Interview core

Mediums from real onsites

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Total results3,613 problems

Fixing the Bugs
Medium7
Dynamic programming, Probability
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Moogle Maps
Medium7
Dynamic programming, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hiking Trails
Medium7
Graph, Union-find+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Segment Pricing
Medium7
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Locate Mining Center
Medium7
Geometry, Binary search+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Top 2000
Medium7
Dynamic programming, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Attack of the Giant n-pus
Medium7
Binary search, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Polly Wants a Cracker
Medium7
Dynamic programming, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Miners
Medium7
Dynamic programming, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Post Office
Medium7
Dynamic programming, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Lightest Mobile
Medium7
Tree, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Longest Chain
Medium7
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Airplane Parking
Medium7
Dynamic programming, Intervals+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Uncle Tom's Inherited Land
Medium7
Graph, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
RealPhobia
Medium7
Number theory, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
What's Up With Gravity
Medium7
BFS, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Fuel Economy
Medium7
Greedy, Stack+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Blink
Medium7
Matrix, Bit manipulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Photo
Medium7
Greedy, Intervals+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Haywire
Medium7
Backtracking, Brute force+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Cow Run
Medium7
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Necklace
Medium7
Dynamic programming, String matching+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Poker Hands
Medium7
Greedy, Array+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Liars and Truth Tellers
Medium7
Graph, Union-find+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bookshelf
Medium7
Dynamic programming, Segment tree+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Surveillance Cameras
Medium7
Brute force, Recursion+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Haybale Restacking
Medium7
Greedy, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Efficient Cow Buying
Medium7
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Mountain Climbing
Medium7
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cow Calisthenics
Medium7
Tree, Binary search+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Threatening Letter
Medium7
String, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Job Hunt
Medium7
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Covering the Corral
Medium7
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Need For Speed
Medium7
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cow Politics
Medium7
Tree, DFS+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
The Baric Bovine
Medium7
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Maximum Flow
Medium7
Graph, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Spreading Out the Cows
Medium7
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Bovine Accordion and Banjo Orchestra
Medium7
Dynamic programming, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cow Jogging
Medium7
Graph, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Corn Fields
Medium7
Dynamic programming, Bit manipulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Rooftop Garden Benchmarking
Medium7
Stack, Array+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cow Sorting
Medium7
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Gold Balanced Lineup
Medium7
Hash map, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Dining
Medium7
Graph, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
City Horizon
Medium7
Segment tree, Divide and conquer+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Solitaire
Medium7
BFS, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
It's not a Bug, it's a Feature!
Medium7
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Fast Food
Medium7
Dynamic programming, Divide and conquer+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sorting Slides
Medium7
Binary search, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pushing Boxes
Medium7
BFS, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Atlantis
Medium7
Geometry, Segment tree+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Slash Maze
Medium7
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Formatting Text
Medium7
Dynamic programming, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Robot
Medium7
BFS, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
To the Max
Medium7
Dynamic programming, Array+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Single Point of Failure
Medium7
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Graph Coloring
Medium7
Graph, Backtracking+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
String Decoding
Medium7
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hall of Fountains
Medium7
BFS, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
New Fruit
Medium7
Dynamic programming, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Charlie the Cockchafer
Medium7
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Arbitrage?
Medium7
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Odd Opportunities
Medium7
Graph, Union-find+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
IVXLCDM
Medium7
Greedy, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Japan Plotter Driver
Medium7
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Mailbox Manufacturers Problem
Medium7
Dynamic programming, Binary search+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Editor Distance
Medium7
Graph, Shortest path+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Firehose
Medium7
Binary search, Greedy+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Wireless
Medium7
Geometry, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Dinner
Medium7
Dynamic programming, Intervals+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Road Construction
Medium7
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Great Spamway Strike
Medium7
Tree, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cheap Gas
Medium7
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Strategic Bombing
Medium7
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Packing Rectangles
Medium7
Brute force, Geometry+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Shopping Offers
Medium7
Dynamic programming, Array+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Barn Expansion
Medium7
Geometry, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Trips
Medium7
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sailing Race
Medium7
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Running Man
Medium7
Graph, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Task Execution
Medium7
Graph, Topological sort+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
QuadTrees
Medium7
Tree, Divide and conquer+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Kingdom of Magic
Medium7
Graph, BFS+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Shortest Regular Brackets Sequence
Medium7
Dynamic programming, Intervals+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Longest Common Increasing Subsequence
Medium7
Dynamic programming, Array+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
B-Matrix
Medium7
Dynamic programming, Matrix+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
GCD!
Medium7
Number theory, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Jakarta Traffic Jam
Medium7
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Central Tree
Medium7
Tree, DFS+2
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Better and Faster!
Medium7
Bit manipulation, Math+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
I'll Do It Tomorrow
Medium7
Greedy, Sorting+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Railways
Medium7
Segment tree, Array+2
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Binary Search Tree Code
Medium7
Tree, Recursion+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Boxes
Medium7
Greedy, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Shift
Medium7
Array, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Banjo
Medium7
Array, Sorting+2
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Sweets
Medium7
Brute force, Greedy+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Studies
Medium7
Graph, Shortest path+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Space Base Construction
Medium7
Geometry, Binary search+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Fixing the BugsWith B bugs, T hours, and a failure factor f, choose each hour's bug by dynamic programming to maximize the expected total severity fixed.	Medium7	Dynamic programmingProbability	No attempts yet	1s	128 MB	Judgeable
Moogle MapsChoose c of h house locations to store so that the average linear interpolation error over all houses is minimized, with endpoints always stored.	Medium7	Dynamic programmingMath+2	No attempts yet	1s	128 MB	Judgeable
Hiking TrailsGiven a graph, add the fewest edges so it becomes connected and every vertex has even degree.	Medium7	GraphUnion-find+2	No attempts yet	1s	128 MB	Judgeable
Segment PricingChoose a non-increasing fare for each boarding stop, with riders boarding only if their budget covers it, to maximize total revenue.	Medium7	Dynamic programmingGreedy+2	No attempts yet	1s	128 MB	Judgeable
Locate Mining CenterPlace a center on integer coordinates minimizing the largest Manhattan distance to given sites, breaking ties by Euclidean distance to the origin and then lexicographically.	Medium7	GeometryBinary search+2	No attempts yet	1s	128 MB	Judgeable
Top 2000Partition a fixed sequence of singles into contiguous blocks, letting each block run under or over M minutes with per-minute penalties, and minimize the total penalty.	Medium7	Dynamic programmingPrefix sum+2	No attempts yet	1s	128 MB	Judgeable
Attack of the Giant n-pusAssign p pirates to n tentacles so the captain can reach the head as early as possible; each pirate pins one tentacle, the captain starts when all are pinned.	Medium7	Binary searchGreedy+2	No attempts yet	1s	128 MB	Judgeable
Polly Wants a CrackerMatch each spoken word to a distinct original word minimizing total Levenshtein edit distance, and report that minimum sum.	Medium7	Dynamic programmingString+2	No attempts yet	1s	128 MB	Judgeable
MinersAssign each of N shipments in order to one of two mines; each shipment scores 1 to 3 based on how many distinct kinds appear among it and the previous two shipments at that mine, and the goal is to maximize the total.	Medium7	Dynamic programmingString+1	No attempts yet	1s	128 MB	Judgeable
Post OfficePlace P post offices in some of V villages on a line so that the sum of each village's distance to its nearest post office is minimized.	Medium7	Dynamic programmingPrefix sum+2	No attempts yet	1s	128 MB	Judgeable
The Lightest MobileGiven a tree of balanced rods with integer lever ratios, assign positive integer masses to all weights so every rod balances and the total mass is minimized.	Medium7	TreeDFS+2	No attempts yet	1s	128 MB	Judgeable
The Longest ChainGiven n strings, each with labeled rings a and b at its ends, find the number of vertices in the longest trail in the resulting multigraph.	Medium7	GraphDFS+2	No attempts yet	1s	128 MB	Judgeable
Airplane ParkingGiven N time intervals (arrival, departure), find the largest subset that can be scheduled in a stack, so planes leave in last-in first-out order.	Medium7	Dynamic programmingIntervals+2	No attempts yet	1s	128 MB	Judgeable
Uncle Tom's Inherited LandGiven a grid where at most 50 squares are usable land and the rest are ponds, find the maximum number of 1x2 dominoes that tile the usable squares.	Medium7	GraphDynamic programming+2	No attempts yet	1s	128 MB	Judgeable
RealPhobiaFor each fraction A/B, find C/D with D < B that minimizes the error \|A/B - C/D\|, breaking ties by the smallest denominator.	Medium7	Number theoryMath+2	No attempts yet	1s	128 MB	Judgeable
What's Up With GravityOn a grid with two gravity directions, find the minimum number of gravity flips to move from C to D, where falling is forced downward and you can step sideways only when blocked below.	Medium7	BFSGraph+2	No attempts yet	1s	128 MB	Judgeable
Fuel EconomyFind the cheapest way to buy fuel along a route with a tank of capacity G, visiting stations with given prices, or report that the trip is impossible.	Medium7	GreedyStack+2	No attempts yet	1s	128 MB	Judgeable
BlinkEach bulb toggles when its left neighbor was on the previous step; given N up to 16 bulbs and a step count B up to 10^15, report the final states.	Medium7	MatrixBit manipulation+2	No attempts yet	1s	128 MB	Judgeable
PhotoGiven N cows in a line and K unfriendly pairs that cannot share a photo, find the minimum number of consecutive-range photos covering every cow.	Medium7	GreedyIntervals+2	No attempts yet	1s	128 MB	Judgeable
HaywireGiven a 3-regular graph on N cows (N at most 12), find the ordering of cows in a row minimizing the sum of pairwise distances between friends.	Medium7	BacktrackingBrute force+1	No attempts yet	1s	128 MB	Judgeable
The Cow RunCows sit at distinct positions on a line; John starts at 0, moves one unit per minute, and each cow costs one dollar per minute until reached. Minimize the sum of arrival times.	Medium7	Dynamic programmingGreedy+2	No attempts yet	1s	128 MB	Judgeable
NecklaceGiven a string and a pattern, delete the fewest characters so the pattern no longer appears as a contiguous substring.	Medium7	Dynamic programmingString matching+2	No attempts yet	1s	128 MB	Judgeable
Poker HandsGiven card counts per rank, find the fewest contiguous-rank straights whose unit cards sum to exactly those counts.	Medium7	GreedyArray+2	No attempts yet	1s	128 MB	Judgeable
Liars and Truth TellersEach statement says whether one cow calls another honest or a liar; find the largest prefix of statements that admits a consistent truth/lie labeling of all cows.	Medium7	GraphUnion-find+2	No attempts yet	1s	128 MB	Judgeable
BookshelfPartition the books, in order, into shelves of total width at most L to minimize the sum of each shelf's max height.	Medium7	Dynamic programmingSegment tree+1	No attempts yet	1s	128 MB	Judgeable
Surveillance CamerasGiven up to 50,000 distinct grid points, decide whether three axis-parallel lines (full rows or columns) can cover all of them.	Medium7	Brute forceRecursion+2	No attempts yet	1s	128 MB	Judgeable
Haybale RestackingGiven N piles in a circle with current and target amounts of hay, move bales at cost equal to circular distance to reach the target with minimum total work.	Medium7	GreedyPrefix sum+2	No attempts yet	1s	128 MB	Judgeable
Efficient Cow BuyingGiven N cows with a full price and a cheaper coupon price, and K coupons plus M dollars, find the maximum number of cows that can be bought.	Medium7	GreedySorting+2	No attempts yet	1s	128 MB	Judgeable
Mountain ClimbingTwo farmers each handle one leg of the trip, so at most one cow climbs up and one climbs down at a time. Find the minimum total time with reorderable descent.	Medium7	GreedySorting+2	No attempts yet	1s	128 MB	Judgeable
Cow CalisthenicsRemove exactly S edges from a tree so that the largest diameter among the resulting components is as small as possible, and output that minimum diameter.	Medium7	TreeBinary search+2	No attempts yet	2s	128 MB	Judgeable
Threatening LetterGiven a newspaper string and a message, split the message into the fewest contiguous pieces, each of which appears somewhere in the newspaper. Output that minimum count.	Medium7	StringDynamic programming+2	No attempts yet	1s	128 MB	Judgeable
Job HuntBessie earns at most D per city visit, travels free paths and paid flights, and can repeat cities; find the maximum total profit or -1 if unbounded.	Medium7	GraphShortest path+2	No attempts yet	1s	128 MB	Judgeable
Covering the CorralGiven arcs of given start and length on a circle of circumference C, find the fewest arcs whose union covers the whole circle.	Medium7	GreedySorting+2	No attempts yet	1s	128 MB	Judgeable
Need For SpeedGiven a car's base force and mass plus N parts that each add force and mass, choose the subset maximizing total force over total mass, breaking ties by smaller total mass.	Medium7	GreedySorting+2	No attempts yet	1s	128 MB	Judgeable
Cow PoliticsGiven a tree with each node belonging to one of K parties, find the diameter (greatest distance between any two nodes) of the nodes in each party.	Medium7	TreeDFS+2	No attempts yet	2s	128 MB	Judgeable
The Baric BovineChoose the smallest subset of N pressure readings so the total interpolation-style error stays within E, and report that size plus the least error for it.	Medium7	Dynamic programmingGreedy+2	No attempts yet	1s	128 MB	Judgeable
Maximum FlowCompute the maximum flow from node A to node Z through a network of pipes with given capacities, using series and parallel reductions.	Medium7	GraphImplementation+2	No attempts yet	1s	128 MB	Judgeable
Spreading Out the CowsPlace N cows into S stalls so adjacent gaps are D or D+1 with as many D as possible, minimizing total movement from given start positions.	Medium7	Dynamic programmingGreedy+2	No attempts yet	1s	128 MB	Judgeable
The Bovine Accordion and Banjo OrchestraChoose increasing pairs between two length-N sequences to maximize the sum of A_i*B_j minus the squared sums of each maximal block of unpaired elements on both sides.	Medium7	Dynamic programmingPrefix sum+2	No attempts yet	1s	128 MB	Judgeable
Cow JoggingGiven a DAG with edges pointing from higher to lower numbered nodes, report the K shortest path lengths from node N to node 1, with duplicates allowed.	Medium7	GraphDynamic programming+2	No attempts yet	1s	128 MB	Judgeable
Corn FieldsCount subsets of fertile cells in an M by N grid, M,N at most 12, with no two chosen cells sharing an edge, modulo 100000000.	Medium7	Dynamic programmingBit manipulation+2	No attempts yet	1s	128 MB	Judgeable
Rooftop Garden BenchmarkingCount, over every building, how many strictly shorter buildings stand to its right before a building at least as tall blocks the view.	Medium7	StackArray+2	No attempts yet	1s	128 MB	Judgeable
Cow SortingRearrange a permutation into sorted order by swapping any two elements at a cost equal to their sum, minimizing the total cost.	Medium7	GreedySorting+2	No attempts yet	1s	128 MB	Judgeable
Gold Balanced LineupGiven N cows each with a K-bit feature ID, find the longest contiguous range where every one of the K features appears the same number of times.	Medium7	Hash mapPrefix sum+2	No attempts yet	1s	128 MB	Judgeable
DiningEach cow likes certain foods and drinks, each item can go to one cow; maximize the number of cows that get a liked food and a liked drink.	Medium7	GraphDynamic programming+2	No attempts yet	1s	128 MB	Judgeable
City HorizonGiven N axis-aligned rectangles that all rest on the ground, compute the area of their union.	Medium7	Segment treeDivide and conquer+2	No attempts yet	1s	128 MB	Judgeable
SolitaireGiven two placements of four identical pieces on an 8x8 board, decide whether slides and jumps reach the second from the first within 8 moves.	Medium7	BFSGraph+2	No attempts yet	1s	128 MB	Judgeable
It's not a Bug, it's a Feature!Each bug state is a bitmask; find the shortest total patch time from all bugs present to no bugs, where patches have presence and absence preconditions.	Medium7	GraphShortest path+2	No attempts yet	1s	128 MB	Judgeable
Fast FoodGiven sorted restaurant positions, choose k of them as depots to minimize the total distance from every restaurant to its nearest depot.	Medium7	Dynamic programmingDivide and conquer+2	No attempts yet	1s	128 MB	Judgeable
Sorting SlidesGiven rectangles and points, print the slide letters whose matching number is the same across every valid one-to-one assignment.	Medium7	Binary searchBrute force+2	No attempts yet	1s	128 MB	Judgeable
Pushing BoxesGiven a grid maze with a player, a box, and a target, find the minimum number of pushes to move the box to the target, then the minimum total moves among those solutions.	Medium7	BFSShortest path+2	No attempts yet	1s	128 MB	Judgeable
AtlantisGiven up to 100 axis-aligned rectangles, compute the area of their union and print it with two decimals.	Medium7	GeometrySegment tree+2	No attempts yet	1s	128 MB	Judgeable
Slash MazeCount the closed loops in a grid of slash and backslash walls and report the longest loop's length, where each cell splits into two triangles.	Medium7	GraphDFS+2	No attempts yet	1s	128 MB	Judgeable
Formatting TextBreak a paragraph into lines of fixed width, choosing line breaks to minimize total badness with a lexicographic tie-break on gap widths.	Medium7	Dynamic programmingString+2	No attempts yet	1s	128 MB	Judgeable
RobotA circular robot on a grid of tracks must go from a start crossing with a given facing to a target crossing, moving 1 to 3 meters per GO and turning 90 degrees per TURN, each command costing one second; find the minimum time, or -1.	Medium7	BFSGraph+2	No attempts yet	1s	128 MB	Judgeable
To the MaxFind the contiguous rectangular subregion of an N by N integer matrix with the largest possible sum and print that sum.	Medium7	Dynamic programmingArray+2	No attempts yet	1s	128 MB	Judgeable
Single Point of FailureFor each undirected connected graph, list every articulation point and the number of connected components its removal creates.	Medium7	GraphDFS+2	No attempts yet	1s	128 MB	Judgeable
Graph ColoringFor each graph, find a maximum independent set and output one optimal coloring whose sorted black node list is lexicographically smallest.	Medium7	GraphBacktracking+2	No attempts yet	1s	128 MB	Judgeable
String DecodingGiven a string, a permutation, and a large repetition count m, recover the string that the permutation maps to the given encoded string.	Medium7	MathImplementation+2	No attempts yet	1s	128 MB	Judgeable
Hall of FountainsGiven n fountains inside n rooms, each periodically on/off with period 2p and offset q, find the earliest time to walk from before room 1 to past room n using one-second steps, entering a room only while its fountain is off.	Medium7	BFSGraph+2	No attempts yet	1s	128 MB	Judgeable
New FruitFor each pair of strings, output the shortest common supersequence, breaking ties by choosing the lexicographically smallest one.	Medium7	Dynamic programmingString+2	No attempts yet	1s	128 MB	Judgeable
Charlie the CockchaferFind the fastest route on a 3D segment network where cost combines travel distance and turn angles between consecutive segments.	Medium7	GraphShortest path+2	No attempts yet	1s	128 MB	Judgeable
Arbitrage?Given exchange rates between currencies, decide whether any sequence of trades returns a strictly larger amount of the starting currency (arbitrage).	Medium7	GraphShortest path+2	No attempts yet	1s	128 MB	Judgeable
Odd OpportunitiesGiven a graph and a parity requirement (odd or even degree) for every vertex, decide whether some subset of edges can be kept so each vertex meets its required degree parity.	Medium7	GraphUnion-find+2	No attempts yet	1s	128 MB	Judgeable
IVXLCDMGiven a lowercase inscription line, find the largest value of a valid Roman numeral readable as a subsequence of its letters, or 0 if none.	Medium7	GreedyString+2	No attempts yet	1s	128 MB	Judgeable
Japan Plotter DriverEmulate a plotter's POINT, TEXT, LINE, CLEAR, and PRINT commands on an ASCII grid, merging overlapping characters by fixed rules, and frame each finished picture.	Medium7	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
The Mailbox Manufacturers ProblemWith k identical mailboxes usable up to m firecrackers, find the minimum worst-case cost in firecrackers to pin down exactly how many each can survive.	Medium7	Dynamic programmingBinary search+2	No attempts yet	1s	128 MB	Judgeable
Editor DistanceGiven the character counts of N lines up to 80 wide, find the fewest arrow-key presses to move a cursor from a start position to a finish position, where vertical moves clamp to each line's end.	Medium7	GraphShortest path+2	No attempts yet	2s	512 MB	Judgeable
FirehosePlace k hydrants on a circle of circumference 1000000 so the largest arc-distance from any of H houses to its nearest hydrant is minimized, and report that distance.	Medium7	Binary searchGreedy+2	No attempts yet	2s	512 MB	Judgeable
WirelessGiven K circles with integer centers and integer radii on a grid of intersections, compute the maximum total bitrate sum any intersection receives and how many intersections achieve it.	Medium7	GeometryImplementation+2	No attempts yet	1s	128 MB	Judgeable
DinnerGiven a line of G and H programmers, repeatedly remove a run of at least K equal letters; find the minimum number of removals to clear the line, or -1.	Medium7	Dynamic programmingIntervals+2	No attempts yet	1s	128 MB	Judgeable
Road ConstructionGiven a connected undirected graph, add the fewest edges so that deleting any single edge still leaves the graph connected.	Medium7	GraphDFS+2	No attempts yet	1s	128 MB	Judgeable
The Great Spamway StrikeChoose a rooted tree over zombies with allowed bidirectional links, minimizing the round-trip time for a gather broadcast that includes each node's per-message read lag.	Medium7	TreeDynamic programming+2	No attempts yet	1s	128 MB	Judgeable
Cheap GasOn an m by n grid with a fuel tank of capacity f, find the cheapest way to buy gas at priced stations while driving from (1,1) to (m,n), or report that the trip is impossible.	Medium7	GraphShortest path+2	No attempts yet	1s	128 MB	Judgeable
Strategic BombingGiven an undirected graph of at most 26 points, find every edge whose removal disconnects A from B, listing them in input order.	Medium7	GraphDFS+2	No attempts yet	1s	128 MB	Judgeable
Packing RectanglesGiven four rectangles, find every smallest enclosing axis-parallel rectangle that fits all four without overlap, using the six basic layouts.	Medium7	Brute forceGeometry+2	No attempts yet	1s	512 MB	Judgeable
Shopping OffersGiven regular item prices and bundle offers, find the minimum cost to buy exactly the listed quantities without buying extras.	Medium7	Dynamic programmingArray+2	No attempts yet	1s	512 MB	Judgeable
Barn ExpansionGiven up to 25000 non-overlapping axis-aligned rectangles, count how many touch no other rectangle at any corner or along any wall.	Medium7	GeometrySorting+1	No attempts yet	1s	128 MB	Judgeable
TripsMatch group sizes to trip intervals so that each interval gets at most one group and the number of matched intervals is maximized.	Medium7	GreedySorting+2	No attempts yet	1s	128 MB	Judgeable
Sailing RaceGiven sign positions on a line, find the visiting order minimizing the sum of cumulative distances, where each next sign adds the distance from the previous sign.	Medium7	Dynamic programmingGreedy+2	No attempts yet	1s	128 MB	Judgeable
The Running ManIn a small grid maze with paths, doors, walls and one entrance, find every single door whose locking alone disconnects the starting path cell from the entrance.	Medium7	GraphBrute force+2	No attempts yet	1s	128 MB	Judgeable
Task ExecutionGiven a DAG of N unit-time tasks, find the minimum completion time with unlimited processors, then the fewest processors that still achieve it.	Medium7	GraphTopological sort+2	No attempts yet	1s	128 MB	Judgeable
QuadTreesGiven pre-order strings of two quadtrees for N x N binary images, count the nodes in the quadtree of their pixelwise AND intersection, collapsing uniform quadrants.	Medium7	TreeDivide and conquer+2	No attempts yet	1s	128 MB	Judgeable
Kingdom of MagicOn a graph of up to 100 cities, two people who must always sit on adjacent distinct vertices move to a target adjacent pair, minimizing total single or paired moves.	Medium7	GraphBFS+2	No attempts yet	2s	128 MB	Judgeable
Shortest Regular Brackets SequenceGiven a string of brackets, find the length of the shortest regular bracket sequence that contains it as a subsequence.	Medium7	Dynamic programmingIntervals+2	No attempts yet	1s	128 MB	Judgeable
Longest Common Increasing SubsequenceGiven two integer sequences, find the length of the longest common increasing subsequence of both.	Medium7	Dynamic programmingArray+2	No attempts yet	1s	256 MB	Judgeable
B-MatrixFind two non-overlapping all-zero rectangles in a binary grid maximizing the total number of cells they cover.	Medium7	Dynamic programmingMatrix+2	No attempts yet	1s	128 MB	Judgeable
GCD!For each pair n and k, compute gcd(n!, k); n can reach 1e9 so n! cannot be built, which forces a bound on the prime factors of k that matter.	Medium7	Number theoryMath+2	No attempts yet	1s	128 MB	Judgeable
Jakarta Traffic JamFind the fastest travel time between two intersections where each street is driven at half speed during its own daily rush hour, and you never stop to wait. Each test case gives up to 20 nodes; report the minimum minutes to two decimals.	Medium7	GraphShortest path+2	No attempts yet	1s	128 MB	Judgeable
Central TreeFor each weighted tree, find the vertex minimizing the sum of weighted distances to all other vertices and output that minimum sum.	Medium7	TreeDFS+2	No attempts yet	3s	128 MB	Judgeable
Better and Faster!Compute a CRC-style bit checksum of a string after each of up to 1e5 character substitutions, fast enough that recomputing from scratch times out.	Medium7	Bit manipulationMath+1	No attempts yet	2s	512 MB	Judgeable
I'll Do It TomorrowGiven n jobs with lengths and deadlines, find the longest idle prefix of days, counting from day 1, before some work must begin.	Medium7	GreedySorting+2	No attempts yet	2s	256 MB	Judgeable
RailwaysProcess train seat requests in order; accept a request only if every section it covers has enough free seats, and report T or N for each.	Medium7	Segment treeArray+2	No attempts yet	3s	128 MB	Judgeable
Binary Search Tree CodeGiven n and k, output the n-th preorder string among all BSTs built from the first k letters, listed in alphabetical order.	Medium7	TreeRecursion+2	No attempts yet	1s	128 MB	Judgeable
BoxesBoxes stand in a circle with at most n balls total; move balls to neighbors so each box holds at most one, minimizing the number of moves.	Medium7	GreedyPrefix sum+2	No attempts yet	1s	128 MB	Judgeable
ShiftGiven a permutation of 1 to n, decide whether it can be sorted using only two moves: bring the last element to the front, or bring the third element to the front.	Medium7	ArrayImplementation+2	No attempts yet	1s	128 MB	Judgeable
BanjoPick two separate one-minute intervals to maximize the number of people present for at least one full minute.	Medium7	ArraySorting+2	No attempts yet	5s	128 MB	Judgeable
SweetsPartition n boxes (n up to 24) of sweets into three groups with sums A <= D <= B, minimizing B - A.	Medium7	Brute forceGreedy+2	No attempts yet	2s	512 MB	Judgeable
StudiesGiven a directed graph with edge weights, find every vertex that lies on a closed walk of positive total weight.	Medium7	GraphShortest path+1	No attempts yet	1s	128 MB	Judgeable
Space Base ConstructionFor each query rectangle, decide if its center lies on some platform or if at least three of its four corners lie on platforms.	Medium7	GeometryBinary search+1	No attempts yet	1s	128 MB	Judgeable