Problems

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Total results29,460 problems

Proof of Knowledge
Medium4
Implementation, Recursion+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
jfen
Medium4
String, Implementation+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Misawa's Rooted Trees
Medium4
Recursion, String+2
No attempts yet
Time limit
10s
Memory limit
512 MB
Judgeable
You Are the Judge
Medium4
Simulation, Sorting+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
YAML
Medium4
String, Implementation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
FizzBuzz
Medium4
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Class Representative Witch
Medium4
Sorting, Binary search+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Sum of Consecutive Integers
Medium4
Math, Brute force+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Mr. Miyagi's Earth Invasion Diary
Medium4
Math, Binary search+1
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Infected Computer
Medium4
Sorting, Graph+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Sort by Hand
Medium4
Dynamic programming, Array
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Strange Currency System
Medium4
Greedy, Sorting+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Deadly Dice Game
Medium4
Dynamic programming, Probability
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Space Coconut Crab
Medium4
Brute force, Math+1
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Surrounding Area
Medium4
BFS, Matrix+1
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Amida, the City of Miracle
Medium4
Sorting, Simulation+1
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Monkey Business
Medium4
Math, Number theory+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Rolling Cubes
Medium4
Simulation, Implementation+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
First Experience
Medium4
Simulation, Implementation+1
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
How Many Days Are There?
Medium4
Math, Implementation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Get Many Persimmon Trees
Medium4
Prefix sum, Array+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Pile Up!
Medium4
Simulation, Implementation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Kanglish : Analysis on Artificial Language
Medium4
String, Simulation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
What is the Number in my Mind?
Medium4
Brute force, Implementation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Multi-column List
Medium4
Simulation, Implementation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Cyber Guardian
Medium4
Implementation, String+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Family Tree
Medium4
Implementation, Tree+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Square Coins
Medium4
Dynamic programming, Math+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Similar Inorder Traversal
Medium4
Tree, DFS+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Fatigue
Medium4
Greedy, Simulation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Bus Terminal
Medium4
Sorting, Intervals+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Moons and Umbrellas
Medium4
Greedy, Dynamic programming+2
No attempts yet
Time limit
10s
Memory limit
1024 MB
Judgeable
You be The Judge, Again
Medium4
Implementation, Simulation+2
No attempts yet
Time limit
2s
Memory limit
2048 MB
Judgeable
The Professor's Calculator Is Broken!
Medium4
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Linear System of Equations
Medium4
Math, Brute force+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
RPG Master Oh Myeongjin
Medium4
Simulation, Implementation+2
No attempts yet
Time limit
0.3s
Memory limit
512 MB
Judgeable
Songi's Card Game
Medium4
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Dodo's Food Preparation
Medium4
Binary search, Greedy+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Balance
Medium4
Dynamic programming, Tree+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Recycled Problem
Medium4
Array, Implementation+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Consecutive Primes
Medium4
Number theory, Math+2
No attempts yet
Time limit
15s
Memory limit
1024 MB
Judgeable
Trash Bins
Medium4
Array, Implementation+2
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
Othello
Medium4
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Balanced Ternary
Medium4
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Histogram Sequence 3
Medium4
Implementation, Array+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
APL Lives!
Medium4
Simulation, Implementation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Barcodes
Medium4
Implementation, String+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Sierpiński circumference
Medium4
Math, Number theory+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Struts and Springs
Medium4
Simulation, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Suffix-Replacement Grammars
Medium4
String, BFS
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Block
Medium4
Math, Greedy+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Dogs and Cats
Medium4
Simulation, Implementation+2
No attempts yet
Time limit
Not set
Memory limit
1024 MB
Judgeable
Social Hierarchy
Medium4
Simulation, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Aju Survival
Medium4
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Web Browser 2
Medium4
Simulation, Stack+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Propagation and Merging 2
Medium4
Graph, DFS+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
AKARAKA
Medium4
String, Recursion+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Sum of Distances 2
Medium4
Sorting, Prefix sum+2
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
Drunk Passenger
Medium4
Probability, Math+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Almost Always
Medium4
Sorting, Math+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Ice Growth
Medium4
Array, Prefix sum+2
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Escalator
Medium4
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Kathmandu
Medium4
Array, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Backup
Medium4
Implementation, Greedy+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Steve's perfectionism
Medium4
Greedy, Math
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Least Common Divisor
Medium4
String, Math+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Gaokao
Medium4
Math, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Find the House
Medium4
Hash map, Simulation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Trampler
Medium4
Simulation, Implementation+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Devil's Annual Leave Calculator
Medium4
Implementation, Math+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Find the Longest Subsequence
Medium4
Bit manipulation, Array
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Sincere Side-to-Side Repeat Jump
Medium4
Math, Implementation
No attempts yet
Time limit
0.15s
Memory limit
512 MB
Judgeable
Marbles Tell Your Lucky Number
Medium4
Simulation, Implementation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Physics Experiment
Medium4
Greedy, Math+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Successful String
Medium4
String, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Cramming
Medium4
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Player-based Team Distribution
Medium4
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Card Control
Medium4
Brute force, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Knitpicking
Medium4
Greedy, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
2,147,483,648 Game
Medium4
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Humanities and Arts Exploration Week
Medium4
Sorting, Prefix sum+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Coprime Graph
Medium4
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
A Certain Milk Delivery List (Easy)
Medium4
Tree, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Lampice
Medium4
Brute force, Implementation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Algorithm Class - Selection Sort 2
Medium4
Simulation, Sorting+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Algorithm Class - Selection Sort 4
Medium4
Implementation, Sorting+2
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Bus Routes
Medium4
Greedy, Math+1
No attempts yet
Time limit
10s
Memory limit
1024 MB
Judgeable
ATM Queue
Medium4
Sorting, Simulation+2
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
Kick Start
Medium4
String, String matching+1
No attempts yet
Time limit
Not set
Memory limit
1024 MB
Judgeable
Combination Lock
Medium4
Array, Math+2
No attempts yet
Time limit
40s
Memory limit
1024 MB
Judgeable
Training
Medium4
Sorting, Sliding window+2
No attempts yet
Time limit
15s
Memory limit
1024 MB
Judgeable
Building Palindromes
Medium4
Prefix sum, Hash map+2
No attempts yet
Time limit
30s
Memory limit
1024 MB
Judgeable
H-index
Medium4
Sorting, Greedy+1
No attempts yet
Time limit
50s
Memory limit
1024 MB
Judgeable
Algorithm Class - Bubble Sort 2
Medium4
Simulation, Sorting+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Finding the Password
Medium4
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
X Squared
Medium4
Matrix, Greedy+2
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
Pretty Cake
Medium4
Math, Number theory
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Algorithm Class - Insertion Sort 2
Medium4
Simulation, Sorting+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Advertisement
Medium4
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Building Decoration
Medium4
Dynamic programming, Array+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Proof of KnowledgeParse a small expression tree over four bit variables a-d, evaluate it for a given 4-digit password, and count how many of the 10000 passwords yield the same bit.	Medium4	ImplementationRecursion+2	No attempts yet	8s	512 MB	Judgeable
jfenGiven a board in jfen notation and a move command, apply the move and re-output the board in jfen notation.	Medium4	StringImplementation+2	No attempts yet	8s	512 MB	Judgeable
Misawa's Rooted TreesParse two binary trees given in a nested bracket notation, overlay them recursively, and print the resulting tree in the same notation.	Medium4	RecursionString+2	No attempts yet	10s	512 MB	Judgeable
You Are the JudgeGiven a contest log of correct and wrong submissions, compute each team's solved count and penalty, then print teams in rank order.	Medium4	SimulationSorting+2	No attempts yet	8s	512 MB	Judgeable
YAMLParse a small YAML-like nested mapping from indentation, then walk a dotted query path and report whether the target is a string, object, or missing.	Medium4	StringImplementation+2	No attempts yet	2s	512 MB	Judgeable
FizzBuzzGiven an index s up to 10^18, output the 20 characters of the FizzBuzz String starting at position s.	Medium4	MathImplementation+2	No attempts yet	1s	512 MB	Judgeable
Class Representative WitchEach thread runs from the witch outward; given the held endpoint distance si, the far endpoint distance ti, and all cut distances pi, find the total length of thread left after every cut.	Medium4	SortingBinary search+2	No attempts yet	2s	512 MB	Judgeable
Sum of Consecutive IntegersFor each N up to 1000, count how many ways N can be written as a sum of two or more consecutive positive integers.	Medium4	MathBrute force+2	No attempts yet	8s	512 MB	Judgeable
Mr. Miyagi's Earth Invasion DiaryGiven N Draculas where exactly one is heavier than the rest, find the minimum number of balance-scale weighings needed in the worst case to identify the heavier original.	Medium4	MathBinary search+1	No attempts yet	8s	512 MB	Judgeable
Infected ComputerGiven packets with send times between computers, count how many computers get infected starting from computer 1, where a computer is infected only when it receives a packet from an already infected computer.	Medium4	SortingGraph+2	No attempts yet	8s	512 MB	Judgeable
Sort by HandGiven a permutation of n books (n at most 20), find the minimum number of single-book insertions needed to sort the shelf, or report impossible.	Medium4	Dynamic programmingArray	No attempts yet	8s	512 MB	Judgeable
Strange Currency SystemGiven a multiset of up to 10000 bill values, find the smallest positive amount that cannot be formed as a subset sum.	Medium4	GreedySorting+2	No attempts yet	8s	512 MB	Judgeable
Deadly Dice GameGiven a ring of red and black cells, find the start cell that maximizes the chance of landing on red after T die rolls moving clockwise.	Medium4	Dynamic programmingProbability	No attempts yet	8s	512 MB	Judgeable
Space Coconut CrabFor each energy e, find the minimum of x+y+z over nonnegative integers x,y,z with x+y^2+z^3=e, and print that minimum.	Medium4	Brute forceMath+1	No attempts yet	8s	512 MB	Judgeable
Surrounding AreaCount empty cells that flood fill from black stakes can reach without touching white stakes, and the symmetric count for white stakes.	Medium4	BFSMatrix+1	No attempts yet	8s	512 MB	Judgeable
Amida, the City of MiracleGiven n vertical lines and m horizontal rungs at various heights, trace line a downward, switching lines at each rung, and report the final line. Multiple datasets end with 0 0 0.	Medium4	SortingSimulation+1	No attempts yet	8s	512 MB	Judgeable
Monkey BusinessGiven N doors toggled by monkeys in rounds of 1 through N, print the door numbers left open, one per line, with a blank line between test cases.	Medium4	MathNumber theory+2	No attempts yet	8s	512 MB	Judgeable
Rolling CubesSimulate rolling a 1x2x4 block on a grid and report its new corner position plus the colors on its front, left, and top faces.	Medium4	SimulationImplementation+2	No attempts yet	8s	512 MB	Judgeable
First ExperienceSimulate a four-digit calculator with registers for result, input, and pending operator, printing E once an intermediate value falls outside 0 to 9999.	Medium4	SimulationImplementation+1	No attempts yet	8s	512 MB	Judgeable
How Many Days Are There?Count days between two dates whose weekday equals m and day-of-month equals n, using a proleptic Gregorian calendar that extends from 2000000 BC to 2000000 AD.	Medium4	MathImplementation+2	No attempts yet	2s	512 MB	Judgeable
Get Many Persimmon TreesGiven tree coordinates in a W by H grid and a fixed S by T window, find the window placement containing the most trees.	Medium4	Prefix sumArray+2	No attempts yet	2s	512 MB	Judgeable
Pile Up!Simulate a robot that moves numbered cubes between piles under specific stack rules, then report the final pile heights in ascending order.	Medium4	SimulationImplementation+2	No attempts yet	2s	512 MB	Judgeable
Kanglish : Analysis on Artificial LanguageTokenize each sentence into 38 possible Kan-characters using longest-match-first, then for every adjacent pair report the most frequent successor of each character, breaking ties by Kan-order.	Medium4	StringSimulation+2	No attempts yet	2s	512 MB	Judgeable
What is the Number in my Mind?Given hit-and-blow hints about a secret L-digit number with distinct digits, find the unique consistent number or report NO.	Medium4	Brute forceImplementation+2	No attempts yet	2s	512 MB	Judgeable
Multi-column ListFormat input text into pages of fixed-height columns, wrapping long lines and padding every cell with dots.	Medium4	SimulationImplementation+2	No attempts yet	2s	512 MB	Judgeable
Cyber GuardianGiven up to 1024 permit/deny rules with wildcard address patterns, decide for each packet the outcome of the highest-priority matching rule and print the legal packets.	Medium4	ImplementationString+2	No attempts yet	2s	512 MB	Judgeable
Family TreeParse an indented family tree by space count, build parent and sibling relations, then answer true/false queries about child, parent, sibling, descendant, and ancestor links.	Medium4	ImplementationTree+2	No attempts yet	2s	512 MB	Judgeable
Square CoinsCount the number of ways to represent each amount below 300 as a sum of square-valued coins (1, 4, 9, ..., 289), with order ignored.	Medium4	Dynamic programmingMath+2	No attempts yet	2s	512 MB	Judgeable
Similar Inorder TraversalSimulate a depth-first walk from the root that mimics inorder traversal, and count the total number of moves between nodes.	Medium4	TreeDFS+2	No attempts yet	1s	1024 MB	Judgeable
FatigueOver 24 hours choose work or rest each hour; work adds A fatigue and B output while rest cuts fatigue by C, and find the most output staying at or under M.	Medium4	GreedySimulation+2	No attempts yet	1s	1024 MB	Judgeable
Bus TerminalGiven N bus arrival and departure times, find the minimum number of service spaces so that no bus ever has to wait, with departures processed before simultaneous arrivals.	Medium4	SortingIntervals+2	No attempts yet	1s	1024 MB	Judgeable
Moons and UmbrellasFill each ? in a string of C, J, and ? with C or J to minimize the total cost, where each CJ substring costs X and each JC substring costs Y.	Medium4	GreedyDynamic programming+2	No attempts yet	10s	1024 MB	Judgeable
You be The Judge, AgainGiven a 2^n by 2^n grid of color labels, check whether it is a valid tiling by L-shaped triominoes with exactly one empty cell.	Medium4	ImplementationSimulation+2	No attempts yet	2s	2048 MB	Judgeable
The Professor's Calculator Is Broken!Multiply N pairs of decimals given to 9 places and print each product with exactly 18 digits after the decimal point, no exponent notation.	Medium4	MathImplementation+2	No attempts yet	1s	512 MB	Judgeable
Linear System of EquationsGiven N linear equations in N unknowns with a unique solution, find and print the values of x1 through xN.	Medium4	MathBrute force+2	No attempts yet	2s	512 MB	Judgeable
RPG Master Oh MyeongjinSimulate a turn-based fight between a hero and a demon lord whose HP triggers a one-time heal of S when it falls between 1 and P, and report whether the hero wins.	Medium4	SimulationImplementation+2	No attempts yet	0.3s	512 MB	Judgeable
Songi's Card GameSimulate a Josephus-like circle of N*K cards where each removed card's value decides the next jump; report the owner and value of the final card.	Medium4	SimulationImplementation+2	No attempts yet	1s	1024 MB	Judgeable
Dodo's Food PreparationDistribute up to C permanent time reductions among N cooks so that K dishes finish as early as possible, and report the earliest completion time.	Medium4	Binary searchGreedy+2	No attempts yet	2s	1024 MB	Judgeable
BalanceGiven a vertex budget V, find the maximum possible height of an AVL tree built with at most V vertices.	Medium4	Dynamic programmingTree+2	No attempts yet	1s	1024 MB	Judgeable
Recycled ProblemGiven a sequence, find the length of the longest contiguous subsequence that strictly increases then strictly decreases.	Medium4	ArrayImplementation+2	No attempts yet	2s	1024 MB	Judgeable
Consecutive PrimesFor each query Z, find the largest product of two consecutive primes that does not exceed Z.	Medium4	Number theoryMath+2	No attempts yet	15s	1024 MB	Judgeable
Trash BinsGiven a string of 0s and 1s marking houses with trash bins, sum the distance from every house to its nearest bin.	Medium4	ArrayImplementation+2	No attempts yet	20s	1024 MB	Judgeable
OthelloGiven an Othello board with Black to move, find the empty cell where placing a black stone flips the most white stones, or print PASS if no move is legal.	Medium4	SimulationImplementation+2	No attempts yet	1s	1024 MB	Judgeable
Balanced TernaryConvert a decimal integer between -10^9 and 10^9 into its unique balanced ternary representation, printing -1 digits as the letter T.	Medium4	MathImplementation+2	No attempts yet	1s	1024 MB	Judgeable
Histogram Sequence 3Given the height sequence produced by expanding a histogram sequence, recover any valid histogram sequence that generates it.	Medium4	ImplementationArray+2	No attempts yet	2s	1024 MB	Judgeable
APL Lives!Evaluate each line of a small APL subset with right-to-left operators, variables, rho, iota, and drop, then print the resulting vector or array.	Medium4	SimulationImplementation+1	No attempts yet	2s	1024 MB	Judgeable
BarcodesDecode a Code-11 barcode from measured light and dark region widths, check the C and K characters, and print the message or the first error found.	Medium4	ImplementationString+1	No attempts yet	2s	1024 MB	Judgeable
Sierpiński circumferenceEach iteration multiplies the number of triangles by 3 and the side length by 1/2; report the number of digits of the total perimeter 3*(3/2)^n.	Medium4	MathNumber theory+1	No attempts yet	2s	1024 MB	Judgeable
Struts and SpringsGiven inner windows with struts and springs, compute each window's new position and size for every resize of the outer window.	Medium4	SimulationImplementation	No attempts yet	2s	1024 MB	Judgeable
Suffix-Replacement GrammarsGiven a start string S, a target T, and suffix-replacement rules X to Y, find the fewest rule applications that turn S into T, or report that it is impossible.	Medium4	StringBFS	No attempts yet	2s	1024 MB	Judgeable
BlockGiven A unit squares, B dominoes, and C L-shaped trominoes, decide whether they tile a height-2 rectangle with no gaps and all tiles used.	Medium4	MathGreedy+2	No attempts yet	1s	1024 MB	Judgeable
Dogs and CatsSimulate feeding animals in line order, adding M cat portions after each dog eats, and report whether every dog gets fed before the cat food runs out.	Medium4	SimulationImplementation+2	No attempts yet	Not set	1024 MB	Judgeable
Social HierarchyGiven each person's new rank after N people are split into K groups, recover the original ranks and print each group's ranks in ascending order.	Medium4	SimulationArray	No attempts yet	1s	1024 MB	Judgeable
Aju SurvivalProcess a log of moves, farms, crafts, and attacks across 53 regions, flag the cheating entries, and list the players to block.	Medium4	SimulationImplementation+2	No attempts yet	1s	512 MB	Judgeable
Web Browser 2Simulate a web browser with backward, forward, access, and compress operations, then print the current page and both history stacks.	Medium4	SimulationStack+2	No attempts yet	1s	512 MB	Judgeable
Propagation and Merging 2Given a grid where each cell references zero, one, or two other cells, decide whether the reference graph contains a cycle.	Medium4	GraphDFS+2	No attempts yet	2s	512 MB	Judgeable
AKARAKADecide whether a string is a palindrome whose first and last half-length prefixes and suffixes are themselves akaraka palindromes, recursively.	Medium4	StringRecursion+2	No attempts yet	1s	512 MB	Judgeable
Sum of Distances 2Given n coordinates on a line, compute the sum of absolute differences over all ordered pairs.	Medium4	SortingPrefix sum+2	No attempts yet	0.5s	1024 MB	Judgeable
Drunk PassengerGiven n passengers where the first sits in a random seat and each displaced passenger picks a random free seat, find the probability that the last passenger's seat is taken.	Medium4	ProbabilityMath+2	No attempts yet	1s	1024 MB	Judgeable
Almost AlwaysGiven n random integers up to 2e9, output two distinct indices i and j such that a_i divides a_j. The probability that no such pair exists is negligible for large n.	Medium4	SortingMath+2	No attempts yet	2s	1024 MB	Judgeable
Ice GrowthIce thickness changes each day by a_i/5, never dropping below zero; for each person, count the days the thickness reaches their required minimum.	Medium4	ArrayPrefix sum+2	No attempts yet	1.5s	1024 MB	Judgeable
EscalatorSimulate a bidirectional escalator that carries riders in 10-second trips, where riders going against the current direction wait, and report the time the last rider exits.	Medium4	SimulationImplementation+2	No attempts yet	1s	1024 MB	Judgeable
KathmanduGiven flight length D, meal times, and required sleep T, decide whether there is a block of T consecutive minutes containing no meal.	Medium4	ArrayGreedy+1	No attempts yet	1s	1024 MB	Judgeable
BackupGiven a weekly schedule of backup levels and a recovery day, list the days whose backups are needed, in increasing order of day and level.	Medium4	ImplementationGreedy+2	No attempts yet	2s	256 MB	Judgeable
Steve's perfectionismGiven an array of positive integers, output a strictly increasing array of the same length where each element is a multiple of the matching input element, at most 1e9.	Medium4	GreedyMath	No attempts yet	1s	256 MB	Judgeable
Least Common DivisorGiven two short strings, find the shortest string that divides both, meaning it repeats a whole number of times to form each, or report that none exists.	Medium4	StringMath+2	No attempts yet	2s	512 MB	Judgeable
GaokaoFor each of up to 500 queries, count how many entries in row K of Pascal's triangle are odd, where K can reach 10^18.	Medium4	MathCombinatorics+2	No attempts yet	1s	256 MB	Judgeable
Find the HouseStarting from a given position, repeatedly follow the triple whose start matches the current position, then print the position reached after all triples are used.	Medium4	Hash mapSimulation+1	No attempts yet	1s	1024 MB	Judgeable
TramplerFor each starting cell of an H by W grid, follow a fixed move string and output the sum of visited cell times, or 0 if the path leaves the field.	Medium4	SimulationImplementation+2	No attempts yet	2s	256 MB	Judgeable
Devil's Annual Leave CalculatorGiven a joining date and a later date on a 30-day month, 12-month year calendar, compute total monthly and annual leave earned plus days of service.	Medium4	ImplementationMath+2	No attempts yet	1s	512 MB	Judgeable
Find the Longest SubsequenceFind the longest subsequence whose bitwise AND is nonzero; this equals the largest count of elements sharing any single set bit.	Medium4	Bit manipulationArray	No attempts yet	1s	512 MB	Judgeable
Sincere Side-to-Side Repeat JumpGiven N and K, ZeroX jumps K, 2K, 3K, ... alternating right and left, and stops after total distance N-1; report the final coordinate and facing direction.	Medium4	MathImplementation	No attempts yet	0.15s	512 MB	Judgeable
Marbles Tell Your Lucky NumberSimulate repeatedly subtracting the leftmost minimum value from all other non-empty bowls until one non-empty bowl remains, and report its count.	Medium4	SimulationImplementation+1	No attempts yet	2s	1024 MB	Judgeable
Physics ExperimentRound a given integer zero or more times to any place to maximize its value, and print the maximum reachable result.	Medium4	GreedyMath+2	No attempts yet	1s	1024 MB	Judgeable
Successful StringCount substrings of a given string that contain at least one pair of equal adjacent characters.	Medium4	StringCombinatorics+2	No attempts yet	1s	1024 MB	Judgeable
CrammingGiven chapter study times, simulate 30-minute study blocks that cut off the current chapter when a block ends, and count chapters studied at least half.	Medium4	SimulationImplementation+2	No attempts yet	1s	1024 MB	Judgeable
Player-based Team DistributionPartition N players into teams; a player with value a_i in a team of size s scores s*a_i. Maximize the total score.	Medium4	GreedySorting+2	No attempts yet	1s	1024 MB	Judgeable
Card ControlGiven a deck of N O cards and N X cards, find the fewest times you must move a chosen card to the top so that Junseok, who takes cards 1, 3, 5, ..., wins.	Medium4	Brute forceGreedy+1	No attempts yet	1s	1024 MB	Judgeable
KnitpickingGiven groups of socks with a type and a fit (left, right, any), find the minimum number of socks that must be drawn to guarantee a matching pair, or report impossible.	Medium4	GreedyMath+1	No attempts yet	1s	1024 MB	Judgeable
2,147,483,648 GameGiven an 8x8 2048-style board and one arrow key, apply the slide-and-merge rules once and print the resulting board.	Medium4	SimulationImplementation+2	No attempts yet	1s	512 MB	Judgeable
Humanities and Arts Exploration WeekGiven N tree positions and Q query points, output for each query the sum of absolute distances to all trees.	Medium4	SortingPrefix sum+2	No attempts yet	2s	512 MB	Judgeable
Coprime GraphCount pairs (a, b) with 1 <= a < b <= N whose greatest common divisor is 1.	Medium4	MathNumber theory+2	No attempts yet	1s	512 MB	Judgeable
A Certain Milk Delivery List (Easy)On a tree, each type 1 query adds 1, 2, 3, ... to successive rooms along the path from u to v; type 2 queries ask the total delivered to a room.	Medium4	TreePrefix sum+2	No attempts yet	1s	512 MB	Judgeable
LampiceGiven a sequence of n colors, cut any prefix and suffix so that the remaining block is some pattern repeated exactly k times, and print that pattern.	Medium4	Brute forceImplementation+2	No attempts yet	1s	512 MB	Judgeable
Algorithm Class - Selection Sort 2Simulate selection sort on an array and print the array right after the K-th swap, or -1 if fewer than K swaps occur.	Medium4	SimulationSorting+2	No attempts yet	1s	512 MB	Judgeable
Algorithm Class - Selection Sort 4Simulate selection sort on N distinct integers and print the array right after the K-th swap, or -1 if fewer than K swaps happen.	Medium4	ImplementationSorting+2	No attempts yet	3s	512 MB	Judgeable
Bus RoutesGiven bus routes with fixed periods and a deadline D, find the latest day to start so every route can be boarded in order by D. Work backward from D, rounding each boarding down to the largest multiple of its period.	Medium4	GreedyMath+1	No attempts yet	10s	1024 MB	Judgeable
ATM QueueEach person in a queue needs a fixed amount, takes at most X per turn, and rejoins the back if more is owed; output the order in which people finish.	Medium4	SortingSimulation+2	No attempts yet	20s	1024 MB	Judgeable
Kick StartCount the substrings of a given string that begin with KICK and end with START, treating different positions as different fragments.	Medium4	StringString matching+1	No attempts yet	Not set	1024 MB	Judgeable
Combination LockGiven W wheel positions on a cycle of values 1..N, find the target value minimizing the total circular distance all wheels must travel.	Medium4	ArrayMath+2	No attempts yet	40s	1024 MB	Judgeable
TrainingChoose exactly P students and raise their skills to a common value by adding 1 per hour; find the minimum total hours.	Medium4	SortingSliding window+2	No attempts yet	15s	1024 MB	Judgeable
Building PalindromesCount how many substrings of a string can be rearranged into a palindrome, using prefix counts of each letter to check odd frequencies.	Medium4	Prefix sumHash map+2	No attempts yet	30s	1024 MB	Judgeable
H-indexGiven a stream of citation counts, report the H-index after each new paper, where the H-index is the largest h with h papers cited at least h times.	Medium4	SortingGreedy+1	No attempts yet	50s	1024 MB	Judgeable
Algorithm Class - Bubble Sort 2Simulate bubble sort on N distinct integers and print the array right after the K-th swap, or -1 if fewer than K swaps happen.	Medium4	SimulationSorting+2	No attempts yet	1s	512 MB	Judgeable
Finding the PasswordFind the smallest positive integer P such that for every element a of A, the difference a - (P mod a) equals K.	Medium4	MathNumber theory+2	No attempts yet	1s	512 MB	Judgeable
X SquaredGiven an odd N by N grid holding exactly 2N-1 X tiles, decide whether row and column swaps can place every X on the two main diagonals.	Medium4	MatrixGreedy+2	No attempts yet	20s	1024 MB	Judgeable
Pretty CakeFor each N, decide whether the base can be an a by b rectangle with a times b equal to N and a plus b divisible by 3.	Medium4	MathNumber theory	No attempts yet	1s	1024 MB	Judgeable
Algorithm Class - Insertion Sort 2Simulate insertion sort on N distinct integers and print the array right after the K-th element shift, or -1 if fewer than K shifts occur.	Medium4	SimulationSorting+2	No attempts yet	1s	512 MB	Judgeable
AdvertisementGiven a directed graph of who knows whose contact, find the minimum number of people to seed so the news reaches everyone.	Medium4	GraphDFS+2	No attempts yet	1s	1024 MB	Judgeable
Building DecorationGiven a sequence of building heights, find the length of the longest strictly increasing subsequence.	Medium4	Dynamic programmingArray+1	No attempts yet	1s	1024 MB	Judgeable