Problems

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Total results29,469 problems

HDD
Easy3
Array, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Sea Battle
Easy3
Matrix, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Blog Rating Game
Easy3
Prefix sum, Simulation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Jedi versus Sith
Easy3
Math, Brute force
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Fibonacci Strings
Easy3
Recursion, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Uncle Fyodor's Candies
Easy3
Math, Brute force
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Arranging Books
Easy3
Brute force, Backtracking
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Dates
Easy3
Implementation, Simulation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Income Tax
Easy3
Implementation, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Trams
Easy3
Simulation, Two pointers
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Balls
Easy3
Math, Simulation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Electronic Clock
Easy3
Implementation, Simulation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Bryak
Easy3
Simulation, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Alpha-ville and Beta-ville
Easy3
Array, Greedy
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Hotel
Easy3
Matrix, Implementation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Text
Easy3
Greedy, String
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Calendar
Easy3
Prefix sum, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Rectangular polygon
Easy3
Math, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Olympic Games
Easy3
Hash map, Sorting
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Cutting the Blank
Easy3
Math, Brute force
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
A True Expression
Easy3
Brute force, Implementation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
File System
Easy3
String, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Apricot Harvest
Easy3
Prefix sum, Brute force
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
ShaShka (ШАШКА)
Easy3
Simulation, Hash map+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Coins and Nests
Easy3
Dynamic programming
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Modular Inverse
Easy3
Number theory, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Movie Booking Chaos
Easy3
Array, Sliding window
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Penguin's Day
Easy3
Matrix, BFS
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Finding the password
Easy3
Brute force, Backtracking+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Clap in a Row
Easy3
Prefix sum, Sliding window+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Night Watch Duty of Brisi
Easy3
Math, Combinatorics
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Variant Chess: Dabbaba
Easy3
Hash map, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Bsil's Admission Strategy
Easy3
Sorting, Hash map+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Among the many YouTubers, virtual YouTubers exist
Easy3
Hash map, Simulation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Maximize the score
Easy3
Prefix sum, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Colliding Encoding
Easy3
Hash map, String
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
Rainbow Sort
Easy3
Array, Hash map+1
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
Erda Nova and Origin Skill
Easy3
Greedy, Sorting+1
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
What is your Suneung score?
Easy3
Brute force, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
My Favorite Teammate
Easy3
Queue, Simulation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Circus
Easy3
BFS, Graph
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Driving in the Mountains
Easy3
Implementation, Prefix sum
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Palindrome
Easy3
String, Greedy
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Broken Piano
Easy3
Brute force, Array+1
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
Ranking
Easy3
Hash map, Sorting
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
No Change
Easy3
Sorting, Greedy
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Monkeying Around
Easy3
Math, Simulation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Dividing apples
Easy3
Array, Prefix sum
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Deducing relationships
Easy3
Brute force, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Sum
Easy3
Two pointers, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Cave Trip
Easy3
BFS, Graph+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Board Game
Easy3
Graph, BFS
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Rabbit Hooks
Easy3
Array, Dynamic programming
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Fatigue-Fighting Vacation
Easy3
Simulation, Two pointers
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
Investigating Zeroes and Ones
Easy3
Prefix sum, Math
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
Lexicographical Challenge
Easy3
String, Sorting+1
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
Line on Paper
Easy3
Math, Simulation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Tashu
Easy3
Greedy, Prefix sum
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Lecture Room Reservation System
Easy3
Array, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Cheeseburger Making 2
Easy3
Implementation, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Preparing for the Event
Easy3
Sorting, Greedy
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Slice String
Easy3
String, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
INK
Easy3
Simulation, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Function String
Easy3
String, Stack
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Escape Room
Easy3
String, Greedy
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Smart Scale
Easy3
Simulation, Binary search
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Parking Lot
Easy3
Hash map, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Badminton
Easy3
Brute force, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Hike
Easy3
Simulation, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Crossword
Easy3
Brute force, String+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Exams
Easy3
Sorting, Intervals
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Golden coins
Easy3
Matrix, Dynamic programming
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Voriukas
Easy3
Hash map, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Postcards
Easy3
Graph, BFS
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Polite People
Easy3
Simulation, Queue
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Vaccine Development
Easy3
Brute force, String
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Hyeon's Robot Vacuum
Easy3
Graph, BFS
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Find Terrorists
Easy3
Math, Number theory+1
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Square-Free Numbers
Easy3
Number theory, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Christmas Play
Easy3
Sorting, Sliding window
No attempts yet
Time limit
10s
Memory limit
1024 MB
Judgeable
Plus Shape in a Picture
Easy3
Implementation, Matrix
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Marginimas
Easy3
Math, Number theory
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Military Off-Base Meal
Easy3
Math, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Rightsizing
Easy3
Heap, Hash map
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Snailography
Easy3
Simulation, Matrix+1
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Increasing Sequence
Easy3
Greedy, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
P-22 is ready for his Closeup
Easy3
Hash map, Array
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Requiescat in Pace
Easy3
Geometry, Brute force
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Velsas
Easy3
Sliding window, Two pointers+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Average Temperature
Easy3
Prefix sum, Hash map
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Quarry
Easy3
Prefix sum, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Zvimbalius
Easy3
String, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Beautiful Houses
Easy3
Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Better Dice
Easy3
Sorting, Two pointers+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Finding Forks
Easy3
Sorting, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Idle Terminal
Easy3
Simulation, Heap+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Just a Joystick
Easy3
String, Greedy
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Better Chance
Easy3
Math, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Location, Location, Location
Easy3
Sorting, Math
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Linas and Tangerines
Easy3
Greedy, Sorting
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
HDDGiven block numbers in disk rotation order, count the full rotations needed to read blocks 1 through n in sequence.	Easy3	ArrayImplementation	No attempts yet	2s	1024 MB	Judgeable
Sea BattleGiven an n by m board and k ships, print INCORRECT if any ships overlap or touch, otherwise count the cells where a new 1x1 ship can go without touching any ship.	Easy3	MatrixImplementation	No attempts yet	2s	1024 MB	Judgeable
Blog Rating GameGiven fixed daily changes and bounded unknown changes, find the first day the rating can exceed M (Petya) and the first day it can drop below -M (Vasya).	Easy3	Prefix sumSimulation	No attempts yet	2s	1024 MB	Judgeable
Jedi versus SithGiven Jedi and Sith abilities that grow linearly each day, find the first day when every Jedi ability is at least the matching Sith ability, or report that it never happens.	Easy3	MathBrute force	No attempts yet	2s	1024 MB	Judgeable
Fibonacci StringsGiven n and k, find the k-th character of the Fibonacci string F_n, where F_0 is a, F_1 is b, and F_i is F_(i-2) followed by F_(i-1).	Easy3	RecursionMath	No attempts yet	2s	1024 MB	Judgeable
Uncle Fyodor's CandiesGiven n candies, decide whether they can form a truncated tetrahedron, where consecutive triangular-number layers are stacked with the top layers removed.	Easy3	MathBrute force	No attempts yet	2s	1024 MB	Judgeable
Arranging BooksCount the orderings of n books on a shelf where every adjacent pair's combined page count is at most the limit a_i between them.	Easy3	Brute forceBacktracking	No attempts yet	2s	1024 MB	Judgeable
DatesGiven the set of digits the calendar can show and a date range, count the days in the range (both ends included) whose DD.MM.YYYY form uses only those digits.	Easy3	ImplementationSimulation	No attempts yet	2s	1024 MB	Judgeable
Income TaxGiven income X and progressive tax brackets with thresholds U_i and rates p_i, the task is to compute the total income tax.	Easy3	ImplementationMath	No attempts yet	2s	1024 MB	Judgeable
TramsGiven tram arrival times, passenger arrival times, and tram capacity, the task finds which tram each passenger boards in queue order, or -1 if none.	Easy3	SimulationTwo pointers	No attempts yet	2s	1024 MB	Judgeable
BallsGiven two balls with integer positions and velocities that swap velocities on each elastic collision, print each ball's position and velocity at time T.	Easy3	MathSimulation	No attempts yet	2s	1024 MB	Judgeable
Electronic ClockGiven ten n by m LED digit pictures, find the total number of LED switches over all 1440 minute changes in a day, including the wrap from 23:59 to 00:00.	Easy3	ImplementationSimulation	No attempts yet	1s	1024 MB	Judgeable
BryakGiven containers with volumes and concentrations and a list of pours between them, find the final volume and concentration of each container.	Easy3	SimulationImplementation	No attempts yet	2s	1024 MB	Judgeable
Alpha-ville and Beta-villeGiven a waiting list of N numbers and M friend numbers, find the fewest swaps that move every friend ahead of all non-friends.	Easy3	ArrayGreedy	No attempts yet	1s	512 MB	Judgeable
HotelGiven a grid of blue corridor cells and red room cells, find the area of the largest red rectangle, or -1 if there is none.	Easy3	MatrixImplementation+1	No attempts yet	2s	1024 MB	Judgeable
TextSplit a text into the fewest lines of at most k characters each, keeping every word and the word order unchanged.	Easy3	GreedyString	No attempts yet	2s	1024 MB	Judgeable
CalendarCount, across all months, the day numbers from 1 to each month's length that contain at least one broken digit.	Easy3	Prefix sumImplementation	No attempts yet	2s	1024 MB	Judgeable
Rectangular polygonGiven area S and perimeter P, find integer side lengths a and b (a >= b) of a rectangle with those values, or print -1 if none exist.	Easy3	MathImplementation	No attempts yet	2s	1024 MB	Judgeable
Olympic GamesGiven n medal sets of gold, silver, and bronze winners, find the country that ranks first by medal counts, breaking ties by name.	Easy3	Hash mapSorting	No attempts yet	2s	1024 MB	Judgeable
Cutting the BlankGiven the cut widths a and b and the remaining area S, find the integer side length L of the original square, or report -1 if none exists.	Easy3	MathBrute force	No attempts yet	2s	1024 MB	Judgeable
A True ExpressionGiven an expression A ? B = C with up to 1000-digit integers, list every base from 2 to 10 in which the equation holds.	Easy3	Brute forceImplementation+1	No attempts yet	2s	1024 MB	Judgeable
File SystemConvert a file name to the 8.3 format by uppercasing it, cleaning spaces, forbidden characters, and dots, then truncating to a six-character stem and a three-character extension.	Easy3	StringImplementation	No attempts yet	2s	1024 MB	Judgeable
Apricot HarvestCount all square sub-tables of the n by m grid whose sum is less than S, over every square size.	Easy3	Prefix sumBrute force	No attempts yet	2s	1024 MB	Judgeable
ShaShka (ШАШКА)Update Elo ratings after each game in input order, then print all players by rating descending and surname ascending.	Easy3	SimulationHash map+1	No attempts yet	2s	1024 MB	Judgeable
Coins and NestsGiven n nests holding a_i coins that fall at b_i, pick nests to fill with at most m coins to maximize the total b_i collected from fallen nests.	Easy3	Dynamic programming	No attempts yet	2s	1024 MB	Judgeable
Modular InverseGiven a prime m and a number a with 1 at most a less than m, find b in [1, m) with a times b leaving remainder 1 modulo m.	Easy3	Number theoryMath	No attempts yet	2s	1024 MB	Judgeable
Movie Booking ChaosCount the ways to place K club members in consecutive empty seats along one horizontal row, where '1' marks reserved seats.	Easy3	ArraySliding window	No attempts yet	1s	1024 MB	Judgeable
Penguin's DayFind the shortest walk from S through at least one F cell to H on a grid where D cells are blocked, or report -1 if none exists.	Easy3	MatrixBFS	No attempts yet	1s	1024 MB	Judgeable
Finding the passwordGiven the known digits and positions, find the longest time to open the lock when every candidate is tried once and each run of three failures forces a Y-second wait.	Easy3	Brute forceBacktracking+1	No attempts yet	1s	1024 MB	Judgeable
Clap in a RowGiven an N by M grid of clap counts, find the largest total clap count over any A consecutive columns spanning all rows.	Easy3	Prefix sumSliding window+1	No attempts yet	2s	1024 MB	Judgeable
Night Watch Duty of BrisiCount the length-N sequences of soldiers from M candidates in which the fixed soldier Brisi appears at least once, modulo 1,000,000,007.	Easy3	MathCombinatorics	No attempts yet	1s	1024 MB	Judgeable
Variant Chess: DabbabaCount the distinct empty squares on an N by N board that at least one Dabbaba can reach by moving exactly 2 squares up, down, left, or right.	Easy3	Hash mapImplementation	No attempts yet	2s	1024 MB	Judgeable
Bsil's Admission StrategyGiven subject scores, find the minimum and maximum total of M subjects that must include the K publicly announced ones.	Easy3	SortingHash map+1	No attempts yet	1s	1024 MB	Judgeable
Among the many YouTubers, virtual YouTubers existGiven broadcast logs, find the YouTubers who have 5 broadcasts in some Sunday-to-Saturday week with 60 hours or more of total live time.	Easy3	Hash mapSimulation+1	No attempts yet	1s	1024 MB	Judgeable
Maximize the scoreChoose K distinct destination classrooms so that the sum of prefix sums of A up to each chosen index is as large as possible.	Easy3	Prefix sumSorting+1	No attempts yet	1s	1024 MB	Judgeable
Colliding EncodingGiven a digit for each letter A to Z and a list of words, determine whether two different words encode to the same digit string.	Easy3	Hash mapString	No attempts yet	20s	1024 MB	Judgeable
Rainbow SortGiven colored cards in a line, list the colors in the order their integers must follow, or report IMPOSSIBLE if some color's cards are not contiguous.	Easy3	ArrayHash map+1	No attempts yet	20s	1024 MB	Judgeable
Erda Nova and Origin SkillGiven hotkey press times for two skills with cooldowns of 100 and 360 seconds, count how many presses actually apply each skill to the monster.	Easy3	GreedySorting+1	No attempts yet	1.5s	1024 MB	Judgeable
What is your Suneung score?Given a student ID, find every pair of Korean-English and math-inquiry score differences that produces it under the Hanyang formula.	Easy3	Brute forceMath+1	No attempts yet	1s	1024 MB	Judgeable
My Favorite TeammateEach student in a line pairs with the X-th person from the front, moving the passed ones to the back; output the initials of the last one left.	Easy3	QueueSimulation	No attempts yet	1s	1024 MB	Judgeable
CircusFind the fewest die rolls needed to move a piece from square 1 to square N past snakes and ladders, and print one optimal sequence of die results.	Easy3	BFSGraph	No attempts yet	1s	1024 MB	Judgeable
Driving in the MountainsGiven ground heights and Juta's height changes per meter, output whether she is on the ground, on a viaduct, or in a tunnel after each meter.	Easy3	ImplementationPrefix sum	No attempts yet	1s	1024 MB	Judgeable
PalindromeGiven a string of N uppercase letters, find the fewest replacements needed to make it a palindrome, and print the alphabetically smallest result.	Easy3	StringGreedy	No attempts yet	1s	1024 MB	Judgeable
Broken PianoGiven broken piano keys and a MIDI piece, count the notes that cannot be played and find the smallest transposition that makes the whole piece playable.	Easy3	Brute forceArray+1	No attempts yet	0.5s	1024 MB	Judgeable
RankingGiven N solutions, each with a participant, a task, and points, output each participant's total, where each task counts only the best score they submitted.	Easy3	Hash mapSorting	No attempts yet	1s	1024 MB	Judgeable
No ChangeGiven N coin values, find the smallest positive amount that cannot be formed by summing some subset of the coins.	Easy3	SortingGreedy	No attempts yet	1s	1024 MB	Judgeable
Monkeying AroundEach monkey has one unknown jump that makes its total displacement zero. Find the monkey whose average height over the M jumps is highest.	Easy3	MathSimulation	No attempts yet	1s	1024 MB	Judgeable
Dividing applesGiven N baskets of apples, find the split point where the apple totals on the left and right differ by the least amount.	Easy3	ArrayPrefix sum	No attempts yet	1s	1024 MB	Judgeable
Deducing relationshipsGiven two relations among a, b, and c, fill the 3x3 table with the strongest relation deducible for each pair, or print VASTUOLU if they contradict.	Easy3	Brute forceImplementation	No attempts yet	1s	1024 MB	Judgeable
SumCount the pairs of distinct elements in a sorted array of N distinct integers that add up to S.	Easy3	Two pointersArray	No attempts yet	1s	1024 MB	Judgeable
Cave TripFind the shortest path from the '@' cell to any border cell of a grid cave and mark it with asterisks, or print -1 if no exit is reachable.	Easy3	BFSGraph+1	No attempts yet	1s	1024 MB	Judgeable
Board GameGiven a cyclic board where 0 cells roll a six-sided die and other cells jump by their value, find which cells can be visited from cell 1.	Easy3	GraphBFS	No attempts yet	1s	1024 MB	Judgeable
Rabbit HooksGiven N points recorded in order, find the most hops in a consecutive run where northeast and southeast hops strictly alternate.	Easy3	ArrayDynamic programming	No attempts yet	1s	1024 MB	Judgeable
Fatigue-Fighting VacationGiven starting disposition D and two ordered activity lists, count how many activities William can perform under his choose-tiring-first rule.	Easy3	SimulationTwo pointers	No attempts yet	0.5s	1024 MB	Judgeable
Investigating Zeroes and OnesCount the contiguous subarrays of a binary array that contain an odd number of ones, with N up to 10^5.	Easy3	Prefix sumMath	No attempts yet	0.5s	1024 MB	Judgeable
Lexicographical ChallengeGiven a string S and an integer K, find the lexicographically smallest string reachable by swapping S_i with S_(i+K) any number of times.	Easy3	StringSorting+1	No attempts yet	0.5s	1024 MB	Judgeable
Line on PaperGiven a step count N up to 10^18, the task is to find the grid cell reached by a spiral-like polyline path starting at (1, 1).	Easy3	MathSimulation	No attempts yet	1s	1024 MB	Judgeable
TashuGiven current and target bike counts per station, find the minimum number of single-bike moves to reach the target counts.	Easy3	GreedyPrefix sum	No attempts yet	1s	1024 MB	Judgeable
Lecture Room Reservation SystemGiven reservation requests sorted by start time, decide for each whether it overlaps an accepted booking in the same room and print YES or NO.	Easy3	ArrayGreedy+1	No attempts yet	1s	1024 MB	Judgeable
Cheeseburger Making 2Given A patties and B cheese slices, decide whether every item can go into burgers that each have exactly one more patty than cheese, and print one valid build if so.	Easy3	ImplementationMath	No attempts yet	1s	1024 MB	Judgeable
Preparing for the EventEach item is bought at store 1 or store 2, with exactly A items from store 1, and the task asks for the minimum total cost.	Easy3	SortingGreedy	No attempts yet	1s	1024 MB	Judgeable
Slice StringGiven character and digit delimiters, mergers that exempt characters from splitting, and a string, print the pieces left after splitting on spaces and delimiters.	Easy3	StringImplementation	No attempts yet	1s	1024 MB	Judgeable
INKSimulate a square on an N by N grid that moves, stores ink, and jumps to dye obstacles within Manhattan distance, then print the final grid.	Easy3	SimulationImplementation	No attempts yet	1s	1024 MB	Judgeable
Function StringEvaluate a prefix-notation string of f, g, and x, where x is 0, g adds 1, and f takes the smaller of two sub-strings, or print -1 if the string is malformed.	Easy3	StringStack	No attempts yet	1s	1024 MB	Judgeable
Escape RoomFind the shortest prefix of the hint string that contains RAKTAS as a subsequence, and print its length.	Easy3	StringGreedy	No attempts yet	1s	1024 MB	Judgeable
Smart ScaleGiven N weight measurements and a threshold D, count how many distinct customers the scale registers under the stated assignment rules.	Easy3	SimulationBinary search	No attempts yet	1s	1024 MB	Judgeable
Parking LotGiven timestamped entry and exit records for cars, print each car number and the seconds it stayed, in the order the cars left.	Easy3	Hash mapImplementation	No attempts yet	1s	1024 MB	Judgeable
BadmintonPair Bitai's six players into three teams to maximize the wins among nine pair-versus-pair matches against Baitai's three pair strengths.	Easy3	Brute forceImplementation	No attempts yet	1s	1024 MB	Judgeable
HikeGiven the altitude sequence of a route and the energy costs of climbing, descending, and resting, find the total time for a hike that starts and ends at sea level.	Easy3	SimulationImplementation	No attempts yet	1s	1024 MB	Judgeable
CrosswordGiven three words, find crossings that connect all three into a valid crossword and print each crossing's letter positions.	Easy3	Brute forceString+1	No attempts yet	1s	1024 MB	Judgeable
ExamsGiven N exams, each occupying minutes a_i up to but excluding b_i, find the largest number of exams that overlap at any single minute.	Easy3	SortingIntervals	No attempts yet	1s	1024 MB	Judgeable
Golden coinsFind the maximum gold coins collected on a grid moving only down or right from the top left cell, avoiding buildings.	Easy3	MatrixDynamic programming	No attempts yet	1s	1024 MB	Judgeable
VoriukasGiven sock kinds and wash operations that each lose some socks, report after every wash how many full sets of K same-kind socks remain.	Easy3	Hash mapMath	No attempts yet	2s	1024 MB	Judgeable
PostcardsCount the friends reachable from Linas's close friends through known-each-other links, since every reached friend must also get a postcard.	Easy3	GraphBFS	No attempts yet	1s	1024 MB	Judgeable
Polite PeopleGiven N people in a line and a sequence of A doors (front person moves to the back) and B doors (line reverses), print the final order.	Easy3	SimulationQueue	No attempts yet	1s	1024 MB	Judgeable
Vaccine DevelopmentGiven up to 9 strings, find the shortest length after joining them in some order, merging each adjacent pair by its largest overlap.	Easy3	Brute forceString	No attempts yet	1s	1024 MB	Judgeable
Hyeon's Robot VacuumCount the connected components of an N by M height grid, where adjacent cells connect when their height difference is at most K.	Easy3	GraphBFS	No attempts yet	1s	1024 MB	Judgeable
Find TerroristsFor each range L to H, the task lists every integer whose divisor count is prime, or prints -1 when none exists.	Easy3	MathNumber theory+1	No attempts yet	5s	1024 MB	Judgeable
Square-Free NumbersGiven N, find the fewest square-free factors (each greater than 1) whose product is N.	Easy3	Number theoryMath	No attempts yet	2s	1024 MB	Judgeable
Christmas PlayPick K of N heights so that the gap between the tallest and shortest picked heights is as small as possible, and report that gap for each test case.	Easy3	SortingSliding window	No attempts yet	10s	1024 MB	Judgeable
Plus Shape in a PictureDecide whether a grid of stars and dots contains exactly one plus shape whose four arms each have at least one star.	Easy3	ImplementationMatrix	No attempts yet	1s	1024 MB	Judgeable
MarginimasCount the eggs fully painted within N hours, where an egg is complete only if every robot works in the hour it is placed, so the answer is N divided by the LCM of all a_i.	Easy3	MathNumber theory	No attempts yet	1s	1024 MB	Judgeable
Military Off-Base MealGiven soldier counts for N barracks and a divisor X, decide whether all barracks can be split into groups whose soldier totals are each divisible by X.	Easy3	MathArray	No attempts yet	1s	1024 MB	Judgeable
RightsizingGiven raises and firings in order, print the name and salary of each fired employee, the one with the highest salary at that moment (ties go to the earlier name).	Easy3	HeapHash map	No attempts yet	5s	1024 MB	Judgeable
SnailographyFill an n by n odd-sized grid with the message letters in an outward spiral from the center, then read the grid row by row.	Easy3	SimulationMatrix+1	No attempts yet	5s	1024 MB	Judgeable
Increasing SequenceGiven a sequence a, find the smallest possible last value b_n of a strictly increasing positive sequence where each b_i differs from a_i.	Easy3	GreedyImplementation	No attempts yet	1s	1024 MB	Judgeable
P-22 is ready for his CloseupGiven camera setups and P-22 sightings by time and location, find the largest glamour of a location where both happen at the same time.	Easy3	Hash mapArray	No attempts yet	5s	1024 MB	Judgeable
Requiescat in PaceGiven candidate points and line segments for trails and roads, find the candidate whose distance to the nearest segment is largest.	Easy3	GeometryBrute force	No attempts yet	1s	1024 MB	Judgeable
VelsasFind the shortest contiguous run of daily route heights whose sum is at least M, or report NEPAVYKS if no such run exists.	Easy3	Sliding windowTwo pointers+1	No attempts yet	1s	1024 MB	Judgeable
Average TemperatureGiven a string of N plus and minus signs, find the length of the longest contiguous stretch with equal counts of each.	Easy3	Prefix sumHash map	No attempts yet	1s	1024 MB	Judgeable
QuarryApply K range commands that each lower the elevations on [S, E] by H to an initial array, then print every final elevation.	Easy3	Prefix sumArray	No attempts yet	1s	1024 MB	Judgeable
ZvimbaliusGiven a string of N moves in four directions, find the fewest moves to change so the drone ends at its starting point, or report NEGALIMA.	Easy3	StringMath	No attempts yet	1s	1024 MB	Judgeable
Beautiful HousesFor each house, find how many floors it must gain to be taller than every house with a larger number, or 0 if it already is.	Easy3	Array	No attempts yet	1s	1024 MB	Judgeable
Better DiceGiven two dice with n faces each, decide which die is more likely to roll a higher number, or whether the two chances are equal.	Easy3	SortingTwo pointers+1	No attempts yet	1s	1024 MB	Judgeable
Finding ForksGiven the number of forks of each type left in the drawer, find the fewest forks that could have been in the dishwasher to leave two places empty.	Easy3	SortingImplementation	No attempts yet	1s	1024 MB	Judgeable
Idle TerminalGiven n jobs run first-come-first-serve on k cores, find the longest gap between job completions, counting from time 0.	Easy3	SimulationHeap+1	No attempts yet	1s	1024 MB	Judgeable
Just a JoystickGiven two equal-length uppercase strings, find the fewest up or down joystick moves to change one into the other, with wrap-around between A and Z.	Easy3	StringGreedy	No attempts yet	1s	1024 MB	Judgeable
Better ChanceGiven two regional team ranks and their site scores, decide which regional gives your team the better chance of advancing to the playoff.	Easy3	MathImplementation	No attempts yet	1s	1024 MB	Judgeable
Location, Location, LocationGiven n integer points, find the point that minimizes the total Manhattan distance to all of them, breaking ties by smallest x, then smallest y.	Easy3	SortingMath	No attempts yet	3s	1024 MB	Judgeable
Linas and TangerinesGiven tangerines with their expiry days and a limit of K per day, find the most tangerines Linas can eat before they go bad.	Easy3	GreedySorting	No attempts yet	1s	1024 MB	Judgeable