Problems

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Total results29,442 problems

L-Board
Medium5
Dynamic programming, Matrix
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Dongwoo, is his heart kind or cruel?
Medium5
Tree, DFS+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Efficient Anime Watching
Medium5
Dynamic programming, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Fluffy Fox Tail
Medium5
Sliding window, Array+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Analyzing UMR's Tetris Play
Medium5
Implementation, Simulation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
JOI Four Students (JOI04)
Medium5
Sorting, Sliding window+2
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Paint Fill
Medium5
Graph, BFS+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Dirigent
Medium5
Array, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Rabbit Carrot
Medium5
Dynamic programming, Binary search+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Cards
Medium5
Hash map, Combinatorics
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Coins
Medium5
Dynamic programming, Matrix+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Sales Tax
Medium5
Math, Binary search+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Dungeon
Medium5
Greedy, Math
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Solar Charging
Medium5
Dynamic programming, Implementation
No attempts yet
Time limit
0.5s
Memory limit
512 MB
Judgeable
Particle Experiment
Medium5
Dynamic programming, Bit manipulation
No attempts yet
Time limit
1.5s
Memory limit
512 MB
Judgeable
Cutting Wooden Sticks
Medium5
Dynamic programming, Array
No attempts yet
Time limit
0.5s
Memory limit
512 MB
Judgeable
Counting Special Integer Pairs
Medium5
Binary search, Sorting+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Stop Leaving Me on Read!
Medium5
Dynamic programming, Recursion
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Oh no, XOR again?
Medium5
Dynamic programming, Bit manipulation
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Platform Placing
Medium5
Greedy, Sorting
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Spidey Distance
Medium5
Math, Geometry+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
String Conversion and Queries
Medium5
String, Implementation
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Amazing Images
Medium5
Dynamic programming, Prefix sum+1
No attempts yet
Time limit
0.6s
Memory limit
1024 MB
Judgeable
Infinity War
Medium5
Bit manipulation, Prefix sum+1
No attempts yet
Time limit
0.8s
Memory limit
8 MB
Judgeable
Password
Medium5
Greedy, String
No attempts yet
Time limit
1.6s
Memory limit
1024 MB
Judgeable
Lazy
Medium5
Minimum spanning tree, Union-find+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Make 1 (Part 3)
Medium5
Dynamic programming, Recursion+1
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
Movie Director Shom 3
Medium5
Dynamic programming, Combinatorics
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
String Conversion and Queries 3
Medium5
String, Prefix sum+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Good Night in the Lab
Medium5
Dynamic programming, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Is the Order Pottery?
Medium5
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Chainsaw Man
Medium5
Dynamic programming, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Parenthesis Sequence Character
Medium5
Recursion, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Adjacent Pairs
Medium5
Hash map, Array+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Nice Subset
Medium5
Number theory, Probability+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Suffix Operations
Medium5
Array, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
White Lines
Medium5
Prefix sum, Matrix+1
No attempts yet
Time limit
1.5s
Memory limit
256 MB
Judgeable
Compress Words
Medium5
String, String matching
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Relative Pitch Song Search
Medium5
String matching, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Function Sequence and Queries
Medium5
Segment tree, Array+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Snake
Medium5
Math, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Drawing a Snake
Medium5
Implementation, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Hitting Targets
Medium5
Hash map, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Bead Sort
Medium5
Sorting, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Hanging a Banner
Medium5
Hash map, Two pointers+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Cheese
Medium5
Graph, Dynamic programming
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Canal
Medium5
Union-find, Graph+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Find and Replace
Medium5
Graph, DFS
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Air Conditioning II
Medium5
Brute force, Bit manipulation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
ICPC Advertisement
Medium5
Dynamic programming, Matrix
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Alchemy
Medium5
String, Greedy
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Chocolate Chip Fabrication
Medium5
BFS, Matrix
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Distinct Parity Excess
Medium5
Number theory, Prefix sum
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Family Visits
Medium5
Greedy, Heap
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Repetitive Song
Medium5
Hash map, Implementation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Another Wine Tasting Event
Medium5
Prefix sum, Implementation
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
A Musical Question
Medium5
Dynamic programming, Array
No attempts yet
Time limit
11s
Memory limit
1024 MB
Judgeable
It's About Time
Medium5
Brute force, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Two Charts Become One
Medium5
Tree, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Sum of Three Cubes
Medium5
Number theory, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Wooden Fence
Medium5
Dynamic programming, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Tennis Game
Medium5
Math, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Judicious cuts (Easy)
Medium5
Math, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Inchworm Cut
Medium5
Prefix sum, Two pointers+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
AB
Medium5
Hash map, String+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Exam
Medium5
Binary search, Sorting+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Ferries (Easy)
Medium5
BFS, Graph+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Kill switch
Medium5
Implementation, Brute force
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Turning gears (hard)
Medium5
Graph, BFS+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
A+B
Medium5
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Cells
Medium5
String, Hash map+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Dragon Slayer
Medium5
BFS, Graph+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Amazing Mobistudy
Medium5
Union-find, Hash map
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Cowherd and Weaver Girl
Medium5
Tree, DFS+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Sequence Rearrangement
Medium5
Array, Sorting+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Shift Operations
Medium5
Greedy, Simulation
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
World Cup Group Stage
Medium5
Binary search, Implementation+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Saving the universe again
Medium5
String, Greedy+1
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
Trouble Sort
Medium5
Sorting, Array
No attempts yet
Time limit
Not set
Memory limit
1024 MB
Judgeable
Waffle Choppers
Medium5
Prefix sum, Math+1
No attempts yet
Time limit
6s
Memory limit
1024 MB
Judgeable
Bit Party
Medium5
Binary search, Sorting+1
No attempts yet
Time limit
15s
Memory limit
1024 MB
Judgeable
Rounding Error
Medium5
Greedy, Math
No attempts yet
Time limit
10s
Memory limit
1024 MB
Judgeable
Ant Stack
Medium5
Dynamic programming, Greedy
No attempts yet
Time limit
15s
Memory limit
1024 MB
Judgeable
Alien Rhyme
Medium5
Trie, Greedy+1
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
Pattern Matching
Medium5
String, String matching+1
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
Square Dance
Medium5
Simulation, Linked list+1
No attempts yet
Time limit
40s
Memory limit
1024 MB
Judgeable
Cow-libi
Medium5
Sorting, Binary search+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Watching Mooloo
Medium5
Dynamic programming, Intervals+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Crane Operator
Medium5
Hash map, Implementation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Sum of Remainders
Medium5
Number theory, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Appearance of the Runo
Medium5
Combinatorics, Bit manipulation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Gahui and the ILGAM lake
Medium5
Array, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Gahee and the Subway Station Storage System 2
Medium5
Shortest path, Simulation+1
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Gahee and Seoul Subway Line 3
Medium5
Dynamic programming, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Gahui and the Subway Station Storage System 1
Medium5
Bit manipulation, Hash map+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Special student ID
Medium5
Dynamic programming, Matrix
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Special Serving
Medium5
Greedy, Heap
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Special Fire Alarm
Medium5
Greedy, Array
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
2D Paper Play
Medium5
Sorting, Prefix sum+1
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Apartment Complexes
Medium5
Binary search, Dynamic programming+1
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
L-BoardPick a cell as the corner of an L and maximise the vertical and horizontal segment sums through it, counting the corner once.	Medium5	Dynamic programmingMatrix	No attempts yet	2s	1024 MB	Judgeable
Dongwoo, is his heart kind or cruel?Given a weighted tree of N villages with signed edge costs, find the minimum and maximum total path cost from one house point (on a village or along a road) to all villages.	Medium5	TreeDFS+1	No attempts yet	2s	1024 MB	Judgeable
Efficient Anime WatchingFind the most episodes watchable within M hours, where episodes play in groups of at most K and each group lasts as long as its longest episode.	Medium5	Dynamic programmingSorting+1	No attempts yet	1s	1024 MB	Judgeable
Fluffy Fox TailGiven fluffy periods and at most K casts that each last T hours, find the longest continuous fluffy stretch between hours 0 and M.	Medium5	Sliding windowArray+1	No attempts yet	1s	1024 MB	Judgeable
Analyzing UMR's Tetris PlayGiven the field before and after one tetromino is placed and full rows are cleared, find which tetromino types could explain the change.	Medium5	ImplementationSimulation	No attempts yet	2s	1024 MB	Judgeable
JOI Four Students (JOI04)Pick one height from each of four lists of N values so that the gap between the tallest and shortest chosen height is as small as possible.	Medium5	SortingSliding window+2	No attempts yet	3s	1024 MB	Judgeable
Paint FillGiven an H by W color grid, find the largest region size you can get by recoloring one connected region once with any color.	Medium5	GraphBFS+1	No attempts yet	2s	1024 MB	Judgeable
DirigentAfter each swap in a circle of n students, decide whether cutting one neighbouring pair leaves the labels in sorted order.	Medium5	ArrayImplementation	No attempts yet	1s	1024 MB	Judgeable
Rabbit CarrotFind the fewest poles whose heights must change so a rabbit starting at height 0 can cross, rising at most M per jump and falling freely.	Medium5	Dynamic programmingBinary search+1	No attempts yet	1s	1024 MB	Judgeable
CardsCount the unordered pairs of 2x2 letter cards that can be placed side by side or stacked with matching edges, without rotating or flipping.	Medium5	Hash mapCombinatorics	No attempts yet	1s	1024 MB	Judgeable
CoinsRearrange an N x N grid of copper and silver coins so all copper sits in a staircase region at the top left, using the fewest swaps.	Medium5	Dynamic programmingMatrix+1	No attempts yet	2s	1024 MB	Judgeable
Sales TaxGiven item prices and the dollar part of a receipt total, find the minimum and maximum sales tax values that fit the receipt.	Medium5	MathBinary search+1	No attempts yet	1s	512 MB	Judgeable
DungeonGiven monster damage and scroll effects for each room, find the minimum starting health that lets the hero defeat every monster in order.	Medium5	GreedyMath	No attempts yet	1s	512 MB	Judgeable
Solar ChargingEach day the battery is either charged by sunlight or used, and the task is to find the minimum electricity cost while ending at or above the starting charge.	Medium5	Dynamic programmingImplementation	No attempts yet	0.5s	512 MB	Judgeable
Particle ExperimentCount the ways to place 1x2 switches on an R by C grid so every particle reaches the sensor positive, modulo 1e9+7.	Medium5	Dynamic programmingBit manipulation	No attempts yet	1.5s	512 MB	Judgeable
Cutting Wooden SticksGiven sticks of various lengths and a cutting cost a(L-1)^2+b per stick, find the minimum total cost to obtain at least K unit-length sticks.	Medium5	Dynamic programmingArray	No attempts yet	0.5s	512 MB	Judgeable
Counting Special Integer PairsGiven arrays A and B, find the smallest D where the number of pairs with Z(i, j) at most D equals K, or report -1 if none exists.	Medium5	Binary searchSorting+1	No attempts yet	1s	512 MB	Judgeable
Stop Leaving Me on Read!Given n, s, and t, find the minimum time to write the message n times by typing it or doubling the copies with copy and paste.	Medium5	Dynamic programmingRecursion	No attempts yet	1s	512 MB	Judgeable
Oh no, XOR again?Count the integers x from A to B inclusive where x XOR N has exactly K ones in its binary form.	Medium5	Dynamic programmingBit manipulation	No attempts yet	1s	512 MB	Judgeable
Platform PlacingPlace one platform of length s to k under each foundation point so that neighboring platforms never overlap, maximizing the total length.	Medium5	GreedySorting	No attempts yet	1.5s	1024 MB	Judgeable
Spidey DistanceGiven taxi-cab distance t and Spidey distance s, output the reduced fraction of lattice points within Spidey distance s that are also within taxi-cab distance t.	Medium5	MathGeometry+1	No attempts yet	1s	1024 MB	Judgeable
String Conversion and QueriesApply character replacement queries to a string in order and print the current string for each print query.	Medium5	StringImplementation	No attempts yet	3s	512 MB	Judgeable
Amazing ImagesCount the colorings of an M by N pixel grid where every K consecutive columns include a column with at least F black pixels, modulo 1,000,000,007.	Medium5	Dynamic programmingPrefix sum+1	No attempts yet	0.6s	1024 MB	Judgeable
Infinity WarGiven N armies of soldier powers, answer Q range queries: count the powers that appear in an odd number of armies from x to y.	Medium5	Bit manipulationPrefix sum+1	No attempts yet	0.8s	8 MB	Judgeable
PasswordGiven strings A and B, find the lexicographically smallest anagram of B that is a subsequence of A, or report impossible if none exists.	Medium5	GreedyString	No attempts yet	1.6s	1024 MB	Judgeable
LazyPick N-1 roads that connect all N cities, minimizing the total C1 first, then maximizing the sum of C1 times C2 among ties.	Medium5	Minimum spanning treeUnion-find+2	No attempts yet	1s	1024 MB	Judgeable
Make 1 (Part 3)Given N up to 10^18, find the minimum number of operations (divide by 3, divide by 2, or subtract 1) to reduce N to 1.	Medium5	Dynamic programmingRecursion+1	No attempts yet	0.5s	1024 MB	Judgeable
Movie Director Shom 3Given N, print the Nth smallest number that contains at least three 6s in a row, with N up to 10^18.	Medium5	Dynamic programmingCombinatorics	No attempts yet	0.5s	1024 MB	Judgeable
String Conversion and Queries 3Given a string S of uppercase letters and a table mapping each letter to a lowercase string, answer queries on the expanded string by printing a range or counting the most frequent letter in a range.	Medium5	StringPrefix sum+2	No attempts yet	2s	512 MB	Judgeable
Good Night in the LabGiven N pages and M scattered papers, find the minimum ink to print every missing page, where printing K consecutive pages costs 5+2K.	Medium5	Dynamic programmingImplementation	No attempts yet	1s	1024 MB	Judgeable
Is the Order Pottery?Given customer arrival times, decide whether one worker can make, fill, and serve a pot for each customer on time before its coffee turns muddy.	Medium5	GreedySorting+1	No attempts yet	1s	1024 MB	Judgeable
Chainsaw ManGiven a grid shape, find the minimum cost to cut its boundary using rays (fixed cost F each) and integer-length segments (cost by length), without cutting internal edges.	Medium5	Dynamic programmingImplementation	No attempts yet	1s	1024 MB	Judgeable
Parenthesis Sequence CharacterGiven n and k, find the k-th character of the bracket string S_n = (S_{n-2} S_{n-1}), or print 0 if k exceeds its length.	Medium5	RecursionMath+1	No attempts yet	1s	1024 MB	Judgeable
Adjacent PairsGiven a good array (no equal adjacent elements), find the fewest element changes so that exactly two distinct values remain and the array stays good.	Medium5	Hash mapArray+1	No attempts yet	3s	1024 MB	Judgeable
Nice SubsetGiven N integers from 2 to 1e9, pick ceil(N/2) of them that share a common divisor greater than 1, or report that no such subset exists.	Medium5	Number theoryProbability+1	No attempts yet	1s	1024 MB	Judgeable
Suffix OperationsGiven an array, find the fewest suffix increment or decrement operations needed to make all elements equal, after optionally changing one element to any value.	Medium5	ArrayPrefix sum+1	No attempts yet	1s	512 MB	Judgeable
White LinesGiven an n by n grid of black and white cells, paint one k by k square white to maximize the number of fully white rows and columns.	Medium5	Prefix sumMatrix+1	No attempts yet	1.5s	256 MB	Judgeable
Compress WordsMerge the words left to right, removing the longest prefix of each new word that matches a suffix of the result, then print the final word.	Medium5	StringString matching	No attempts yet	1s	256 MB	Judgeable
Relative Pitch Song SearchGiven N songs of note values and a melody, list the indices of songs that contain the melody at any constant pitch offset, or print -1.	Medium5	String matchingArray	No attempts yet	1s	1024 MB	Judgeable
Function Sequence and QueriesGiven n permutations of 1 to 5, each query updates one permutation so the composition over a range matches a target, then prints the new permutation.	Medium5	Segment treeArray+1	No attempts yet	2s	1024 MB	Judgeable
SnakeGiven an n by m grid, find the longest snake whose head and tail stay adjacent, which is the longest cycle that fits in the grid.	Medium5	MathImplementation	No attempts yet	1s	1024 MB	Judgeable
Drawing a SnakeGiven an n by m grid, find the longest snake that can stay stable with its head and tail adjacent, and print one placement of its cells.	Medium5	ImplementationMath+1	No attempts yet	1s	1024 MB	Judgeable
Hitting TargetsGiven a thrower's position and n integer targets, find the maximum number of targets one horizontally thrown parabolic ball can hit.	Medium5	Hash mapMath	No attempts yet	1s	1024 MB	Judgeable
Bead SortGiven n positive integers, find the total number of cells all beads fall in bead sort, modulo 1000000007.	Medium5	SortingMath	No attempts yet	2s	1024 MB	Judgeable
Hanging a BannerGiven N values, determine whether some window of M consecutive values contains at least ceil(0.9M) copies of one value.	Medium5	Hash mapTwo pointers+1	No attempts yet	1s	1024 MB	Judgeable
CheeseEach shop sells a bundle of two cheeses for a set price. Find the cheapest set of bundles that covers all N cheese kinds at least once.	Medium5	GraphDynamic programming	No attempts yet	1s	1024 MB	Judgeable
CanalChoose one vertical cut between two adjacent columns to minimize the total number of same-elevation connected regions on both sides.	Medium5	Union-findGraph+1	No attempts yet	2s	1024 MB	Judgeable
Find and ReplaceGiven an input and an output string, find the fewest letter-replace keystrokes that turn one into the other, or -1 if impossible.	Medium5	GraphDFS	No attempts yet	2s	1024 MB	Judgeable
Air Conditioning IIPick a subset of air conditioners with the lowest total running cost so that every cow's stalls get at least its required cooling.	Medium5	Brute forceBit manipulation	No attempts yet	2s	1024 MB	Judgeable
ICPC AdvertisementCount fillings of the '?' cells in an n by m grid with C, I, P so that some 2x2 block reads IC over PC, modulo 998244353.	Medium5	Dynamic programmingMatrix	No attempts yet	1s	1024 MB	Judgeable
AlchemyFind the fewest operations, each changing two adjacent letters to new values, that turn a lowercase string of length up to 100 into a palindrome.	Medium5	StringGreedy	No attempts yet	1s	1024 MB	Judgeable
Chocolate Chip FabricationGiven a grid cookie shape, find the minimum number of chocolate chip exposures needed to chipify every cookie square.	Medium5	BFSMatrix	No attempts yet	1s	1024 MB	Judgeable
Distinct Parity ExcessFor each range [a, b] with b up to 10^7, compute the count of integers with an even number of distinct prime factors minus the count with an odd number.	Medium5	Number theoryPrefix sum	No attempts yet	3s	1024 MB	Judgeable
Family VisitsGiven daily mess and cleaning capacities and the visit days, find the fewest afternoons of cleaning so the room is clean at every visit, or -1 if impossible.	Medium5	GreedyHeap	No attempts yet	2s	1024 MB	Judgeable
Repetitive SongGiven n words, find the longest word subsequence that can be matched by two different index tuples, or print 0 if none exists.	Medium5	Hash mapImplementation+1	No attempts yet	1s	1024 MB	Judgeable
Another Wine Tasting EventGiven a string of 2n-1 R and W bottles, find a count x so that n distinct intervals of length at least n each contain exactly x white bottles.	Medium5	Prefix sumImplementation	No attempts yet	0.5s	1024 MB	Judgeable
A Musical QuestionPick songs for two CDs of capacity c minutes each to maximize total playing time, breaking ties by the smallest gap between the two CDs.	Medium5	Dynamic programmingArray	No attempts yet	11s	1024 MB	Judgeable
It's About TimeGiven a planet's orbit radius, orbital speed, and day length, find leap-year divisors n1 < n2 < n3 <= 1000 that best approximate its year.	Medium5	Brute forceMath+1	No attempts yet	1s	1024 MB	Judgeable
Two Charts Become OneGiven two nested department charts as text, decide whether they show the same hierarchy when the order of sibling departments is ignored.	Medium5	TreeSorting+1	No attempts yet	1s	1024 MB	Judgeable
Sum of Three CubesGiven N below 50, print three integers whose cubes sum to N, or print 0 if no such triple exists.	Medium5	Number theoryImplementation	No attempts yet	1s	1024 MB	Judgeable
Wooden FenceDecide whether N boards of given lengths, each used exactly once, can tile a rectangular fence of height 2 without overlap.	Medium5	Dynamic programmingMath+1	No attempts yet	2s	1024 MB	Judgeable
Tennis GameGiven K, S, and N, decide whether a match of S sets, each won with at least K games and a 2-game lead, can total exactly N games.	Medium5	MathImplementation	No attempts yet	1s	1024 MB	Judgeable
Judicious cuts (Easy)Given n, output lines y = mx + b (at most 1000 lines, coefficients within 10000) that split the plane into exactly n regions.	Medium5	MathGreedy+1	No attempts yet	1s	1024 MB	Judgeable
Inchworm CutCount the ways to split an array into head, chest, and abdomen segments whose sums satisfy head < abdomen < chest.	Medium5	Prefix sumTwo pointers+1	No attempts yet	1s	1024 MB	Judgeable
ABMaintain string sets A and B with add and delete, and count ways to write a query string as a prefix of an A element joined with a suffix of a B element.	Medium5	Hash mapString+1	No attempts yet	2s	1024 MB	Judgeable
ExamChoose K of N exams, where exam i has P_i correct answers out of Q_i questions, to maximize the sum of P divided by the sum of Q.	Medium5	Binary searchSorting+1	No attempts yet	2s	1024 MB	Judgeable
Ferries (Easy)Given 2n cars and the positions your car must hold in order, find the fewest L/R ferry crossings that produce them and output one such string.	Medium5	BFSGraph+1	No attempts yet	1s	1024 MB	Judgeable
Kill switchGiven C++ and Python versions of a sorting function with a hidden trigger, find the shortest array of 32-bit unsigned integers it fails to sort.	Medium5	ImplementationBrute force	No attempts yet	1s	1024 MB	Judgeable
Turning gears (hard)Given circles whose touching pairs form a tree, find the speed and direction of gear n when gear 1 turns clockwise at 1 revolution per second.	Medium5	GraphBFS+1	No attempts yet	2s	1024 MB	Judgeable
A+BRearrange the given digits into two numbers without leading zeros so that their sum is as large as possible, and print that sum.	Medium5	GreedySorting+1	No attempts yet	1s	1024 MB	Judgeable
CellsGiven formulas with cell references and the operators + - * /, compute every cell's value and print them sorted by cell name.	Medium5	StringHash map+1	No attempts yet	1s	1024 MB	Judgeable
Dragon SlayerGiven a dragon with N heads and two swords (c, g), decide whether the prince can kill it and survive, can only kill it while dying (DRAW), or cannot kill it.	Medium5	BFSGraph+1	No attempts yet	1s	1024 MB	Judgeable
Amazing MobistudyGiven agreement graphs from three studies on N employees, find every group of two or more employees who share the same connected component in all three.	Medium5	Union-findHash map	No attempts yet	1s	256 MB	Judgeable
Cowherd and Weaver GirlGiven two weighted trees, pick one vertex from each and join them with a unit edge to minimize the sum of distances over all cross pairs.	Medium5	TreeDFS+1	No attempts yet	1s	1024 MB	Judgeable
Sequence RearrangementGiven a permutation of 1 to N, rearrange one window of K consecutive elements so the longest contiguous increasing run is as long as possible, then print its length.	Medium5	ArraySorting+1	No attempts yet	2s	512 MB	Judgeable
Shift OperationsGiven a 0/1 sequence, find the fewest L-shifts and R-shifts that turn every element into 0, and print the operation string.	Medium5	GreedySimulation	No attempts yet	2s	512 MB	Judgeable
World Cup Group StageGiven a group table with one missing score for team T, find the smallest goal count that lets T finish in the top two, or -1 if none exists up to K.	Medium5	Binary searchImplementation+1	No attempts yet	2s	512 MB	Judgeable
Saving the universe againGiven a C/S program and a damage limit D, find the fewest adjacent instruction swaps that bring total shot damage to D or less.	Medium5	StringGreedy+1	No attempts yet	20s	1024 MB	Judgeable
Trouble SortGiven a list processed by Trouble Sort, report whether the result is in non-decreasing order, or the index of the first value larger than its successor.	Medium5	SortingArray	No attempts yet	Not set	1024 MB	Judgeable
Waffle ChoppersGiven a grid of chocolate chips, decide whether H horizontal and V vertical cuts can split it into (H+1)(V+1) pieces with equal chip counts.	Medium5	Prefix sumMath+1	No attempts yet	6s	1024 MB	Judgeable
Bit PartyGiven robots and cashiers with capacity, scan time, and fixed fee, find the earliest time all robots can finish after splitting the bits among them.	Medium5	Binary searchSorting+1	No attempts yet	15s	1024 MB	Judgeable
Rounding ErrorGiven vote counts so far in a survey of N people, find the largest possible sum of rounded percentages after the remaining people respond.	Medium5	GreedyMath	No attempts yet	10s	1024 MB	Judgeable
Ant StackGiven ants listed by increasing length with their weights, find the largest stack where each ant carries at most 6 times its own weight above it.	Medium5	Dynamic programmingGreedy	No attempts yet	15s	1024 MB	Judgeable
Alien RhymeEach word gets one accented suffix, and the task is to find the most words that can form pairs sharing equal suffixes, with no suffix reused across pairs.	Medium5	TrieGreedy+1	No attempts yet	20s	1024 MB	Judgeable
Pattern MatchingGiven N wildcard patterns where * matches any string, find one name of at most 10^4 letters that matches all of them, or print * if none exists.	Medium5	StringString matching+1	No attempts yet	20s	1024 MB	Judgeable
Square DanceRepeatedly eliminate dancers whose skill is below the average of their nearest neighbors in four directions, and sum the skills over all rounds.	Medium5	SimulationLinked list+1	No attempts yet	40s	1024 MB	Judgeable
Cow-libiGiven grazing spots with times and cow alibis with locations and times, count the alibis that make it impossible for the cow to reach every grazing at speed 1.	Medium5	SortingBinary search+1	No attempts yet	4s	1024 MB	Judgeable
Watching MoolooGiven N watch days, find the minimum total cost of subscriptions where a subscription of length d costs d plus K and must cover every watch day.	Medium5	Dynamic programmingIntervals+1	No attempts yet	1s	1024 MB	Judgeable
Crane OperatorCount the fewest box moves needed to turn the identity layout into a target layout built by open-addressing probes, using one empty slot.	Medium5	Hash mapImplementation+1	No attempts yet	1s	1024 MB	Judgeable
Sum of RemaindersGiven S_K(1) to S_K(N) for an unknown multiset K of integers at least 2, recover K from these sums of remainders.	Medium5	Number theoryMath+1	No attempts yet	2s	1024 MB	Judgeable
Appearance of the RunoCount the ways to pick one item per category (four categories, N items each) so that none of the M forbidden item pairs is worn together.	Medium5	CombinatoricsBit manipulation+1	No attempts yet	2s	1024 MB	Judgeable
Gahui and the ILGAM lakeGiven a ring of 4n weighted points with three subway stations attached to every n-th point, find the distance from each queried point to its nearest station.	Medium5	ArrayPrefix sum+1	No attempts yet	1s	1024 MB	Judgeable
Gahee and the Subway Station Storage System 2For each request, find the nearest cache node, serve the station from its LRU cache or the bucket node, and print the round-trip time.	Medium5	Shortest pathSimulation+1	No attempts yet	1.5s	1024 MB	Judgeable
Gahee and Seoul Subway Line 3Count the ways to assign each of n stations a ground floor (5 choices) or underground floor (11 choices) so the longest alternating run has length m, modulo 1e9+7.	Medium5	Dynamic programmingImplementation	No attempts yet	1s	1024 MB	Judgeable
Gahui and the Subway Station Storage System 1Given stations and a stream of feature updates, count the stations that have all the features named in each query.	Medium5	Bit manipulationHash map+1	No attempts yet	2s	512 MB	Judgeable
Special student IDCount the paths from (0, 0) to (N-1, M-1) on a grid where runs move right or down and at most one portal teleport is allowed, modulo 10^9+7.	Medium5	Dynamic programmingMatrix	No attempts yet	1s	1024 MB	Judgeable
Special ServingGiven N values x_i, find the fewest students to switch from pamuntwi to eggplant so the running sum never reaches M.	Medium5	GreedyHeap	No attempts yet	1s	512 MB	Judgeable
Special Fire AlarmGiven a permutation and at most L adjacent swaps, find the maximum number of inversions that can be reached.	Medium5	GreedyArray	No attempts yet	1s	512 MB	Judgeable
2D Paper PlayFor each block, count the sheets with w at least x and h at least y, then answer each query by counting blocks whose count falls in [L, U].	Medium5	SortingPrefix sum+1	No attempts yet	3s	512 MB	Judgeable
Apartment ComplexesSplit sorted apartment positions into consecutive groups of at least M, each spanning at most X, and answer each query X.	Medium5	Binary searchDynamic programming+1	No attempts yet	1.5s	1024 MB	Judgeable