Interview warm-up

Short whiteboard warmups

Under construction

Still being built. Things may change

Total results4,880 problems

iPhone 9S
Medium4
Array, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Rope Folding
Medium4
Array, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Overplanting
Medium4
Geometry, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bale Share
Medium4
Brute force, Recursion+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Gift
Medium4
Sorting, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Moo Sick
Medium4
Array, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Book Club
Medium4
Hash map, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Space Exploration
Medium4
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Meeting Place
Medium4
Tree, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pathfinding
Medium4
Graph, BFS
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bessie's Weight Problem
Medium4
Dynamic programming, Array+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Heat Wave
Medium4
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Chivalrous Cow
Medium4
BFS, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cow Pinball
Medium4
Dynamic programming, Array+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Music Notes
Medium4
Prefix sum, Binary search+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Selfish Grazing
Medium4
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Find the Playing Note
Medium4
Prefix sum, Binary search+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Chocolate Buying
Medium4
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Maximize the Acceleration
Medium4
Brute force, Bit manipulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
MasterMind
Medium4
Brute force, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Longest Contiguous Subsequence
Medium4
Dynamic programming, Array+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Widest Mountain
Medium4
Array, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cow Pals
Medium4
Number theory, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Mountain Watching
Medium4
Array, Two pointers+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Guarding the Farm
Medium4
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Time Management
Medium4
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Strange Towers of Hanoi
Medium4
Dynamic programming, Recursion+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Look Up
Medium4
Stack, Array+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Dairy Queen
Medium4
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hide and Seek
Medium4
Graph, BFS+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Cow Line
Medium4
Queue, Linked list+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
O Those Fads
Medium4
Sorting, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Speed Reading
Medium4
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Going to Meet Sina
Medium4
BFS, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bookshelf 2
Medium4
Brute force, Bit manipulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Election Time
Medium4
Sorting, Array+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Dining Cows
Medium4
Dynamic programming, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Long Distance Racing
Medium4
Array, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Oh Those Rollers
Medium4
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Roads Around the Farm
Medium4
Recursion, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Word Power
Medium4
String, Two pointers+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Clear and Present Danger
Medium4
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Clear Cold Water
Medium4
Tree, BFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cow Pie Treasures
Medium4
Dynamic programming, Matrix
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hungry Cows
Medium4
Dynamic programming, Binary search+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cow Picnic
Medium4
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Eating Puzzle
Medium4
Brute force, Bit manipulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Bale Tower
Medium4
Dynamic programming, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Buy One Get One Free
Medium4
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Argus
Medium4
Heap, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cow Solitaire
Medium4
Dynamic programming, Matrix+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bronze Cow Party
Medium4
Shortest path, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Team Arrangement
Medium4
Sorting, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Barbara Bennett's Wild Numbers
Medium4
Combinatorics, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Word Puzzle
Medium4
Array, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The die is cast
Medium4
DFS, BFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Number Base Conversion
Medium4
Math, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Microprocessor Simulation
Medium4
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Sultan's Successors
Medium4
Backtracking, Recursion+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Is It a Tree?
Medium4
Graph, Union-find+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Optimal Array Multiplication Sequence
Medium4
Dynamic programming, Matrix+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pseudo-Random Numbers
Medium4
Hash map, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Octal Fractions
Medium4
Math, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Risk
Medium4
Graph, BFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Volleyball Stats
Medium4
Implementation, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Excuses, Excuses!
Medium4
String, Hash map+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
M*A*S*H
Medium4
Simulation, Array+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Intersection of Two Lines
Medium4
Geometry, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Making Random Numbers
Medium4
Simulation, Hash map+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Etaoin Shrdlu
Medium4
String, Hash map+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Goldbach's Conjecture
Medium4
Number theory, Math+2
No attempts yet
Time limit
0.5s
Memory limit
256 MB
Judgeable
The Sangbeom Building
Medium4
BFS, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Intergalactic Mortgage
Medium4
Simulation, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Digital Display
Medium4
Implementation, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Intriguing Identifiers
Medium4
Implementation, String+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Suspicious Stocks
Medium4
Array, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Stock Exchange
Medium4
Array, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Emag eht htiw Em Pleh
Medium4
Implementation, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
English Number Translator
Medium4
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
R.Ø.L.P. Code Wheel
Medium4
String, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Parsing Real Numbers
Medium4
String, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Expression Evaluator
Medium4
String, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bridge Transport
Medium4
Sliding window, Array+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Who is taller?
Medium4
Graph, DFS+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Palindrome Bases
Medium4
Math, Brute force+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Knight Hop
Medium4
BFS, Graph+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
From Prefix to Postfix
Medium4
Stack, Tree+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Maze
Medium4
BFS, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Keep on Truckin'
Medium4
Dynamic programming, Array+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Boxes
Medium4
Sorting, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Waterpark
Medium4
Dynamic programming, Graph
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
It’s tough being a teen!
Medium4
Graph, Topological sort+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Othello
Medium4
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Attack of the CipherTexts
Medium4
Hash map, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Space Turtle
Medium4
Geometry, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Floor Plan
Medium4
DFS, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bridge Crossing
Medium4
Dynamic programming, Array+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Spirals
Medium4
Matrix, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Monkey Dance
Medium4
Graph, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Golf
Medium4
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
iPhone 9SRemove everyone in the line who wants one chosen capacity, then report the longest run of equal capacities that remains. Choose the capacity to maximize that run.	Medium4	ArrayImplementation+2	No attempts yet	1s	128 MB	Judgeable
Rope FoldingGiven knots at integer positions on a rope, count the fold points where every knot in the overlapping interval mirrors onto another knot.	Medium4	ArrayBrute force+2	No attempts yet	1s	128 MB	Judgeable
OverplantingGiven up to 10 axis-aligned rectangles, find the total area of their union.	Medium4	GeometryImplementation+1	No attempts yet	1s	128 MB	Judgeable
Bale ShareAssign N bales (N up to 20) to three barns so the largest barn total is as small as possible, and print that smallest possible largest total.	Medium4	Brute forceRecursion+2	No attempts yet	1s	128 MB	Judgeable
GiftGiven each friend's item price and shipping cost and one coupon that halves a single item price, find the most gifts buyable within budget B.	Medium4	SortingGreedy+2	No attempts yet	1s	128 MB	Judgeable
Moo SickFind every window of C consecutive notes whose sorted, min-subtracted shape matches the given chord's shape.	Medium4	ArraySorting+2	No attempts yet	1s	128 MB	Judgeable
Book ClubGiven each of N cows' answers to NQ questions, count how many cows match all P given question-answer pairs simultaneously.	Medium4	Hash mapImplementation+2	No attempts yet	1s	128 MB	Judgeable
Space ExplorationCount the connected components of asterisk cells in an N x N grid, where cells connect only along shared edges, not corners.	Medium4	GraphDFS+2	No attempts yet	1s	128 MB	Judgeable
Meeting PlaceGiven a rooted tree and M queries, report the lowest common ancestor of two nodes for each query.	Medium4	TreeDFS+2	No attempts yet	1s	128 MB	Judgeable
PathfindingGiven a directed graph as an adjacency matrix and a start node, print the nodes first reached at each successive distance using BFS.	Medium4	GraphBFS	No attempts yet	1s	128 MB	Judgeable
Bessie's Weight ProblemGiven N haybale weights and a limit H, find the largest total weight at most H that can be formed by choosing each bale at most once.	Medium4	Dynamic programmingArray+2	No attempts yet	1s	128 MB	Judgeable
Heat WaveGiven an undirected weighted graph, find the minimum total cost of a route from a source town to a destination town.	Medium4	GraphShortest path+2	No attempts yet	1s	128 MB	Judgeable
The Chivalrous CowFind the fewest knight-move jumps on an X by Y grid with obstacles to get from the start square to the hay bale.	Medium4	BFSGraph+2	No attempts yet	1s	128 MB	Judgeable
Cow PinballGiven a triangle of nail scores with R rows, find the maximum sum along a path from the top nail down to the last row, moving to one of the two adjacent nails below each step.	Medium4	Dynamic programmingArray+2	No attempts yet	1s	128 MB	Judgeable
Music NotesGiven note durations that divide a timeline into consecutive intervals, answer queries asking which 1-based note covers a given time. Use prefix sums and binary search.	Medium4	Prefix sumBinary search+2	No attempts yet	1s	128 MB	Judgeable
Selfish GrazingGiven N intervals, find the maximum number of intervals that can be chosen so that no two of them overlap.	Medium4	GreedySorting+2	No attempts yet	1s	128 MB	Judgeable
Find the Playing NoteGiven note durations that partition a timeline, answer queries asking which note covers a given beat by locating the prefix sum that brackets it.	Medium4	Prefix sumBinary search+2	No attempts yet	1s	128 MB	Judgeable
Chocolate BuyingGiven N chocolate types with a cost per piece and a number of cows wanting each, spend a budget B to satisfy as many cows as possible.	Medium4	GreedySorting+2	No attempts yet	1s	128 MB	Judgeable
Maximize the AccelerationGiven N parts that each add force and mass, choose the subset maximizing total force divided by total mass, breaking ties by smaller mass.	Medium4	Brute forceBit manipulation+2	No attempts yet	1s	128 MB	Judgeable
MasterMindGiven up to 100 guesses with exact and wrong-position counts, find the smallest four-digit secret consistent with all of them, or NONE.	Medium4	Brute forceImplementation+2	No attempts yet	1s	128 MB	Judgeable
Longest Contiguous SubsequenceGiven two integer sequences, find the length of the longest run of consecutive elements that appears in both.	Medium4	Dynamic programmingArray+2	No attempts yet	1s	128 MB	Judgeable
The Widest MountainGiven a sequence of heights, find the longest contiguous run that is non-decreasing then non-increasing; valleys are shared by both neighboring mountains.	Medium4	ArrayImplementation+2	No attempts yet	1s	128 MB	Judgeable
Cow PalsFind the smallest number n >= S whose proper-divisor sum m satisfies n as the proper-divisor sum of m, then print n and m.	Medium4	Number theoryBrute force+2	No attempts yet	1s	128 MB	Judgeable
Mountain WatchingGiven a sequence of heights, find the longest consecutive block that rises (non-strictly) then falls (non-strictly), allowing a block that only rises or only falls.	Medium4	ArrayTwo pointers+2	No attempts yet	1s	128 MB	Judgeable
Guarding the FarmCount connected groups of equal-altitude cells, using 8-direction adjacency, that are surrounded only by lower altitude or the map edge.	Medium4	GraphDFS+2	No attempts yet	1s	128 MB	Judgeable
Time ManagementGiven each chore's duration and deadline, find the latest start time that lets John finish all chores before their deadlines, or print -1.	Medium4	GreedySorting+2	No attempts yet	1s	128 MB	Judgeable
Strange Towers of HanoiCompute the minimum number of moves to transfer n disks (n at most 12) from tower A to tower D using four towers.	Medium4	Dynamic programmingRecursion+2	No attempts yet	1s	128 MB	Judgeable
Look UpFor each cow, find the smallest index j > i with H_j > H_i, or print 0 if none exists.	Medium4	StackArray+1	No attempts yet	1s	128 MB	Judgeable
Dairy QueenCount the number of ways to make N cents using unlimited coins of the given C denominations, ignoring order.	Medium4	Dynamic programmingCombinatorics+1	No attempts yet	1s	128 MB	Judgeable
Hide and SeekIn a connected undirected graph, find the barn farthest from barn 1. Print the smallest such barn number, its distance, and how many barns tie at that distance.	Medium4	GraphBFS+2	No attempts yet	1s	256 MB	Judgeable
Cow LineMaintain a deque of cows under left/right insertions and left/right bulk removals, then print the remaining cows left to right.	Medium4	QueueLinked list+2	No attempts yet	1s	128 MB	Judgeable
O Those FadsCows join a fad when its attractiveness L reaches their resistance; each joiner raises L by K. Count the final number of participants.	Medium4	SortingGreedy+2	No attempts yet	1s	128 MB	Judgeable
Speed ReadingFor each cow, simulate reading in bursts of at most T minutes with R-minute rests between, and report the total minutes rounded up to finish N pages.	Medium4	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
Going to Meet SinaGiven up to 10^4 blocked cells on a bounded grid, find the shortest 4-directional path from (0,0) to (X,Y) avoiding all puddles.	Medium4	BFSGraph+2	No attempts yet	1s	128 MB	Judgeable
Bookshelf 2Given up to 20 cow heights and a target bookshelf height B, find the minimum amount by which some subset's total height exceeds or equals B.	Medium4	Brute forceBit manipulation+2	No attempts yet	1s	128 MB	Judgeable
Election TimeEach cow has first round votes A and second round votes B; the top K by A advance, then the one with the largest B among them wins. Output the winner's index.	Medium4	SortingArray+2	No attempts yet	1s	128 MB	Judgeable
Dining CowsGiven a sequence of 1s and 2s, find the minimum number of values to change so the sequence becomes nondecreasing.	Medium4	Dynamic programmingPrefix sum+2	No attempts yet	1s	128 MB	Judgeable
Long Distance RacingGiven a terrain string and per-unit times, find the farthest segment index k whose round-trip time stays within M seconds.	Medium4	ArrayPrefix sum+2	No attempts yet	1s	128 MB	Judgeable
Oh Those RollersRollers touch when the distance between centers equals the sum of radii. Starting from the roller at the origin, follow the chain to the roller that drives no other and print its coordinates.	Medium4	GraphDFS+2	No attempts yet	1s	128 MB	Judgeable
Roads Around the FarmGiven N cows and a difference K, a group of size s splits into two nonempty groups differing by K when possible; count the final grazing groups.	Medium4	RecursionMath+2	No attempts yet	1s	128 MB	Judgeable
Word PowerFor each of N cow names, count how many of M good strings appear as a case-insensitive subsequence of the name.	Medium4	StringTwo pointers+2	No attempts yet	1s	128 MB	Judgeable
Clear and Present DangerGiven a danger matrix and a required sequence of islands, find the minimum total danger of a walk that visits those islands in order, allowing detours through others.	Medium4	GraphShortest path+2	No attempts yet	1s	128 MB	Judgeable
Clear Cold WaterGiven a rooted binary tree described by branch points, print the distance from the barn to the endpoint of every pipe.	Medium4	TreeBFS+2	No attempts yet	1s	128 MB	Judgeable
Cow Pie TreasuresGiven an R by C grid of coin counts, find the maximum sum collected moving right one column each step, changing row by at most one, starting at (1,1) and ending at (R,C).	Medium4	Dynamic programmingMatrix	No attempts yet	1s	128 MB	Judgeable
Hungry CowsGiven a sequence of N cow brands, find the length of the longest strictly increasing subsequence in the given order.	Medium4	Dynamic programmingBinary search+2	No attempts yet	1s	128 MB	Judgeable
Cow PicnicGiven K starting pastures and a directed graph, count the pastures reachable from every one of the K starting positions.	Medium4	GraphDFS+2	No attempts yet	1s	128 MB	Judgeable
The Eating PuzzleGiven up to 21 bucket sizes and a calorie limit, choose a subset with the largest sum that does not exceed the limit.	Medium4	Brute forceBit manipulation+2	No attempts yet	1s	128 MB	Judgeable
The Bale TowerGiven up to 20 bales with distinct widths and breadths, find the longest chain where each bale is strictly smaller than the one below it.	Medium4	Dynamic programmingSorting+2	No attempts yet	1s	128 MB	Judgeable
Buy One Get One FreeBuy all N high quality bales, then pair as many of the M low quality bales as possible so each free bale is strictly smaller than its distinct high quality partner. Output N plus the maximum number of pairs.	Medium4	GreedySorting+2	No attempts yet	1s	128 MB	Judgeable
ArgusGiven queries that each fire every Period seconds starting at time Period, output the Q_num of the first K results, breaking ties by smaller Q_num.	Medium4	HeapSimulation+1	No attempts yet	1s	128 MB	Judgeable
Cow SolitaireGiven an N by N grid of cards with point values, find the maximum total score along a monotone path from the lower-left corner to the upper-right corner moving only right or up.	Medium4	Dynamic programmingMatrix+2	No attempts yet	1s	128 MB	Judgeable
Bronze Cow PartyGiven a connected undirected weighted graph, find twice the largest shortest-path distance from a fixed farm X, which is the longest round trip any cow makes.	Medium4	Shortest pathGraph+2	No attempts yet	1s	128 MB	Judgeable
Team ArrangementPick the lowest-numbered players for each role to match a formation, then name the selected player with the most years served as captain.	Medium4	SortingGreedy+2	No attempts yet	1s	128 MB	Judgeable
Barbara Bennett's Wild NumbersGiven a wild number W with digit and ? positions and a same-length number X, count the length-n digit strings matching W that are strictly greater than X.	Medium4	CombinatoricsMath+2	No attempts yet	1s	128 MB	Judgeable
Word PuzzleGiven a letter grid and a list of words, find each word's starting cell and one of eight reading directions, choosing the earliest match by row, column, then direction.	Medium4	ArrayBrute force+2	No attempts yet	1s	128 MB	Judgeable
The die is castGiven a grid picture of dice drawn with background, die, and dot pixels, count the connected dot regions inside each connected die region and print the counts sorted.	Medium4	DFSBFS+2	No attempts yet	1s	128 MB	Judgeable
Number Base ConversionConvert a number given in one base to another base, where digits run 0-9, A-Z, a-z, and print a blank line after each conversion.	Medium4	MathString+2	No attempts yet	1s	128 MB	Judgeable
Microprocessor SimulationSimulate a 4-bit microprocessor from a 256-word hex memory dump and print the final memory state when the stop instruction runs.	Medium4	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
The Sultan's SuccessorsFor each 8x8 board, place 8 non-attacking queens to maximize the sum of the numbers on the occupied squares.	Medium4	BacktrackingRecursion+2	No attempts yet	1s	128 MB	Judgeable
Is It a Tree?For each test case, read directed edges until a pair of zeros and decide whether the graph is a tree under the three given conditions, printing the case number and verdict.	Medium4	GraphUnion-find+2	No attempts yet	1s	128 MB	Judgeable
Optimal Array Multiplication SequenceGiven the dimensions of a chain of matrices, find the minimum number of scalar multiplications needed to compute their product.	Medium4	Dynamic programmingMatrix+2	No attempts yet	1s	128 MB	Judgeable
Pseudo-Random NumbersFor each quadruple (Z, I, M, L), follow the recurrence L = (Z*L + I) mod M and report how many distinct values appear before the sequence starts repeating.	Medium4	Hash mapSimulation+2	No attempts yet	1s	128 MB	Judgeable
Octal FractionsRead octal fractions from 0 to 1 and print each one's exact decimal value, with trailing zeros stripped.	Medium4	MathString+2	No attempts yet	1s	128 MB	Judgeable
RiskGiven a 20-country border graph, answer queries for the fewest countries to conquer when moving from one country to another, counting the destination.	Medium4	GraphBFS+2	No attempts yet	1s	128 MB	Judgeable
Volleyball StatsParse volleyball play-by-play lines, track kills, errors, hits, blocks, and digs per player and team, and print formatted reports on demand.	Medium4	ImplementationSimulation+2	No attempts yet	1s	128 MB	Judgeable
Excuses, Excuses!Find the excuses containing the most keyword occurrences, where keywords match case-insensitively and only as whole words.	Medium4	StringHash map+2	No attempts yet	1s	128 MB	Judgeable
MAS*HSimulate a card-driven counting-out lottery on a line of P people until X survivors remain, then print their original positions in increasing order.	Medium4	SimulationArray+2	No attempts yet	1s	128 MB	Judgeable
Intersection of Two LinesGiven two lines each defined by two integer points, decide whether they meet at one point, are parallel, or coincide, printing the intersection rounded to two decimals.	Medium4	GeometryMath+2	No attempts yet	1s	128 MB	Judgeable
Making Random NumbersSimulate the middle-square method with four-digit numbers and count how many distinct values appear before the first repeat.	Medium4	SimulationHash map+2	No attempts yet	1s	256 MB	Judgeable
Etaoin ShrdluConcatenate each sample's lines, count overlapping adjacent character pairs, then print the five most frequent digrams with their counts and rounded relative frequencies.	Medium4	StringHash map+2	No attempts yet	1s	128 MB	Judgeable
Goldbach's ConjectureFor each even n up to one million, find the split into two odd primes with the largest difference, printing n = a + b.	Medium4	Number theoryMath+2	No attempts yet	0.5s	256 MB	Judgeable
The Sangbeom BuildingGiven a 3D grid of blocked and open cells with a start and an exit, find the minimum number of moves (or report impossible).	Medium4	BFSGraph+2	No attempts yet	1s	128 MB	Judgeable
Intergalactic MortgageSimulate monthly compound interest at r/12 percent on a debt, subtract a fixed payment, and report whether the balance reaches zero within N years.	Medium4	SimulationMath+2	No attempts yet	1s	128 MB	Judgeable
Digital DisplayRender each input time as a seven-segment digital clock face 29 characters wide and 7 rows tall, then print end after all times.	Medium4	ImplementationSimulation+2	No attempts yet	1s	128 MB	Judgeable
Intriguing IdentifiersValidate each given identifier as a Czech Personal ID for a birth between 1920 and 2009, and report the gender or mark it invalid.	Medium4	ImplementationString+2	No attempts yet	1s	256 MB	Judgeable
Suspicious StocksGiven daily stock prices and starting cash, buy as many whole shares as possible on one day, then sell all on a later day, and report the maximum profit.	Medium4	ArrayBrute force+2	No attempts yet	1s	128 MB	Judgeable
Stock ExchangeFor each issuer, for every bid output the agents on the opposite side whose price could match it, in input order.	Medium4	ArrayImplementation+2	No attempts yet	1s	128 MB	Judgeable
Emag eht htiw Em PlehGiven White and Black piece lists, print the 8x8 chess board as ASCII art with alternating light and dark square fills.	Medium4	ImplementationSimulation+2	No attempts yet	1s	128 MB	Judgeable
English Number TranslatorParse English number words such as 'one thousand five hundred' into their integer value, handling negatives and an empty-line terminator.	Medium4	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
R.Ø.L.P. Code WheelFor each encoded message, try all 42 wheel shifts and print every decoding that contains the substring RØLP.	Medium4	StringBrute force+2	No attempts yet	1s	128 MB	Judgeable
Parsing Real NumbersGiven T lines, decide whether each line is a valid real number with optional sign, decimal point, and exponent, allowing surrounding blanks.	Medium4	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
Expression EvaluatorEvaluate a C-style expression of letter variables with binary + and -, plus pre and post ++ and --, then report the result and each used variable's final value.	Medium4	StringSimulation+2	No attempts yet	1s	128 MB	Judgeable
Bridge TransportGiven car weights and a bridge that holds at most 4 cars, find the largest prefix that can cross without any window of 4 consecutive cars exceeding the weight limit.	Medium4	Sliding windowArray+2	No attempts yet	1s	128 MB	Judgeable
Who is taller?Given comparisons stating x is taller than y, decide whether p is taller than q, q is taller than p, or neither is known.	Medium4	GraphDFS+1	No attempts yet	1s	128 MB	Judgeable
Palindrome BasesFor a given X, list every base b with 2 <= b < X in which X is written as a palindrome.	Medium4	MathBrute force+1	No attempts yet	1s	256 MB	Judgeable
Knight HopOn an 8 by 8 board, find the fewest knight moves from a start square to a target square.	Medium4	BFSGraph+2	No attempts yet	2s	512 MB	Judgeable
From Prefix to PostfixTranslate each prefix arithmetic expression over + and - into its equivalent postfix form, stopping at the terminating 0.	Medium4	StackTree+2	No attempts yet	1s	128 MB	Judgeable
MazeFind the shortest path in a grid where each cell dictates which directions you may exit, counting cells visited.	Medium4	BFSGraph+1	No attempts yet	1s	128 MB	Judgeable
Keep on Truckin'Given fixed and added motel distances, count overnight stop sequences where each day covers between A and B km.	Medium4	Dynamic programmingArray+1	No attempts yet	1s	128 MB	Judgeable
BoxesFor each item, find the standard box with the smallest volume that can contain it after 90-degree rotations, or report that none fits.	Medium4	SortingImplementation	No attempts yet	1s	128 MB	Judgeable
WaterparkCount the number of distinct paths from point 1 to point n in a DAG where every edge goes from a lower to a higher numbered point.	Medium4	Dynamic programmingGraph	No attempts yet	1s	128 MB	Judgeable
It’s tough being a teen!Given a fixed list of seven tasks with precedence rules plus up to ten extra constraints, output a valid order using the smallest available task first, or report that no order exists.	Medium4	GraphTopological sort+2	No attempts yet	1s	128 MB	Judgeable
OthelloSimulate up to 30 Othello moves on an 8x8 board starting from one of three configurations, then print the final black and white disc counts.	Medium4	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
Attack of the CipherTextsGiven one plaintext/ciphertext pair, invert the letter substitution to decrypt a second ciphertext, printing a period for undetermined characters.	Medium4	Hash mapString+1	No attempts yet	1s	128 MB	Judgeable
Space TurtleSimulate a 3D grid path of moves and 90-degree turns, and report the minimum distance from the path to a fixed target point.	Medium4	GeometrySimulation+1	No attempts yet	1s	128 MB	Judgeable
Floor PlanGiven a grid of walls and floor cells, count connected rooms, sort them by size, floor as many of the largest rooms as the wood supply allows, and report how many rooms got flooring plus the leftover wood.	Medium4	DFSSorting+2	No attempts yet	1s	128 MB	Judgeable
Bridge CrossingSplit a line of people into consecutive groups of at most M, where each group costs its slowest member's time, and minimize the total cost.	Medium4	Dynamic programmingArray+2	No attempts yet	1s	128 MB	Judgeable
SpiralsPlace the numbers x through y into a square-ish grid spiraling counter-clockwise outward from x at the center, then print the grid with numbers right-aligned to the width of y.	Medium4	MatrixSimulation+1	No attempts yet	1s	128 MB	Judgeable
The Monkey DanceEach monkey follows one outgoing arrow per step on a permutation; find the step count when all monkeys are back home, which is the LCM of the cycle lengths.	Medium4	GraphMath+2	No attempts yet	1s	128 MB	Judgeable
GolfGiven a target distance and up to 32 distinct club distances, find how many strokes give an exact sum, using unlimited repeats of each club.	Medium4	Dynamic programmingGreedy+2	No attempts yet	1s	128 MB	Judgeable