choose and DivideFor each line, compute the binomial coefficient C(p,q) divided by C(r,s) and print the quotient to five decimal places.	Medium6	MathNumber theory+1	No attempts yet	1s	128 MB	Judgeable
BilliardGiven table dimensions, travel time, and bounce counts off the vertical and horizontal sides, find the launch angle and initial speed of a ball starting at the center and returning to it.	Medium6	MathGeometry+2	No attempts yet	1s	128 MB	Judgeable
The Brick Stops HereGiven N brick types with copper content and price, answer C queries: pick exactly M distinct types whose copper sum lies in [MCmin, MCmax] at minimum total price.	Medium6	Dynamic programmingSorting+2	No attempts yet	1s	128 MB	Judgeable
Watching WatchesTwo slow 12-hour analog watches are set to midnight; find the next time they read the same, rounded to the nearest minute.	Medium6	MathNumber theory+2	No attempts yet	1s	128 MB	Judgeable
Dick and JaneGiven that Spot was s when Puff was born, Puff was p when Yertle was born, and Spot was y when Yertle was born, find the three current ages.	Medium6	MathBrute force+1	No attempts yet	1s	128 MB	Judgeable
Stupendous ManGiven a sequence where each label 1..N appears twice, decide whether the labels can trace one closed loop of a self-crossing path or not.	Medium6	StackImplementation+1	No attempts yet	1s	128 MB	Judgeable
Sang-geun's LockCount the number of height-balanced binary trees with N nodes, print the last 9 digits padded to width 9.	Medium6	Dynamic programmingRecursion+1	No attempts yet	1s	128 MB	Judgeable
Fibonacci Number AnalysisFor each lo-hi range in hexadecimal, print every Fibonacci number inside it with its index, base-2 log, and prime factorization.	Medium6	MathImplementation+2	No attempts yet	1s	128 MB	Judgeable
Pride and Prejudice and ZombiesFor each number up to 18 digits, decide whether its digits split into two equal-length factors with no leading or consecutive zeros.	Medium6	Brute forceBacktracking+1	No attempts yet	1s	128 MB	Judgeable
George Lucas and 1138Given a digit string, use all its digits with +, -, *, / and parentheses, and report the smallest positive integer that no expression can produce.	Medium6	Divide and conquerBrute force+2	No attempts yet	1s	128 MB	Judgeable
PebblesPlace pebbles on an N by N board so no two touch even diagonally, maximizing the sum of covered cell values.	Medium6	Dynamic programmingBit manipulation+2	No attempts yet	1s	128 MB	Judgeable
All Your BaseRead two mixed-radix numbers, where digit n (from the right) has base n+1, apply the given addition or subtraction, and print the result in the same system or Invalid.	Medium6	MathImplementation+2	No attempts yet	1s	128 MB	Judgeable
Words and the Periodic TableSplit each word into element symbols, case-insensitively, choosing the split with the fewest parts, then the lowest atomic-number sum.	Medium6	Dynamic programmingString+1	No attempts yet	1s	128 MB	Judgeable
The Neptune AdventureGiven a directed graph with travel times and a flood time per location, find the earliest safe arrival time from S to R, or report failure.	Medium6	Shortest pathGraph+1	No attempts yet	1s	128 MB	Judgeable
Phil in the BlanksA puzzle sentence has up to four blanks to fill with number words (zero to one hundred); the filled sentence must correctly count letters, vowels, consonants, or given characters including the inserted words. Count solutions.	Medium6	Brute forceString+2	No attempts yet	1s	128 MB	Judgeable
I'm Attacking the Darkness!Parse a dice expression with up to six dice and integer modifiers, then compute the reduced fraction of outcomes whose total meets or beats a target value.	Medium6	Dynamic programmingProbability+2	No attempts yet	1s	128 MB	Judgeable
Like Water for ClayGiven a grid of blocks and open cells, compute how much water is trapped when the shape is dunked with each of its four sides facing up.	Medium6	SimulationBFS+2	No attempts yet	1s	128 MB	Judgeable
Cables ... in Spaaace!Given a planet's diameter and up to 100 city coordinates, compute the minimum cable length of a strongly connected network and compare it to the available length L.	Medium6	GraphMinimum spanning tree+2	No attempts yet	1s	128 MB	Judgeable
No Wormholes Were Harmed...For each dataset, find the minimum aging an agent accumulates during a round trip from a start year to each destination year and back, using wormholes with fractional forward and backward aging costs.	Medium6	GraphShortest path+2	No attempts yet	3s	128 MB	Judgeable
Another Brick in the WallGiven a grid of bricks, each labeled by a letter, remove the fewest bricks so the removed cells form a connected top-to-bottom gap.	Medium6	GraphShortest path+1	No attempts yet	1s	128 MB	Judgeable
Schottkey 7th PathGiven files in locations and per-user search paths, return the files matching each request within two extra characters, honoring location priority.	Medium6	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
The Final CountdownGiven a countdown start time and conditional holds at distinct clock minutes, find the minimum and maximum real duration over all truth assignments.	Medium6	ImplementationSimulation+2	No attempts yet	1s	128 MB	Judgeable
Children of the Candy CornFor each maze, report the number of squares visited along the left-hand wall-following route, the right-hand route, and the shortest route from S to E.	Medium6	BFSSimulation+2	No attempts yet	1s	128 MB	Judgeable
Janken TacticsOn a hex grid with terrain costs and enemy-threat rules, validate a sequence of moves by finding the cheapest legal path and reporting leftover movement points.	Medium6	GraphShortest path+2	No attempts yet	1s	128 MB	Judgeable
Bingo!Given column draw counts and X candidate 5x5 patterns, combine any Y of them into winning patterns and find the fewest additional draws that make some pattern fully markable.	Medium6	Brute forceCombinatorics+2	No attempts yet	1s	128 MB	Judgeable