Problems

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Total results29,458 problems

The True FA Student
Medium4
Dynamic programming, Simulation
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Waterworld
Medium4
Math, Geometry
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Making ChatGPT
Medium4
String, Hash map+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Ternary OR and Queries
Medium4
Trie, Greedy
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Painting the Floodwall
Medium4
Dynamic programming, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Lost is Close to Lose
Medium4
String, Hash map
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Orphan Backups
Medium4
Hash map, String+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Playing the Slots
Medium4
Geometry, Brute force
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Honeycomb Distance
Medium4
Math, Implementation
No attempts yet
Time limit
8s
Memory limit
1024 MB
Judgeable
SoleMap
Medium4
Prefix sum, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Shuffle Machine
Medium4
Array, Divide and conquer
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Cutting in Line
Medium4
Prefix sum, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Find the Joker 2
Medium4
Tree, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
AirDrop
Medium4
Graph, BFS
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Solution 2
Medium4
Prefix sum, Sorting
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Portal Game
Medium4
Shortest path, Graph
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Express Train
Medium4
Greedy, Sorting
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Minimize Insulation Sections
Medium4
Graph, BFS+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Solution Relay
Medium4
Dynamic programming, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Contact
Medium4
Union-find, Implementation
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Knight Cruising
Medium4
Math, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
MatKor Cup Preliminary Seat Assignment
Medium4
Math, Probability
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
The Game of Death
Medium4
Graph, Simulation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Glass Bead
Medium4
Array, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
You and Me (NAVILLERA)
Medium4
Math, Geometry
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Starting Today, We (Me gustas tu)
Medium4
BFS, Graph+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
ABB to BA (Easy)
Medium4
String, Simulation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
What's the Order Anyway?
Medium4
Backtracking, Brute force+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Picture Caption
Medium4
Binary search, Greedy+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Identical Letters
Medium4
Sliding window, String+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Professor Won, please give me an A+
Medium4
Binary search, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Magnet Chess
Medium4
Prefix sum, Matrix+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Swallow Messenger
Medium4
Hash map, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Book Search Program
Medium4
Recursion, String+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Balloon Popping
Medium4
Math, Binary search
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
4-Cycle (Easy)
Medium4
Graph, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Daejeon Urban Railway Line 2
Medium4
Tree, DFS+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Bacon Number
Medium4
BFS, Graph+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Lexicographically Maximum
Medium4
Bit manipulation, Greedy
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Animal Farm
Medium4
Sorting, Prefix sum+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Mukjjippa
Medium4
Dynamic programming, Probability+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Kitten of Chaos
Medium4
String, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Ellipse Eclipse
Medium4
Math, Geometry
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Friends of Similar Height
Medium4
Segment tree, Array
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Shortest Path or Negative Cycle
Medium4
Shortest path, Graph
No attempts yet
Time limit
4s
Memory limit
128 MB
Judgeable
Ornithology
Medium4
Array, Prefix sum
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Intelligence Exploration
Medium4
Array, Math+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Aaawww... or Aaayyy!!!
Medium4
Simulation, Implementation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Industry Improvements
Medium4
Binary search, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Occupation
Medium4
Greedy, Heap+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Counting Strange Roots
Medium4
Tree, DFS
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
String Reduction
Medium4
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Rectangle
Medium4
Math, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Jeongmin's Sequence Recipe
Medium4
Math, Number theory+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Guess the Random Number
Medium4
Prefix sum, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Game of Death (Easy)
Medium4
Graph, BFS
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Emoticons
Medium4
Brute force, String+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Expected Flight Delay
Medium4
Math, Probability+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Sandwich Art
Medium4
Graph, BFS+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Up and Down
Medium4
Dynamic programming, Binary search
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Number POP
Medium4
Sliding window, Two pointers+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Connecting Grid Cells
Medium4
Dynamic programming, Matrix
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Permutations and Increasing Sequences
Medium4
Math, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Ant on a Cube
Medium4
Graph, BFS+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Word Game
Medium4
Graph, DFS
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Anonymous M and Call Signs
Medium4
Simulation, String+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Octopus
Medium4
Math, Graph
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
N+1 Promotion
Medium4
Binary search, Math
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Gahui and Club Audition 3
Medium4
Combinatorics, Math+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Takahashi's Card Game
Medium4
Math, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Mouse Pursuit
Medium4
Prefix sum, Sorting+1
No attempts yet
Time limit
3s
Memory limit
2048 MB
Judgeable
Taking Out the Trash
Medium4
Greedy, Sorting+1
No attempts yet
Time limit
3s
Memory limit
2048 MB
Judgeable
Average Substring Value
Medium4
Stack, String+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Leapfrog Encryption
Medium4
Implementation, Simulation+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Letter Balloons
Medium4
Bit manipulation, Brute force
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Smart Password Validation
Medium4
Implementation, String+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Bottles
Medium4
Sorting, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Triangles of a Square
Medium4
Geometry, Implementation
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Duel of Cards
Medium4
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Herb Mixing
Medium4
Dynamic programming, Implementation
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Traffic Lights
Medium4
Simulation, Number theory
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Stone Removal Grid Game nm
Medium4
Game theory, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Alternative Encryption
Medium4
String, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Misère
Medium4
Greedy, Sorting+1
No attempts yet
Time limit
2s
Memory limit
2048 MB
Judgeable
Cave
Medium4
BFS, Prefix sum
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Kim's Quest
Medium4
Dynamic programming, Math
No attempts yet
Time limit
3s
Memory limit
2048 MB
Judgeable
Farmer John's Cheese Block
Medium4
Array, Implementation
No attempts yet
Time limit
2s
Memory limit
2048 MB
Judgeable
Savvy Seller
Medium4
Dynamic programming, Binary search+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Party Medley
Medium4
Brute force, Sorting+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Walking Around
Medium4
Tree, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Obstacle Course
Medium4
Array, Implementation
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Diet Plan
Medium4
Greedy, Heap
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
ICPC Provincial
Medium4
Sorting, Greedy
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Mirror Maze
Medium4
Simulation, Brute force+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
K-Sort
Medium4
Number theory, Array
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
The segment is not even.
Medium4
Sliding window, Hash map+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Masking Tape
Medium4
Array, Simulation+1
No attempts yet
Time limit
2s
Memory limit
2048 MB
Judgeable
Micromasters Certificates
Medium4
Brute force, Hash map+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
GPT DarkDown
Medium4
String, Simulation+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
I am Sherlocked
Medium4
Simulation, String+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
The True FA StudentFind the minimum time to reach zone N, choosing at each crosswalk whether to wait for the green signal or take the footbridge.	Medium4	Dynamic programmingSimulation	No attempts yet	1s	512 MB	Judgeable
WaterworldGiven water percentages for n latitude bands in m longitude slices of a sphere, compute the percentage of the whole surface covered by water.	Medium4	MathGeometry	No attempts yet	3s	1024 MB	Judgeable
Making ChatGPTGiven a corpus of bracketed sentences, each character is followed by its most frequent next character, and the task is to output characters K to K+M-1 of the generated string.	Medium4	StringHash map+1	No attempts yet	1s	1024 MB	Judgeable
Ternary OR and QueriesMaintain a set S of integers and, for each query x, print the largest OR_3(a, x) over all a in S, where OR_3 takes digit-wise maxima in base 3.	Medium4	TrieGreedy	No attempts yet	4s	1024 MB	Judgeable
Painting the FloodwallPick non-overlapping wall intervals from the applications to maximize total painted length, where a mural may start where another ends.	Medium4	Dynamic programmingSorting+1	No attempts yet	1s	1024 MB	Judgeable
Lost is Close to LoseGiven lines of text, list each word core alongside the other word cores reachable from it by one deletion, insertion, substitution, or adjacent transposition.	Medium4	StringHash map	No attempts yet	1s	1024 MB	Judgeable
Orphan BackupsGiven a list of backup image names and a list of backup file names, print the files with no index entry and the index entries with no files, each sorted.	Medium4	Hash mapString+1	No attempts yet	1s	1024 MB	Judgeable
Playing the SlotsGiven a convex polygon, find the smallest slot width through which the polygon fits after any rotation.	Medium4	GeometryBrute force	No attempts yet	1s	1024 MB	Judgeable
Honeycomb DistanceGiven a cell (x, y) on a hexagonal grid with axial coordinates, the task is to find the minimum number of steps from (0, 0) to that cell.	Medium4	MathImplementation	No attempts yet	8s	1024 MB	Judgeable
SoleMapFor each road, find the minimum sum of squared vehicle counts across its w lanes when c daily vehicles use the road, with traffic added along city paths.	Medium4	Prefix sumMath+1	No attempts yet	2s	1024 MB	Judgeable
Shuffle MachineFor each of the K shuffles, apply technique X_i a total of Y_i times in order, starting from the sorted deck, and print the final card order.	Medium4	ArrayDivide and conquer	No attempts yet	1.5s	1024 MB	Judgeable
Cutting in LineGiven each student's satisfaction, find the maximum total when each student either cuts to the front or joins the back of the line.	Medium4	Prefix sumGreedy+1	No attempts yet	1s	1024 MB	Judgeable
Find the Joker 2Given shuffles that rotate the deck by one card or point back to an earlier deck state, find the joker's final position starting from position 1.	Medium4	TreePrefix sum+1	No attempts yet	1s	1024 MB	Judgeable
AirDropFind which friends holding a photo Puang can receive, directly or through relay friends within distance K and version gap T.	Medium4	GraphBFS	No attempts yet	1s	1024 MB	Judgeable
Solution 2Given N integers, find the contiguous range whose sum has the smallest absolute value, and report that sum with the range's endpoints.	Medium4	Prefix sumSorting	No attempts yet	1s	1024 MB	Judgeable
Portal GameFind the minimum time to walk from cell 0 to cell N-1 when red portals must be taken and blue portals are optional, or report -1 if unreachable.	Medium4	Shortest pathGraph	No attempts yet	1s	1024 MB	Judgeable
Express TrainPick exactly M stations for passing tracks to minimize the total running time of X regular trains and Y express trains.	Medium4	GreedySorting	No attempts yet	1s	1024 MB	Judgeable
Minimize Insulation SectionsGiven stations joined by DC or AC tracks, find the fewest power-type changes on a route from station A to station B.	Medium4	GraphBFS+1	No attempts yet	1s	1024 MB	Judgeable
Solution RelayCount the ways to call students in N rows of two so everyone hears the solution and no two consecutive rows lack a relay, modulo 10^9+7.	Medium4	Dynamic programmingMath	No attempts yet	1s	1024 MB	Judgeable
ContactGiven people labeled male or female, after each meeting, count the male-female pairs that can reach each other through chains of exchanged phone numbers.	Medium4	Union-findImplementation	No attempts yet	3s	1024 MB	Judgeable
Knight CruisingFor each query point, decide whether a knight starting at the origin can reach it when each move changes the coordinates by 1, 2, and 3 in some order.	Medium4	MathImplementation	No attempts yet	1s	1024 MB	Judgeable
MatKor Cup Preliminary Seat AssignmentGiven N participants and M seats, find the expected number of correct seat predictions as a reduced fraction.	Medium4	MathProbability	No attempts yet	1s	1024 MB	Judgeable
The Game of DeathEach friend names one friend, and starting from friend 1 the task is to find where T repeated moves along these names end up, with T up to 1e18.	Medium4	GraphSimulation	No attempts yet	1s	1024 MB	Judgeable
Glass BeadGiven a 0/1 string of length N, find the maximum number of beads in the pyramid, where each bead needs the two beads below it.	Medium4	ArrayMath	No attempts yet	1s	1024 MB	Judgeable
You and Me (NAVILLERA)Find the minimum number of moves, each of exact length c in the plane, needed to go from (0,0) to (X,Y).	Medium4	MathGeometry	No attempts yet	1s	1024 MB	Judgeable
Starting Today, We (Me gustas tu)Given an N by M grid and a target cell (a,b), choose a wind direction for each cell so that every heart starting anywhere reaches (a,b).	Medium4	BFSGraph+1	No attempts yet	1s	1024 MB	Judgeable
ABB to BA (Easy)Repeatedly replace the leftmost "ABB" with "BA" in a string of A and B characters, then print the final string.	Medium4	StringSimulation	No attempts yet	2s	1024 MB	Judgeable
What's the Order Anyway?Count the orderings of n comedy acts (n up to 10) that satisfy all given precedence and non-adjacency clues.	Medium4	BacktrackingBrute force+1	No attempts yet	2s	1024 MB	Judgeable
Picture CaptionSplit n names, in fixed order, into k consecutive lines so the longest line (letters plus single spaces between names) is as short as possible, and print that minimum length.	Medium4	Binary searchGreedy+1	No attempts yet	1s	1024 MB	Judgeable
Identical LettersGiven a lowercase string and an integer m, find the longest run of one repeated letter you can form by deleting at most m letters.	Medium4	Sliding windowString+1	No attempts yet	2s	1024 MB	Judgeable
Professor Won, please give me an A+Find the minimum final exam score Kim Hanyang needs to place in the top M ranks among students whose IDs start with 2024.	Medium4	Binary searchSorting+1	No attempts yet	1s	1024 MB	Judgeable
Magnet ChessGiven an N by N board of magnets and a touch distance D, find the empty cell where a new magnet touches the fewest existing magnets, or none if a cell touches zero.	Medium4	Prefix sumMatrix+1	No attempts yet	1s	1024 MB	Judgeable
Swallow MessengerGiven N points and M allowed integer slopes, count the ordered pairs of distinct points that lie on a common line with one of those slopes.	Medium4	Hash mapMath	No attempts yet	2s	1024 MB	Judgeable
Book Search ProgramFor each nested AND, OR, NOT search expression, count the books in the DB whose name, author, and tags satisfy every condition.	Medium4	RecursionString+1	No attempts yet	3s	1024 MB	Judgeable
Balloon PoppingGiven N balloons popped by A, B, and C at multiples of x, y, and z (ties go to A, then B, then C), print who pops the last balloon.	Medium4	MathBinary search	No attempts yet	0.5s	1024 MB	Judgeable
4-Cycle (Easy)Given a simple undirected graph with up to 1000 vertices and 1000 edges, count the distinct simple cycles of length 4 modulo 10^9+7.	Medium4	GraphCombinatorics+1	No attempts yet	2s	1024 MB	Judgeable
Daejeon Urban Railway Line 2Count unordered pairs of intersections off the 1-to-N path whose tree path touches that path at least once.	Medium4	TreeDFS+1	No attempts yet	1s	1024 MB	Judgeable
Bacon NumberGiven the actor lists of N movies, find a shortest chain of actors and movies linking two query actors for each query, or report -1 if none exists.	Medium4	BFSGraph+1	No attempts yet	1s	1024 MB	Judgeable
Lexicographically MaximumBits in the same position can be swapped between any two numbers, so find the lexicographically largest array reachable after any number of swaps.	Medium4	Bit manipulationGreedy	No attempts yet	1s	1024 MB	Judgeable
Animal FarmPick one pig, then add every non-pig animal whose influence is strictly below the pig's, to get the maximum total influence.	Medium4	SortingPrefix sum+1	No attempts yet	2s	1024 MB	Judgeable
MukjjippaGiven each player's per-turn choice probabilities, find the probability that A wins mukjjippa, printed as a value modulo 998244353.	Medium4	Dynamic programmingProbability+1	No attempts yet	2s	1024 MB	Judgeable
Kitten of ChaosGiven a string of b, d, p, q and a sequence of h, v, r flips and rotations, find the string seen after all transformations are applied in order.	Medium4	StringBit manipulation+1	No attempts yet	1s	1024 MB	Judgeable
Ellipse EclipseGiven the two foci and the major axis length of an ellipse, find the corners of its tightest axis-aligned bounding box.	Medium4	MathGeometry	No attempts yet	1s	1024 MB	Judgeable
Friends of Similar HeightFor each person, find the farthest person at or to the left of them whose height is between A_i minus K and A_i, then sum those distances.	Medium4	Segment treeArray	No attempts yet	2s	1024 MB	Judgeable
Shortest Path or Negative CycleGiven a directed weighted graph and a source vertex s, output a negative cycle if one exists, otherwise the shortest distance from s to every vertex.	Medium4	Shortest pathGraph	No attempts yet	4s	128 MB	Judgeable
OrnithologyCount the pairs of bird segments from the first line to the second line that cross, given each start position's desired targets.	Medium4	ArrayPrefix sum	No attempts yet	5s	1024 MB	Judgeable
Intelligence ExplorationGiven a 0/1 array, answer queries with the left-to-right implication value over each subarray from position l to r.	Medium4	ArrayMath+1	No attempts yet	4s	1024 MB	Judgeable
Aaawww... or Aaayyy!!!Given a frozen scoreboard and the pending submissions in reveal order, find the final rank of your favourite team from the length of each chant.	Medium4	SimulationImplementation+1	No attempts yet	2s	1024 MB	Judgeable
Industry ImprovementsFind the smallest machine capacity that lets all boxes, in their given order, be split into at most k contiguous groups whose weight sums each stay within the capacity.	Medium4	Binary searchGreedy+1	No attempts yet	2s	1024 MB	Judgeable
OccupationStarting from node r, capture adjacent nodes whose requirement A_i is at most your current stamina, gain B_i for each, and find the final stamina.	Medium4	GreedyHeap+1	No attempts yet	3s	1024 MB	Judgeable
Counting Strange RootsGiven a tree and two vertices A and B, count the roots K for which the lowest common ancestor of A and B is neither A nor B.	Medium4	TreeDFS	No attempts yet	3s	1024 MB	Judgeable
String ReductionGiven a string, repeatedly delete the smallest letter (the earliest one on ties) M times and print what remains.	Medium4	GreedySorting+1	No attempts yet	1s	1024 MB	Judgeable
RectangleGiven N unit squares on distinct grid cells, find the smallest possible perimeter of an axis-parallel rectangle that contains all of them, for each N up to 1e9.	Medium4	MathImplementation	No attempts yet	1s	1024 MB	Judgeable
Jeongmin's Sequence RecipeFor each query [a, b], count the starting integers in range, where the starting set is 1 plus all primes up to N.	Medium4	MathNumber theory+1	No attempts yet	1s	1024 MB	Judgeable
Guess the Random NumberGiven member weights and the winners in draw order, print a ticket index for each draw that makes that member win, using the remaining tickets.	Medium4	Prefix sumArray	No attempts yet	1s	1024 MB	Judgeable
Game of Death (Easy)Given a directed graph where each person points at two others, find a K from 10 to 99 such that a walk of K steps from person 1 never ends back at person 1.	Medium4	GraphBFS	No attempts yet	1s	1024 MB	Judgeable
EmoticonsGiven a message, replace every occurrence of one character with another (or none), convert emoticons from the left, and report the minimum and maximum resulting lengths.	Medium4	Brute forceString+1	No attempts yet	3s	1024 MB	Judgeable
Expected Flight DelayGiven the meeting weekday, weekday and weekend flight success rates, and a required on-time probability, find the earliest departure day that reaches it.	Medium4	MathProbability+1	No attempts yet	1s	1024 MB	Judgeable
Sandwich ArtGiven a partial sandwich and ingredient dependencies, decide whether adding required ingredients can produce a finished sandwich that fits one genre within the ingredient limit.	Medium4	GraphBFS+1	No attempts yet	3s	1024 MB	Judgeable
Up and DownFind the longest subsequence that strictly increases up to one peak element and then strictly decreases, with at least two elements on each side.	Medium4	Dynamic programmingBinary search	No attempts yet	3s	1024 MB	Judgeable
Number POPGiven a sequence of N values, find the longest run of equal values that can be formed by deleting at most K elements.	Medium4	Sliding windowTwo pointers+1	No attempts yet	1s	1024 MB	Judgeable
Connecting Grid CellsGiven an N by M grid of integers, find the maximum sum of cell values along a shortest path between two chosen cells.	Medium4	Dynamic programmingMatrix	No attempts yet	1s	1024 MB	Judgeable
Permutations and Increasing SequencesCount permutations of 1 to N whose length-K window sums strictly increase, printed modulo 1e9+7.	Medium4	MathCombinatorics+1	No attempts yet	2s	1024 MB	Judgeable
Ant on a CubeGiven the V and P commands an ant has executed on a cube, find the shortest command sequence that returns it to its starting vertex.	Medium4	GraphBFS+1	No attempts yet	1s	1024 MB	Judgeable
Word GameDecide whether all dictionary words can form one chain where each word starts with the previous word's last character, and print an order if so.	Medium4	GraphDFS	No attempts yet	1s	1024 MB	Judgeable
Anonymous M and Call SignsGiven a concert transcript, count how many lead call signs are shouted and how many of the five fixed sets end, following the set order and the greedy repeat rule for set A.	Medium4	SimulationString+1	No attempts yet	1s	1024 MB	Judgeable
OctopusStarting from N vertices with no edges, find the most vertices that can each have exactly K incident edges in a simple undirected graph.	Medium4	MathGraph	No attempts yet	1s	1024 MB	Judgeable
N+1 PromotionFor each product, find the fewest units to buy so that the total received, including free units that can feed further promotions, reaches the target a_i.	Medium4	Binary searchMath	No attempts yet	2s	1024 MB	Judgeable
Gahui and Club Audition 3Count the patterns of a level lv key note under random reverse mode, where at most 6 reverse keys appear, modulo 1e9+7.	Medium4	CombinatoricsMath+1	No attempts yet	1s	512 MB	Judgeable
Takahashi's Card GameCount the subsets of at least 2 cards where every proper nonempty draw, in any order, forms a palindrome, modulo 10^9 + 7.	Medium4	MathCombinatorics+2	No attempts yet	1s	512 MB	Judgeable
Mouse PursuitGiven n events, each a caught or missed mouse with a time offset and cheese and glory changes, find the totals gained in the last k seconds.	Medium4	Prefix sumSorting+1	No attempts yet	3s	2048 MB	Judgeable
Taking Out the TrashGiven n trash bags with weights, find the fewest trips needed when each trip carries one bag or two bags with total weight at most m.	Medium4	GreedySorting+1	No attempts yet	3s	2048 MB	Judgeable
Average Substring ValueGiven a digit string of length up to 200000, find the average of the largest digit over all substrings, printed as a reduced fraction.	Medium4	StackString+1	No attempts yet	1s	2048 MB	Judgeable
Leapfrog EncryptionGiven a key and a text, the task encrypts plaintext or decrypts ciphertext by alternately filling empty cells at key-defined skip intervals.	Medium4	ImplementationSimulation+1	No attempts yet	1s	2048 MB	Judgeable
Letter BalloonsGiven p problems and t school initials, find the largest number of schools that can each be the first solver of every problem spelled by their initials, with no overlap.	Medium4	Bit manipulationBrute force	No attempts yet	1s	2048 MB	Judgeable
Smart Password ValidationFor each attempt, decide whether it matches the password after at most one hand-shift, extra, or missing character error, with CAPS LOCK optionally on.	Medium4	ImplementationString+1	No attempts yet	1s	2048 MB	Judgeable
BottlesGiven each runner's time in every range, find for each range the maximum number of runners in it at the same moment.	Medium4	SortingPrefix sum+1	No attempts yet	1s	2048 MB	Judgeable
Triangles of a SquareGiven a square of side 2024 and one segment joining two of its sides, find the fewest extra segments needed to split the square into triangles.	Medium4	GeometryImplementation	No attempts yet	1s	2048 MB	Judgeable
Duel of CardsGiven Alice's n cards out of 2n, find the minimum and maximum number of rounds she can win over all possible deck orders.	Medium4	GreedySorting+1	No attempts yet	1s	2048 MB	Judgeable
Herb MixingGiven counts of green and red herbs, find the maximum health boost from combining them using the listed recipes.	Medium4	Dynamic programmingImplementation	No attempts yet	1s	2048 MB	Judgeable
Traffic LightsGiven n traffic lights with red and green durations that all turn red together, find the earliest time when every light is green again, or -1 if that never happens.	Medium4	SimulationNumber theory	No attempts yet	1s	2048 MB	Judgeable
Stone Removal Grid Game nmPlayers alternately take every stone in one full row or column of an n by m grid; for each query, decide whether the first player wins.	Medium4	Game theoryMath	No attempts yet	1s	1024 MB	Judgeable
Alternative EncryptionGiven strings of lowercase letters, encrypt or decrypt each one so that the output keeps its length, and each letter differs from the original at the same position.	Medium4	StringMath+1	No attempts yet	2s	1024 MB	Judgeable
MisèreGiven n cards in a hand from an A-by-B deck, find the fewest cards to swap so that every suit meets the misère condition.	Medium4	GreedySorting+1	No attempts yet	2s	2048 MB	Judgeable
CaveGiven a grid with walls and rupees, choose a lamp radius L measured by BFS distance from the start to maximize total rupees minus L times C.	Medium4	BFSPrefix sum	No attempts yet	2s	1024 MB	Judgeable
Kim's QuestCount the subsequences of length at least 3 in which every three consecutive elements have an even sum, modulo 998244353.	Medium4	Dynamic programmingMath	No attempts yet	3s	2048 MB	Judgeable
Farmer John's Cheese BlockAfter each removal of a unit cube from an N x N x N block, count the 1 x 1 x N bricks that still fit in the remaining cheese.	Medium4	ArrayImplementation	No attempts yet	2s	2048 MB	Judgeable
Savvy SellerPick meetings whose time intervals do not overlap (touching endpoints allowed) to maximize the total expected profit.	Medium4	Dynamic programmingBinary search+1	No attempts yet	1s	1024 MB	Judgeable
Party MedleyCount the teams of three distinct students whose max minus min rating is at most M, and find the largest rating sum among those teams.	Medium4	Brute forceSorting+1	No attempts yet	1s	2048 MB	Judgeable
Walking AroundGiven a weighted tree, find the minimum and maximum XOR of edge weights over all paths between two distinct vertices.	Medium4	TreeBit manipulation+1	No attempts yet	1s	2048 MB	Judgeable
Obstacle CourseGiven heights on odd-numbered segments with free even-numbered segments, find the longest run of consecutive segments where Adrian can step up or down by exactly 1 each time.	Medium4	ArrayImplementation	No attempts yet	1s	2048 MB	Judgeable
Diet PlanGiven daily milk needs P_i, M mL of milk, and K biscuits, find the maximum number of days the diet can last.	Medium4	GreedyHeap	No attempts yet	1s	2048 MB	Judgeable
ICPC ProvincialGiven 3N skill ratings, split them into N teams of three so that the weakest team's median is as large as possible, and print that median.	Medium4	SortingGreedy	No attempts yet	1s	2048 MB	Judgeable
Mirror MazeGiven a grid of forward and back mirrors, find every border position where a laser can be placed so its beam hits all mirrors.	Medium4	SimulationBrute force+1	No attempts yet	1s	2048 MB	Judgeable
K-SortGiven a permutation and K, decide whether swapping elements K positions apart (cyclically) can sort it into ascending order.	Medium4	Number theoryArray	No attempts yet	1.5s	1024 MB	Judgeable
The segment is not even.Find the longest contiguous subarray whose first half and second half contain the same multiset of values, where the halves are split at the midpoint.	Medium4	Sliding windowHash map+1	No attempts yet	1s	1024 MB	Judgeable
Masking TapeProcess paint and tape operations on a grid of 2x2 blocks, then print each cell's color after all tape is removed, where a cell keeps the color it had when first covered.	Medium4	ArraySimulation+1	No attempts yet	2s	2048 MB	Judgeable
Micromasters CertificatesGiven micromaster curriculums drawn as ASCII boxes, find the fewest distinct courses needed to complete any three of them.	Medium4	Brute forceHash map+1	No attempts yet	1s	2048 MB	Judgeable
GPT DarkDownGiven Darkdown chunks with arrival times, find the earliest start so the rendered text prints at 1 character per millisecond without waiting.	Medium4	StringSimulation+1	No attempts yet	1s	2048 MB	Judgeable
I am SherlockedGiven a phonebook of digit strings and a list of cursor commands, print the digits written to the output, or MISS ME! if a command is invalid.	Medium4	SimulationString+1	No attempts yet	1s	2048 MB	Judgeable