Interview core

Mediums from real onsites

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Total results3,617 problems

TOLLS
Medium5
Union-find, Sorting+1
No attempts yet
Time limit
0.25s
Memory limit
1024 MB
Judgeable
Rhythm Flow
Medium5
Dynamic programming, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Grade Conversion 2
Medium5
Prefix sum, Greedy
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Raehwan's Course Registration
Medium5
Bit manipulation, Hash map+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Skokovi
Medium5
Dynamic programming, Segment tree
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Giganotosaurus Game
Medium5
Dynamic programming, Array+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Buggy Blinkers
Medium5
BFS, Graph+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Interrail Pass
Medium5
Dynamic programming, Binary search
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Museum Visit
Medium5
Dynamic programming, Intervals+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Hunting the Mavericks
Medium5
Prefix sum, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Card Flipping Game
Medium5
Array, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
One-Sided Love
Medium5
Graph, DFS
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Partition
Medium5
Array, Number theory+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Two Stacks
Medium5
Prefix sum, Two pointers+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
A_i \times A_j
Medium5
Array, Sorting+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Two Decks
Medium5
Prefix sum, Brute force+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
The Labyrinth with Changing Exits
Medium5
Graph, Shortest path+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Find the Root of the Tree
Medium5
Tree, DFS
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Guard Evaders
Medium5
Brute force, Simulation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Grades
Medium5
Matrix, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
End-Balanced Subarrays
Medium5
Prefix sum, Hash map
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Illuminated Lights II
Medium5
Dynamic programming, String
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Dutch Pay
Medium5
Sorting, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Intergalactic Team
Medium5
Graph, Union-find
No attempts yet
Time limit
3s
Memory limit
2048 MB
Judgeable
Pianissimo
Medium5
Sorting, Array
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Unskippable subway game
Medium5
Game theory, Array+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Comso Christmas
Medium5
Greedy, Sorting+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Sequence and Queries HY
Medium5
Array, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Nayeon Sort
Medium5
Array, Binary search+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Maximum Submatrix Sum
Medium5
Dynamic programming, Prefix sum+1
No attempts yet
Time limit
0.2s
Memory limit
1024 MB
Judgeable
Evolving Etymology
Medium5
Math, Number theory+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Minimization by Swaps
Medium5
Greedy, Queue+1
No attempts yet
Time limit
2s
Memory limit
2048 MB
Judgeable
Magnet Play
Medium5
Dynamic programming, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Strange Operation
Medium5
Math, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
U, Our Star!
Medium5
Dynamic programming, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Morning Routine and Roll Call
Medium5
Dynamic programming, Array
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Choosing Chopsticks
Medium5
Binary search, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Strange Grid
Medium5
Sorting, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Fun Pipe Puzzle
Medium5
Dynamic programming, Greedy+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
The Sparsest Number in Between
Medium5
Bit manipulation, Greedy+1
No attempts yet
Time limit
2s
Memory limit
2048 MB
Judgeable
Odd and Even Game
Medium5
Game theory, Dynamic programming
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Fix Flooded Floor
Medium5
Dynamic programming, Implementation
No attempts yet
Time limit
3s
Memory limit
2048 MB
Judgeable
Mahjong Giant Robot 1
Medium5
Math, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Job Completion
Medium5
Greedy, Sorting+1
No attempts yet
Time limit
2s
Memory limit
2048 MB
Judgeable
Double Derangement
Medium5
Dynamic programming, Bit manipulation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Powers of Two
Medium5
Bit manipulation, Math+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Plus or Times
Medium5
Dynamic programming, Implementation
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Horse Carts
Medium5
Greedy, Heap+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Double Chunks
Medium5
Dynamic programming, Hash map
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Counting DFS Trees
Medium5
Dynamic programming, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Feng Shui
Medium5
Array, Greedy
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Star Wars
Medium5
Dynamic programming, Matrix
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Conference Rides
Medium5
Binary search, Graph
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Old Orhei
Medium5
Segment tree, Array
No attempts yet
Time limit
3s
Memory limit
2048 MB
Judgeable
AI Armagedon
Medium5
Greedy, Array+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Bitcoin Bubble
Medium5
Stack, Prefix sum+1
No attempts yet
Time limit
2s
Memory limit
2048 MB
Judgeable
Coatis and Owls
Medium5
Simulation, Stack+1
No attempts yet
Time limit
2s
Memory limit
2048 MB
Judgeable
Efficient Grading
Medium5
Greedy, Math
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Family Tree
Medium5
Tree, BFS
No attempts yet
Time limit
3s
Memory limit
2048 MB
Judgeable
Sangheon's Course Registration Challenge
Medium5
Dynamic programming, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Centrifuge
Medium5
Tree, DFS+1
No attempts yet
Time limit
1.5s
Memory limit
2048 MB
Judgeable
Periodic Sequence
Medium5
String, String matching
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Scheduling
Medium5
Greedy, Heap+1
No attempts yet
Time limit
3s
Memory limit
2048 MB
Judgeable
Remove Exactly Two
Medium5
Tree, Greedy+1
No attempts yet
Time limit
2s
Memory limit
2048 MB
Judgeable
The Interview Problem
Medium5
Greedy, String+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Make a Palindrome
Medium5
Hash map, String+1
No attempts yet
Time limit
2s
Memory limit
2048 MB
Judgeable
Easily Broadcastable Tensors
Medium5
Dynamic programming, Array
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Benzinska
Medium5
Greedy, Heap
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Art Class
Medium5
Geometry, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Painting Exchange
Medium6
Dynamic programming, Bit manipulation+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Fractal Plane
Medium6
Divide and conquer, Recursion+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Park Seongwon's Probability
Medium6
Dynamic programming, Bit manipulation+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Card Shuffling
Medium6
Array, Math+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Power Plants
Medium6
Dynamic programming, Bit manipulation+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Building a Swimming Pool
Medium6
Heap, BFS+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
News Broadcast
Medium6
Tree, DFS+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Delivery
Medium6
BFS, Shortest path+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Jewel Thief
Medium6
Greedy, Heap+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Making Roads One-Way
Medium6
Graph, DFS+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Making a Number
Medium6
Greedy, String+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Largest Zero Submatrix
Medium6
Stack, Dynamic programming+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Histogram
Medium6
Stack, Array+1
No attempts yet
Time limit
0.7s
Memory limit
128 MB
Judgeable
Maximum Submatrix Sum
Medium6
Dynamic programming, Matrix+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Cup Ramen
Medium6
Greedy, Heap+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Strange Keyboard
Medium6
Dynamic programming, Greedy+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Refueling
Medium6
Greedy, Heap+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Ball Replacement
Medium6
Greedy, Simulation+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Lecture Tour
Medium6
Greedy, Union-find+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Building a Human Tower
Medium6
Greedy, Sorting
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
GPS Encoding
Medium6
Dynamic programming, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Phone Number Mnemonics
Medium6
Dynamic programming, String matching+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Representative Players
Medium6
Heap, Greedy+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Hexagonal Puzzle
Medium6
BFS, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
New Language Alphabet Order
Medium6
Topological sort, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Number Circle
Medium6
Math, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
An Arithmetic Rectangle
Medium6
Math, Matrix+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Key Task
Medium6
BFS, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Copying Books
Medium6
Binary search, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Random Walk
Medium6
Dynamic programming, Probability+1
No attempts yet
Time limit
10s
Memory limit
128 MB
Judgeable
Genetic Fraud
Medium6
String, Two pointers+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
TOLLSFor each query [l, r], sum the costs of all city pairs whose path's largest toll falls in [l, r], where the cost is that largest toll.	Medium5	Union-findSorting+1	No attempts yet	0.25s	1024 MB	Judgeable
Rhythm FlowMatch expected and actual presses in order, each at most once, to maximize the total points, where each pair scores 7, 6, 4, 2, or 0 based on the time gap.	Medium5	Dynamic programmingArray	No attempts yet	1s	1024 MB	Judgeable
Grade Conversion 2Given the new grades b, recover old grades a that produce them under the averaging rule, or print -1 if no such sequence exists.	Medium5	Prefix sumGreedy	No attempts yet	2s	1024 MB	Judgeable
Raehwan's Course RegistrationGiven each student's enrollments in S_1 to S_{N-1}, count the subsets of students for S_N that keep every student's course set nonempty and distinct.	Medium5	Bit manipulationHash map+1	No attempts yet	1s	1024 MB	Judgeable
SkokoviGiven flower heights and a limit K, mark which flowers a grasshopper can reach from the first one by jumping only rightward to flowers whose height differs by at most K.	Medium5	Dynamic programmingSegment tree	No attempts yet	5s	1024 MB	Judgeable
Giganotosaurus GameCount the ways to cross a row of n cells with cactus obstacles, moving one cell right or jumping over k cells on the kth jump, modulo 1e9+7.	Medium5	Dynamic programmingArray+1	No attempts yet	1s	1024 MB	Judgeable
Buggy BlinkersFind the shortest route from intersection 1 to intersection n when the blinkers can be switched on at most k times and each turn needs its matching blinker.	Medium5	BFSGraph+1	No attempts yet	4s	1024 MB	Judgeable
Interrail PassGiven travel days with individual fares and pass types that cover the first d travel days of a p-day window, find the minimum total cost to cover all travel days.	Medium5	Dynamic programmingBinary search	No attempts yet	1s	1024 MB	Judgeable
Museum VisitChoose visit days with the smallest total discomfort so that every exhibition's day range contains at least one chosen day.	Medium5	Dynamic programmingIntervals+1	No attempts yet	4s	1024 MB	Judgeable
Hunting the MavericksChoose a starting level on a circle of n levels so that the number of armour upgrades whose unlock weapon is obtained after the upgrade's level is minimized.	Medium5	Prefix sumArray	No attempts yet	1s	1024 MB	Judgeable
Card Flipping GameGiven N cards with colors 0 or 1, flip the prefix of cards 1 through X at most once to find the longest run of equal colors.	Medium5	ArrayPrefix sum+1	No attempts yet	1s	1024 MB	Judgeable
One-Sided LoveFor each node x other than 1, decide whether two paths from node 1 to x share no node besides 1 and x, and output a binary string.	Medium5	GraphDFS	No attempts yet	2s	1024 MB	Judgeable
PartitionGiven an integer array, decide whether it can be cut into equal-length contiguous segments (each shorter than N) where every segment has the same minimum plus maximum.	Medium5	ArrayNumber theory+1	No attempts yet	1s	1024 MB	Judgeable
Two StacksGiven two stacks of item weights, remove at most K top items in total to minimize the weight of the heavier remaining backpack.	Medium5	Prefix sumTwo pointers+1	No attempts yet	1s	1024 MB	Judgeable
A_i \times A_jGiven an array, pick two different elements, replace both with their product, and find the maximum array sum possible with at most one such operation.	Medium5	ArraySorting+2	No attempts yet	1s	1024 MB	Judgeable
Two DecksWonbin removes at most K items from the top or bottom of two stacks to minimize the weight of the heavier backpack he is left carrying.	Medium5	Prefix sumBrute force+1	No attempts yet	1s	1024 MB	Judgeable
The Labyrinth with Changing ExitsFind the shortest time Hyungjin needs to start at vertex 1 and leave through an exit that is open when he reaches it, where exits open in turn every K seconds.	Medium5	GraphShortest path+1	No attempts yet	1s	1024 MB	Judgeable
Find the Root of the TreeGiven an unrooted tree and the fact that LCA(a, b) = x for the unknown root, count the vertices that could be that root.	Medium5	TreeDFS	No attempts yet	1s	1024 MB	Judgeable
Guard EvadersGiven the initial facing of each guard and the number of players, decide whether every player can slip through a gap between two guards without being caught.	Medium5	Brute forceSimulation	No attempts yet	1s	1024 MB	Judgeable
GradesGiven an N by N grid of scores, find the largest pocket money left after deleting one rectangular sub-table, where each score adds (score minus 50).	Medium5	MatrixDynamic programming+1	No attempts yet	1s	1024 MB	Judgeable
End-Balanced SubarraysCount the subarrays with l < r where the sum of the two endpoint elements equals the sum of the elements strictly between them.	Medium5	Prefix sumHash map	No attempts yet	1s	1024 MB	Judgeable
Illuminated Lights IICount the subsets of lights, each pointing L or R, that illuminate every light in the row, modulo 1e9+7.	Medium5	Dynamic programmingString	No attempts yet	1s	1024 MB	Judgeable
Dutch PaySplit each dish's price evenly among the diners present at its order time, then output the average amount paid per person.	Medium5	SortingPrefix sum+1	No attempts yet	1s	1024 MB	Judgeable
Intergalactic TeamGiven directed wish lists, count the teams of exactly k competitors where every pair names each other and mutual pairs stay together.	Medium5	GraphUnion-find	No attempts yet	3s	2048 MB	Judgeable
PianissimoGiven each note's played power and the sheet's dynamic markings, count the unordered pairs of notes with different dynamics whose power order breaks the dynamic order.	Medium5	SortingArray	No attempts yet	1s	2048 MB	Judgeable
Unskippable subway gameGiven N stations where some are transfer stops, two players take turns advancing a subway model, and whoever places it at station N wins. Find the winner.	Medium5	Game theoryArray+1	No attempts yet	1s	1024 MB	Judgeable
Comso ChristmasDecide if N problems, each needing s_i wrong answers before its accepted verdict, can be submitted so that verdicts alternate, starting with Accepted.	Medium5	GreedySorting+1	No attempts yet	2s	1024 MB	Judgeable
Sequence and Queries HYGiven a sequence A of length N, answer each query m by printing the minimum and maximum of the remainders A_i mod m, with m up to 300000.	Medium5	ArrayMath+1	No attempts yet	2s	1024 MB	Judgeable
Nayeon SortGiven an array, find the minimum number of stacks needed to sort it in ascending order using Nayeon sort.	Medium5	ArrayBinary search+1	No attempts yet	2s	1024 MB	Judgeable
Maximum Submatrix SumGiven an N by M integer matrix, find the maximum sum of any contiguous rectangular submatrix, where the empty submatrix counts as 0.	Medium5	Dynamic programmingPrefix sum+1	No attempts yet	0.2s	1024 MB	Judgeable
Evolving EtymologyGiven a word s of length n, apply the every-second-letter transform k times (k up to 10^18) and print the resulting word.	Medium5	MathNumber theory+1	No attempts yet	1s	1024 MB	Judgeable
Minimization by SwapsGiven a digit string s and at most k swaps of adjacent digits, find the smallest number that can be formed.	Medium5	GreedyQueue+1	No attempts yet	2s	2048 MB	Judgeable
Magnet PlayFind the maximum sum of card values a magnet can collect on a 2xN grid while moving from the top-left to the bottom-right cell, counting each card once.	Medium5	Dynamic programmingArray	No attempts yet	1s	1024 MB	Judgeable
Strange OperationEach operation sets one element to the negative of the current sum; find the maximum sum reachable by repeating it.	Medium5	MathArray	No attempts yet	1s	1024 MB	Judgeable
U, Our Star!Given products with limited counts and prices, find the smallest payment that maximizes points, where points are floor(payment / X) times Y, capped at D.	Medium5	Dynamic programmingMath	No attempts yet	1s	1024 MB	Judgeable
Morning Routine and Roll CallChoose actions whose stage prerequisites are met and whose total time is at most T, then output the maximum total satisfaction.	Medium5	Dynamic programmingArray	No attempts yet	1.5s	1024 MB	Judgeable
Choosing ChopsticksGiven N colors with A_i chopsticks each, find the minimum number X of chopsticks that guarantees K same-color pairs for any selection, or print -1 if no X works.	Medium5	Binary searchGreedy+1	No attempts yet	1s	1024 MB	Judgeable
Strange GridGiven N people on a grid where each direction has its own movement cost, find the minimum total cost for everyone to gather at one cell.	Medium5	SortingPrefix sum+1	No attempts yet	1s	1024 MB	Judgeable
Fun Pipe PuzzleGiven a 2-row grid of I and L pipes, decide whether rotating them can connect a path from cell (1, 1) to cell (2, N).	Medium5	Dynamic programmingGreedy+1	No attempts yet	1s	2048 MB	Judgeable
The Sparsest Number in BetweenGiven positive integers a and b with a at most b, find the integer in that range with the fewest 1 bits in binary, choosing the smallest if there is a tie.	Medium5	Bit manipulationGreedy+1	No attempts yet	2s	2048 MB	Judgeable
Odd and Even GameTwo players alternately take cards, and after each player's first card, every card they take must share its parity. Determine the winner under optimal play.	Medium5	Game theoryDynamic programming	No attempts yet	1s	1024 MB	Judgeable
Fix Flooded FloorGiven a 2xn grid where '#' marks blocked cells and '.' marks empty cells, decide if the empty cells have exactly one, multiple, or no tilings with 1x2 dominoes.	Medium5	Dynamic programmingImplementation	No attempts yet	3s	2048 MB	Judgeable
Mahjong Giant Robot 1Fill an H by W grid with C ones and D nines so every row sum is strictly larger than the row above it, or report -1 if that is impossible.	Medium5	MathGreedy+1	No attempts yet	1s	1024 MB	Judgeable
Job CompletionGiven jobs with start deadlines s_i and durations t_i, find the most jobs that can be finished when they run one at a time from time 0.	Medium5	GreedySorting+1	No attempts yet	2s	2048 MB	Judgeable
Double DerangementGiven two permutations a and b of length N (up to 16), count the permutations c where c_i differs from both a_i and b_i at every index.	Medium5	Dynamic programmingBit manipulation	No attempts yet	1s	1024 MB	Judgeable
Powers of TwoStarting from N = 0, apply Q queries that add or subtract a power of two, and print YES after each query where N is 0.	Medium5	Bit manipulationMath+1	No attempts yet	1s	2048 MB	Judgeable
Plus or TimesGiven a starting value P and N rounds where each round offers either adding c or multiplying by c, find the maximum final value.	Medium5	Dynamic programmingImplementation	No attempts yet	1s	2048 MB	Judgeable
Horse CartsGiven N treasures with weights and values and M carts with weight limits, each cart carries one treasure, so find the maximum total value you can take.	Medium5	GreedyHeap+1	No attempts yet	1s	2048 MB	Judgeable
Double ChunksSplit an array of N chunk values into consecutive pieces so all two-chunk pieces share one sum, and find the maximum number of such pieces.	Medium5	Dynamic programmingHash map	No attempts yet	1s	2048 MB	Judgeable
Counting DFS TreesCount the distinct preorder depth sequences of trees with n nodes whose leaves all sit at depth K, then multiply f(A_i) for all queries modulo 998244353.	Medium5	Dynamic programmingPrefix sum+1	No attempts yet	1s	2048 MB	Judgeable
Feng ShuiGiven a permutation of 1 to N, find the minimum number of adjacent swaps to make it decrease and then increase.	Medium5	ArrayGreedy	No attempts yet	1s	2048 MB	Judgeable
Star WarsPick one white piece on a grid so that, moving up one row at a time without landing on other white pieces, it captures the most black pieces.	Medium5	Dynamic programmingMatrix	No attempts yet	1s	2048 MB	Judgeable
Conference RidesAssign each carless attendee to one driver so that the time until every attendee reaches home is minimized.	Medium5	Binary searchGraph	No attempts yet	1s	2048 MB	Judgeable
Old OrheiWalk a one-way graph by the edge indices in a range of an array, answering range queries for the final vertex and supporting point updates.	Medium5	Segment treeArray	No attempts yet	3s	2048 MB	Judgeable
AI ArmagedonGiven the order in which T-shirts arrive for K piles, find the fewest times the script must move off a pile that is about to receive a shirt.	Medium5	GreedyArray+1	No attempts yet	1s	2048 MB	Judgeable
Bitcoin BubbleGiven price segments of consecutive days, find the maximum of the longest window around a day x where no price drops below the price on x, times that price.	Medium5	StackPrefix sum+1	No attempts yet	2s	2048 MB	Judgeable
Coatis and OwlsCoati and owl squads meet in a line, and each fight costs the winner ceil(l^2/w) pikemen. Simulate the battles and report the winning army and its remaining size.	Medium5	SimulationStack+1	No attempts yet	2s	2048 MB	Judgeable
Efficient GradingGiven n exams and a time t per grading or training step, find the minimum total time to grade all exams and the fewest graders needed to meet it.	Medium5	GreedyMath	No attempts yet	1s	2048 MB	Judgeable
Family TreeGiven a family tree of n people, find the minimum width of a drawing where children sit one level below parents and pictures in a level may shift sideways.	Medium5	TreeBFS	No attempts yet	3s	2048 MB	Judgeable
Sangheon's Course Registration ChallengeGiven N courses with preference and credits, choose a subset of at least one course with total credits at most M that maximizes total preference, and print the chosen indices.	Medium5	Dynamic programmingArray	No attempts yet	1s	1024 MB	Judgeable
CentrifugeGiven a tree with fluid in each node, find each node's expected final fluid when a random node is the center and fluid flows outward, mod 998244353.	Medium5	TreeDFS+1	No attempts yet	1.5s	2048 MB	Judgeable
Periodic SequenceGiven two repeating digit blocks, decide whether one can match the other after repetition and cyclic shifting.	Medium5	StringString matching	No attempts yet	1s	2048 MB	Judgeable
SchedulingGiven n meetings with time windows, find integer start times so each one-hour meeting has at least one hour free before and after, or report -1 if impossible.	Medium5	GreedyHeap+1	No attempts yet	3s	2048 MB	Judgeable
Remove Exactly TwoGiven a tree, remove exactly two vertices (each with its incident edges) to find the maximum number of connected components that remain.	Medium5	TreeGreedy+1	No attempts yet	2s	2048 MB	Judgeable
The Interview ProblemGiven a string of brackets and digits, can each digit delete that many earlier characters so the remaining brackets form a balanced sequence?	Medium5	GreedyString+1	No attempts yet	1s	2048 MB	Judgeable
Make a PalindromeGiven a lowercase string, decide whether swapping characters two positions apart can turn it into a palindrome.	Medium5	Hash mapString+1	No attempts yet	2s	2048 MB	Judgeable
Easily Broadcastable TensorsFind the fewest 1s to insert into two size lists so that, aligned from the right, every overlapping pair is equal or contains a 1.	Medium5	Dynamic programmingArray	No attempts yet	1s	2048 MB	Judgeable
BenzinskaFind the fewest restaurants Malnar must dine at to cycle from x=0 to x=X with starting energy D without energy going negative, or -1 if impossible.	Medium5	GreedyHeap	No attempts yet	1s	2048 MB	Judgeable
Art ClassGiven N points above the x-axis, count the distinct intersection points of the slope +1 and slope -1 lines drawn through them, on or above the axis.	Medium5	GeometrySorting+1	No attempts yet	1s	1024 MB	Judgeable
Painting ExchangeGiven who can sell to whom at what price, find the longest chain of distinct buyers starting from artist 1 where each resale price never drops below the purchase price.	Medium6	Dynamic programmingBit manipulation+2	No attempts yet	2s	128 MB	Judgeable
Fractal PlanePrint a rectangular window of the grid at time s, where each step splits every cell into N x N and blacks out a centered K x K block.	Medium6	Divide and conquerRecursion+2	No attempts yet	2s	128 MB	Judgeable
Park Seongwon's ProbabilityCount permutations of up to 15 numbers whose concatenation is divisible by K, and output the probability as a reduced fraction.	Medium6	Dynamic programmingBit manipulation+2	No attempts yet	2s	128 MB	Judgeable
Card ShufflingGiven a permutation of card positions and a target assignment of each card to a player, find the minimum number of shuffles so every card reaches its target player, or -1.	Medium6	ArrayMath+2	No attempts yet	2s	128 MB	Judgeable
Power PlantsGiven restart costs between plants and which plants are already on, find the minimum total cost to reach at least P working plants, or -1.	Medium6	Dynamic programmingBit manipulation+2	No attempts yet	2s	128 MB	Judgeable
Building a Swimming PoolGiven an N by M grid of pillar heights 1 to 9, count the total water trapped on top after water flows off any path to the outside.	Medium6	HeapBFS+2	No attempts yet	2s	128 MB	Judgeable
News BroadcastGiven a rooted tree, each informed employee calls one subordinate at a time, each call lasting one minute; find the minimum time until every employee knows the news.	Medium6	TreeDFS+2	No attempts yet	2s	128 MB	Judgeable
DeliveryFind the minimum moves in a grid from a start cell to visit two target cells, forbidding two consecutive moves in the same direction.	Medium6	BFSShortest path+2	No attempts yet	2s	128 MB	Judgeable
Jewel ThiefGiven N jewels with weight and value and K bags with weight limits (one jewel per bag), maximize total value stolen using a greedy plus max-heap approach.	Medium6	GreedyHeap+1	No attempts yet	1s	256 MB	Judgeable
Making Roads One-WayDecide if every two-way road between N cities can be made one-way so that no directed cycle remains in the whole road network.	Medium6	GraphDFS+1	No attempts yet	2s	128 MB	Judgeable
Making a NumberGiven how many cards exist for each digit 0-9, build the largest possible number using some or all cards so that no two adjacent digits match and no leading zero appears.	Medium6	GreedyString+1	No attempts yet	2s	128 MB	Judgeable
Largest Zero SubmatrixGiven a binary matrix, find the maximum area rectangle of consecutive rows and columns that contains only zeros.	Medium6	StackDynamic programming+2	No attempts yet	2s	128 MB	Judgeable
HistogramGiven bar heights of a histogram, find the maximum-area rectangle that fits inside it using a stack-based approach.	Medium6	StackArray+1	No attempts yet	0.7s	128 MB	Judgeable
Maximum Submatrix SumGiven an N by M integer matrix, find the maximum possible sum over all contiguous rectangular submatrices.	Medium6	Dynamic programmingMatrix+2	No attempts yet	2s	128 MB	Judgeable
Cup RamenGiven N jobs each taking one time unit with a deadline and a reward, choose which jobs to schedule to maximize total reward earned by finishing before deadlines.	Medium6	GreedyHeap+1	No attempts yet	2s	256 MB	Judgeable
Strange KeyboardGiven a string on a cursor-based keyboard, find the minimum Left/Right/Enter presses needed to print every character in alphabetical order.	Medium6	Dynamic programmingGreedy+2	No attempts yet	2s	128 MB	Judgeable
RefuelingFind the minimum number of gas station stops a truck must make, given starting fuel and station positions with fuel amounts, to reach a village on a line.	Medium6	GreedyHeap+1	No attempts yet	2s	128 MB	Judgeable
Ball ReplacementSimulate a 4-slot cache using an eviction strategy (like Belady's algorithm) that minimizes total insertions and replacements while processing a sequence of digit cards.	Medium6	GreedySimulation+1	No attempts yet	2s	128 MB	Judgeable
Lecture TourGiven jobs each with a fee and a deadline, schedule at most one job per day to maximize total fee collected before deadlines.	Medium6	GreedyUnion-find+1	No attempts yet	2s	128 MB	Judgeable
Building a Human TowerGiven weights and strengths of N acrobats, order them into a tower to minimize the maximum of (weight above - strength) over all acrobats.	Medium6	GreedySorting	No attempts yet	2s	128 MB	Judgeable
GPS EncodingGiven a letter permutation encoding numbers 0-25, find the shortest way to encode a digit string as letters using single digits or valid two-digit pairs, breaking ties by lexicographically largest result.	Medium6	Dynamic programmingGreedy+1	No attempts yet	1s	128 MB	Judgeable
Phone Number MnemonicsFind the minimum number of dictionary words whose digit encodings concatenate to exactly match a given phone number, using the letter to digit telephone mapping.	Medium6	Dynamic programmingString matching+1	No attempts yet	2s	128 MB	Judgeable
Representative PlayersGiven N classes each with M distinct scores, pick one student per class to minimize the range between the highest and lowest chosen scores.	Medium6	HeapGreedy+1	No attempts yet	2s	256 MB	Judgeable
Hexagonal PuzzleFind the shortest sequence of coin moves on a 7-cell hexagonal puzzle graph to restore each labeled coin to its matching outer cell, or report impossibility.	Medium6	BFSGraph+1	No attempts yet	1s	128 MB	Judgeable
New Language Alphabet OrderGiven a sorted list of words in an unknown alphabet, reconstruct the unique letter order or report impossibility or ambiguity.	Medium6	Topological sortGraph+1	No attempts yet	1s	128 MB	Judgeable
Number CircleGiven a circular array of sums of each element and its two neighbors, reconstruct one valid original positive-integer circular array.	Medium6	MathSimulation+1	No attempts yet	1s	128 MB	Judgeable
An Arithmetic RectangleDetermine whether missing cells in a grid can be filled with rationals so every row and column becomes an arithmetic progression.	Medium6	MathMatrix+1	No attempts yet	1s	128 MB	Judgeable
Key TaskFind the shortest path from a start cell to any exit in a grid maze where doors require previously collected matching keys.	Medium6	BFSBit manipulation+1	No attempts yet	1s	128 MB	Judgeable
Copying BooksSplit a sequence of book page counts into k contiguous groups minimizing the maximum group sum, breaking ties by minimizing earlier scribes' loads first.	Medium6	Binary searchGreedy+1	No attempts yet	1s	128 MB	Judgeable
Random WalkGiven n steps with probabilities of moving left, right, or staying, compute the expected value of the maximum position reached.	Medium6	Dynamic programmingProbability+1	No attempts yet	10s	128 MB	Judgeable
Genetic FraudDecide whether two equal-length strings share an aligned substring of length at least ceil(N/2) where every pair of aligned letters differs by at most 1.	Medium6	StringTwo pointers+2	No attempts yet	1s	128 MB	Judgeable