Problems

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Total results29,416 problems

Almost-K Increasing Subsequence
Medium6
Dynamic programming, Array+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Oh Right, the Umbrella
Medium6
BFS, Bit manipulation+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Ssi Ssi
Medium6
Graph, Shortest path+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Galactic Railway
Medium6
Union-find, Graph+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Overflowing Gifts
Medium6
Simulation, Greedy
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Oil Overflow
Medium6
Tree, Greedy
No attempts yet
Time limit
1.5s
Memory limit
512 MB
Judgeable
Tough Guy
Medium6
Graph, BFS+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Curse of the Meeting
Medium6
Dynamic programming, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Rotating an Array
Medium6
Implementation, Matrix+2
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Stock
Medium6
Sliding window, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Binary String
Medium6
String, Simulation+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Candy Delivery
Medium6
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Life in Wartime
Medium6
Tree, Hash map+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Getting-Up Syndrome
Medium6
Bit manipulation, Greedy+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Text Editor
Medium6
Implementation, Linked list+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Walk Only the Lightbulb Path
Medium6
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Number of Sequences Related to Palindromes
Medium6
Combinatorics, Math+2
No attempts yet
Time limit
0.25s
Memory limit
512 MB
Judgeable
Taxi
Medium6
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Okto Rabbit Solves the Correspondence Course!!
Medium6
Sorting, Greedy
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Bracket
Medium6
Implementation, Divide and conquer+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Uncrossed Knights' Tour
Medium6
Sorting, Greedy+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Line Segment Intersection 2
Medium6
Geometry, Math+2
No attempts yet
Time limit
0.25s
Memory limit
512 MB
Judgeable
Finger Snap
Medium6
BFS, Number theory+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
RGB Street 2
Medium6
Dynamic programming, Implementation+2
No attempts yet
Time limit
0.5s
Memory limit
128 MB
Judgeable
Rotate Array 4
Medium6
Brute force, Backtracking+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Bracket String and Queries
Medium6
String, Prefix sum+2
No attempts yet
Time limit
0.5s
Memory limit
512 MB
Judgeable
Count of Increasing Subsequences
Medium6
Dynamic programming, Binary search+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Huge Integer!
Medium6
Number theory, Math+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Game
Medium6
Number theory, Math
No attempts yet
Time limit
1.5s
Memory limit
256 MB
Judgeable
Sorting
Medium6
Greedy, Sorting+2
No attempts yet
Time limit
0.5s
Memory limit
256 MB
Judgeable
Saving the Ryan Statue
Medium6
Array, Prefix sum+2
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Rank Calculation
Medium6
Implementation, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Parallel Universe
Medium6
Math, Greedy+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Christmalo.win
Medium6
String, Hash map+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
God
Medium6
Number theory, Math+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Jinwoo's Moon Trip (Small)
Medium6
Dynamic programming, Matrix+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Building a Bridge to Wowdo
Medium6
Graph, Union-find+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Feeding the Cats
Medium6
Dynamic programming, Bit manipulation+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Stealing Snacks from Juniors
Medium6
Dynamic programming, Greedy+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Piano Performance
Medium6
Dynamic programming, Implementation
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Beer Festival
Medium6
Binary search, Greedy+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Ringo and Permutation
Medium6
Greedy, Array+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Time Traveler's Experiment Log
Medium6
Tree, DFS+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Balanced String
Medium6
Dynamic programming, Combinatorics+2
No attempts yet
Time limit
0.5s
Memory limit
512 MB
Judgeable
Byte Coin
Medium6
Dynamic programming, Brute force+2
No attempts yet
Time limit
0.5s
Memory limit
512 MB
Judgeable
Canal
Medium6
Binary search, Sorting+2
No attempts yet
Time limit
1.5s
Memory limit
512 MB
Judgeable
Dryer
Medium6
Dynamic programming, Sorting
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Star Trek
Medium6
Dynamic programming, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Two Machines
Medium6
Dynamic programming, Greedy+2
No attempts yet
Time limit
0.5s
Memory limit
512 MB
Judgeable
Crossings With Danger
Medium6
Simulation, Sorting+1
No attempts yet
Time limit
1.5s
Memory limit
512 MB
Judgeable
Exhibition of Clownfish
Medium6
Greedy, Sorting
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Getting Confidence
Medium6
Dynamic programming, Bit manipulation+2
No attempts yet
Time limit
0.5s
Memory limit
512 MB
Judgeable
Jar of Water Game
Medium6
Simulation, Implementation+1
No attempts yet
Time limit
0.5s
Memory limit
512 MB
Judgeable
Keep Calm and Sell Balloons
Medium6
Dynamic programming, Math
No attempts yet
Time limit
0.5s
Memory limit
512 MB
Judgeable
Deceptive Dice
Medium6
Dynamic programming, Probability+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Exits in Excess
Medium6
Graph, DFS+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Monument Tour
Medium6
Math, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Rounding
Medium6
Math, Implementation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Kings
Medium6
Two pointers, Greedy+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Slow Leak
Medium6
Shortest path, Graph+2
No attempts yet
Time limit
14s
Memory limit
1024 MB
Judgeable
Zipline
Medium6
Geometry, Binary search+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Factorization
Medium6
Math, Number theory+2
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Two-Pan Balance
Medium6
Brute force, Backtracking+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Gathering Balls
Medium6
Greedy, String+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Finding the Rank
Medium6
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Colouring a rectangle
Medium6
Dynamic programming, Graph
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Count Squares
Medium6
Array, Hash map+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Triangle
Medium6
Geometry, Hash map+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Jump!
Medium6
Math, Binary search+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Lamps
Medium6
String, Greedy
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
AAQQZ
Medium6
Sorting, Prefix sum+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
JOIOJI
Medium6
Prefix sum, Hash map+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Straps
Medium6
Dynamic programming, Tree+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Bus Tour
Medium6
Shortest path, Graph+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Hazard
Medium6
Simulation, Queue+1
No attempts yet
Time limit
3.5s
Memory limit
512 MB
Judgeable
Word
Medium6
Combinatorics, Math+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Chinese Restaurant
Medium6
Sorting, Greedy+2
No attempts yet
Time limit
1.5s
Memory limit
512 MB
Judgeable
Gerrymandering 2
Medium6
Brute force, Simulation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
New Game
Medium6
Simulation, Implementation+2
No attempts yet
Time limit
0.5s
Memory limit
512 MB
Judgeable
Keep Him Inside
Medium6
Geometry, Math+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Automatic Accountant
Medium6
Sorting, Binary search+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Integral Pyramid
Medium6
Combinatorics, Math+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Beer Barrels
Medium6
Combinatorics, Math+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Beer Marathon
Medium6
Sorting, Greedy+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Beer Vision
Medium6
Hash map, Geometry+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Hongik University Underground Campus
Medium6
Shortest path, Graph+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Seungbeom's Interviews
Medium6
Graph, Shortest path+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Follow the Bouncing Ball
Medium6
Simulation, Geometry
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Square Rooms
Medium6
Greedy, Matrix+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Pass the Buck
Medium6
Probability, Graph+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Gerrymandering Criterion
Medium6
Geometry, Math
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Problematic Public Keys
Medium6
Number theory, Math+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Bus Planning
Medium6
Bit manipulation, Dynamic programming+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Programming Contest Cup
Medium6
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Backpack Buddies
Medium6
Graph, Shortest path
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
ISP Merger
Medium6
Graph, Greedy+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Typo Squatting
Medium6
Hash map, String+2
No attempts yet
Time limit
4s
Memory limit
512 MB
Judgeable
Candy Packaging
Medium6
Greedy, Sorting+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Streaming Services
Medium6
Dynamic programming, Greedy
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Haiku
Medium6
Dynamic programming, String+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Almost-K Increasing SubsequenceFind the longest subsequence of a given sequence that has at most K positions where consecutive elements decrease.	Medium6	Dynamic programmingArray+2	No attempts yet	1s	256 MB	Judgeable
Oh Right, the UmbrellaOn a grid with walls, find the shortest walk from S that picks up every X item (at most 5) and ends at E.	Medium6	BFSBit manipulation+2	No attempts yet	1s	256 MB	Judgeable
Ssi SsiGiven M facts that two people have a certain kinship distance, answer Q queries asking the distance between two people, or -1 if it cannot be determined.	Medium6	GraphShortest path+2	No attempts yet	2s	256 MB	Judgeable
Galactic RailwayAdd up to M edges between N galaxies one at a time; after each edge print the total planet count in the merged component.	Medium6	Union-findGraph+2	No attempts yet	5s	512 MB	Judgeable
Overflowing GiftsGiven workers beside a conveyor belt shaped like a reversed C, each with a fixed wrap time, find the maximum number of gifts they can wrap.	Medium6	SimulationGreedy	No attempts yet	1s	256 MB	Judgeable
Oil OverflowGiven a perfect binary tree of oil tanks fed by pumps at the leaves, find the earliest time each tank becomes full.	Medium6	TreeGreedy	No attempts yet	1.5s	512 MB	Judgeable
Tough GuyCount the cells reachable from a start on a grid where you move up and down freely but left and right at most L and R times total, with walls blocked.	Medium6	GraphBFS+2	No attempts yet	1s	256 MB	Judgeable
Curse of the MeetingCount the ways N people around a round table can pair up and shake hands simultaneously without any arms crossing, modulo 987654321.	Medium6	Dynamic programmingCombinatorics+2	No attempts yet	1s	256 MB	Judgeable
Rotating an ArrayGiven an odd n x n grid and a rotation angle that is a multiple of 45 degrees, shift the four lines (main diagonal, middle column, anti-diagonal, middle row) cyclically and print the resulting grid.	Medium6	ImplementationMatrix+2	No attempts yet	3s	512 MB	Judgeable
StockFind the shortest subarray whose sum minus y times its length is at least Z and whose length times y is at most X, breaking ties by the latest start.	Medium6	Sliding windowPrefix sum+2	No attempts yet	1s	512 MB	Judgeable
Binary StringGiven a binary string and m operations that insert complements of substrings after position y, print the first k characters of the final string.	Medium6	StringSimulation+1	No attempts yet	2s	512 MB	Judgeable
Candy DeliveryGiven N candies weighing 3 g or 5 g with sweetness values and a weight limit w, choose a subset to maximize total sweetness.	Medium6	GreedySorting+2	No attempts yet	1s	512 MB	Judgeable
Life in WartimeGiven N distinct cities (all below 250) in an infinite binary heap tree, count cities that either host a unit or lie on the unique path between two units.	Medium6	TreeHash map+2	No attempts yet	2s	512 MB	Judgeable
Getting-Up SyndromeChoose an initial integer x in [0, m] so that applying n bitwise OR/XOR/AND gates with given parameters maximizes the final value.	Medium6	Bit manipulationGreedy+2	No attempts yet	1s	512 MB	Judgeable
Text EditorSimulate a text editor with cursor moves, inserts, deletes, and reads over a large text, where each Get returns the n characters after the cursor.	Medium6	ImplementationLinked list+1	No attempts yet	2s	256 MB	Judgeable
Walk Only the Lightbulb PathArrange N binary strings in some order so the concatenation has the fewest adjacent 01 or 10 transitions, and print that minimum count; N is at most 10.	Medium6	GreedySorting+2	No attempts yet	1s	512 MB	Judgeable
Number of Sequences Related to PalindromesCount length-N sequences with values up to M such that every length-K window is a palindrome, modulo 1e9+7.	Medium6	CombinatoricsMath+2	No attempts yet	0.25s	512 MB	Judgeable
TaxiSimulate a taxi that follows a fixed list of movement and pickup commands, tracking fuel, refueling at three priced gas stations, passenger capacity, fares, and check the end conditions.	Medium6	SimulationImplementation+2	No attempts yet	1s	1024 MB	Judgeable
Okto Rabbit Solves the Correspondence Course!!Given N problems with solve times T_i, schedule them so that at most two run at once and the largest gap between consecutive finish times is minimized.	Medium6	SortingGreedy	No attempts yet	1s	1024 MB	Judgeable
BracketPlace N teams into a power-of-2 bracket so the most and fewest matches to win differ by at most one, breaking ties by the lexicographically smallest slot sequence.	Medium6	ImplementationDivide and conquer+1	No attempts yet	1s	1024 MB	Judgeable
Uncrossed Knights' TourAssign each of N knights a distinct landmark across the river so that no two straight routes cross, or report -1 if that is impossible.	Medium6	SortingGreedy+1	No attempts yet	3s	1024 MB	Judgeable
Line Segment Intersection 2Given two line segments by their integer endpoints, decide whether they intersect, counting endpoint touching as an intersection.	Medium6	GeometryMath+2	No attempts yet	0.25s	512 MB	Judgeable
Finger SnapStarting from N, use halve, third, increment, and decrement operations to reach a prime in [A, B] with the fewest operations, or report -1.	Medium6	BFSNumber theory+2	No attempts yet	2s	512 MB	Judgeable
RGB Street 2Paint N houses in a cycle with three colors so that every adjacent pair differs, minimizing total cost.	Medium6	Dynamic programmingImplementation+2	No attempts yet	0.5s	128 MB	Judgeable
Rotate Array 4Try every order of up to 6 rotation operations on the grid and report the largest possible minimum row sum after all rotations.	Medium6	Brute forceBacktracking+2	No attempts yet	1s	512 MB	Judgeable
Bracket String and QueriesFlip one character per query and count how many prefixes of the query sequence leave the string as a correct bracket sequence.	Medium6	StringPrefix sum+2	No attempts yet	0.5s	512 MB	Judgeable
Count of Increasing SubsequencesCount the strictly increasing subsequences of length K in a sequence of N distinct values, reported modulo 1e9+7.	Medium6	Dynamic programmingBinary search+2	No attempts yet	1s	512 MB	Judgeable
Huge Integer!Given N digit-and-length pairs, form the huge number made by concatenating each digit A_i exactly B_i times, then print its remainder modulo K.	Medium6	Number theoryMath+2	No attempts yet	1s	256 MB	Judgeable
GameStarting from two sheets that both show 1, find the fewest sum-and-overwrite steps that put the target x on one sheet, and print the colors chosen.	Medium6	Number theoryMath	No attempts yet	1.5s	256 MB	Judgeable
SortingGiven N and M, construct a permutation of 1..N for which insertion sort performs exactly M shifts, or report that it is impossible.	Medium6	GreedySorting+2	No attempts yet	0.5s	256 MB	Judgeable
Saving the Ryan StatueChoose one integer point on each side of an N by N square to form a smaller rectangle, maximizing the total value of statues it covers, including those on its border.	Medium6	ArrayPrefix sum+2	No attempts yet	3s	1024 MB	Judgeable
Rank CalculationGiven Tamref's intermediate rank after his turn and the ranks reported after each later contestant, determine the highest and lowest final rank he could hold.	Medium6	ImplementationGreedy+1	No attempts yet	1s	1024 MB	Judgeable
Parallel UniverseYou leave Earth at one initial speed, may only decrease it afterward, and each leg's speed must be a positive integer multiple of its required value. Find the smallest starting speed that lets you finish all n legs.	Medium6	MathGreedy+2	No attempts yet	1s	1024 MB	Judgeable
Christmalo.winGiven N short strings, pick two and a shared letter to splice their prefix and suffix, minimizing the total deleted characters.	Medium6	StringHash map+2	No attempts yet	1s	1024 MB	Judgeable
GodGiven the vote ratios in each of the three candidates' own polls, decide whether some consistent assignment of actual vote counts lets Donghyun collect a strict plurality. Print GOD if he can, KDH otherwise.	Medium6	Number theoryMath+2	No attempts yet	1s	1024 MB	Judgeable
Jinwoo's Moon Trip (Small)Given an N by M grid of fuel costs with N, M at most 6, find the minimum cost path from any cell in the top row to any cell in the bottom row, where each step moves downward and no two consecutive steps use the same direction.	Medium6	Dynamic programmingMatrix+1	No attempts yet	1s	256 MB	Judgeable
Building a Bridge to WowdoGiven a cycle of N buildings, prohibited edges, and a required stone count S[i] at each building to reach an island, decide whether the total stones needed to connect all buildings stays within K.	Medium6	GraphUnion-find+2	No attempts yet	2s	256 MB	Judgeable
Feeding the CatsStarting at (0,0), visit all N cats on a grid, moving in Manhattan steps, and return to (0,0) in the shortest time.	Medium6	Dynamic programmingBit manipulation+2	No attempts yet	1s	256 MB	Judgeable
Stealing Snacks from JuniorsChoose a subset of snacks whose total fullness reaches M, minimizing total satisfaction, or report that it is impossible.	Medium6	Dynamic programmingGreedy+1	No attempts yet	1s	256 MB	Judgeable
Piano PerformanceGiven two starting notes and a sequence of piano notes, find the minimum total semitone movement of two fingers and which finger plays each note.	Medium6	Dynamic programmingImplementation	No attempts yet	1s	256 MB	Judgeable
Beer FestivalGiven K beers each with a preference and an alcohol level, pick N distinct beers maximizing total preference while minimizing the maximum alcohol level; output that minimum level or -1.	Medium6	Binary searchGreedy+2	No attempts yet	1s	256 MB	Judgeable
Ringo and PermutationGiven N and K, construct a permutation of 1..N whose inversion count is exactly K, or report that none exists.	Medium6	GreedyArray+2	No attempts yet	1s	256 MB	Judgeable
Time Traveler's Experiment LogGiven a sequence of mix, query, JUMP, and LOAD actions on a timeline, print the pocket notebook lookups and the lab notebook mixing records that survive the rewinds.	Medium6	TreeDFS+1	No attempts yet	1s	512 MB	Judgeable
Balanced StringCount binary strings of length n where every prefix has at most one more 0 than 1 or one more 1 than 0, modulo 16769023.	Medium6	Dynamic programmingCombinatorics+2	No attempts yet	0.5s	512 MB	Judgeable
Byte CoinGiven n up to 15 days of Byte Coin prices and initial cash W, buy and sell whole coins each day to maximize the cash held after selling everything on day n.	Medium6	Dynamic programmingBrute force+2	No attempts yet	0.5s	512 MB	Judgeable
CanalPlace one horizontal and one vertical line so the largest distance from any given point to the nearer line is minimized, and print that distance.	Medium6	Binary searchSorting+2	No attempts yet	1.5s	512 MB	Judgeable
DryerGiven n clothes with damage temperatures and wetness values, split them into at most k groups to minimize the total drying time, where each group runs at the temperature that its slowest cloth needs.	Medium6	Dynamic programmingSorting	No attempts yet	1s	512 MB	Judgeable
Star TrekFind the minimum travel time from planet 1 to planet n, where you may switch ships at intermediate planets, paying a preparation time plus pace times distance for each leg.	Medium6	Dynamic programmingPrefix sum+2	No attempts yet	1s	512 MB	Judgeable
Two MachinesAssign each of n tasks to machine A or B, minimizing the maximum total load across the two machines.	Medium6	Dynamic programmingGreedy+2	No attempts yet	0.5s	512 MB	Judgeable
Crossings With DangerGiven C vehicles on an N by M grid that each move straight at one crossing per second, count how many never collide.	Medium6	SimulationSorting+1	No attempts yet	1.5s	512 MB	Judgeable
Exhibition of ClownfishGiven the male and female counts in each tank, find the fewest single-fish moves needed to make every clownfish female.	Medium6	GreedySorting	No attempts yet	1s	512 MB	Judgeable
Getting ConfidenceGiven an N by N matrix of confidence values, assign each of N ornaments to a distinct position so that the product of the chosen values is maximized, and output the assignment.	Medium6	Dynamic programmingBit manipulation+2	No attempts yet	0.5s	512 MB	Judgeable
Jar of Water GameSimulate a circular card-passing game with N players, a wildcard, and a fixed passing rule until one player holds four equal cards.	Medium6	SimulationImplementation+1	No attempts yet	0.5s	512 MB	Judgeable
Keep Calm and Sell BalloonsCount the Hamiltonian paths on a 2 by N grid of houses where moves go horizontally, vertically, or diagonally, modulo 1e9+7, with N up to 1e9.	Medium6	Dynamic programmingMath	No attempts yet	0.5s	512 MB	Judgeable
Deceptive DiceGiven an n-sided die and at most k rolls, find the maximum expected final score when you may stop rolling at any point.	Medium6	Dynamic programmingProbability+2	No attempts yet	1s	512 MB	Judgeable
Exits in ExcessGiven a directed graph, choose at most half of its edges to delete so that the remaining graph has no directed cycle.	Medium6	GraphDFS+2	No attempts yet	2s	512 MB	Judgeable
Monument TourPick one eastbound row for the bus to travel; the cost is the horizontal distance across plus twice the vertical detours to visit every monument, and we minimize it.	Medium6	MathPrefix sum+2	No attempts yet	1s	512 MB	Judgeable
RoundingGiven rounded integer percentages from 10000 respondents, find the possible range of each place's true percentage, or report IMPOSSIBLE if no consistent assignment exists.	Medium6	MathImplementation+2	No attempts yet	2s	512 MB	Judgeable
KingsGiven n kings on an n by n board, find the minimum total moves to shift every king onto the main diagonal, where a move shifts one king one cell horizontally or vertically.	Medium6	Two pointersGreedy+2	No attempts yet	1s	512 MB	Judgeable
Slow LeakGiven weighted roads and refill stations, find the shortest school-to-home route where no stretch between refills exceeds distance d, or report stuck.	Medium6	Shortest pathGraph+2	No attempts yet	14s	1024 MB	Judgeable
ZiplineFor each zipline, find the minimum and maximum cable length so the rider's lowest point stays at least r meters above the flat ground.	Medium6	GeometryBinary search+2	No attempts yet	1s	1024 MB	Judgeable
FactorizationGiven a prime p and residues a0, a1, find b0, b1 in [0, p-1] with b0*b1 = a0 and b0+b1 = a1 mod p, or report none.	Medium6	MathNumber theory+2	No attempts yet	3s	512 MB	Judgeable
Two-Pan BalanceGiven up to 13 distinct weights, count how many integers from 1 to their sum cannot be formed when each weight goes on the bowl side, the other pan, or unused.	Medium6	Brute forceBacktracking+2	No attempts yet	1s	512 MB	Judgeable
Gathering BallsGiven a row of red and blue balls, find the minimum number of jumps (moving only one color) to group each color together.	Medium6	GreedyString+2	No attempts yet	1s	512 MB	Judgeable
Finding the RankGiven a set of pairwise comparisons among N students, find the best and worst possible rank of student X over all total orders consistent with the comparisons.	Medium6	GraphDFS+2	No attempts yet	1s	512 MB	Judgeable
Colouring a rectangleEvery cell must be covered by one of its two diagonals, one going in each direction. Find the minimum total cost of diagonals that covers the whole grid.	Medium6	Dynamic programmingGraph	No attempts yet	2s	512 MB	Judgeable
Count SquaresGiven coordinates of h horizontal and v vertical lines, count how many axis-aligned squares have all four sides drawn by those lines.	Medium6	ArrayHash map+2	No attempts yet	2s	512 MB	Judgeable
TriangleGiven N plane points and Q query points, count epsilon-isosceles triangles having the query point as vertex and two distinct given points as the others, where two side lengths differ by less than 0.0001.	Medium6	GeometryHash map+1	No attempts yet	2s	512 MB	Judgeable
Jump!Each person's cap height over time is a parabola clipped at zero; find the earliest time when the highest and lowest cap heights are closest.	Medium6	MathBinary search+2	No attempts yet	2s	512 MB	Judgeable
LampsGiven two binary strings A and B of length N, find the fewest range set-to-0, set-to-1, or flip operations that turn A into B.	Medium6	StringGreedy	No attempts yet	1s	256 MB	Judgeable
AAQQZGiven a sequence of N integers, sort one contiguous segment in ascending order, then find the longest palindromic segment that can appear afterward.	Medium6	SortingPrefix sum+2	No attempts yet	2s	512 MB	Judgeable
JOIOJIGiven a string of J, O, and I, find the longest contiguous substring with equal counts of all three letters.	Medium6	Prefix sumHash map+2	No attempts yet	1s	512 MB	Judgeable
StrapsChoose a set of straps forming a rooted tree: each strap occupies one port of its parent, one strap hangs from the phone, and total happiness is maximized.	Medium6	Dynamic programmingTree+2	No attempts yet	1s	512 MB	Judgeable
Bus TourFind the earliest time JOI can reach the venue by transferring between clockwise rectangular bus routes on a grid, where each transfer needs at least a 1-minute wait.	Medium6	Shortest pathGraph+1	No attempts yet	3s	256 MB	Judgeable
HazardGiven each boy's savings in queue order and a repeating win/lose cycle, find how many games pass until one boy loses all his money, or -1 if none does.	Medium6	SimulationQueue+1	No attempts yet	3.5s	512 MB	Judgeable
WordFind the k-th word in lexicographic order among words of length at most n over letters a, b, c with no two equal adjacent letters, or report that fewer than k exist.	Medium6	CombinatoricsMath+2	No attempts yet	2s	512 MB	Judgeable
Chinese RestaurantGiven the dish each member wants, find for every dish K might eat the minimum total turntable rotation needed so all other members can eat.	Medium6	SortingGreedy+2	No attempts yet	1.5s	512 MB	Judgeable
Gerrymandering 2For an N x N grid, try every valid 5-way district split defined by a reference point and two boundary lengths, and report the smallest difference between the largest and smallest district populations.	Medium6	Brute forceSimulation+2	No attempts yet	1s	512 MB	Judgeable
New GameSimulate a board game where K stacked pieces move in numbered order and reverse, redirect, or merge based on cell color, and report the turn a stack reaches 4 pieces or -1.	Medium6	SimulationImplementation+2	No attempts yet	0.5s	512 MB	Judgeable
Keep Him InsideGiven a convex polygon of guard points and an interior prisoner point, assign nonnegative weights summing to 1 whose weighted average equals the prisoner.	Medium6	GeometryMath+2	No attempts yet	1s	512 MB	Judgeable
Automatic AccountantEach coin slides along a track and drops into the first slot whose width is at least the coin's thickness and whose trigger mass is at most the coin's mass; sum the drop positions.	Medium6	SortingBinary search+2	No attempts yet	2s	512 MB	Judgeable
Integral PyramidGiven n and x, decide whether positive integers can fill the bottom row of Pascal-style sums so the single top cell equals x, and print a valid pyramid.	Medium6	CombinatoricsMath+2	No attempts yet	2s	512 MB	Judgeable
Beer BarrelsCount occurrences of digit C across all K-digit strings made only of digits A and B, modulo 1e9+7.	Medium6	CombinatoricsMath+2	No attempts yet	2s	512 MB	Judgeable
Beer MarathonGiven N beer booth positions and a fixed spacing K, choose an arithmetic progression of N positions (any start) minimizing the total absolute movement of the booths.	Medium6	SortingGreedy+2	No attempts yet	2s	512 MB	Judgeable
Beer VisionCount the nonzero shift vectors (X, Y) for which some set of stars, shifted by that vector, equals the given set of points.	Medium6	Hash mapGeometry+2	No attempts yet	2s	512 MB	Judgeable
Hongik University Underground CampusFind the minimum total printing time of models that connect the front gate on floor R to the back gate on floor D within N floors, where each model may be flipped left to right.	Medium6	Shortest pathGraph+1	No attempts yet	1s	256 MB	Judgeable
Seungbeom's InterviewsGiven a directed weighted graph with several marked sites, find the city whose shortest distance to any site is largest, and report that distance.	Medium6	GraphShortest path+2	No attempts yet	1s	256 MB	Judgeable
Follow the Bouncing BallGiven convex objects with hit counters and a gun that fires n bouncing balls, find each object's final counter value after all balls leave the screen.	Medium6	SimulationGeometry	No attempts yet	2s	512 MB	Judgeable
Square RoomsGiven a grid of treasure, rock, and empty cells, split the empty cells into square rooms that each hold exactly one treasure, or report elgnatcer if no split exists.	Medium6	GreedyMatrix+1	No attempts yet	2s	512 MB	Judgeable
Pass the BuckGiven a graph where each holder moves to a random neighbor or wins with probability 1/(d+1), find the win probability of a target player from a given start.	Medium6	ProbabilityGraph+2	No attempts yet	1s	512 MB	Judgeable
Gerrymandering CriterionGiven a counter-clockwise polygon, find the area of its overlap with the disc centered at its centroid that has the same area, divided by the polygon's area.	Medium6	GeometryMath	No attempts yet	1s	512 MB	Judgeable
Problematic Public KeysGiven M flawed RSA-style public keys, find the prime factors of each and print all distinct primes in ascending order, five per line.	Medium6	Number theoryMath+2	No attempts yet	1s	512 MB	Judgeable
Bus PlanningSplit n kids (n up to 17) into the fewest groups so no two enemies share a group and each group has at most c kids, then output one valid grouping.	Medium6	Bit manipulationDynamic programming+2	No attempts yet	2s	512 MB	Judgeable
Programming Contest CupGiven every contestant's scores from the first n-1 contests, find the worst rank you can end up at if you skip the last contest and others play it optimally against you.	Medium6	GreedySorting+1	No attempts yet	1s	512 MB	Judgeable
Backpack BuddiesFind how many hours Dr. Knight waits at cabin n-1 when Mr. Day must end each day at a cabin, while Dr. Knight can stop anywhere after at most 12 hours.	Medium6	GraphShortest path	No attempts yet	1s	512 MB	Judgeable
ISP MergerDecide whether at most k edge additions or removals can make a graph connected while keeping each vertex's degree within its socket limit.	Medium6	GraphGreedy+1	No attempts yet	2s	512 MB	Judgeable
Typo SquattingFor each domain name, count how many other given domains differ from it in exactly one character position.	Medium6	Hash mapString+2	No attempts yet	4s	512 MB	Judgeable
Candy PackagingPack the most boxes of K candies each, with at least two kinds per box and no kind filling a whole box, and report the fewest candies to re-kind.	Medium6	GreedySorting+1	No attempts yet	2s	512 MB	Judgeable
Streaming ServicesGiven the daily release days for two streaming services, find the fewest K-day subscriptions needed so every day has a subscribed service releasing an episode.	Medium6	Dynamic programmingGreedy	No attempts yet	2s	512 MB	Judgeable
HaikuGiven a set of syllables, decide whether the three input phrases can each be split into syllables so their syllable counts are 5, 7, and 5.	Medium6	Dynamic programmingString+2	No attempts yet	1s	512 MB	Judgeable