Problems

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Total results29,463 problems

Exotic Foods
Medium4
Dynamic programming, Array+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Oily Currents
Medium4
Simulation, BFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Ecosystem
Medium4
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Risk Assessment
Medium4
String, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Emergency Response
Medium4
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Presentation Error
Medium4
String, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Who Is the Winner?
Medium4
Implementation, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Stump Speech
Medium4
String, String matching+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Rotate
Medium4
Implementation, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pythagorean Triples
Medium4
Hash map, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Shut the Box I
Medium4
Backtracking, Array+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Breaking the Vigenère Cipher
Medium4
String, Hash map+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Most Frequent Square
Medium4
Brute force, Geometry+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Prefix Codes
Medium4
Tree, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Frodo Sequence
Medium4
Math, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Factoring
Medium4
Number theory, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Transport
Medium4
Brute force, Backtracking+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Coin Collection
Medium4
Dynamic programming, Matrix+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Open Intervals
Medium4
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Next Permutation
Medium4
Array, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hex
Medium4
Graph, DFS+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Quick out of the Harbour
Medium4
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Diamond Dealer
Medium4
Geometry, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
AC
Medium4
Implementation, Array+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Stacking Books
Medium4
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Rolling Dice
Medium4
Simulation, Matrix+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Have a Nice Day
Medium4
Implementation, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Parking Lot
Medium4
Simulation, Queue+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Signboard
Medium4
String, Brute force+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
The Best Pizza
Medium4
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pasta
Medium4
Dynamic programming, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Planet Exploration
Medium4
Prefix sum, Array+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Cheese
Medium4
BFS, Graph+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Wedding
Medium4
Graph, BFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pizza
Medium4
Binary search, Array+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
The Longest Staircase
Medium4
Sorting, Two pointers+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Product Order Totals
Medium4
Hash map, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Road Shop
Medium4
Combinatorics, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
In-circles Again
Medium4
Geometry, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tornado!
Medium4
Greedy, Array+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hour Hand and Minute Hand
Medium4
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Army Buddies
Medium4
Union-find, Linked list+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
King's Poker
Medium4
Implementation, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Average and Median
Medium4
Math, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hexagonal Tiles
Medium4
Dynamic programming, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Brothers
Medium4
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Car Plates Competition
Medium4
Implementation, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Soccer League
Medium4
Hash map, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Where Are My Genes
Medium4
Simulation, Array+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Make a Guess
Medium4
Brute force, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Dice
Medium4
Simulation, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Noise Effect
Medium4
Implementation, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Log Books
Medium4
Implementation, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Avoiding a Disaster
Medium4
Brute force, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Message Relay
Medium4
Graph, DFS+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cow Crossings
Medium4
Sorting, Array+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Perimeter
Medium4
BFS, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Meet and Greet
Medium4
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
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
Haybale Stacking
Medium4
Prefix sum, Array+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tile Exchanging
Medium4
Dynamic programming, Math
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
The Bovine Fire Drill
Medium4
Simulation, Implementation+1
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
Darts
Medium4
Brute force, Implementation+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
Scrabble
Medium4
String, Greedy+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
Cruel Math Teacher
Medium4
Math, Implementation+1
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
Card Stacking
Medium4
Simulation, Queue+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Exotic FoodsGiven a sequence of food values, choose a subset with no two chosen positions adjacent so the total value is as large as possible.	Medium4	Dynamic programmingArray+2	No attempts yet	1s	128 MB	Judgeable
Oily CurrentsSimulate oil spreading on a grid for t steps, where each contaminated cell pushes oil up to its strength in its current's direction. Print the final contaminated cells.	Medium4	SimulationBFS+2	No attempts yet	1s	128 MB	Judgeable
EcosystemGiven populations and per-member diets for species ordered by food chain position, simulate feeding in increasing species order and report survivors.	Medium4	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
Risk AssessmentScore each company from text by applying sentence modifiers to quality words and attributing words to the most recent company name.	Medium4	StringSimulation+1	No attempts yet	1s	128 MB	Judgeable
Emergency ResponseGiven a directed weighted graph, answer multiple queries: the shortest travel time from any of several start nodes to one crime intersection.	Medium4	GraphShortest path+2	No attempts yet	1s	128 MB	Judgeable
Presentation ErrorNormalize two strings by case, spacing around special symbols, bracket and comma/semicolon equivalence, then decide if they match.	Medium4	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
Who Is the Winner?Given a log of contest submissions with verdicts and times, compute each contestant's solved count and ICPC-style penalty score, then output them ranked.	Medium4	ImplementationSorting+2	No attempts yet	1s	128 MB	Judgeable
Stump SpeechGiven scored key phrases and a speech, sum each phrase's score times its number of occurrences in the speech.	Medium4	StringString matching+1	No attempts yet	1s	128 MB	Judgeable
RotateReverse a sequence of operations: first undo a rotation of each block of K, then undo a rotation of the whole sequence, recovering the original array.	Medium4	ImplementationSimulation+1	No attempts yet	1s	128 MB	Judgeable
Pythagorean TriplesGiven up to 50 distinct positive integers, list all Pythagorean triples x<y<z present in the set, sorted lexicographically, or report that none exist.	Medium4	Hash mapMath+2	No attempts yet	1s	128 MB	Judgeable
Shut the Box IGiven a target sum and a sorted list of open card values, choose the subset summing to the target that is lexicographically largest when sorted.	Medium4	BacktrackingArray+2	No attempts yet	1s	128 MB	Judgeable
Breaking the Vigenère CipherFrom a ciphertext, collect all repeated 3-letter groups and their occurrence distances, then report every key length from 4 to 20 dividing at least 90% of those distances.	Medium4	StringHash map+2	No attempts yet	1s	128 MB	Judgeable
Most Frequent SquareGiven up to 30 integer grid points, count all axis-parallel squares formed by four of them and report the side length with the most squares, breaking ties by the largest length.	Medium4	Brute forceGeometry+2	No attempts yet	1s	128 MB	Judgeable
Prefix CodesDecode several binary messages with a prefix code given as a heap-indexed tree string, where a bit 0 or 1 walks to a child until a leaf symbol is reached.	Medium4	TreeImplementation+2	No attempts yet	1s	128 MB	Judgeable
Frodo SequenceGiven repeated values of n less than 2^31, print the n-th term of the sequence defined by Fro_n = Fro_{n-1} + Fro_{n-2} - Fro_{n-3}.	Medium4	MathDynamic programming+2	No attempts yet	1s	128 MB	Judgeable
FactoringFor each integer, print 'prime' or its prime factorization in ascending order with repeated factors listed.	Medium4	Number theoryImplementation	No attempts yet	1s	128 MB	Judgeable
TransportWith at most 20 items, choose a subset whose total weight is at most W and whose total value is as large as possible.	Medium4	Brute forceBacktracking+1	No attempts yet	1s	128 MB	Judgeable
Coin CollectionA robot walks right or down only from the top-left to the bottom-right of a grid, and we want the most coins it can pick up along the way.	Medium4	Dynamic programmingMatrix+2	No attempts yet	1s	128 MB	Judgeable
Open IntervalsGiven up to 50 open intervals per test case, pick the largest subset where no two intervals overlap, counting touching endpoints as compatible.	Medium4	GreedySorting+2	No attempts yet	1s	128 MB	Judgeable
Next PermutationGiven an integer A, find the smallest permutation of its digits that is strictly greater than A, or print USELESS if none exists.	Medium4	ArrayString+2	No attempts yet	1s	128 MB	Judgeable
HexGiven a Hex board of size n, decide whether Black, White, or nobody has a connecting path between the required edges.	Medium4	GraphDFS+1	No attempts yet	1s	128 MB	Judgeable
Quick out of the HarbourFind the shortest time from S to outside the grid, where water cells cost 1 and drawbridges cost 1+d, on a grid up to 500x500.	Medium4	GraphShortest path+2	No attempts yet	1s	128 MB	Judgeable
Diamond DealerFor each simple polygon given clockwise, count concave vertices (dents) and edges not touching any dent, then print max(-ap + bq, 0).	Medium4	GeometryImplementation+2	No attempts yet	1s	128 MB	Judgeable
ACApply a string of reverse (R) and discard-first (D) operations to an integer array, printing the result or error if D hits an empty array.	Medium4	ImplementationArray+1	No attempts yet	1s	256 MB	Judgeable
Stacking BooksGiven a stack of book sizes, find the fewest moves that pull one book to the top (only when the part above it is non-decreasing) to sort the stack.	Medium4	GreedySorting+2	No attempts yet	1s	128 MB	Judgeable
Rolling DiceParse a run-length encoded sequence of moves and plus/minus direction flips, tracking the die's position and top face value.	Medium4	SimulationMatrix+1	No attempts yet	1s	128 MB	Judgeable
Have a Nice DayFor each date, check that every digit occurring in day, month, and year appears equally often, and that day, month, and the two year halves split into two equal-sum groups.	Medium4	ImplementationBrute force+2	No attempts yet	1s	128 MB	Judgeable
Parking LotSimulate cars arriving and leaving a parking lot, assigning each to the lowest-numbered free space or a waiting queue, and sum weight times rate.	Medium4	SimulationQueue+2	No attempts yet	1s	128 MB	Judgeable
SignboardCount how many of the given strings contain the store name as an equally spaced subsequence, where each string counts at most once.	Medium4	StringBrute force+1	No attempts yet	1s	256 MB	Judgeable
The Best PizzaChoose any subset of toppings, each costing B, to maximize total calories divided by total price, and print the floor of that ratio.	Medium4	GreedySorting+2	No attempts yet	1s	128 MB	Judgeable
PastaCount sequences of length N over three kinds where no kind appears three or more times in a row, with some positions fixed, modulo 10000.	Medium4	Dynamic programmingImplementation	No attempts yet	1s	128 MB	Judgeable
Planet ExplorationGiven a grid of jungle, sea, and ice cells, answer many rectangle queries by counting how many cells of each terrain type fall inside.	Medium4	Prefix sumArray+2	No attempts yet	1s	256 MB	Judgeable
CheeseIn a grid maze, find the total shortest walking time for a mouse to eat cheeses of hardness 1 through N in order, each raising its strength by one.	Medium4	BFSGraph+2	No attempts yet	1s	256 MB	Judgeable
WeddingGiven a friendship graph among n classmates, count everyone within distance 2 of classmate 1.	Medium4	GraphBFS+2	No attempts yet	1s	128 MB	Judgeable
PizzaGiven store positions on a circular road and delivery points, sum the distance from each point to its nearest store.	Medium4	Binary searchArray+1	No attempts yet	2s	128 MB	Judgeable
The Longest StaircaseGiven k cards with distinct values 1 to n plus one blank card (0) you can set to any value, find the longest run of consecutive integers formable.	Medium4	SortingTwo pointers+1	No attempts yet	1s	128 MB	Judgeable
Product Order TotalsSum the order quantities for each distinct product name, then print each product with its total sorted by name length, then alphabetically.	Medium4	Hash mapSorting+2	No attempts yet	1s	128 MB	Judgeable
Road ShopCount the number of ways to choose bead counts for n colors summing to r, with at least m beads of each color.	Medium4	CombinatoricsMath+1	No attempts yet	1s	128 MB	Judgeable
In-circles AgainEach circle tangent to two sides of a triangle and its incircle has radius r divided by the sine of a half-angle; recover the three angles from r, r1, r2, r3 and compute the area.	Medium4	GeometryMath+2	No attempts yet	1s	128 MB	Judgeable
Tornado!Given a circular fence of N posts marked standing or broken, choose the fewest broken posts to fill so no wire span between standing posts exceeds 4 meters.	Medium4	GreedyArray+2	No attempts yet	1s	128 MB	Judgeable
Hour Hand and Minute HandGiven an integer A, decide whether the hour and minute hands of a ticking clock can ever form an angle of exactly A degrees. Read A until EOF.	Medium4	MathNumber theory+2	No attempts yet	1s	128 MB	Judgeable
Army BuddiesAfter each loss report removes living soldiers L through R, print the nearest surviving neighbors on both sides, or * when none exists.	Medium4	Union-findLinked list+1	No attempts yet	1s	128 MB	Judgeable
King's PokerGiven a three-card poker hand, print the weakest set or pair that beats it, or * if none exists.	Medium4	ImplementationSorting+2	No attempts yet	1s	128 MB	Judgeable
Average and MedianFor each pair A and B, find the smallest integer C so that the average and the median of A, B, C are equal.	Medium4	MathSorting+2	No attempts yet	1s	128 MB	Judgeable
Hexagonal TilesCount the sequences of increasing tile numbers from the start tile to tile N, where each move goes forward by 1 or 2.	Medium4	Dynamic programmingCombinatorics+2	No attempts yet	1s	128 MB	Judgeable
BrothersGiven a grid of counties owned by heirs in a cycle, apply K simultaneous rounds where a cell switches to the previous heir if an orthogonal neighbor already has that heir, then print the grid.	Medium4	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
Car Plates CompetitionDecide whether Isa's 7-character plate is a legal plate newer than Martin's by at most C positions ahead in the ACM sequence.	Medium4	ImplementationMath+2	No attempts yet	1s	128 MB	Judgeable
Soccer LeagueRead a list of soccer match results and output the league table sorted by points, then goal difference, then first appearance in the input.	Medium4	Hash mapSorting+2	No attempts yet	1s	128 MB	Judgeable
Where Are My GenesApply a sequence of reversals to the identity genome and report the final position of each queried gene.	Medium4	SimulationArray+1	No attempts yet	1s	128 MB	Judgeable
Make a GuessGiven MasterMind guesses and their excellent/good counts, decide for each position whether every consistent password shares the same character, else print '?'.	Medium4	Brute forceImplementation+1	No attempts yet	1s	128 MB	Judgeable
DiceSimulate a board game where players advance by dice totals, skip a turn when landing on one of three traps, and the first past the last square wins.	Medium4	SimulationImplementation+1	No attempts yet	1s	128 MB	Judgeable
Noise EffectGiven two L by L grayscale images, find the highest percentage of scanned pixels whose value differs from the corresponding standard pixel by at most 100 over the eight rotations and flips.	Medium4	ImplementationMath+1	No attempts yet	1s	128 MB	Judgeable
Log BooksFor each log book, sum total and night driving minutes and check the 50-hour, 10-hour, and 2-hour per-session limits, printing PASS or NON.	Medium4	ImplementationSimulation+2	No attempts yet	1s	128 MB	Judgeable
Avoiding a DisasterThree 12-hour watch readings come from one correct time, one watch x minutes slow, and one x minutes fast, with x at most 480; find the unique correct time or report ambiguity.	Medium4	Brute forceImplementation+2	No attempts yet	1s	128 MB	Judgeable
Message RelayEach cow forwards to at most one other cow; count cows whose messages never reach a cycle and instead stop.	Medium4	GraphDFS+1	No attempts yet	1s	128 MB	Judgeable
Cow CrossingsCount cows whose straight crossing paths intersect no other cow, where two paths cross exactly when the start and end left-to-right orders differ.	Medium4	SortingArray+2	No attempts yet	1s	128 MB	Judgeable
PerimeterGiven up to 10000 occupied cells in a 100 by 100 grid forming one connected region, find the outer perimeter, ignoring any holes.	Medium4	BFSGraph+2	No attempts yet	1s	128 MB	Judgeable
Meet and GreetSimulate two cows walking along a line at unit speed and count how many times they meet after being apart, excluding the start.	Medium4	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
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
Haybale StackingAdd one bale to every stack in each given range, then report the median height among all N stacks.	Medium4	Prefix sumArray+2	No attempts yet	1s	128 MB	Judgeable
Tile ExchangingFor each of N tiles, pick a new side length (or keep the old one) so the total area equals M, minimizing the sum of squared side-length changes.	Medium4	Dynamic programmingMath	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
The Bovine Fire DrillSimulate cows on a circular ring of N chairs, each moving clockwise by its own number, and report the cow that ends the drill.	Medium4	SimulationImplementation+1	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
DartsCount unordered triples of dart hits (single, double, treble regions, bulls, or misses) whose scores sum to a given turn score.	Medium4	Brute forceImplementation+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
ScrabbleGiven a tray of T letters (some blanks that score 0) and an alphabetized dictionary, pick the highest-scoring dictionary word formable from the tray, breaking ties alphabetically.	Medium4	StringGreedy+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
Cruel Math TeacherCompute N raised to the power P exactly, then print the result with 70 digits per line and no leading zeros.	Medium4	MathImplementation+1	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
Card StackingSimulate a deck where each dealt card is followed by moving P cards to the bottom, and report the original positions that reach Bessie.	Medium4	SimulationQueue+2	No attempts yet	1s	128 MB	Judgeable