Problems

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Total results29,286 problems

Strong Jovsi
Medium6
Prefix sum, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Balance by Elimination
Medium6
Tree, DFS+1
No attempts yet
Time limit
3s
Memory limit
2048 MB
Judgeable
Eurovision
Medium6
Binary search, Greedy+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Highways of the Future
Medium6
Graph, DFS+1
No attempts yet
Time limit
6s
Memory limit
2048 MB
Judgeable
Alleys Construction
Medium6
Combinatorics, Number theory+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Alien Journey
Medium6
Shortest path, Sliding window+1
No attempts yet
Time limit
5s
Memory limit
2048 MB
Judgeable
Chill and Netflix
Medium6
Number theory, Math+1
No attempts yet
Time limit
2s
Memory limit
2048 MB
Judgeable
Balloon Party
Medium6
Matrix, Heap+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Generate Optimal Key
Medium6
Greedy, Heap+1
No attempts yet
Time limit
2s
Memory limit
2048 MB
Judgeable
Exactly one condition
Medium6
Math, Hash map+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Multiple sequence
Medium6
Dynamic programming, Math
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
Sosogogeum
Medium6
Hash map, Prefix sum+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Vacation Plan
Medium6
Graph, Minimum spanning tree+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Infinity Triples
Medium6
Number theory, Math
No attempts yet
Time limit
4s
Memory limit
2048 MB
Judgeable
Subsequence Update
Medium6
Greedy, Sorting+1
No attempts yet
Time limit
1.5s
Memory limit
2048 MB
Judgeable
Triangle Tree
Medium6
Tree, DFS+2
No attempts yet
Time limit
2s
Memory limit
2048 MB
Judgeable
The Quest for the Sacred Groves
Medium6
Segment tree, Tree+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
The Romanian Sieve
Medium6
Math, Binary search+1
No attempts yet
Time limit
2s
Memory limit
2048 MB
Judgeable
The Cypriote Mermaid
Medium6
Combinatorics, String+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
The Lottery WINNER
Medium6
Brute force, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Irreducible Fractions
Medium6
Number theory, Bit manipulation+1
No attempts yet
Time limit
3s
Memory limit
2048 MB
Judgeable
Mixed Messages
Medium6
Dynamic programming, String
No attempts yet
Time limit
2s
Memory limit
2048 MB
Judgeable
Growing Sequences
Medium6
Combinatorics, Math+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Institute
Medium6
Graph, DFS+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Billiard
Medium6
Math, Number theory
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Hocolate Hame
Medium6
Dynamic programming, Prefix sum+1
No attempts yet
Time limit
2s
Memory limit
2048 MB
Judgeable
Team Training
Medium6
Dynamic programming, Array+1
No attempts yet
Time limit
1s
Memory limit
2048 MB
Judgeable
Binary String
Medium6
Bit manipulation, String+1
No attempts yet
Time limit
4s
Memory limit
2048 MB
Judgeable
Sequences, Queries, and Probability 3
Medium6
Probability, Math+2
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Cookie Factory
Medium6
Segment tree, Greedy+1
No attempts yet
Time limit
3s
Memory limit
1024 MB
Judgeable
Bracket Strings
Medium7
Combinatorics, Dynamic programming+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Star Showdown
Medium7
Greedy, Graph+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Moving Pieces
Medium7
BFS, Brute force+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Smallest Integer with K Distinct Digits
Medium7
Dynamic programming, Greedy+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
DNA Deletions and Protein Count
Medium7
Dynamic programming, Greedy+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Roads
Medium7
Greedy, Union-find+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Palindrome Factory
Medium7
Dynamic programming, String+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Convex Polygon Intersection Area
Medium7
Geometry, Divide and conquer+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Difference from Reversal
Medium7
Math, Brute force+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Mafia
Medium7
Bit manipulation, DFS+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Largest Room Number 2
Medium7
Greedy, Math+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Magic String
Medium7
String matching, Brute force+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Twin Villages
Medium7
Dynamic programming, Bit manipulation+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Coin Board Game
Medium7
Dynamic programming, DFS+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Cutting a Log
Medium7
Binary search, Greedy+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Perfect Permutation 2
Medium7
Combinatorics, Greedy+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Counting K-gons
Medium7
Dynamic programming, Combinatorics+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Restore an Addition Equation
Medium7
Dynamic programming, Greedy+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Placing Puzzle Pieces
Medium7
Dynamic programming, Greedy+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Backup
Medium7
Greedy, Heap+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Modified Hanoi
Medium7
Simulation, Recursion+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Tilted Square Display
Medium7
Geometry, Simulation+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Number of Vertex Cactus Components
Medium7
Graph, DFS+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Teacher Cho Force
Medium7
Intervals, Math+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Adding Edges
Medium7
Union-find, Graph+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Last Josephus Survivor
Medium7
Math, Recursion+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
European Trip
Medium7
Minimum spanning tree, Graph+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Paper Cutting
Medium7
Backtracking, Bit manipulation+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Mafia
Medium7
Graph, BFS+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Oh Min-sik's Worry
Medium7
Graph, Shortest path+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Parliament
Medium7
Dynamic programming, Sorting+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
War
Medium7
Dynamic programming, Tree+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Stock King Dongho
Medium7
Dynamic programming, Array+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Picnic
Medium7
Segment tree, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Palindrome Word Sequences
Medium7
Dynamic programming, String matching+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Palindrome Smart
Medium7
Combinatorics, Math+2
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Special Nodes
Medium7
Dynamic programming, Tree+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Custom Dice
Medium7
Combinatorics, Dynamic programming+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Gem Shop Lighting
Medium7
Graph, Dynamic programming+1
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Biomagnification
Medium7
Dynamic programming, Graph+2
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
War - Escape Part 2
Medium7
Shortest path, Graph+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Bead Necklace
Medium7
Combinatorics, Math+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Magic Square
Medium7
Math, Matrix+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Running Course
Medium7
Geometry, Sorting+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
RPG
Medium7
Dynamic programming, Sorting+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Group Word Reconstruction
Medium7
Graph, String+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Jimin and Hansu's Orchard Split
Medium7
Geometry, Sorting+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
High-Rise Buildings
Medium7
Combinatorics, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Number of NKD Sequences
Medium7
Dynamic programming, Combinatorics+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Candy Stair Climb
Medium7
Topological sort, Graph+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Architects' Country
Medium7
Minimum spanning tree, Greedy+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Ideal String
Medium7
Greedy, Dynamic programming+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Bubble Sort
Medium7
Sorting, Segment tree+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Honeycomb
Medium7
Geometry, Math+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Tetris
Medium7
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Coin Problem
Medium7
Greedy, Math+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Cargo Truck
Medium7
Shortest path, Graph+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Number of Strings Matching Exactly K Patterns
Medium7
Combinatorics, Bit manipulation+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Keys in Boxes
Medium7
Combinatorics, Probability+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Fan Service
Medium7
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Moving the Monkeys' Ground
Medium7
Math, Binary search+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Number of Polygons
Medium7
Geometry, Math+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Marriage
Medium7
Dynamic programming, Bit manipulation+2
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Distance Conditions for Four Points
Medium7
Geometry, Math+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Knapsack Counting
Medium7
Divide and conquer, Binary search+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Syum Crossword
Medium7
Combinatorics, Brute force+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Paper Overlay
Medium7
Matrix, Brute force+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Fixing an Array
Medium7
Bit manipulation, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Restoring a Picture
Medium7
Matrix, BFS+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Olympic Ranking
Medium7
Dynamic programming, Greedy+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Strong JovsiFind the shortest walk on a line of l bars that picks up and delivers all n packages, with free start and end points.	Medium6	Prefix sumDynamic programming+1	No attempts yet	1s	2048 MB	Judgeable
Balance by EliminationGiven a binary tree, the task is to remove at most one leaf so the tree becomes height-balanced, and print the leaf or report balanced or impossible.	Medium6	TreeDFS+1	No attempts yet	3s	2048 MB	Judgeable
EurovisionGiven segments with pitch and duration, pick at most k breath points after local minima to minimize the longest breath-free stretch in seconds.	Medium6	Binary searchGreedy+1	No attempts yet	1s	2048 MB	Judgeable
Highways of the FutureGiven a directed graph of sectors and one-way highways, find the fewest new directed highways needed so every sector can reach every other sector.	Medium6	GraphDFS+1	No attempts yet	6s	2048 MB	Judgeable
Alleys ConstructionFor each even n, count the non-crossing perfect matchings of n houses on a circle (the Catalan number for n/2) modulo 313109, with n up to 10^18.	Medium6	CombinatoricsNumber theory+1	No attempts yet	1s	2048 MB	Judgeable
Alien JourneyFind the least lift height for an l by l square ship to move from the top-left to the bottom-right corner of a height grid.	Medium6	Shortest pathSliding window+1	No attempts yet	5s	2048 MB	Judgeable
Chill and NetflixCount the distinct positions from 2 to n reachable from second 1 by repeatedly adding one of the m given skip amounts.	Medium6	Number theoryMath+1	No attempts yet	2s	2048 MB	Judgeable
Balloon PartyGiven a grid of ceiling heights, find the maximum volume of helium the tent can hold without any of it spilling over the lowest edge.	Medium6	MatrixHeap+1	No attempts yet	1s	2048 MB	Judgeable
Generate Optimal KeyGiven n binary patterns and m forbidden keys of length L, find the non-forbidden binary key with the smallest total Hamming distance to all patterns.	Medium6	GreedyHeap+1	No attempts yet	2s	2048 MB	Judgeable
Exactly one conditionGiven a list a, integers k and l, find the smallest x at least l that satisfies exactly one of three conditions: x is in a, x is not divisible by k, or x contains the digit 7.	Medium6	MathHash map+1	No attempts yet	1s	2048 MB	Judgeable
Multiple sequenceChoose N integers from M kinds, each kind limited to c_i copies, so every term is a multiple of the previous one, and find the maximum possible sum.	Medium6	Dynamic programmingMath	No attempts yet	0.5s	1024 MB	Judgeable
SosogogeumCount the substrings of a binary string S whose value, read in binary, is divisible by K. N and K are up to 500,000.	Medium6	Hash mapPrefix sum+2	No attempts yet	1s	1024 MB	Judgeable
Vacation PlanGiven rail lines where line i takes 2^i minutes, answer each query with the number of intermediate stations on the shortest path between two stations.	Medium6	GraphMinimum spanning tree+1	No attempts yet	2s	1024 MB	Judgeable
Infinity TriplesCount triples (n, a, b) with n, a, b up to m and a < b, where infinitely many repdigit numbers in base b with digit a are divisible by n.	Medium6	Number theoryMath	No attempts yet	4s	2048 MB	Judgeable
Subsequence UpdateGiven an array and a segment [l,r], reverse one subsequence exactly once to find the minimum possible sum of the segment.	Medium6	GreedySorting+1	No attempts yet	1.5s	2048 MB	Judgeable
Triangle TreeGiven a rooted tree, sum the number of integer side lengths x that form a non-degenerate triangle over all pairs of vertices where neither is an ancestor of the other.	Medium6	TreeDFS+2	No attempts yet	2s	2048 MB	Judgeable
The Quest for the Sacred GrovesGiven a tree on n vertices and a permutation p, count the subarrays of p whose vertices form a connected subgraph of the tree.	Medium6	Segment treeTree+1	No attempts yet	1s	2048 MB	Judgeable
The Romanian SieveGiven t, find the largest n such that the sieve's inner loop runs at most t times, where that count is the sum of floor(n/i) for i from 1 to n.	Medium6	MathBinary search+1	No attempts yet	2s	2048 MB	Judgeable
The Cypriote MermaidCount the ways to fill each ? in a 0/1 string so that repeatedly removing adjacent equal pairs empties it, modulo 998244353.	Medium6	CombinatoricsString+1	No attempts yet	1s	2048 MB	Judgeable
The Lottery WINNERFind the fewest alphanumeric characters that cover at least one digit of every base-12 lottery number, where the letters for 10 and 11 vary per lottery.	Medium6	Brute forceBit manipulation+1	No attempts yet	1s	2048 MB	Judgeable
Irreducible FractionsCount ordered index quadruples (i, j, k, l) of distinct positions so that (a_i * a_j) / (a_k * a_l) is an irreducible fraction, with n up to 2000 and values up to 1e12.	Medium6	Number theoryBit manipulation+1	No attempts yet	3s	2048 MB	Judgeable
Mixed MessagesGiven a string that interleaves several messages, one of which is the word spbsu, find the minimum number of adjacent swaps between different messages that could have produced it.	Medium6	Dynamic programmingString	No attempts yet	2s	2048 MB	Judgeable
Growing SequencesCount arrays of length n where each element is at least twice the previous one and all values lie between 1 and c, modulo 998244353.	Medium6	CombinatoricsMath+1	No attempts yet	1s	2048 MB	Judgeable
InstituteDecide if Tikhon can leave his pass at some vertex reachable from vertex 1, then walk to a vertex he cannot return from without the pass.	Medium6	GraphDFS+1	No attempts yet	1s	2048 MB	Judgeable
BilliardGiven table dimensions n and m, the task is to count the steps a 45-degree billiard ball takes to return to the starting corner, for up to 10^5 queries.	Medium6	MathNumber theory	No attempts yet	1s	2048 MB	Judgeable
Hocolate HameTwo players eat a row of pieces from opposite ends, each move taking k or k+1 pieces, and the task is the optimal sweetness difference between them.	Medium6	Dynamic programmingPrefix sum+1	No attempts yet	2s	2048 MB	Judgeable
Team TrainingGiven 3n distinct levels, repeatedly remove three consecutive students into teams 1, 2, 3, maximizing the team sums lexicographically; output the three sums.	Medium6	Dynamic programmingArray+1	No attempts yet	1s	2048 MB	Judgeable
Binary StringFor each k, count the 1s in T_k, where each ? copies the character k positions before it and leading ? positions become 0.	Medium6	Bit manipulationString+1	No attempts yet	4s	2048 MB	Judgeable
Sequences, Queries, and Probability 3Given an array and M random operations, find the expected ratio of the final sum (S) or product (P) to the initial one, modulo 1e9+7.	Medium6	ProbabilityMath+2	No attempts yet	1.5s	1024 MB	Judgeable
Cookie FactoryFind the earliest day that finishes all cookie orders with start-day limits, after each update that changes one company's box count and start day.	Medium6	Segment treeGreedy+1	No attempts yet	3s	1024 MB	Judgeable
Bracket StringsGiven N and K, find the K-th lexicographically smallest string of length N over '(' and ')' that is not a valid bracket string, using combinatorial counting.	Medium7	CombinatoricsDynamic programming+2	No attempts yet	2s	128 MB	Judgeable
Star ShowdownGiven row and column game counts, build the 0/1 matrix with those degrees that is lexicographically smallest row by row, or print -1 if none exists.	Medium7	GreedyGraph+2	No attempts yet	2s	128 MB	Judgeable
Moving PiecesGiven at most 5 pieces on a 5x5 board, find the minimum number of sliding moves so all pieces form one connected component.	Medium7	BFSBrute force+2	No attempts yet	2s	512 MB	Judgeable
Smallest Integer with K Distinct DigitsGiven N up to 10^18 and K up to 10, construct the smallest integer at least N that contains exactly K distinct decimal digits.	Medium7	Dynamic programmingGreedy+2	No attempts yet	2s	128 MB	Judgeable
DNA Deletions and Protein CountCount, modulo 1e9+7, the distinct proteins obtainable by deleting some nucleotides from a DNA string and translating the remaining codons via a given table.	Medium7	Dynamic programmingGreedy+2	No attempts yet	2s	128 MB	Judgeable
RoadsChoose exactly M edges from a graph on N cities so the result is connected and the sorted edge list is lexicographically smallest, or report impossible.	Medium7	GreedyUnion-find+2	No attempts yet	2s	128 MB	Judgeable
Palindrome FactoryCompute the minimum number of insertions, deletions, replacements, and at most one swap needed to turn a given string into a palindrome.	Medium7	Dynamic programmingString+1	No attempts yet	2s	128 MB	Judgeable
Convex Polygon Intersection AreaGiven two convex polygons with vertices in counterclockwise order, compute the exact area of their intersection region within a tight error tolerance.	Medium7	GeometryDivide and conquer+1	No attempts yet	2s	128 MB	Judgeable
Difference from ReversalFind the smallest nonnegative integer x whose value minus its decimal reversal equals a given natural number D, or report that none exists.	Medium7	MathBrute force+2	No attempts yet	2s	128 MB	Judgeable
MafiaGiven guilt scores and a reaction matrix, the mafia Eunjin picks one night victim at a time and must survive as long as possible, returning the maximum number of nights.	Medium7	Bit manipulationDFS+2	No attempts yet	2s	128 MB	Judgeable
Largest Room Number 2Given per-digit purchase costs and a budget, find the largest number (no leading zero) affordable, then output its length and its first and last 50 digits.	Medium7	GreedyMath+2	No attempts yet	2s	128 MB	Judgeable
Magic StringCount permutations of up to 8 given words whose concatenation is a string that has exactly K circular shifts equal to itself.	Medium7	String matchingBrute force+2	No attempts yet	2s	512 MB	Judgeable
Twin VillagesSelect as many village pairs as possible with Manhattan distance at least D and degree at most P per village, then minimize the total distance among maximum selections.	Medium7	Dynamic programmingBit manipulation+2	No attempts yet	2s	128 MB	Judgeable
Coin Board GameA coin on a grid jumps exactly the digit on its cell in one of four directions; find the maximum number of moves before it leaves the board or hits a hole, or -1 if it can move forever.	Medium7	Dynamic programmingDFS+2	No attempts yet	2s	512 MB	Judgeable
Cutting a LogGiven a log of length L, allowed cut positions, and a cap C on the number of cuts, minimize the longest piece and report the smallest achievable first cut position.	Medium7	Binary searchGreedy+2	No attempts yet	2s	128 MB	Judgeable
Perfect Permutation 2Given a permutation P, find a permutation Q minimizing mismatches with P such that repeatedly applying Q from 0 visits every index exactly once.	Medium7	CombinatoricsGreedy+2	No attempts yet	2s	128 MB	Judgeable
Counting K-gonsCount the subsets of exactly K segments (from N, N up to 50) whose longest side is shorter than the sum of the rest, forming a valid K-gon.	Medium7	Dynamic programmingCombinatorics+2	No attempts yet	2s	128 MB	Judgeable
Restore an Addition EquationFill the ? digits in an addition equation A+B=C with digits (no leading zeros) so the sum holds, maximizing C then A.	Medium7	Dynamic programmingGreedy+2	No attempts yet	2s	128 MB	Judgeable
Placing Puzzle PiecesGiven a board length and a set of piece lengths, find the minimum number of pieces to place so that no remaining piece can fit in any leftover gap.	Medium7	Dynamic programmingGreedy+2	No attempts yet	2s	128 MB	Judgeable
BackupGiven n sorted company positions on a line, choose k disjoint pairs (2k companies) minimizing the total sum of pairwise distances.	Medium7	GreedyHeap+2	No attempts yet	2s	128 MB	Judgeable
Modified HanoiSimulate a modified Tower of Hanoi with a no-repeat-move rule and a fixed move priority order, counting moves until all disks gather on one pole.	Medium7	SimulationRecursion+2	No attempts yet	2s	128 MB	Judgeable
Tilted Square DisplayPlace 45-degree tilted squares along the x-axis one by one without overlap, then find which squares are visible when viewed from directly above.	Medium7	GeometrySimulation+2	No attempts yet	2s	128 MB	Judgeable
Number of Vertex Cactus ComponentsGiven a graph, count connected components that are vertex cacti, meaning every vertex lies in at most one simple cycle.	Medium7	GraphDFS+1	No attempts yet	2s	128 MB	Judgeable
Teacher Cho ForceGiven a moving catcher and N moving students, compute the maximum number of students that can simultaneously lie within radius R at any nonnegative time.	Medium7	IntervalsMath+2	No attempts yet	2s	128 MB	Judgeable
Adding EdgesFind the minimum number of edges to add to a graph so it becomes connected and admits an Euler trail.	Medium7	Union-findGraph+2	No attempts yet	2s	128 MB	Judgeable
Last Josephus SurvivorGiven N people in a circle and a step size K up to 90, find the last person remaining after repeatedly removing every K-th person, with N up to 10^15.	Medium7	MathRecursion+1	No attempts yet	2s	128 MB	Judgeable
European TripChoose N-1 roads to keep every country connected, then find the closed tour that pays each road cost twice plus visit costs, and return the least total.	Medium7	Minimum spanning treeGraph+2	No attempts yet	2s	128 MB	Judgeable
Paper CuttingDecide whether five fixed-shape pieces can be translated without rotation to exactly tile an L x L grid, then print the lexicographically smallest piece-number layout or gg if impossible.	Medium7	BacktrackingBit manipulation+2	No attempts yet	2s	128 MB	Judgeable
MafiaGiven a graph of tollgates and highways, choose a minimum-cost set of intermediate tollgates whose removal disconnects the start from the destination, solved via vertex-split min-cut/max-flow.	Medium7	GraphBFS+1	No attempts yet	2s	128 MB	Judgeable
Oh Min-sik's WorryFind the maximum money achievable traveling from city A to city B using weighted directed edges and city rewards, detecting infinite gain via positive cycles.	Medium7	GraphShortest path+2	No attempts yet	2s	128 MB	Judgeable
ParliamentGiven seat counts for N parties, find the maximum-seat coalition that has more than half the total seats but loses majority if any single member is removed.	Medium7	Dynamic programmingSorting+1	No attempts yet	2s	128 MB	Judgeable
WarGiven a forest of vassal relations and per-country conquest costs, find the minimum days needed to conquer or force surrender of at least M countries using tree knapsack DP.	Medium7	Dynamic programmingTree+1	No attempts yet	2s	128 MB	Judgeable
Stock King DonghoGiven prices for C stocks over D days and starting cash M, find the maximum cash obtainable by buying and selling whole shares each day using knapsack-style dynamic programming.	Medium7	Dynamic programmingArray+2	No attempts yet	2s	128 MB	Judgeable
PicnicGiven N students in a circle removing every K-th person Josephus-style, find the round number in which a specific student M is eliminated, with N and K up to 5,000,000.	Medium7	Segment treeSimulation+2	No attempts yet	1s	128 MB	Judgeable
Palindrome Word SequencesCount ordered sequences of given words, reused any number of times, whose concatenation has exact length L and forms a palindrome.	Medium7	Dynamic programmingString matching+2	No attempts yet	2s	128 MB	Judgeable
Palindrome SmartCount palindromic strings of length 1 to N built from lowercase letters that use at most K distinct letters, modulo 1234567891.	Medium7	CombinatoricsMath+2	No attempts yet	3s	128 MB	Judgeable
Special NodesIn a rooted tree where child weights exceed parent weights, mark vertices special or ordinary to minimize the total of each ordinary vertex's weight minus its nearest special ancestor's weight.	Medium7	Dynamic programmingTree+2	No attempts yet	2s	128 MB	Judgeable
Custom DiceCount six-faced dice with distinct positive integers averaging at most M, treating rotations as identical, and print the count mod 1e9+7.	Medium7	CombinatoricsDynamic programming+2	No attempts yet	2s	128 MB	Judgeable
Gem Shop LightingGiven required light values for an N by M grid of gems, find the minimum total intensity of row and column lamps so every gem's light requirement is met, which reduces to a maximum weight bipartite matching problem.	Medium7	GraphDynamic programming+1	No attempts yet	5s	128 MB	Judgeable
BiomagnificationGiven a DAG of predator-prey species where each consumer picks prey via an unbounded knapsack to meet its calorie need while minimizing heavy metal, determine if the human species survives and find its minimum accumulated metal.	Medium7	Dynamic programmingGraph+2	No attempts yet	5s	128 MB	Judgeable
War - Escape Part 2Given a weighted graph, find the shortest path from city 1 to city N after removing every edge that lies on any shortest path between them.	Medium7	Shortest pathGraph+1	No attempts yet	2s	128 MB	Judgeable
Bead NecklaceCount distinct linear arrangements of beads with given color counts (3 to 5 colors, up to 35 beads total) so that every three consecutive beads have different colors.	Medium7	CombinatoricsMath+2	No attempts yet	2s	128 MB	Judgeable
Magic SquareConstruct and print any N by N magic square for a given N between 3 and 300 using integers 1 through N^2.	Medium7	MathMatrix+2	No attempts yet	2s	128 MB	Judgeable
Running CourseGiven up to 100,000 2D points, compute the squared distance between the farthest pair of points.	Medium7	GeometrySorting+2	No attempts yet	2s	256 MB	Judgeable
RPGGiven quests that require either a strength or intelligence threshold and grant points to freely raise those stats, find the maximum number of quests completable.	Medium7	Dynamic programmingSorting+2	No attempts yet	2s	128 MB	Judgeable
Group Word ReconstructionReconstruct the unique group word, where every letter forms one contiguous block, by arranging all given unordered pieces, or report impossibility or multiple solutions.	Medium7	GraphString+2	No attempts yet	2s	128 MB	Judgeable
Jimin and Hansu's Orchard SplitGiven up to 50 weighted points on a plane, find a line avoiding all points that splits them into two groups minimizing the difference of their value sums.	Medium7	GeometrySorting+2	No attempts yet	2s	128 MB	Judgeable
High-Rise BuildingsCount permutations of heights 1..N arranged so exactly L buildings are visible from the left and R from the right, modulo 1e9+7.	Medium7	CombinatoricsDynamic programming+1	No attempts yet	2s	128 MB	Judgeable
Number of NKD SequencesCount length-K strictly increasing sequences summing to N where consecutive differences are at most D and the first term is at most D, modulo 1e9+7.	Medium7	Dynamic programmingCombinatorics+2	No attempts yet	2s	512 MB	Judgeable
Candy Stair ClimbFind the maximum candies collectible by jumping between horizontal stair segments within distance K, never decreasing height, starting from the ground.	Medium7	Topological sortGraph+2	No attempts yet	2s	128 MB	Judgeable
Architects' CountryConnect disjoint cities with new roads and pick an order to build required houses so total payments to participating architects are minimized.	Medium7	Minimum spanning treeGreedy+2	No attempts yet	2s	128 MB	Judgeable
Ideal StringBuild the lexicographically smallest length-N string where each character's total occurrence count equals the position of its first appearance, or output -1 if none exists.	Medium7	GreedyDynamic programming+2	No attempts yet	2s	128 MB	Judgeable
Bubble SortGiven an array, compute how many bubble sort passes occur before no swaps happen, without simulating the O(N^2) sort directly for N up to 500,000.	Medium7	SortingSegment tree+2	No attempts yet	2s	128 MB	Judgeable
HoneycombMap spiral-numbered hexagonal rooms to coordinates and print the room numbers along a shortest hex-grid path between two given rooms.	Medium7	GeometryMath+2	No attempts yet	2s	128 MB	Judgeable
TetrisCount the number of ways to tile a 3xN grid using square, T, S, Z, L, and J tetrominoes (no straight piece), modulo 1,000,000.	Medium7	Dynamic programmingCombinatorics+1	No attempts yet	2s	128 MB	Judgeable
Coin ProblemFind the minimum number of coins from denominations 10^K and 25x100^K needed to make an exact price up to 10^15.	Medium7	GreedyMath+2	No attempts yet	2s	128 MB	Judgeable
Cargo TruckCompute the minimum travel time across a grid road network where intersections have periodic traffic lights that permit entry only during the correct green phase.	Medium7	Shortest pathGraph+2	No attempts yet	2s	128 MB	Judgeable
Number of Strings Matching Exactly K PatternsCount lowercase strings that match exactly K out of N given letter/question-mark patterns of equal length, modulo 1,000,003.	Medium7	CombinatoricsBit manipulation+2	No attempts yet	2s	128 MB	Judgeable
Keys in BoxesGiven a uniformly random permutation of N keys among N locked boxes, find the exact probability that M bombs suffice to open every box, as a reduced fraction A/B.	Medium7	CombinatoricsProbability+2	No attempts yet	2s	128 MB	Judgeable
Fan ServiceCount length-2K ticket numbers over a given digit set where the two halves have equal digit sums or the odd/even positions have equal digit sums, modulo 999983.	Medium7	Dynamic programmingCombinatorics+1	No attempts yet	2s	128 MB	Judgeable
Moving the Monkeys' GroundPick an integer height for a horizontal ground so that the maximum pairwise distance between monkeys, computed via tree climbs and ground walks, is minimized.	Medium7	MathBinary search+1	No attempts yet	2s	128 MB	Judgeable
Number of PolygonsGiven up to 50 lines defined by point pairs, compute the number of bounded convex polygonal regions formed by their arrangement.	Medium7	GeometryMath+2	No attempts yet	2s	128 MB	Judgeable
MarriageGiven up to 12 men and 12 women with mutual liking pairs, partition everyone into star-shaped marriages (one person of one gender with several of the other) to cover all people with the fewest marriages, or report impossibility.	Medium7	Dynamic programmingBit manipulation+2	No attempts yet	5s	128 MB	Judgeable
Distance Conditions for Four PointsGiven all pairwise distances among four points as a 4x4 integer matrix, decide if distinct points realizing these distances exist in 3D space.	Medium7	GeometryMath+1	No attempts yet	2s	128 MB	Judgeable
Knapsack CountingGiven up to 30 items with large weights and a capacity limit, count how many subsets have total weight at most the capacity.	Medium7	Divide and conquerBinary search+2	No attempts yet	1s	128 MB	Judgeable
Syum CrosswordCount distinct grid arrangements of four given words split into two horizontal and two vertical words that cross each other exactly once under strict adjacency and gap rules.	Medium7	CombinatoricsBrute force+2	No attempts yet	2s	128 MB	Judgeable
Paper OverlayOverlay two grid papers, each freely rotated, flipped, and positioned, then find the largest all-X rectangle in the combined grid.	Medium7	MatrixBrute force+2	No attempts yet	2s	128 MB	Judgeable
Fixing an ArrayFor each array value, find the number within a given range that has the smallest Hamming distance in binary, breaking ties by choosing the smallest value.	Medium7	Bit manipulationDynamic programming+1	No attempts yet	2s	128 MB	Judgeable
Restoring a PictureRestore the minimum number of white cells to black in a corrupted grid so every black group becomes row and column convex and connected again.	Medium7	MatrixBFS+2	No attempts yet	2s	128 MB	Judgeable
Olympic RankingGiven current medal counts, decide how to award all remaining silver and bronze medals so that team 1 (which wins every remaining gold) reaches the best possible final rank.	Medium7	Dynamic programmingGreedy+2	No attempts yet	2s	128 MB	Judgeable