Problems

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Total results29,458 problems

Amidakuji
Medium4
Brute force, Simulation+1
No attempts yet
Time limit
8s
Memory limit
1024 MB
Judgeable
Beusi's marble ice cream
Medium4
Hash map, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Slime Hunt and Level Up!
Medium4
Math, Binary search
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Rick-Roll Virus
Medium4
Greedy, Intervals
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Black Holes and Asteroids
Medium4
Sorting, Binary search+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
DDR Stamina Management
Medium4
Dynamic programming, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Drawing a Tree
Medium4
Sorting, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Square Root Sequence
Medium4
Dynamic programming, Prefix sum
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Palindrome Name
Medium4
Greedy, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Coloring by Numbers
Medium4
Greedy, Intervals+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Illumination Optimization
Medium4
Greedy, Intervals
No attempts yet
Time limit
10s
Memory limit
1024 MB
Judgeable
ASCII Art
Medium4
Math, Binary search
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
I Don't Want to Be Late
Medium4
Segment tree, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Turning Pencils
Medium4
Greedy, String+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Prizes
Medium4
Array, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Carrying the Bags
Medium4
Dynamic programming, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Rumors
Medium4
Graph, BFS+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Air Leak
Medium4
Graph, BFS
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Racing Strategy
Medium4
Dynamic programming
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Tennis Tournament
Medium4
Simulation, Brute force
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Fence Painting
Medium4
Sorting, Intervals+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Strange Machine
Medium4
Dynamic programming, Simulation
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Practice
Medium4
Prefix sum, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Gift Bag
Medium4
Hash map, Brute force
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Machine Shop
Medium4
Dynamic programming, Graph+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Superknight
Medium4
BFS, Graph+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Two forms of a message
Medium4
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Team ranking
Medium4
Sorting, Hash map+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Voltage Drops
Medium4
Union-find, Graph
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Lining up Children
Medium4
Graph, Union-find+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Martian Calendar
Medium4
Math, Binary search+1
No attempts yet
Time limit
0.2s
Memory limit
1024 MB
Judgeable
Solving a cubic equation
Medium4
Brute force, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Medals
Medium4
Array, Greedy
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Dolbear's Law
Medium4
Brute force, Implementation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Junyoung's Love
Medium4
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Picking the Student Council
Medium4
Bit manipulation, Greedy
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Cornfield
Medium4
Heap, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Multiples of K
Medium4
Dynamic programming, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
K-Words Problem
Medium4
String, Simulation
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Overdose Runner
Medium4
Simulation, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Rock-Paper-Scissors
Medium4
Simulation, Game theory+1
No attempts yet
Time limit
15s
Memory limit
1024 MB
Judgeable
HJS
Medium4
Brute force, Implementation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Distance Keeping Game
Medium4
Math, Brute force
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Snow-covered path
Medium4
Prefix sum, Simulation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
YouTube
Medium4
Sorting, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Karosai
Medium4
Minimum spanning tree, Union-find+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Change
Medium4
Greedy, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Bicycle Track Race
Medium4
Math, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
The Most Important Bridge
Medium4
Graph, DFS+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Interview Room of Terror
Medium4
Greedy, Sorting
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Make a New String
Medium4
String, String matching
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
So I Quit Photography
Medium4
Sorting, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Educational Tree Problem
Medium4
Sorting, Tree+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Compass
Medium4
Graph, Geometry+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Playing Field
Medium4
Prefix sum, Geometry+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Crazy Malvika discovers Crazy Fibonacci function
Medium4
Math, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Squared Weighted Sums
Medium4
Prefix sum, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Novel
Medium4
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Bicycle
Medium4
Dynamic programming
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Vehicle Placement
Medium4
BFS, Graph+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
April Fools
Medium4
Brute force, Bit manipulation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Weighted Window Sums
Medium4
Prefix sum, Sorting
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Union
Medium4
Brute force, Bit manipulation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Highway from Hell
Medium4
Simulation, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Candy Split
Medium4
Dynamic programming, Array+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Darts
Medium4
Prefix sum, Matrix
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Rally
Medium4
Graph, Brute force
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
Sieve Game
Medium4
Number theory, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Cheap Flying
Medium4
Greedy, Math
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Mysterious words
Medium4
Dynamic programming, Hash map+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Oak Tree Heights
Medium4
Prefix sum, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Stubborn Little Frog
Medium4
Dynamic programming, Sliding window
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Lietus (Rain)
Medium4
Array, Two pointers
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Snake
Medium4
Math, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Break a Prison
Medium4
BFS, Graph+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Non-Rotating Calipers
Medium4
Geometry, Sorting
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Ducks and the Clapping Chunbae
Medium4
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Museum Tour
Medium4
Prefix sum, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Chunbae Who Stole Nabi's Snack
Medium4
Dynamic programming, Brute force
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Graph Game
Medium4
Graph, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Rebirth
Medium4
Dynamic programming, Array
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Heroes of Velmar
Medium4
Implementation, Simulation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Jamboree
Medium4
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Symmetry of Stars
Medium4
Hash map, Sorting+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Group Jump Rope
Medium4
Dynamic programming, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Hanging a Banner
Medium4
Brute force, Binary search+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Switch
Medium4
Dynamic programming, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Fishing
Medium4
Prefix sum, Matrix
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
K-String
Medium4
Bit manipulation, Hash map+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Why Hoban-woo Was Late to School 4
Medium4
Union-find, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Inversions
Medium4
Math, String+1
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
Geometry Game
Medium4
Geometry, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
SASA Manito
Medium4
Implementation, Graph
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Hate Stagnant Water
Medium4
BFS, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Prof. Fumblemore and the Collatz Conjecture
Medium4
Brute force, Simulation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Modified Gray Code
Medium4
Brute force, Simulation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Mini-Tetris 3023
Medium4
Math, Implementation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Klyukalo
Medium4
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
First Solved, Last Coded
Medium4
Stack, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Alloys
Medium4
Sorting, Array
No attempts yet
Time limit
15s
Memory limit
1024 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
AmidakujiGiven an amidakuji and a start line p, find the position of one added bar that routes p's trace to line q, or report OK or NG.	Medium4	Brute forceSimulation+1	No attempts yet	8s	1024 MB	Judgeable
Beusi's marble ice creamApply Q steps to a multiset of marbles: each step removes A_i and adds B_i only when every marble in A_i is present, then print what remains.	Medium4	Hash mapImplementation	No attempts yet	1s	1024 MB	Judgeable
Slime Hunt and Level Up!After N slimes, where the k-th slime gives k experience and each level-up costs 2 more than the last, find the level Bsil reaches.	Medium4	MathBinary search	No attempts yet	1s	1024 MB	Judgeable
Rick-Roll VirusGiven a line of N people with infected ones marked R, decide whether M cures can stop the virus that spreads K cells per day.	Medium4	GreedyIntervals	No attempts yet	2s	1024 MB	Judgeable
Black Holes and AsteroidsGiven black hole and asteroid positions, find the smallest integer P so that every asteroid is within P/w of some black hole.	Medium4	SortingBinary search+1	No attempts yet	1s	1024 MB	Judgeable
DDR Stamina ManagementChoose which sections to play so total points are maximized, where stamina recovers by K before each section (capped at 100) and playing costs h_i stamina.	Medium4	Dynamic programmingImplementation	No attempts yet	1s	1024 MB	Judgeable
Drawing a TreeConnect N given points with N-1 segments that form a tree and do not cross, then print the endpoint index pairs.	Medium4	SortingImplementation	No attempts yet	1s	1024 MB	Judgeable
Square Root SequenceCount the sequences of length L that start at N, end at 1, and where each term is less than the square root of the term before it.	Medium4	Dynamic programmingPrefix sum	No attempts yet	1s	1024 MB	Judgeable
Palindrome NameBuild a string of length N using exactly K distinct lowercase letters that has the most distinct palindromic substrings, choosing the lexicographically smallest on ties.	Medium4	GreedyMath+1	No attempts yet	1s	1024 MB	Judgeable
Coloring by NumbersGiven a 1 x W grid and N blocks placed in order with at least one gap between them, find every cell colored in all valid placements.	Medium4	GreedyIntervals+1	No attempts yet	1s	1024 MB	Judgeable
Illumination OptimizationGiven M, R, and sorted street light positions, find the fewest bulbs whose lit segments cover the whole freeway from 0 to M, or report IMPOSSIBLE.	Medium4	GreedyIntervals	No attempts yet	10s	1024 MB	Judgeable
ASCII ArtGiven N, find the N-th character printed by a program that prints each letter A to Z i times in round i, for i from 1 upward.	Medium4	MathBinary search	No attempts yet	20s	1024 MB	Judgeable
I Don't Want to Be LateGiven route populations under point updates, report the first and second route numbers of a fastest Aeji Hall to ITBT path, breaking ties by smallest index.	Medium4	Segment treeArray	No attempts yet	1s	1024 MB	Judgeable
Turning PencilsGiven N pencils, each pointing sharp end up or blunt end up, find the fewest segment flips that make all pencils face the same way and print those flips.	Medium4	GreedyString+1	No attempts yet	1s	1024 MB	Judgeable
PrizesGiven N prize prices and a budget K, determine whether three different prizes have prices that sum to exactly K.	Medium4	ArraySorting+1	No attempts yet	1s	1024 MB	Judgeable
Carrying the BagsGiven K bags, a walking time X, and a per-bag delay Y, find the trip plan that moves all bags to the award table in the least total time.	Medium4	Dynamic programmingMath	No attempts yet	1s	1024 MB	Judgeable
RumorsFor each rumor originator, count how many students hear it when every listener repeats it to all of their social circles.	Medium4	GraphBFS+1	No attempts yet	1s	1024 MB	Judgeable
Air LeakGiven the open doors between modules in a 25x25x25 grid, find every module that air can flow to from the damaged module.	Medium4	GraphBFS	No attempts yet	1s	1024 MB	Judgeable
Racing StrategyPick a starting tyre and pit stops over N laps so the total race time is minimal, given each tyre's first-lap time, per-lap wear, and a fixed pit cost K.	Medium4	Dynamic programming	No attempts yet	1s	1024 MB	Judgeable
Tennis TournamentGiven the draw order of eight players and the seven match winners sorted by number, the task is to recover who won each match in every round.	Medium4	SimulationBrute force	No attempts yet	1s	1024 MB	Judgeable
Fence PaintingGiven painted house numbers and a distance K, list the unpainted houses within K of a painted house, merging consecutive runs as a..b.	Medium4	SortingIntervals+1	No attempts yet	1s	1024 MB	Judgeable
Strange MachineGiven a button press sequence where some presses are unknown (-1), find which of the four bulbs can be lit after the last press.	Medium4	Dynamic programmingSimulation	No attempts yet	3s	1024 MB	Judgeable
PracticeGiven daily task counts, answer for each query Y whether some run of consecutive days sums to exactly Y.	Medium4	Prefix sumArray	No attempts yet	1s	1024 MB	Judgeable
Gift BagGiven item prices and a gift list, find the lowest total cost after swapping the prices of at most one pair of items.	Medium4	Hash mapBrute force	No attempts yet	1s	1024 MB	Judgeable
Machine ShopFind the lowest cost of obtaining machine K, either by buying it outright or by building it from its component machines, each obtained at its own lowest cost.	Medium4	Dynamic programmingGraph+1	No attempts yet	1s	1024 MB	Judgeable
SuperknightFind the fewest moves for a knight on an R by V board with blocked squares, where one move may be a 3-by-1 supermove, and print one shortest path.	Medium4	BFSGraph+1	No attempts yet	1s	1024 MB	Judgeable
Two forms of a messagePack a brace-wrapped list of integers into a hexadecimal string by encoding zero runs and length prefixes, then print the result.	Medium4	StringImplementation+1	No attempts yet	1s	1024 MB	Judgeable
Team rankingGiven each competitor's gender, distance, time, and optional team, compute each team's total from its three best eligible members and print the ranked team results.	Medium4	SortingHash map+1	No attempts yet	1s	1024 MB	Judgeable
Voltage DropsGiven voltage differences between pairs of nodes, decide whether all measurements can be consistent with one set of node potentials, printing JAH or EI.	Medium4	Union-findGraph	No attempts yet	1s	1024 MB	Judgeable
Lining up ChildrenGiven friend pairs among N children, find a line order where every friend pair stands next to each other, or report that no such order exists.	Medium4	GraphUnion-find+1	No attempts yet	1s	1024 MB	Judgeable
Martian CalendarFind the sum of each day's position within its month for all days from the A-th to the B-th day of the year, where month m has m days.	Medium4	MathBinary search+1	No attempts yet	0.2s	1024 MB	Judgeable
Solving a cubic equationGiven a cubic with integer coefficients that has an integer root, find all three real roots and print them as exact integers, sqrt forms, or reduced fractions.	Medium4	Brute forceMath	No attempts yet	1s	1024 MB	Judgeable
MedalsGiven medal numbers from several series, split them into the fewest runs of consecutive competition numbers and report the run count.	Medium4	ArrayGreedy	No attempts yet	2s	1024 MB	Judgeable
Dolbear's LawGiven a per-second record of chirps, find the fewest crickets that could explain it when each cricket chirps at a fixed period between a start and a stop.	Medium4	Brute forceImplementation+1	No attempts yet	1s	1024 MB	Judgeable
Junyoung's LoveRearrange N pearl values in a circle to maximize the sum of products of adjacent pearls, then print the maximum and one arrangement that reaches it.	Medium4	GreedySorting+1	No attempts yet	1s	1024 MB	Judgeable
Picking the Student CouncilPick K of N integers so that their bitwise AND is as large as possible, and print that maximum value.	Medium4	Bit manipulationGreedy	No attempts yet	1s	1024 MB	Judgeable
CornfieldGiven a grid of distinct values, repeatedly harvest the largest-valued cell reachable from the border through already harvested cells, and print the first K positions in order.	Medium4	HeapGreedy+1	No attempts yet	1s	1024 MB	Judgeable
Multiples of KCount the M-digit numbers made only from the given digits that are multiples of K, modulo 1,000,000,007.	Medium4	Dynamic programmingMath	No attempts yet	1s	1024 MB	Judgeable
K-Words ProblemGiven sentences, merge each 'Korea' with the word after it or the word before 'of' into a K-word by the stated rules, then print the result.	Medium4	StringSimulation	No attempts yet	3s	1024 MB	Judgeable
Overdose RunnerSimulate a grid game where a player teleports, fires attacks at monsters, takes medicine, and reaches the goal, then print the final state.	Medium4	SimulationImplementation	No attempts yet	2s	1024 MB	Judgeable
Rock-Paper-ScissorsPlay rock-paper-scissors against 10 fixed programs over stdin and stdout, and maximize your total score until the opponent sends L.	Medium4	SimulationGame theory+1	No attempts yet	15s	1024 MB	Judgeable
HJSGiven three H/J/S patterns of equal length, check whether distinct digits 1 to 9 can be assigned to H, J, and S so that the numbers satisfy p < q < r.	Medium4	Brute forceImplementation+1	No attempts yet	1s	1024 MB	Judgeable
Distance Keeping GameGiven an N x M grid and a distance D, count the cells whose farthest grid cell is still closer than D in taxicab distance, since Hyoseok must block exactly those.	Medium4	MathBrute force	No attempts yet	1s	1024 MB	Judgeable
Snow-covered pathGiven the snow depth on each meter of a path, find the total energy spent when each thrown load of snow adds a 1 cm layer to the meters ahead.	Medium4	Prefix sumSimulation	No attempts yet	1s	1024 MB	Judgeable
YouTubePick videos with durations t_i and values of 1 or 2 to reach a total value of at least V with the least watch time, or print -1 if it is impossible.	Medium4	SortingPrefix sum+1	No attempts yet	1s	1024 MB	Judgeable
KarosaiGiven ponds joined by partitions with fixed heights, find the minimum water level at pond 1 that allows a path to pond N.	Medium4	Minimum spanning treeUnion-find+1	No attempts yet	1s	1024 MB	Judgeable
ChangeFor each change request, output the fewest bit banknotes from the register's stock, listed from largest to smallest denomination.	Medium4	GreedyImplementation	No attempts yet	1s	1024 MB	Judgeable
Bicycle Track RaceGiven each racer's time per lap and the race length in laps, count the racers who are never lapped and finish the race.	Medium4	MathImplementation	No attempts yet	1s	1024 MB	Judgeable
The Most Important BridgeFind the bridge whose removal splits the 2N islands into two disconnected groups of exactly N islands each, and print its number.	Medium4	GraphDFS+1	No attempts yet	1s	1024 MB	Judgeable
Interview Room of TerrorInterviews run one at a time. Find the minimum sum of the finish times of all departments, given each department's total interview time.	Medium4	GreedySorting	No attempts yet	1s	1024 MB	Judgeable
Make a New StringGiven each string S, build the shortest X that starts with S and whose reverse also starts with S.	Medium4	StringString matching	No attempts yet	1s	1024 MB	Judgeable
So I Quit PhotographyFind the minimum and maximum photo score over all orderings of N students, how many orderings reach each, and one example of each.	Medium4	SortingGreedy+1	No attempts yet	1s	1024 MB	Judgeable
Educational Tree ProblemGiven a rooted tree where each child's value is at most its parent's, find the maximum sum of a parent-closed vertex set for each size k from 1 to N.	Medium4	SortingTree+1	No attempts yet	1s	1024 MB	Judgeable
CompassCount the circles from which a chain of pairwise intersecting or touching circles reaches the sheet edge, given the sheet size and N circles.	Medium4	GraphGeometry+1	No attempts yet	1s	1024 MB	Judgeable
Playing FieldGiven a convex polygon and several diagonals, find the area of the smaller piece that each diagonal cuts off.	Medium4	Prefix sumGeometry+2	No attempts yet	2s	1024 MB	Judgeable
Crazy Malvika discovers Crazy Fibonacci functionGiven f(1)=A, f(2)=B, and f(x)=f(x-1)+f(x+1), find f(N) modulo 10^9+7 for up to 10^5 queries.	Medium4	MathImplementation	No attempts yet	1s	1024 MB	Judgeable
Squared Weighted SumsGiven N integers, print for each k the sum of (k-i)^2 times a_i over the first k elements, for k from 1 to N.	Medium4	Prefix sumMath	No attempts yet	1s	1024 MB	Judgeable
NovelFind the largest line width L so that no K identical lowercase letters appear consecutively within a single line of the string.	Medium4	StringImplementation+1	No attempts yet	1s	1024 MB	Judgeable
BicycleGiven morning and evening rain forecasts for N days, find the maximum number of days Aleksas can ride his bike, tracking whether the bike is at home or at work.	Medium4	Dynamic programming	No attempts yet	1s	1024 MB	Judgeable
Vehicle PlacementCount the vehicle placements on a road graph where no two vehicles reach location 1 at the same time, modulo 1000000007.	Medium4	BFSGraph+1	No attempts yet	1s	1024 MB	Judgeable
April FoolsEach newspaper prints exactly one false fact. Find the smallest and largest total number of false facts that can be consistent with this.	Medium4	Brute forceBit manipulation	No attempts yet	1s	1024 MB	Judgeable
Weighted Window SumsGiven a sequence and window size k, list each window's start index and weighted sum (1a1 + 2a2 + ...), sorted by sum with ties broken by start index.	Medium4	Prefix sumSorting	No attempts yet	5s	1024 MB	Judgeable
UnionGiven n sets of positive integers, find the largest union of some of them that differs from the union of all sets.	Medium4	Brute forceBit manipulation+1	No attempts yet	2s	1024 MB	Judgeable
Highway from HellGiven cars with lane, start position, and speed, and a +/-/0 crossing strategy, report whether P-22 survives or the first time step he is hit.	Medium4	SimulationImplementation	No attempts yet	1s	1024 MB	Judgeable
Candy SplitChoose a set of candy boxes whose total is even and as large as possible, then print half of that total.	Medium4	Dynamic programmingArray+1	No attempts yet	1s	1024 MB	Judgeable
DartsGiven an N by N grid of scores and an accuracy L, find the cell whose clipped (2L+1) by (2L+1) neighborhood has the highest average score.	Medium4	Prefix sumMatrix	No attempts yet	1s	1024 MB	Judgeable
RallyGiven an undirected road graph, find four distinct cities forming a cycle, or report that no such track exists.	Medium4	GraphBrute force	No attempts yet	0.5s	1024 MB	Judgeable
Sieve GameGiven a target array t, find the fewest operations that add or subtract 1 on all multiples of an index i to reach t, or print -1 if impossible.	Medium4	Number theoryImplementation	No attempts yet	1s	1024 MB	Judgeable
Cheap FlyingDecide when to buy an aircraft for repeated flights without knowing how many flights will come, keeping total cost within twice the offline optimum.	Medium4	GreedyMath	No attempts yet	3s	1024 MB	Judgeable
Mysterious wordsGiven a dictionary of words, find the longest chain of dictionary words where each one is formed by deleting a single letter from the previous one, and output the chain's length.	Medium4	Dynamic programmingHash map+1	No attempts yet	1s	1024 MB	Judgeable
Oak Tree HeightsGiven N oak heights and a neighbor distance D, find the oak whose height exceeds the average height of its neighbors by the largest margin.	Medium4	Prefix sumArray	No attempts yet	1s	1024 MB	Judgeable
Stubborn Little FrogFind the least total fly-catching time for a frog to hop from leaf 0 to the shore leaf, jumping at most L leaves at a time.	Medium4	Dynamic programmingSliding window	No attempts yet	1s	1024 MB	Judgeable
Lietus (Rain)Given the heights of N columns in a box, find how many unit cubes of rainwater stay trapped between the columns.	Medium4	ArrayTwo pointers	No attempts yet	1s	1024 MB	Judgeable
SnakeGiven a screen of width N and height M filled by a spiral snake with its head at (0, 0), find the length in cells from the head to body cell (X, Y).	Medium4	MathImplementation	No attempts yet	1s	1024 MB	Judgeable
Break a PrisonFind the fewest moves from S to E on a grid where two consecutive moves may not turn right, and surveillance cells are blocked.	Medium4	BFSGraph+1	No attempts yet	2s	1024 MB	Judgeable
Non-Rotating CalipersGiven N integer points, find the distance a caliper with axis-parallel jaws measures when it closes on the point set.	Medium4	GeometrySorting	No attempts yet	1s	1024 MB	Judgeable
Ducks and the Clapping ChunbaeGiven N quack times and a window K, find the fewest claps so that every interval [X_i, X_i+K] contains at least one clap.	Medium4	GreedySorting+1	No attempts yet	1s	1024 MB	Judgeable
Museum TourGiven each kitten's viewing order, find the hall where the entrance minimizes the total walking distance for all kittens, choosing the smallest number on ties.	Medium4	Prefix sumGreedy+1	No attempts yet	2s	1024 MB	Judgeable
Chunbae Who Stole Nabi's SnackChunbae picks Crouch, Walk on all fours, or Scare Nabi each turn to keep the most HP after N punches, with damage reduced by distance.	Medium4	Dynamic programmingBrute force	No attempts yet	1s	1024 MB	Judgeable
Graph GameGiven N vertices, add K edges one at a time without repeating an edge or creating an odd cycle, or report that it is impossible.	Medium4	GraphMath+1	No attempts yet	1s	1024 MB	Judgeable
RebirthDecide whether choosing Correct or Wrong for each of K problems can move Sii from dimension M to 0 while avoiding L unstable dimensions.	Medium4	Dynamic programmingArray	No attempts yet	1s	512 MB	Judgeable
Heroes of VelmarGiven the final cards each player played at three locations, determine whether Player 1, Player 2, or neither wins the battle.	Medium4	ImplementationSimulation+1	No attempts yet	1s	1024 MB	Judgeable
JamboreeSplit N item sizes among M scouts, each taking one or two items, and find the smallest possible largest total carried.	Medium4	GreedySorting+1	No attempts yet	1s	1024 MB	Judgeable
Symmetry of StarsGiven n stars, find the point p that maximizes how many stars have a partner whose midpoint with them is p, and output that count.	Medium4	Hash mapSorting+1	No attempts yet	2s	1024 MB	Judgeable
Group Jump RopeGiven student heights, find the largest group that can line up so heights strictly rise toward the middle and then strictly fall, so no one faces someone as tall or taller.	Medium4	Dynamic programmingArray	No attempts yet	1s	1024 MB	Judgeable
Hanging a BannerGiven pole positions and flagpole lengths, pick two poles and one flagpole to get the largest triangle area that does not exceed R.	Medium4	Brute forceBinary search+2	No attempts yet	1s	1024 MB	Judgeable
SwitchChoose windows of three consecutive seconds, none overlapping, to double their points, and find the maximum total score.	Medium4	Dynamic programmingArray	No attempts yet	1s	1024 MB	Judgeable
FishingFor each query (W, P), the task is to sum the fish caught by bait placed at (W, P) that is reeled diagonally up-left until it leaves the grid.	Medium4	Prefix sumMatrix	No attempts yet	2s	1024 MB	Judgeable
K-StringCount the index pairs of 10-digit strings whose concatenation contains exactly K distinct digits.	Medium4	Bit manipulationHash map+1	No attempts yet	1s	1024 MB	Judgeable
Why Hoban-woo Was Late to School 4Given N king slimes and M items, report the total slime count after each item, where merging groups of sizes s and t adds s+t-1 mini slimes.	Medium4	Union-findImplementation	No attempts yet	1s	1024 MB	Judgeable
InversionsGiven a string S and an integer N, count the inversions in S repeated N times, modulo 10^9+7.	Medium4	MathString+1	No attempts yet	0.5s	1024 MB	Judgeable
Geometry GameGiven four points in clockwise order, report whether the quadrilateral is a square, rectangle, rhombus, parallelogram, trapezium, kite, or none.	Medium4	GeometryImplementation	No attempts yet	1s	1024 MB	Judgeable
SASA ManitoGiven the revealed Manito pairs, count the students who can be Sejong's Manito, printing NOJAM when exactly one is possible.	Medium4	ImplementationGraph	No attempts yet	1s	1024 MB	Judgeable
Hate Stagnant WaterCount the h by w rectangles on an N by M grid that contain no standing water, where drained cells spread to neighbors at equal or higher height.	Medium4	BFSPrefix sum+1	No attempts yet	1s	1024 MB	Judgeable
Prof. Fumblemore and the Collatz ConjectureGiven a string of E and O letters, find the smallest positive integer whose Collatz sequence type matches it, or report INVALID for a malformed string.	Medium4	Brute forceSimulation+1	No attempts yet	1s	1024 MB	Judgeable
Modified Gray CodeGiven an index K up to 500, print the K-th element of the 10-bit even Gray Code, where each step flips an even number of bits.	Medium4	Brute forceSimulation+1	No attempts yet	2s	1024 MB	Judgeable
Mini-Tetris 3023Given counts of square, S-tile, and corner tiles, find the widest 2 x n rectangle that some or all of them can tile exactly without overlap.	Medium4	MathImplementation	No attempts yet	2s	1024 MB	Judgeable
KlyukaloFind the fewest 1-gram weight changes that bring the total weighted deviation of N parts down to at most K.	Medium4	GreedySorting+1	No attempts yet	1s	1024 MB	Judgeable
First Solved, Last CodedGiven sequences a and b, find push and pop actions on a stack that turn a into b, or report NO if impossible.	Medium4	StackGreedy+1	No attempts yet	2s	1024 MB	Judgeable
AlloysGiven n points with flexibility and conductivity, list the IDs of points that no other point beats on both values, sorted as strings.	Medium4	SortingArray	No attempts yet	15s	1024 MB	Judgeable