Problems

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Total results29,429 problems

Shut the Box II
Medium6
Dynamic programming, Backtracking+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Rotation Maze
Medium6
BFS, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pawns
Medium6
BFS, Simulation+1
No attempts yet
Time limit
0.2s
Memory limit
64 MB
Judgeable
Toponyms
Medium6
String, Trie+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Pirates' Code
Medium6
Sorting, Hash map+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cubing
Medium6
Implementation, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Valid Binary String
Medium6
Greedy, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Buying Notebooks
Medium6
Dynamic programming, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Constructing a Square Root
Medium6
Number theory, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Penguin Bashing
Medium6
Math, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Fractal Distance
Medium6
Divide and conquer, Recursion+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Warfare
Medium6
Graph, Minimum spanning tree+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cell Phone Antenna
Medium6
Geometry, Intervals+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Evacuation
Medium6
Greedy, Math
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Grand Game Tournament
Medium6
Graph, Greedy+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Digit Sum of a Range
Medium6
Math, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Fire!
Medium6
BFS, Graph+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Stifling the Mutiny
Medium6
Dynamic programming, Brute force+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Dividing the Loot
Medium6
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Equal Is Not Really Equal
Medium6
Graph, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
My Cousin Obama
Medium6
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Raisins
Medium6
Dynamic programming, Prefix sum+2
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
King Jaguar's Pyramid
Medium6
Prefix sum, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Average Value Sequence
Medium6
Math, Combinatorics+2
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
Drawing with XOR
Medium6
Array, Matrix+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Batch Scheduling
Medium6
Dynamic programming, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Palindrome
Medium6
Dynamic programming, String+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Car Parking
Medium6
Greedy, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Starry Night
Medium6
DFS, Matrix+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Party Lamps
Medium6
Brute force, Bit manipulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Darts
Medium6
Binary search, Sorting+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Light Bulb Decoration
Medium6
Array, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Card Game is Fun
Medium6
Dynamic programming, Array+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Illumination
Medium6
BFS, Graph+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
The Used Bookstore
Medium6
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Shopping Malls
Medium6
Shortest path, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Walking Santa Claus
Medium6
Math, Geometry+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Microbe Experiment (Bug Party)
Medium6
Greedy, Sorting+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
First Grade
Medium6
Dynamic programming, Array
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Splitting the Snack
Medium6
Dynamic programming, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hop-Hop River Crossing
Medium6
Dynamic programming, Array+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Senbei
Medium6
Brute force, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sea Journey
Medium6
Shortest path, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Oldest Ruins
Medium6
Geometry, Hash map+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Worst Reporter
Medium6
Graph, Topological sort+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Third Smallest Number
Medium6
String, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Prime Palindrome Flags
Medium6
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bacteria
Medium6
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Binary Matrix
Medium6
Greedy, Combinatorics+2
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Warp Speed II
Medium6
Dynamic programming, Greedy+2
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Binary Search Tree
Medium6
Tree, Divide and conquer+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Software Licenses
Medium6
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
App Rating
Medium6
Math, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Nowhere Money
Medium6
Greedy, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cellphone Keypad Autocomplete
Medium6
Trie, Tree+2
No attempts yet
Time limit
1s
Memory limit
192 MB
Judgeable
Stacking Balls
Medium6
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Ants Colony
Medium6
Tree, DFS+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Counting Digits
Medium6
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Another Crisis
Medium6
Tree, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Dinner Hall
Medium6
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Electricity Bill
Medium6
Binary search, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Isosceles Triangles
Medium6
Geometry, Hash map+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Drop the Triples
Medium6
Greedy, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Finding Seats
Medium6
Two pointers, Binary search+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Galou is Back!
Medium6
Graph, BFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
ICPC Scoreboard
Medium6
Math, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Justice League
Medium6
Graph, Divide and conquer+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bubble Maps
Medium6
Tree, Implementation+2
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Report Recovery
Medium6
Backtracking, Brute force+2
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
ICPC Strikes Again
Medium6
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Long Night of Museums
Medium6
Dynamic programming, Bit manipulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Splitting Club
Medium6
Greedy, Two pointers+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Grandpa's Rubik Cube
Medium6
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
This Sentence is False
Medium6
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Will Indiana Jones Get There?
Medium6
Graph, Union-find+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Duty Free Shop
Medium6
Greedy, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
CrossNumber
Medium6
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Fridge Lock
Medium6
Brute force, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Class Packing
Medium6
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Esspe-Peasee
Medium6
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Luxury River Cruise
Medium6
Binary search, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bovine Ballet
Medium6
Simulation, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Farm Painting
Medium6
Sorting, Array+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Perimeter of the Hay Bales
Medium6
Graph, BFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tractor
Medium6
Binary search, Union-find+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cow Lineup
Medium6
Sliding window, Two pointers+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Painting the Fence
Medium6
Intervals, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Painting the Fence
Medium6
Prefix sum, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Wi-Fi Setup
Medium6
Dynamic programming, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Crazy Fences
Medium6
Geometry, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Balanced Cow Breeds
Medium6
Dynamic programming, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Distant Pastures
Medium6
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Horseshoes
Medium6
DFS, Backtracking+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cows in a Skyscraper
Medium6
Dynamic programming, Bit manipulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Flowerpot
Medium6
Two pointers, Sliding window+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Landscaping
Medium6
Dynamic programming, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Connect the Cows
Medium6
Backtracking, Geometry+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Symmetry
Medium6
Geometry, Hash map+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Nearby Cows
Medium6
Tree, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Moo Game
Medium6
Recursion, Divide and conquer+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Shut the Box IIGiven open cards and a rolled total, pick the set summing to the total that maximizes the probability of shutting every card under optimal play, and report that probability.	Medium6	Dynamic programmingBacktracking+2	No attempts yet	1s	128 MB	Judgeable
Rotation MazeGiven a maze where a ball falls under gravity, find the shortest sequence of 90-degree left and right rotations that brings the ball to rest on the goal.	Medium6	BFSSimulation+2	No attempts yet	1s	128 MB	Judgeable
PawnsPawns slide or jump toward their own side on a 1 by N board; find the minimum number of moves to gather all white pawns on the left and black on the right.	Medium6	BFSSimulation+1	No attempts yet	0.2s	64 MB	Judgeable
ToponymsGiven up to a million strings, find a subset maximizing the longest common prefix length times the subset size.	Medium6	StringTrie+2	No attempts yet	2s	128 MB	Judgeable
Pirates' CodeGiven N integers from the foreheads, decide whether the set contains no increasing arithmetic progression of length 3, and if it does, print the lexicographically first witness triple.	Medium6	SortingHash map+2	No attempts yet	1s	128 MB	Judgeable
CubingSimulate a sequence of Rubik's cube face turns from a solved state and print the colors on the up face.	Medium6	ImplementationSimulation+2	No attempts yet	1s	128 MB	Judgeable
Valid Binary StringGiven a binary string with erased positions, decide whether the missing bits can be filled so the counts of 0 and 1 are equal and no character runs three times in a row.	Medium6	GreedyString+2	No attempts yet	1s	128 MB	Judgeable
Buying NotebooksEach store has a fixed shipping fee, a per-notebook price, and limited stock; buy exactly N notebooks across stores at minimum total cost.	Medium6	Dynamic programmingSorting+2	No attempts yet	1s	128 MB	Judgeable
Constructing a Square RootFor each N up to 1e9, find non-negative integers a and r with r^2 - a^2 = N and minimal a, or report IMPOSSIBLE.	Medium6	Number theoryMath+1	No attempts yet	1s	128 MB	Judgeable
Penguin BashingGiven mine and spike positions on flat ground, find the launch angle between -90 and 90 degrees that maximizes the penguin's flight and sliding distance, with mines giving extra speed and spike hits scoring -100.	Medium6	MathSimulation+1	No attempts yet	1s	128 MB	Judgeable
Fractal DistanceGiven the order of two houses along an n-th Hilbert curve, compute the straight-line distance between their grid positions.	Medium6	Divide and conquerRecursion+2	No attempts yet	1s	128 MB	Judgeable
WarfareGiven an undirected multigraph with per-edge cost as the sum of its endpoint weights, find the minimum total cost of edges whose removal destroys every cycle.	Medium6	GraphMinimum spanning tree+2	No attempts yet	1s	128 MB	Judgeable
Cell Phone AntennaPlace one antenna of range 1000 on the line y=0 so that the total inhabitants of all covered houses is maximized, and report that maximum.	Medium6	GeometryIntervals+2	No attempts yet	1s	128 MB	Judgeable
EvacuationGiven walking and elevator times, choose one floor where the descending elevator stops so that all waiting people reach floor 0 as fast as possible.	Medium6	GreedyMath	No attempts yet	1s	128 MB	Judgeable
Grand Game TournamentGiven partial results of a round-robin with draws, find every player who can still finish with the maximum score.	Medium6	GraphGreedy+1	No attempts yet	2s	256 MB	Judgeable
Digit Sum of a RangeFor each query [a,b] with b up to 10^15, output the sum of all decimal digits of every integer in the range.	Medium6	MathDynamic programming+2	No attempts yet	1s	128 MB	Judgeable
Fire!Given a grid with walls, one starting cell, and fire cells that spread each second, find the earliest time the person can step off the map.	Medium6	BFSGraph+2	No attempts yet	1s	256 MB	Judgeable
Stifling the MutinyDistribute k pirates over n ships, each with at least one loyal pirate, so that no ship's loyal count is below the disloyal pirates on it and its neighbors, maximizing disloyal pirates.	Medium6	Dynamic programmingBrute force+1	No attempts yet	1s	128 MB	Judgeable
Dividing the LootGiven N item values and P other pirates, choose a set of items for yourself so no other pirate gets more items than you, maximizing your total value.	Medium6	GreedySorting+2	No attempts yet	1s	128 MB	Judgeable
Equal Is Not Really EqualGiven a string, decide whether a different string of the same length has an identical multiset of consecutive character pairs.	Medium6	GraphString+2	No attempts yet	1s	128 MB	Judgeable
My Cousin ObamaGiven a forest of parent links, find the ancestor path from A0 to B0 that passes through as few mothers as possible.	Medium6	GraphDFS+2	No attempts yet	1s	128 MB	Judgeable
RaisinsSplit an N by M chocolate bar into unit cells by straight cuts; each cut costs the raisins in the piece, and the goal is to minimize the total payment.	Medium6	Dynamic programmingPrefix sum+2	No attempts yet	3s	128 MB	Judgeable
King Jaguar's PyramidPlace an a by b pyramid and an interior c by d chamber on a grid to maximize the sum of base squares minus chamber squares.	Medium6	Prefix sumBrute force+2	No attempts yet	1s	128 MB	Judgeable
Average Value SequenceGiven a non-decreasing average sequence m of length n, count the integer sequences s of length n+1 whose adjacent averages equal m.	Medium6	MathCombinatorics+2	No attempts yet	5s	256 MB	Judgeable
Drawing with XOREach XOR call flips a rectangle anchored at the bottom right, so the number of calls equals the count of pixels that differ from the pixel below and the pixel to the right, plus the bottom-right pixel.	Medium6	ArrayMatrix+2	No attempts yet	1s	512 MB	Judgeable
Batch SchedulingSplit the ordered jobs into consecutive batches, each paying a setup time, and minimize the sum of weighted completion times.	Medium6	Dynamic programmingPrefix sum+1	No attempts yet	1s	128 MB	Judgeable
PalindromeGiven a string, find the minimum number of characters to insert anywhere so the string becomes a palindrome.	Medium6	Dynamic programmingString+2	No attempts yet	1s	256 MB	Judgeable
Car ParkingGiven a row of cars and W workers, find the minimum number of cars that must change places so the types are sorted ascending.	Medium6	GreedyDynamic programming+1	No attempts yet	1s	128 MB	Judgeable
Starry NightFind 8-connected star clusters in a grid and assign the same letter to clusters that match under rotation and reflection.	Medium6	DFSMatrix+2	No attempts yet	1s	128 MB	Judgeable
Party LampsGiven N lamps all starting ON and a press count C, list every distinct final lamp configuration reachable with exactly C presses of four fixed toggle buttons and consistent with up to two ON and two OFF constraints.	Medium6	Brute forceBit manipulation+2	No attempts yet	1s	128 MB	Judgeable
DartsWith up to four darts and N region scores, find the largest total not exceeding M, or 0 if every reachable total is over M.	Medium6	Binary searchSorting+2	No attempts yet	1s	256 MB	Judgeable
Light Bulb DecorationGiven a binary string, flip at most one contiguous range so that some contiguous alternating substring becomes as long as possible, and report that length.	Medium6	ArrayPrefix sum+2	No attempts yet	1s	128 MB	Judgeable
Card Game is FunAnna may delete arbitrary cards from her sequence and Bruno may trim cards from the top and bottom of his; find the longest common subarray obtainable.	Medium6	Dynamic programmingArray+2	No attempts yet	1s	128 MB	Judgeable
IlluminationCount the hexagon edges of occupied cells that border open space reachable from outside the map, excluding walls around enclosed courtyards.	Medium6	BFSGraph+2	No attempts yet	1s	256 MB	Judgeable
The Used BookstoreChoose exactly K of N books to sell, maxing the total where selling t books of one genre adds t(t-1) extra to that genre's group.	Medium6	Dynamic programmingGreedy+2	No attempts yet	1s	128 MB	Judgeable
Shopping MallsGiven a connected weighted graph with some cities holding malls, find the maximum over all points on roads of the distance to the nearest mall, then round to the nearest integer.	Medium6	Shortest pathGraph+2	No attempts yet	1s	128 MB	Judgeable
Walking Santa ClausPlace a depot on a huge grid so that twice the sum of Manhattan distances to all houses, minus the farthest one, is minimized, and print the best cell.	Medium6	MathGeometry+2	No attempts yet	1s	128 MB	Judgeable
Microbe Experiment (Bug Party)Choose the largest subset of microbes so that the average foo released by the subset does not exceed any chosen microbe's tolerance.	Medium6	GreedySorting+2	No attempts yet	2s	128 MB	Judgeable
First GradeCount the ways to place + or - between the first N-1 digits and = before the last digit so that left-to-right evaluation never leaves the range 0 to 20 and the total equals the last digit.	Medium6	Dynamic programmingArray	No attempts yet	1s	128 MB	Judgeable
Splitting the SnackChoose which of the N-1 cut points to cut so that both people get exactly N/2 pieces, minimizing the total force of the chosen cuts.	Medium6	Dynamic programmingPrefix sum+2	No attempts yet	1s	128 MB	Judgeable
Hop-Hop River CrossingStarting from the near bank, hop across stones in n rows using normal jumps or at most m row-skipping jumps, minimizing total jump danger.	Medium6	Dynamic programmingArray+2	No attempts yet	1s	128 MB	Judgeable
SenbeiGiven a binary R x C grid with R at most 10, choose one subset of rows and one subset of columns to flip so the number of 1s is maximized.	Medium6	Brute forceGreedy+2	No attempts yet	1s	128 MB	Judgeable
Sea JourneyProcess a stream of queries where each query asks for the shortest path between two islands after a sequence of edge insertions.	Medium6	Shortest pathGraph+2	No attempts yet	1s	128 MB	Judgeable
The Oldest RuinsGiven up to 3000 integer points, find four that form a square of the largest area and output that area, or 0 if none exist.	Medium6	GeometryHash map+2	No attempts yet	1s	128 MB	Judgeable
The Worst ReporterGiven some match results of a round-robin where higher-ranked teams always win, find the lexicographically smallest ranking and say whether it is unique.	Medium6	GraphTopological sort+2	No attempts yet	1s	128 MB	Judgeable
The Third Smallest NumberGiven n distinct natural numbers, list all two-element ordered concatenations by value and report the third smallest.	Medium6	StringSorting+2	No attempts yet	1s	128 MB	Judgeable
Prime Palindrome FlagsGiven n and an optional middle digit c, output the largest n-digit-palindromic number that is prime if any such palindrome is prime, otherwise the largest palindrome.	Medium6	MathNumber theory+2	No attempts yet	1s	128 MB	Judgeable
BacteriaSimulate K bacteria moving on a grid, each turning by a digit read from its own matrix, and report when all share the trap cell.	Medium6	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
Binary MatrixGiven a binary matrix, flip the fewest entries so every row has the same number of 1s and every column has the same number of 1s, or report that it is impossible.	Medium6	GreedyCombinatorics+2	No attempts yet	5s	128 MB	Judgeable
Warp Speed IIFor each hop sequence, pick a warp-drive state per hop minimizing switch plus hop energy, and return the lexicographically smallest optimal state sequence.	Medium6	Dynamic programmingGreedy+2	No attempts yet	5s	128 MB	Judgeable
Binary Search TreeGiven the preorder traversal of a binary search tree, print its postorder traversal.	Medium6	TreeDivide and conquer+2	No attempts yet	1s	256 MB	Judgeable
Software LicensesSchedule n licenses, one per month, when license i costs P_i * R_i^t if bought after t months, and minimize total cost.	Medium6	GreedySorting+2	No attempts yet	1s	128 MB	Judgeable
App RatingGiven a rounded average rating from 1 to 5, find the minimum number of raters whose exact average rounds to that value.	Medium6	MathBrute force+2	No attempts yet	1s	128 MB	Judgeable
Nowhere MoneyRepresent each amount as a sum of T(s) values (T(n) = Fibonacci-like count) with the fewest slots whose sizes differ by at least 2, and print the sizes and values.	Medium6	GreedyDynamic programming+2	No attempts yet	1s	128 MB	Judgeable
Cellphone Keypad AutocompleteFor each word in a dictionary, compute how many letters a phone keypad must type when unique suffixes are autofilled, then print the average presses.	Medium6	TrieTree+2	No attempts yet	1s	192 MB	Judgeable
Stacking BallsPick balls from a triangular pile, where each ball needs both balls above it picked first, to maximize the total score; stopping early is allowed.	Medium6	Dynamic programmingGreedy+2	No attempts yet	1s	128 MB	Judgeable
Ants ColonyBuild a weighted tree where each new node attaches to an earlier one, then answer distance queries between pairs of nodes.	Medium6	TreeDFS+2	No attempts yet	2s	128 MB	Judgeable
Counting DigitsFor each query range [A, B], count how many times each decimal digit 0 through 9 appears in all integers written out from A to B.	Medium6	MathImplementation+2	No attempts yet	1s	128 MB	Judgeable
Another CrisisGiven a company tree and a threshold T percent, find the minimum number of leaf workers who must petition so that a petition reaches the root.	Medium6	TreeDFS+2	No attempts yet	1s	128 MB	Judgeable
Dinner HallEach card gives a distinct time, either an entry, an exit, or unknown; find the largest number of people who could have been inside at one instant.	Medium6	GreedySorting+2	No attempts yet	1s	128 MB	Judgeable
Electricity BillGiven the combined bill A of two users and the difference B of their individual bills, find the smaller user's own bill under a four-tier progressive rate.	Medium6	Binary searchMath+2	No attempts yet	1s	128 MB	Judgeable
Isosceles TrianglesGiven N integer points with no three collinear, count the triples that form an isosceles triangle.	Medium6	GeometryHash map+2	No attempts yet	2s	128 MB	Judgeable
Drop the TriplesPlayers alternate drawing cards from a stock and may drop valid triples; each maximizes perfect triples then common triples. Report the winner or a tie.	Medium6	GreedyDynamic programming+2	No attempts yet	1s	128 MB	Judgeable
Finding SeatsGiven an R by C grid of free and taken seats, place K people on free seats so the bounding rectangle has the smallest area.	Medium6	Two pointersBinary search+2	No attempts yet	1s	128 MB	Judgeable
Galou is Back!On a hexagonal grid of meshed gears with some initially activated, determine each gear's final state: clockwise, counter-clockwise, free, or blocked.	Medium6	GraphBFS+2	No attempts yet	1s	128 MB	Judgeable
ICPC ScoreboardGiven team results, find the smallest and largest error penalty EP (or * if unbounded) that keep the ICPC standings identical to those at EP=20.	Medium6	MathSorting+2	No attempts yet	1s	128 MB	Judgeable
Justice LeagueDecide whether the graph of heroes can be split into a clique and an independent set.	Medium6	GraphDivide and conquer+2	No attempts yet	1s	128 MB	Judgeable
Bubble MapsGiven a quadtree region name, find the names of its up, down, left, and right neighbors, or <none> if a neighbor falls outside the map.	Medium6	TreeImplementation+2	No attempts yet	3s	128 MB	Judgeable
Report RecoveryRebuild a space-stripped sales report by splitting each digit run into numbers, choosing the lexicographically smallest reconstruction consistent with the report's structure.	Medium6	BacktrackingBrute force+2	No attempts yet	3s	128 MB	Judgeable
ICPC Strikes AgainGiven a DAG of task dependencies, basic significances, and which employees perform which tasks, compute each employee's salary as the sum of significances of tasks they perform that no other task they perform depends on.	Medium6	GraphDFS+2	No attempts yet	1s	128 MB	Judgeable
Long Night of MuseumsWith at most 20 museums, viewing times, and travel times, find the largest number of distinct museums a 420-minute tour can include.	Medium6	Dynamic programmingBit manipulation+2	No attempts yet	1s	128 MB	Judgeable
The Splitting ClubGiven distinct ages with member counts and a ratio R, partition all age groups into the fewest contiguous sections where the max count in a section is at most R times the min count.	Medium6	GreedyTwo pointers+2	No attempts yet	1s	128 MB	Judgeable
Grandpa's Rubik CubeGiven a Rubik's cube configuration and a list of face rotations, decide whether applying them all yields a solved cube with each face a single color.	Medium6	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
This Sentence is FalseEach sentence claims another sentence is true or false; decide whether a consistent assignment exists and, if so, maximize the number of true sentences.	Medium6	GraphDFS+2	No attempts yet	1s	128 MB	Judgeable
Will Indiana Jones Get There?Given axis-aligned wall segments, find the smallest board length such that a path from the first wall to the second keeps every gap no larger than that length.	Medium6	GraphUnion-find+2	No attempts yet	1s	128 MB	Judgeable
Duty Free ShopAssign each box entirely to one of two brands so both totals stay within limits, printing the greedy canonical assignment or Impossible to distribute.	Medium6	GreedyDynamic programming+2	No attempts yet	1s	128 MB	Judgeable
CrossNumberFill a digit-grid puzzle where each across and down run must match a given digit sum, always leaving a word with one blank cell to solve.	Medium6	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
Fridge LockGiven K rings each showing 3 to 49 positive integers and K linear equations, pick one number per ring satisfying all equations and print the selection.	Medium6	Brute forceMath+2	No attempts yet	1s	128 MB	Judgeable
Class PackingGiven enrollments for seven grades, find the fewest classes where each class holds one grade or two consecutive grades within the group size limits (20, 25, or 30).	Medium6	Dynamic programmingGreedy+2	No attempts yet	1s	128 MB	Judgeable
Esspe-PeaseeFor each triple (foom, foob, twob), find non-negative counts A and B with the fewest total coins so that Afoom + Bfoob equals twob.	Medium6	MathNumber theory+2	No attempts yet	1s	128 MB	Judgeable
Luxury River CruiseEach of N ports has a left and right outgoing river; follow a fixed direction string of length M repeated K times from port 1 and report the final port.	Medium6	Binary searchGraph+2	No attempts yet	1s	128 MB	Judgeable
Bovine BalletSimulate a cow's dance of foot moves and 90-degree pivots, track every foot cell over time, and report the smallest bounding rectangle or -1 if two feet ever collide.	Medium6	SimulationImplementation+1	No attempts yet	1s	128 MB	Judgeable
Farm PaintingGiven up to 50,000 non-intersecting axis-aligned rectangles, count how many are not contained inside any other rectangle.	Medium6	SortingArray+2	No attempts yet	1s	128 MB	Judgeable
Perimeter of the Hay BalesGiven up to 50000 grid cells forming one connected region, find the outer perimeter, ignoring any enclosed holes.	Medium6	GraphBFS+2	No attempts yet	1s	128 MB	Judgeable
TractorFind the smallest cost c so that a connected region of at least half the N x N grid is reachable using only steps whose elevation difference is at most c.	Medium6	Binary searchUnion-find+2	No attempts yet	1s	128 MB	Judgeable
Cow LineupGiven a sequence of N breed IDs, remove at most K distinct breed IDs so that the longest run of equal IDs in the remaining sequence is maximized.	Medium6	Sliding windowTwo pointers+2	No attempts yet	1s	128 MB	Judgeable
Painting the FenceBessie walks along a number line and each segment she covers gains a coat of paint; find the total length covered by at least K coats.	Medium6	IntervalsSorting+2	No attempts yet	1s	128 MB	Judgeable
Painting the FenceBessie walks back and forth along a line, each pass adding a coat; find the total length covered by at least two coats.	Medium6	Prefix sumSorting+2	No attempts yet	1s	128 MB	Judgeable
Wi-Fi SetupCover all cow positions on a line with base stations, where a station covering an interval of length 2r costs A + B*r; minimize total cost.	Medium6	Dynamic programmingSorting+2	No attempts yet	1s	128 MB	Judgeable
Crazy FencesGiven horizontal and vertical fences that meet only at endpoints and points for cows, find the largest set of cows that can reach each other without touching a fence.	Medium6	GeometryGraph+2	No attempts yet	1s	128 MB	Judgeable
Balanced Cow BreedsCount the ways to 2-color the parentheses in a string so that each color class, read in order, forms a balanced parenthesis sequence.	Medium6	Dynamic programmingString+2	No attempts yet	1s	128 MB	Judgeable
Distant PasturesEach grid cell has one of two grass types; moving between adjacent cells costs A if types match and B otherwise. Find the largest shortest-path distance over all pairs of cells.	Medium6	GraphShortest path+2	No attempts yet	1s	128 MB	Judgeable
HorseshoesOn an N x N grid (N at most 5) of parentheses, find the longest walk from the top-left cell, visiting each cell at most once, whose collected characters form a run of '(' followed by an equally long run of ')'.	Medium6	DFSBacktracking+2	No attempts yet	1s	128 MB	Judgeable
Cows in a SkyscraperGiven up to 18 cow weights and an elevator capacity, find the minimum number of trips that carry every cow without exceeding the capacity.	Medium6	Dynamic programmingBit manipulation+2	No attempts yet	1s	128 MB	Judgeable
FlowerpotFind the minimum width interval on the x axis that captures raindrops whose heights differ by at least D.	Medium6	Two pointersSliding window+1	No attempts yet	1s	128 MB	Judgeable
LandscapingEach flowerbed has a current and target dirt amount, and dirt can be bought, removed, or moved between beds at a per-unit distance cost; find the cheapest way to hit every target.	Medium6	Dynamic programmingGreedy+2	No attempts yet	1s	128 MB	Judgeable
Connect the CowsCount the axis-parallel tours from the origin that turn exactly once at each of N (at most 10) given cow positions before returning to the origin.	Medium6	BacktrackingGeometry+2	No attempts yet	1s	128 MB	Judgeable
SymmetryGiven N distinct points in the plane, count how many lines reflect the whole set onto itself.	Medium6	GeometryHash map+2	No attempts yet	1s	128 MB	Judgeable
Nearby CowsOn a tree of N fields with C(i) cows at each field, report for every field the total cows within distance K, where K is at most 20.	Medium6	TreeDFS+2	No attempts yet	1s	128 MB	Judgeable
Moo GameGiven N up to 1e9, report whether the N-th character of the recursively defined Moo sequence is 'm' or 'o'.	Medium6	RecursionDivide and conquer+2	No attempts yet	1s	128 MB	Judgeable