Problems

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Total results29,460 problems

Small World Network
Medium4
Graph, BFS+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
The New Year's Bell
Medium4
Sorting, Greedy+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
MooBuzz
Medium4
Math, Binary search+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Where Am I?
Medium4
String, Brute force+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Eloquent Evaluator
Medium4
String, Brute force+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Viyott's Stepping Stone Crossing
Medium4
Math, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Ants
Medium4
Array, Hash map+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Hiding Nuts
Medium4
Math, Brute force+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Antenna
Medium4
Sorting, Math+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Round Trip
Medium4
Array, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Photoshoot
Medium4
Brute force, Implementation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Valid Emails
Medium4
String, Hash map+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Finding Cities at a Specific Distance
Medium4
Graph, BFS+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Arranging Soldiers
Medium4
Dynamic programming, Array+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
2048
Medium4
Simulation, Implementation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
TATCK
Medium4
Geometry, Math+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
LTBL
Medium4
Implementation, Sorting+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
RUN
Medium4
Graph, Shortest path+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Digit Sum
Medium4
Dynamic programming, Math+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Emacs
Medium4
Implementation, Array+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Muscle Loss
Medium4
Brute force, Backtracking+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Jump Jump
Medium4
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Hopscotch 50
Medium4
Dynamic programming, Implementation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Mad Scientist
Medium4
Greedy, String+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Moving 3
Medium4
Greedy, Math+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Maximum Subarray 2147483647
Medium4
Dynamic programming, Array+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Multiverse II
Medium4
Sorting, Hash map+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Coordinate Compression
Medium4
Sorting, Hash map+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Sequence and Queries 38
Medium4
Hash map, Implementation+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Ladder
Medium4
Greedy, Sorting+2
No attempts yet
Time limit
2s
Memory limit
64 MB
Judgeable
Toy Alliances
Medium4
Graph, BFS+2
No attempts yet
Time limit
1.5s
Memory limit
256 MB
Judgeable
Don't Split The Atom!
Medium4
Game theory, Math+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Exit Song
Medium4
Sorting, Implementation+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Triangle
Medium4
Sorting, Greedy+1
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
UFO Rectangles
Medium4
Matrix, Implementation
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Zero Game
Medium4
Sliding window, String+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Repetition
Medium4
Greedy, String+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Frog 2
Medium4
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
On Becoming the Strongest Competitive Programmer After 200 Years of Seclusion
Medium4
Greedy, Implementation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Cyber Opening Ceremony
Medium4
Hash map, Implementation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
The Legend
Medium4
Hash map, String+2
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Beadman
Medium4
Greedy, Math+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Yoyo Simulation
Medium4
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Cow-abunga!
Medium4
Brute force, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Best Place
Medium4
Sorting, Math+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
King's Inspection
Medium4
Greedy, Math+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Metro 2345
Medium4
Shortest path, Graph+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Checking Answers to Test
Medium4
Brute force, Implementation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Fractification
Medium4
Greedy, Sorting+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Escalator
Medium4
Math, Implementation+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Who Wants to Be a Millionaire?
Medium4
Math, Implementation+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
T-Shirt Delivery
Medium4
Simulation, Implementation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Dunes
Medium4
Array, Prefix sum+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Isosceles triangles
Medium4
Combinatorics, Math+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
LaTeX Expert
Medium4
String, Implementation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Misha's Product
Medium4
Math, Array+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Sleep Pattern
Medium4
Implementation, Math+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Mountain Skiing
Medium4
Greedy, Sorting
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Difference of Squares
Medium4
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Chronicle
Medium4
Implementation, Brute force+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Two Measurements
Medium4
Math, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Faulty Mars Rover
Medium4
Math, Greedy+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Hamburger Distribution
Medium4
Greedy, Two pointers+2
No attempts yet
Time limit
0.5s
Memory limit
256 MB
Judgeable
Investment Genius Bae Juhyeong
Medium4
Dynamic programming, Brute force+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Yeongjae's Exam
Medium4
Brute force, Backtracking+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Youngjae's Walk
Medium4
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Robot
Medium4
Implementation, Math
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Bridge Building
Medium4
Implementation, Brute force
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Cube
Medium4
Geometry, Implementation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Professor Chaos
Medium4
Simulation, Math+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Real Numbers
Medium4
Simulation, Implementation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Password Generator
Medium4
Greedy, Implementation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Apple Tree
Medium4
Prefix sum, Array+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Baskin Robbins 31
Medium4
Game theory, Math+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Ranked Matchmaking Queue
Medium4
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Project Teams
Medium4
Greedy, Sorting+2
No attempts yet
Time limit
0.5s
Memory limit
512 MB
Judgeable
Moving Coins
Medium4
String, Implementation
No attempts yet
Time limit
0.5s
Memory limit
512 MB
Judgeable
Measuring the Cookie's Body
Medium4
Implementation, Simulation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Professor's Final Exam
Medium4
Sorting, Intervals+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Game Addiction
Medium4
Dynamic programming, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Let's Shoot an Arrow!
Medium4
Hash map, Math+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Snack Party
Medium4
Dynamic programming, Array+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Wiggly Caterpillar Hoseok - Functional
Medium4
Dynamic programming, Array+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Contact Tracer
Medium4
Graph, BFS+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Inverted Josephus
Medium4
Simulation, Array+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
RREF
Medium4
Math, Implementation+2
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
ASCII Art
Medium4
Implementation, Matrix+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Jigsaw
Medium4
Math, Implementation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Dart-a-Mania
Medium4
Brute force, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Comeback King (Normal)
Medium4
Simulation, Sorting+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Arrow Maze (Easy)
Medium4
BFS, Graph+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Quilindrome
Medium4
String, String matching
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Improving Grades
Medium4
Binary search, Math+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Plan King
Medium4
Greedy, Sorting+2
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Distinct Numbers
Medium4
Implementation, Math+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Visual Cube
Medium4
Implementation, Simulation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Statistics
Medium4
Greedy, Array+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Birds Rituals
Medium4
Array, Linked list+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Proofs
Medium4
Hash map, Implementation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Social running
Medium4
Brute force, Simulation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Small World NetworkGiven a graph of N people and K friendships, check whether every pair of people is connected within 6 steps, printing Small World! or Big World! accordingly.	Medium4	GraphBFS+2	No attempts yet	1s	512 MB	Judgeable
The New Year's BellGiven an N by M grid of who heard each bell ring, decide whether some distance thresholds R can produce exactly this pattern.	Medium4	SortingGreedy+2	No attempts yet	1s	512 MB	Judgeable
MooBuzzGiven N up to 1e9, find the Nth positive integer that is not a multiple of 3 or 5, since those turns are replaced by Moo.	Medium4	MathBinary search+2	No attempts yet	1s	512 MB	Judgeable
Where Am I?Given a string of N mailbox colors, find the smallest K such that all length-K substrings are distinct. The answer is always at most N.	Medium4	StringBrute force+2	No attempts yet	1s	512 MB	Judgeable
Eloquent EvaluatorChecks whether a printed expression like a+b=c is well formatted and correct, and suggests a fix if changing at most two characters can repair it.	Medium4	StringBrute force+1	No attempts yet	1s	512 MB	Judgeable
Viyott's Stepping Stone CrossingCount the ways to jump from stone 1 to stone N when each jump adds any positive integer, modulo 1e9+7.	Medium4	MathCombinatorics+2	No attempts yet	1s	256 MB	Judgeable
AntsGiven N integers, some negative or very large, find the smallest nonnegative integer that does not appear among the valid nonnegative values.	Medium4	ArrayHash map+2	No attempts yet	2s	512 MB	Judgeable
Hiding NutsGiven N grid points, pick the one minimizing the sum of Manhattan distances to all other points, breaking ties by smallest X then smallest Y.	Medium4	MathBrute force+2	No attempts yet	1s	512 MB	Judgeable
AntennaGiven positions of houses on a line, pick the house position that minimizes the total distance to all houses, choosing the smallest such position on ties.	Medium4	SortingMath+2	No attempts yet	1s	256 MB	Judgeable
Round TripA runner travels out and back along N courses given by their lengths; given total distance K, print which course the runner is on or about to enter.	Medium4	ArrayPrefix sum+2	No attempts yet	1s	256 MB	Judgeable
PhotoshootGiven adjacent sums b_i = a_i + a_{i+1} of a hidden permutation of 1..N, reconstruct the lexicographically smallest permutation a.	Medium4	Brute forceImplementation+2	No attempts yet	2s	512 MB	Judgeable
Valid EmailsNormalize each email by its rules, count how many are valid and distinct.	Medium4	StringHash map+2	No attempts yet	2s	512 MB	Judgeable
Finding Cities at a Specific DistanceGiven a directed unweighted graph, print every city whose shortest distance from a start city equals K, in increasing order, or -1 if none exist.	Medium4	GraphBFS+1	No attempts yet	2s	256 MB	Judgeable
Arranging SoldiersGiven a sequence of N combat powers, find the minimum number of soldiers to remove so the remaining values are in strictly decreasing order.	Medium4	Dynamic programmingArray+2	No attempts yet	1s	256 MB	Judgeable
2048Simulate a sequence of 2048 moves, applying gravity, merging equal tiles once per move, and adding merge values to the score.	Medium4	SimulationImplementation+2	No attempts yet	2s	512 MB	Judgeable
TATCKFor each test case, find the area of the smallest axis-aligned square that contains all given points.	Medium4	GeometryMath+2	No attempts yet	2s	512 MB	Judgeable
LTBLRead match results between two teams, accumulate points, wins, draws, losses, and goals, then print the league table sorted by the six tiebreak rules.	Medium4	ImplementationSorting+2	No attempts yet	2s	512 MB	Judgeable
RUNGiven a directed weighted graph of N cells, one exit cell E, and a time limit T, count how many cells have a path to E within T time units.	Medium4	GraphShortest path+2	No attempts yet	2s	512 MB	Judgeable
Digit SumCount how many starting values between 1 and N can reach N by repeatedly adding the sum of their decimal digits.	Medium4	Dynamic programmingMath+2	No attempts yet	2s	512 MB	Judgeable
EmacsCount the non-overlapping, non-touching rectangles of '*' characters in an N by M grid.	Medium4	ImplementationArray+2	No attempts yet	1s	512 MB	Judgeable
Muscle LossCount orderings of N workout kits (N at most 8) such that a starting total of 500, which drops by K each day, never falls below 500.	Medium4	Brute forceBacktracking+2	No attempts yet	1s	256 MB	Judgeable
Jump JumpGiven jump lengths X and Y plus start positions P1 and P2, find the smallest common landing point both jumpers reach, or -1 if none exists.	Medium4	MathNumber theory+2	No attempts yet	1s	256 MB	Judgeable
Hopscotch 50Given an n by n grid of labels 1 to k, find the minimum total Manhattan distance of a path that visits one tile of each label in order, or -1 if some label is missing.	Medium4	Dynamic programmingImplementation+2	No attempts yet	1s	512 MB	Judgeable
Mad ScientistGiven two strings A and B of H and G, find the minimum number of substring flips (toggling all characters) needed to turn B into A.	Medium4	GreedyString+2	No attempts yet	2s	512 MB	Judgeable
Moving 3A path from (0,0) to (N,M) using only down and right steps costs A[r] per down move and B[c] per right move; find the cheapest path.	Medium4	GreedyMath+1	No attempts yet	2s	512 MB	Judgeable
Maximum Subarray 2147483647Given a sequence of n integers, find the maximum possible sum of a contiguous subarray, choosing at least one element.	Medium4	Dynamic programmingArray+2	No attempts yet	2s	512 MB	Judgeable
Multiverse IITwo universes are equal when their planet sizes give the same ordering and tie pattern; count pairs of the M universes that match.	Medium4	SortingHash map+1	No attempts yet	2s	512 MB	Judgeable
Coordinate CompressionFor each of N coordinates, output the number of distinct values smaller than it, which is its rank under coordinate compression.	Medium4	SortingHash map+2	No attempts yet	2s	512 MB	Judgeable
Sequence and Queries 38Maintain a sequence under append, delete-one-copy, and report running sum and XOR of all elements.	Medium4	Hash mapImplementation+2	No attempts yet	2s	256 MB	Judgeable
LadderGiven n sticks that can only be shortened, decide whether two can become length x and k others length y.	Medium4	GreedySorting+2	No attempts yet	2s	64 MB	Judgeable
Toy AlliancesGiven N toys and M dislike pairs, decide whether the toys can be split into two alliances so no dislike pair shares a side, which is checking bipartiteness of the graph.	Medium4	GraphBFS+2	No attempts yet	1.5s	256 MB	Judgeable
Don't Split The Atom!Two players alternately split a pile of atoms, and whoever is forced to split a single atom loses; decide the winner for each n.	Medium4	Game theoryMath+2	No attempts yet	2s	512 MB	Judgeable
Exit SongGiven k blocked seats in an n-row, m-seat hall, count every run of one or more consecutive free seats within a single row.	Medium4	SortingImplementation+1	No attempts yet	2s	512 MB	Judgeable
TriangleGiven N stick lengths, pick six to form two non-degenerate triangles and print the maximum total length, or 0 if that is impossible.	Medium4	SortingGreedy+1	No attempts yet	3s	512 MB	Judgeable
UFO RectanglesFind every flattened rectangle frame drawn with X cells in a grid and print the top-left and bottom-right coordinates of each.	Medium4	MatrixImplementation	No attempts yet	2s	512 MB	Judgeable
Zero GameGiven a binary string and Q values K, find for each K the longest run of zeros that can be formed with at most K moves of single characters.	Medium4	Sliding windowString+1	No attempts yet	1s	512 MB	Judgeable
RepetitionGiven a lowercase string S, find the smallest K such that S is a subsequence of the alphabet repeated K times.	Medium4	GreedyString+1	No attempts yet	1s	256 MB	Judgeable
Frog 2Each frog ends at (a,b) after c unit steps on the grid; find the initial lattice point, or NO, choosing the smallest x then y.	Medium4	MathImplementation+2	No attempts yet	1s	256 MB	Judgeable
On Becoming the Strongest Competitive Programmer After 200 Years of SeclusionGiven contests in fixed order, each with a prize cap and a prize amount, decide whether Yeondu can skip at most one contest while never exceeding the running cap.	Medium4	GreedyImplementation+2	No attempts yet	1s	1024 MB	Judgeable
Cyber Opening CeremonyGiven start, end, and stream-end times plus chat logs, count members who chatted at or before the start and again between the end and stream-end.	Medium4	Hash mapImplementation+2	No attempts yet	1s	1024 MB	Judgeable
The LegendGiven a list of color names and nicknames, decide for each query whether the name splits into some color followed by some nickname.	Medium4	Hash mapString+2	No attempts yet	3s	1024 MB	Judgeable
BeadmanGiven counts of N bead types, repeatedly remove one bead of each of two different types; find the minimum number of beads that can remain.	Medium4	GreedyMath+2	No attempts yet	1s	1024 MB	Judgeable
Yoyo SimulationSimulate D days of weight and basal metabolic rate changes under two models, tracking death, and decide whether the yoyo effect happens.	Medium4	SimulationImplementation+2	No attempts yet	1s	1024 MB	Judgeable
Cow-abunga!Given at most 9 cow weights, choose M of them and print every prime number that appears as a subset sum, in increasing order.	Medium4	Brute forceCombinatorics+2	No attempts yet	1s	1024 MB	Judgeable
Best PlaceGiven N points, find integer coordinates (X, Y) that minimize the sum of Manhattan distances from the point to every participant.	Medium4	SortingMath+2	No attempts yet	1s	512 MB	Judgeable
King's InspectionGiven three coin counts, each second you add one coin to two different chests; find the minimum number of seconds to make all three equal.	Medium4	GreedyMath+2	No attempts yet	1s	512 MB	Judgeable
Metro 2345Given three metro lines meeting at three transfer stations with per-line edge times and a transfer cost, find the shortest travel time between two given stations.	Medium4	Shortest pathGraph+2	No attempts yet	1s	512 MB	Judgeable
Checking Answers to TestGiven the correct answers and each student's answers, find every pair of students whose correct and incorrect answers each match on more than half of the questions.	Medium4	Brute forceImplementation+2	No attempts yet	1s	512 MB	Judgeable
FractificationGiven four positive integers, arrange them into two fractions a/b + c/d so the sum is as small as possible, and print the arrangement.	Medium4	GreedySorting+2	No attempts yet	2s	512 MB	Judgeable
EscalatorGiven n, sum the decimal digit counts of the numbers 1, n, and every multiple of 10 up to n.	Medium4	MathImplementation+1	No attempts yet	1s	512 MB	Judgeable
Who Wants to Be a Millionaire?Starting from 100, each next prize is the smallest number that is at least double the previous one and whose trailing zeros are at least half its digit count.	Medium4	MathImplementation+1	No attempts yet	1s	512 MB	Judgeable
T-Shirt DeliveryGiven travel times and each recipient's earliest availability, simulate Bill's deliveries where he waits at most k minutes per stop and each handover takes t minutes, and report when he finishes.	Medium4	SimulationImplementation+2	No attempts yet	2s	512 MB	Judgeable
DunesEach gust adds +x to l and then alternates signs up to r; answer m queries for the final height at given positions.	Medium4	ArrayPrefix sum+2	No attempts yet	2s	512 MB	Judgeable
Isosceles trianglesCount the isosceles triangles whose three vertices are vertices of a regular n-gon, for n up to 1e9.	Medium4	CombinatoricsMath+2	No attempts yet	1s	512 MB	Judgeable
LaTeX ExpertRead a LaTeX document, extract citation keys in order, compare against the bibitem order, and print the corrected bibliography if they differ.	Medium4	StringImplementation+2	No attempts yet	1s	512 MB	Judgeable
Misha's ProductGiven n distinct integers, concatenate every ordered pair of them and report the sum of all these concatenations modulo 1e9+7.	Medium4	MathArray+2	No attempts yet	1s	512 MB	Judgeable
Sleep PatternGiven weekday sleep intervals on a Mon-Fri timeline, compute the minimum weekend hours needed so total weekly sleep reaches T, or report that even 48 hours is not enough.	Medium4	ImplementationMath+2	No attempts yet	1s	1024 MB	Judgeable
Mountain SkiingGiven winter length n, trip length k, and m days Tanya was at the resort, find the most winter days she could have spent in the city.	Medium4	GreedySorting	No attempts yet	2s	512 MB	Judgeable
Difference of SquaresGiven n up to 2^60, find positive integers x and y with x^2 - y^2 = n, or report that none exist.	Medium4	MathNumber theory+2	No attempts yet	1s	512 MB	Judgeable
ChronicleGiven three two-digit numbers from a disk, list every valid 21st-century date dd/mm/yy that uses the three numbers in some order, or report none.	Medium4	ImplementationBrute force+2	No attempts yet	2s	512 MB	Judgeable
Two MeasurementsCount pairs of hours i < j in [l, r] whose difference is a multiple of the rotation period a.	Medium4	MathCombinatorics+1	No attempts yet	2s	512 MB	Judgeable
Faulty Mars RoverStarting from a, reach exactly b using steps of +1 and +2 while never landing on a multiple of c; find the fewest steps.	Medium4	MathGreedy+2	No attempts yet	2s	512 MB	Judgeable
Hamburger DistributionAlong a line of N positions holding people and hamburgers, each person can eat a hamburger within distance K; find the maximum number of people served.	Medium4	GreedyTwo pointers+2	No attempts yet	0.5s	256 MB	Judgeable
Investment Genius Bae JuhyeongStarting with H won over Y years, choose among three fixed-term investments (1, 3, or 5 years) to maximize final money, truncating fractions at each payout.	Medium4	Dynamic programmingBrute force+2	No attempts yet	1s	512 MB	Judgeable
Yeongjae's ExamCount how many length-10 answer strings avoid three equal consecutive letters and score at least 5 against the given key.	Medium4	Brute forceBacktracking+2	No attempts yet	1s	512 MB	Judgeable
Youngjae's WalkSimulate a walker who moves at speed v for one second, then turns right and updates v to (v*m)%10, and report the final coordinates after t seconds.	Medium4	SimulationImplementation+2	No attempts yet	1s	512 MB	Judgeable
RobotFind move lengths from 1 to 10^6 that match a given turn sequence and final point (x, y), or report that no route exists.	Medium4	ImplementationMath	No attempts yet	2s	512 MB	Judgeable
Bridge BuildingGiven x logs of length a and y logs of length b, find the largest width W so that l rows of whole logs can each have total length at least W.	Medium4	ImplementationBrute force	No attempts yet	2s	512 MB	Judgeable
CubeGiven two segments whose endpoints are vertices of a cube, decide whether the two segments intersect.	Medium4	GeometryImplementation+2	No attempts yet	2s	512 MB	Judgeable
Professor ChaosSimulate a daily process where bacteria multiply by b, c are removed, and the count is capped at d, finding the count after day k.	Medium4	SimulationMath+2	No attempts yet	2s	512 MB	Judgeable
Real NumbersFor each integer v from 1 to r, simulate dividing 1 by v and multiplying back under fixed-point rounding, and report which v fail to give 1 after storing to memory.	Medium4	SimulationImplementation+2	No attempts yet	2s	512 MB	Judgeable
Password GeneratorBuild any length-n string of letters and digits meeting minimum counts of uppercase, lowercase, and digit characters, with no two equal adjacent characters.	Medium4	GreedyImplementation+2	No attempts yet	2s	512 MB	Judgeable
Apple TreeGiven an N by N grid of profits, find the K by K square subgrid with the largest sum.	Medium4	Prefix sumArray+2	No attempts yet	1s	512 MB	Judgeable
Baskin Robbins 31Given the cap A, list every move limit n up to A for which the second player wins the Baskin Robbins game ending at 31 where calling 31 loses.	Medium4	Game theoryMath+2	No attempts yet	1s	512 MB	Judgeable
Ranked Matchmaking QueueSimulate matchmaking: place each player into the earliest created room whose level range fits, filling rooms of capacity m and reporting each room's final state.	Medium4	SimulationImplementation+2	No attempts yet	1s	256 MB	Judgeable
Project TeamsPair 2n students into n teams so that the smallest team skill sum is as large as possible, and print that value.	Medium4	GreedySorting+2	No attempts yet	0.5s	512 MB	Judgeable
Moving CoinsGiven two coin strings S and T and two chosen positions i and j, decide whether one two-finger move turns S into T.	Medium4	StringImplementation	No attempts yet	0.5s	512 MB	Judgeable
Measuring the Cookie's BodyGiven an N by N grid of '*' and '_' forming a cookie shape, find the heart cell and the lengths of both arms, the waist, and both legs.	Medium4	ImplementationSimulation+2	No attempts yet	1s	1024 MB	Judgeable
Professor's Final ExamGiven N non-overlapping exams in a room open for S minutes, find the earliest start time for a new exam of length M that fits without overlap, or -1.	Medium4	SortingIntervals+2	No attempts yet	1s	1024 MB	Judgeable
Game AddictionCount shortest lattice paths between two diagonal points while staying inside the unflooded region y <= x.	Medium4	Dynamic programmingCombinatorics+2	No attempts yet	1s	1024 MB	Judgeable
Let's Shoot an Arrow!Given N points, find the maximum number that lie on a single ray starting from the origin.	Medium4	Hash mapMath+2	No attempts yet	1s	1024 MB	Judgeable
Snack PartyGiven N days each with one positive snack rating, pick a strictly increasing subsequence (starting above 0) to maximize the sum of chosen ratings.	Medium4	Dynamic programmingArray+2	No attempts yet	1s	1024 MB	Judgeable
Wiggly Caterpillar Hoseok - FunctionalGiven N food values and a threshold K, choose non-overlapping consecutive segments whose sums each reach K, maximizing the total excess over K.	Medium4	Dynamic programmingArray+2	No attempts yet	1s	512 MB	Judgeable
Contact TracerGiven contact events in time order and one infected user, count everyone reachable from that user through the contact graph, including the user.	Medium4	GraphBFS+2	No attempts yet	2s	512 MB	Judgeable
Inverted JosephusSimulate removing every K-th person from a circle of N, reversing direction after each block of M removals, and print the removal order.	Medium4	SimulationArray+2	No attempts yet	1s	1024 MB	Judgeable
RREFCompute the reduced row echelon form of an N by M matrix of rational numbers, printing each entry as a reduced fraction.	Medium4	MathImplementation+2	No attempts yet	0.5s	1024 MB	Judgeable
ASCII ArtGiven up to 5000 integer points, draw them as 'x' marks on ASCII axes inside the smallest rectangular '#' frame, with '-' and '\|' filling empty axis cells and 'o' for the origin.	Medium4	ImplementationMatrix+1	No attempts yet	1s	512 MB	Judgeable
JigsawGiven counts of corner, edge, and centre pieces, decide whether they form a complete w by h jigsaw and output any valid dimensions.	Medium4	MathImplementation+2	No attempts yet	2s	512 MB	Judgeable
Dart-a-ManiaGiven starting scores in a 301 darts game, count the combinations and permutations of three darts (each 0, 1 to 20, double, triple, or bull's eye 50) that reach exactly zero.	Medium4	Brute forceCombinatorics+1	No attempts yet	1s	512 MB	Judgeable
Comeback King (Normal)Simulate the unfreeze reveals of post-freeze submissions in the given order and report the participant who gains the most places.	Medium4	SimulationSorting+1	No attempts yet	1s	512 MB	Judgeable
Arrow Maze (Easy)Given an R by C grid of arrows and K scroll sets, decide whether a visitor can get from the top left cell to the bottom right cell by rotating the arrows.	Medium4	BFSGraph+1	No attempts yet	1s	512 MB	Judgeable
QuilindromeFind the shortest string that contains the nickname as a substring and reads as a quilindrome under the mirror table, ignoring case. Print -1 if none exists.	Medium4	StringString matching	No attempts yet	1s	512 MB	Judgeable
Improving GradesGiven counts of scores 2, 3, and 4, find the minimum number of 5s to add so the rounded mean reaches at least 4.	Medium4	Binary searchMath+2	No attempts yet	1s	512 MB	Judgeable
Plan KingGiven N fixed, non-overlapping meetings in a 1440-minute day and K task durations, decide whether all K tasks can be squeezed into the free gaps.	Medium4	GreedySorting+2	No attempts yet	3s	1024 MB	Judgeable
Distinct NumbersGiven integers a and b, count how many distinct values appear among the ten expressions a+b, a-b, a*b, a/b, a^b and their swapped forms, skipping invalid ones.	Medium4	ImplementationMath+2	No attempts yet	2s	512 MB	Judgeable
Visual CubeGiven box dimensions a, b, c, print the 3D-looking wireframe drawing of the rectangular parallelepiped in the required ASCII format.	Medium4	ImplementationSimulation+2	No attempts yet	1s	512 MB	Judgeable
StatisticsGiven daily case counts, reduce each value (never increase) so the sequence becomes non-increasing, minimizing the total amount removed.	Medium4	GreedyArray+1	No attempts yet	2s	512 MB	Judgeable
Birds RitualsMaintain a row of named birds through insert, depart, and relocate operations, then print the final left-to-right order.	Medium4	ArrayLinked list+2	No attempts yet	2s	512 MB	Judgeable
ProofsCheck a sequence of proof lines where each line is valid only if all its assumptions appeared as conclusions on earlier lines, and report the first invalid line.	Medium4	Hash mapImplementation+2	No attempts yet	2s	512 MB	Judgeable
Social runningGiven a cycle of N locations with edge lengths, choose the start point so that the total distance run alone by all runners is minimized.	Medium4	Brute forceSimulation+2	No attempts yet	1s	1024 MB	Judgeable