Problems

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Total results29,455 problems

Running Median
Medium5
Heap, Sorting+1
No attempts yet
Time limit
0.1s
Memory limit
128 MB
Judgeable
Captain Dasom
Medium5
Dynamic programming, Math+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Dasom's Shoe Store
Medium5
Greedy, Sorting+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Petting the Dog
Medium5
Math, Binary search+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Summit Handshakes 2
Medium5
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Number Game
Medium5
Dynamic programming, Math+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Labels Without a Forbidden Digit
Medium5
Math, Combinatorics+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Dog Days
Medium5
Graph, BFS+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Protecting Three People
Medium5
Geometry, Math+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Chessboard in FEN
Medium5
Simulation, Matrix+2
No attempts yet
Time limit
1s
Memory limit
32 MB
Judgeable
Making a Palindrome
Medium5
Dynamic programming, Array+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Power Strip Scheduling
Medium5
Greedy, Simulation+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Convex Hull
Medium5
Geometry, Sorting+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Candidate Recommendation
Medium5
Simulation, Hash map+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Robot
Medium5
BFS, Graph+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Laser
Medium5
Geometry, Sorting+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Number Grouping
Medium5
Greedy, Sorting+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Baking Pizza
Medium5
Binary search, Prefix sum+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Distance Between Vertices
Medium5
Tree, Binary search+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Communicating with the Space Gods
Medium5
Minimum spanning tree, Union-find+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Text Formalization
Medium5
String, String matching+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Number of Papers
Medium5
Divide and conquer, Recursion+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Tiling
Medium5
Dynamic programming, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Maal Gathering
Medium5
BFS, Shortest path+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Balanced Lineup
Medium5
Prefix sum, Hash map+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Sorting the Bookshelf
Medium5
Dynamic programming, Array+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Sum of Numbers 6
Medium5
Combinatorics, Backtracking+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Designing a High-Speed Rail Network
Medium5
Minimum spanning tree, Union-find+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Equation
Medium5
Number theory, Math+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Chariots
Medium5
Combinatorics, Math+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Highway
Medium5
Dynamic programming, Graph+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Quadrants
Medium5
Math, Implementation+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Word Extension
Medium5
Dynamic programming, String+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Lexicographically Smallest Valid Sequence
Medium5
Greedy, Array
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Stacking Boxes
Medium5
Simulation, Array+1
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Weight Limit
Medium5
Union-find, Binary search+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Famous Seven Princesses
Medium5
Backtracking, DFS+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Coin Distribution
Medium5
Dynamic programming, Array
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Chemistry Experiment
Medium5
Binary search, Math+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Prime Path
Medium5
BFS, Graph+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Cheers
Medium5
Dynamic programming, Intervals
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Jump Jump Championship
Medium5
Dynamic programming, Binary search+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Number Game
Medium5
Number theory, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Dramatic Multiplication
Medium5
Math, Number theory+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Hamburger Love
Medium5
Math, Brute force+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Safe Squares on a Chessboard
Medium5
Simulation, Implementation+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Alphabet Path
Medium5
Backtracking, DFS+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Prime Palindromes
Medium5
Math, Number theory+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Assigning Ranks
Medium5
Greedy, Sorting
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Products of Primes
Medium5
Heap, Math+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Minimum Transfer Route
Medium5
BFS, Graph+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Covering a Segment
Medium5
Greedy, Intervals+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Semitone
Medium5
Simulation, Implementation+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Relay Race
Medium5
Dynamic programming
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Minimum Vertex Cover
Medium5
Graph, BFS+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Factorial Decomposition
Medium5
Greedy, Math+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Omok
Medium5
Simulation, Implementation+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Removing Parentheses
Medium5
Recursion, String+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Traveling Salesperson Tour
Medium5
Dynamic programming, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Interval Containing the Most Others
Medium5
Sorting, Binary search+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Final Team Match
Medium5
Bit manipulation, Brute force+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Bug on a Tree
Medium5
Tree, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Ants
Medium5
Simulation, Math+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Bulbs and Switches
Medium5
Greedy, Simulation+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Sum of Subarrays from Two Arrays
Medium5
Array, Hash map+1
No attempts yet
Time limit
2s
Memory limit
64 MB
Judgeable
Building a Bridge
Medium5
BFS, Array+1
No attempts yet
Time limit
2s
Memory limit
192 MB
Judgeable
Super 12
Medium5
Simulation, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Wine Tasting
Medium5
Dynamic programming
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
In-Flight Meal Trip
Medium5
Dynamic programming, Graph
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Mountain Bike
Medium5
Shortest path, Graph+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Number of Rectangles
Medium5
Hash map, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Similar Words
Medium5
String, Sorting+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Letter Board
Medium5
Dynamic programming, Matrix+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Field Mouse Escape
Medium5
Graph, Greedy+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Moving a Unit
Medium5
BFS, Matrix+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
String Copy
Medium5
Dynamic programming, String+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Move by Breaking One Wall
Medium5
BFS, Graph+1
No attempts yet
Time limit
2s
Memory limit
192 MB
Judgeable
Marbles in Boxes
Medium5
Dynamic programming, Array+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Checking Causality
Medium5
Graph, Topological sort+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Team Formation
Medium5
Dynamic programming, Array+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Sequence Reduction
Medium5
Dynamic programming, Recursion
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Plum Tree
Medium5
Dynamic programming
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Proper Divisor Sum
Medium5
Math, Number theory
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Tree Height and Width
Medium5
Tree, BFS+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Water Jugs
Medium5
BFS, Simulation+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Jump
Medium5
Dynamic programming, BFS+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Recover Tree Preorder
Medium5
Tree, Recursion+1
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Sequence
Medium5
Backtracking, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Sum of Three Numbers
Medium5
Two pointers, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Theater Seats
Medium5
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Buying Jewels
Medium5
Dynamic programming, Array+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Tree Cutting
Medium5
Tree, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Fax Compression
Medium5
Dynamic programming, String+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Dance Pad Minimum Energy
Medium5
Dynamic programming, Simulation
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Placing a Basketball Hoop
Medium5
Math, Sorting+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Polygon Partitions
Medium5
Combinatorics, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Number of Permutations
Medium5
Dynamic programming, Combinatorics
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Pipe Cutting
Medium5
Greedy, Sorting
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Sum of Powers of Two
Medium5
Dynamic programming, Math+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Star Printing - 10
Medium5
Recursion, Matrix+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Running MedianGiven integers one by one, output the running median (lower of the two middles when count is even) after each insertion.	Medium5	HeapSorting+1	No attempts yet	0.1s	128 MB	Judgeable
Captain DasomGiven N cannonballs, find the minimum number of tetrahedral-number piles whose sizes sum exactly to N using unbounded coin-change style DP.	Medium5	Dynamic programmingMath+1	No attempts yet	2s	128 MB	Judgeable
Dasom's Shoe StoreChoose which discount coupons to buy, given their price and 1-3% discount rate, to minimize the total cost paid for a shoe.	Medium5	GreedySorting+2	No attempts yet	2s	128 MB	Judgeable
Petting the DogGiven the height gap between a monkey and a dog, find the minimum number of days to close it when daily growth starts and ends at 1 cm and changes by at most 1 cm each day.	Medium5	MathBinary search+1	No attempts yet	2s	128 MB	Judgeable
Summit Handshakes 2Given N seats around a round table, count the ways N representatives can pair up with non-crossing handshake segments, modulo 987654321.	Medium5	Dynamic programmingCombinatorics+1	No attempts yet	2s	128 MB	Judgeable
Number GameGiven a set of numbers including 1 and a limit K, find the first integer that cannot be formed using at most K chosen numbers, then decide the game winner by turn parity.	Medium5	Dynamic programmingMath+1	No attempts yet	2s	128 MB	Judgeable
Labels Without a Forbidden DigitGiven N and a forbidden digit L, find the N-th smallest positive integer whose decimal digits never contain L.	Medium5	MathCombinatorics+2	No attempts yet	2s	128 MB	Judgeable
Dog DaysGiven bunkers on a plane and a speed and survival-time limit, find the minimum number of intermediate bunkers a chicken must visit to reach a target bunker, or report it cannot escape.	Medium5	GraphBFS+1	No attempts yet	1s	128 MB	Judgeable
Protecting Three PeopleGiven a simple polygon with up to 10,000 vertices, determine for three query points whether each lies inside or on the polygon's boundary.	Medium5	GeometryMath+1	No attempts yet	2s	128 MB	Judgeable
Chessboard in FENParse a chess position in FEN notation and count empty squares that are not attacked by any piece of either color.	Medium5	SimulationMatrix+2	No attempts yet	1s	32 MB	Judgeable
Making a PalindromeFind the minimum number of integers to insert into a sequence so it becomes a palindrome, using interval or LCS-based dynamic programming.	Medium5	Dynamic programmingArray+1	No attempts yet	2s	128 MB	Judgeable
Power Strip SchedulingSimulate plugging devices into a strip with N outlets and, when full, evict the device whose next use is farthest away (or never used again), counting total unplugs.	Medium5	GreedySimulation+1	No attempts yet	2s	128 MB	Judgeable
Convex HullCompute the convex hull of up to 100,000 points and count only the hull's true vertices, excluding collinear boundary points.	Medium5	GeometrySorting+1	No attempts yet	2s	128 MB	Judgeable
Candidate RecommendationSimulate N photo frames where each recommendation either updates a displayed student's count or evicts the least-recommended, longest-displayed student to show the new one.	Medium5	SimulationHash map+2	No attempts yet	2s	128 MB	Judgeable
RobotFind the minimum number of move/turn commands for a grid robot to reach a target position and facing direction using BFS over states of position and direction.	Medium5	BFSGraph+1	No attempts yet	2s	128 MB	Judgeable
LaserGroup buildings by the ray from the origin, sort each group by distance, and find buildings whose laser is blocked by a closer, equally tall or taller building.	Medium5	GeometrySorting+2	No attempts yet	2s	128 MB	Judgeable
Number GroupingGiven N integers, decide which pairs to multiply instead of add so that the resulting total sum is maximized.	Medium5	GreedySorting+1	No attempts yet	2s	128 MB	Judgeable
Baking PizzaSimulate inserting pizza doughs into a tapering tube oven, each settling as deep as possible above prior doughs, and report the final dough's position or 0 if any fails to fit.	Medium5	Binary searchPrefix sum+2	No attempts yet	2s	256 MB	Judgeable
Distance Between VerticesGiven a weighted tree with up to 40,000 nodes, answer up to 10,000 queries about the path distance between two vertices, requiring an LCA-based approach for efficiency.	Medium5	TreeBinary search+2	No attempts yet	2s	128 MB	Judgeable
Communicating with the Space GodsGiven points with some already connected, find the minimum total length of new passages needed to connect all points into one network.	Medium5	Minimum spanning treeUnion-find+2	No attempts yet	2s	128 MB	Judgeable
Text FormalizationExpand every contraction and the first occurrence of each acronym in a text, following case rules and leftmost-earliest matching priority.	Medium5	StringString matching+2	No attempts yet	1s	128 MB	Judgeable
Number of PapersGiven an N x N grid of -1, 0, 1 values, recursively split non-uniform blocks into 9 equal sub-squares and count how many final uniform blocks hold each value.	Medium5	Divide and conquerRecursion+2	No attempts yet	2s	256 MB	Judgeable
TilingCount the number of ways to tile a 2×n rectangle using 2×1 and 2×2 tiles for multiple values of n up to 250.	Medium5	Dynamic programmingMath+1	No attempts yet	1s	128 MB	Judgeable
Maal GatheringGiven a grid with K-Maal pieces that jump up to K knight moves per turn, find the minimum total moves to gather all pieces on one square.	Medium5	BFSShortest path+2	No attempts yet	2s	128 MB	Judgeable
Balanced LineupGiven fans sorted by x-coordinate with a gender bit each, find the longest contiguous segment that has an equal number of men and women.	Medium5	Prefix sumHash map+2	No attempts yet	2s	256 MB	Judgeable
Sorting the BookshelfFind the minimum number of single-book relocations needed to sort a permutation of N books into increasing order.	Medium5	Dynamic programmingArray+1	No attempts yet	2s	128 MB	Judgeable
Sum of Numbers 6Given N and the bottom value of a Pascal-like sum triangle built from a permutation of 1..N, reconstruct the lexicographically smallest top row.	Medium5	CombinatoricsBacktracking+2	No attempts yet	2s	128 MB	Judgeable
Designing a High-Speed Rail NetworkGiven a cost matrix where negative values mark already-built rail lines, compute the minimum spanning tree cost forcing existing lines and list the new lines to build.	Medium5	Minimum spanning treeUnion-find+2	No attempts yet	2s	128 MB	Judgeable
EquationGiven N, count triples X+Y=Z with X<=Y under three separate conditions: bounded distinct integers, divisors of N, and primes up to N.	Medium5	Number theoryMath+2	No attempts yet	2s	128 MB	Judgeable
ChariotsConstruct a permutation of size N avoiding both fixed positions on the two main diagonals, or report impossibility for small N.	Medium5	CombinatoricsMath+1	No attempts yet	2s	128 MB	Judgeable
HighwayGiven a directed graph with edge lengths and tolls, find the minimum length path from city 1 to city N whose total toll does not exceed a budget K.	Medium5	Dynamic programmingGraph+1	No attempts yet	2s	128 MB	Judgeable
QuadrantsConvert a quadrant-encoded grid cell of up to 50 digits into coordinates, shift it by given x and y offsets, and print the resulting quadrant code or -1 if it moves off the grid.	Medium5	MathImplementation+1	No attempts yet	2s	128 MB	Judgeable
Word ExtensionGiven a dictionary and a starting 3-letter word, find the longest word reachable by repeatedly inserting one letter such that each intermediate word exists in the dictionary.	Medium5	Dynamic programmingString+1	No attempts yet	2s	128 MB	Judgeable
Lexicographically Smallest Valid SequenceGiven a permutation S, construct the lexicographically smallest permutation T where each element differs from the corresponding S element by at most 1.	Medium5	GreedyArray	No attempts yet	1s	128 MB	Judgeable
Stacking BoxesSimulate stacking N axis-aligned boxes at given footprints using a 2D max-height map and report the final maximum height.	Medium5	SimulationArray+1	No attempts yet	3s	128 MB	Judgeable
Weight LimitGiven a weighted undirected graph, find the maximum possible minimum edge weight (bottleneck) along any path between two given nodes.	Medium5	Union-findBinary search+1	No attempts yet	1s	128 MB	Judgeable
The Famous Seven PrincessesCount connected 7-cell shapes on a 5x5 grid of S/Y students where at least 4 cells are S.	Medium5	BacktrackingDFS+1	No attempts yet	2s	256 MB	Judgeable
Coin DistributionGiven several coin denominations with counts, decide for three test cases whether the coins can be split into two subsets of equal total value.	Medium5	Dynamic programmingArray	No attempts yet	2s	128 MB	Judgeable
Chemistry ExperimentDecide whether M mg of solution can be split into positive integer amounts per reagent so every reagent's linear gas formula a_i*x+b_i gives the same value, and output that value or 0.	Medium5	Binary searchMath+1	No attempts yet	2s	128 MB	Judgeable
Prime PathFind the minimum number of single-digit changes to transform one four-digit prime into another, keeping every intermediate number a four-digit prime, using BFS on the graph of primes.	Medium5	BFSGraph+1	No attempts yet	2s	256 MB	Judgeable
CheersGiven N people around a circle each drinking a cola brand, find the maximum number of non-crossing pairs connecting people with the same brand.	Medium5	Dynamic programmingIntervals	No attempts yet	2s	128 MB	Judgeable
Jump Jump ChampionshipGiven an array, find the longest strictly increasing subsequence and output its length plus the indices of one such subsequence.	Medium5	Dynamic programmingBinary search+1	No attempts yet	2s	128 MB	Judgeable
Number GameFor a given N, sum the trailing zero counts of N written in every base from 2 upward, which reduces to summing over divisors of N greater than 1 how many times each divides N.	Medium5	Number theoryMath+1	No attempts yet	1s	128 MB	Judgeable
Dramatic MultiplicationFind the smallest positive integer X ending in digit k such that multiplying X by n equals X with its last digit moved to the front.	Medium5	MathNumber theory+1	No attempts yet	2s	128 MB	Judgeable
Hamburger LoveGiven eating times n and m for two burger types and a total time t, find the maximum number of burgers eaten (minimizing leftover cola time, then maximizing count) subject to na+mb <= t.	Medium5	MathBrute force+1	No attempts yet	2s	128 MB	Judgeable
Safe Squares on a ChessboardGiven a chessboard with queens, knights, and pawns, count squares that no queen or knight attacks, treating all pieces as movement blockers.	Medium5	SimulationImplementation+1	No attempts yet	2s	128 MB	Judgeable
Alphabet PathFind the longest path from the top-left cell of a grid moving to adjacent cells while never revisiting a letter already used, maximizing visited cells.	Medium5	BacktrackingDFS+1	No attempts yet	2s	256 MB	Judgeable
Prime PalindromesList all palindromic prime numbers between a and b (up to 100 million) in increasing order, ending output with -1.	Medium5	MathNumber theory+1	No attempts yet	1s	256 MB	Judgeable
Assigning RanksAssign each of N students a unique rank from 1 to N to minimize the total absolute difference from their expected ranks.	Medium5	GreedySorting	No attempts yet	2s	256 MB	Judgeable
Products of PrimesFind the N-th smallest number that can be formed as a product of one or more (with repetition) of K given distinct primes, using a heap-based merge.	Medium5	HeapMath+1	No attempts yet	2s	128 MB	Judgeable
Minimum Transfer RouteGiven several subway lines as sequences of stations, compute the minimum number of transfers to travel between two given stations using BFS over lines.	Medium5	BFSGraph+1	No attempts yet	1s	256 MB	Judgeable
Covering a SegmentGiven up to 100,000 segments on a line, find the minimum number needed to fully cover [0, M], or output 0 if impossible.	Medium5	GreedyIntervals+1	No attempts yet	2s	128 MB	Judgeable
SemitoneGiven a sequence of semitone moves, determine which of the 7 white-key starting notes keep every intermediate step on a white key and report each valid start/end note pair.	Medium5	SimulationImplementation+1	No attempts yet	2s	128 MB	Judgeable
Relay RaceGiven N runners in fixed order each running 1 to 3 consecutive days, find the day-count assignment summing to exactly D that maximizes total distance, or -1 if invalid.	Medium5	Dynamic programming	No attempts yet	2s	128 MB	Judgeable
Minimum Vertex CoverGiven a bipartite graph with adjacency lists, compute the size of the minimum vertex cover using König's theorem via bipartite matching.	Medium5	GraphBFS+1	No attempts yet	2s	128 MB	Judgeable
Factorial DecompositionDecide whether a given number up to 10^18 can be written as a sum of factorials of distinct nonnegative integers.	Medium5	GreedyMath+1	No attempts yet	2s	128 MB	Judgeable
OmokSimulate placing stones in given order on a 19x19 Gomoku board and find the first move that creates exactly 5 in a row (not 6+) for its color.	Medium5	SimulationImplementation+1	No attempts yet	2s	128 MB	Judgeable
Removing ParenthesesGiven an arithmetic expression with letters and +,-,*,/,() parse it and print an equivalent expression using the fewest parentheses, applying sign/operator flips when parentheses are removed.	Medium5	RecursionString+1	No attempts yet	2s	128 MB	Judgeable
Traveling Salesperson TourFind the minimum cost Hamiltonian cycle in a directed graph with up to 16 cities using bitmask dynamic programming.	Medium5	Dynamic programmingBit manipulation+1	No attempts yet	1s	128 MB	Judgeable
Interval Containing the Most OthersGiven N intervals with unique endpoints, find the maximum number of intervals strictly contained inside a single interval.	Medium5	SortingBinary search+1	No attempts yet	2s	128 MB	Judgeable
Final Team MatchGiven up to 1000 students each mastering a subset of at most 15 problem types, find the largest group whose combined skill set covers at most K types.	Medium5	Bit manipulationBrute force+1	No attempts yet	2s	128 MB	Judgeable
Bug on a TreeGiven a tree with fruit values on vertices, find the maximum sum path (simple path) and its smallest-numbered starting endpoint.	Medium5	TreeDynamic programming+1	No attempts yet	2s	128 MB	Judgeable
AntsSimulate ants that reverse on collision by treating collisions as pass-throughs, then track identities to find which numbered ant falls off last and when.	Medium5	SimulationMath+1	No attempts yet	2s	128 MB	Judgeable
Bulbs and SwitchesGiven current and target bulb states, determine the minimum number of switch presses (each flipping a small neighborhood) needed, or -1 if impossible.	Medium5	GreedySimulation+1	No attempts yet	2s	128 MB	Judgeable
Sum of Subarrays from Two ArraysCount pairs of contiguous subarrays, one from each of two arrays, whose sums add up to a given target T.	Medium5	ArrayHash map+1	No attempts yet	2s	64 MB	Judgeable
Building a BridgeGiven a grid of land and sea, find the shortest straight sea-cell bridge connecting two different islands.	Medium5	BFSArray+1	No attempts yet	2s	192 MB	Judgeable
Super 12Simulate a rugby league by computing bonus points, sorting standings after every full round, and printing formatted tables.	Medium5	SimulationSorting+1	No attempts yet	1s	128 MB	Judgeable
Wine TastingPick numbers from a sequence maximizing sum while never selecting three consecutive elements.	Medium5	Dynamic programming	No attempts yet	2s	128 MB	Judgeable
In-Flight Meal TripFind the maximum-score path from city 1 to city N using at most M cities, moving only to strictly increasing city numbers along available flights.	Medium5	Dynamic programmingGraph	No attempts yet	2s	128 MB	Judgeable
Mountain BikeFind the minimum travel time from top-left to bottom-right of a grid where each move's duration depends on cumulative speed changes from height differences, solvable via Dijkstra with speed encoded as exponent sums.	Medium5	Shortest pathGraph+1	No attempts yet	2s	128 MB	Judgeable
Number of RectanglesGiven up to 5000 points, count axis-aligned rectangles whose four corners are all present among the points.	Medium5	Hash mapCombinatorics+1	No attempts yet	2s	128 MB	Judgeable
Similar WordsGiven up to 20,000 distinct words, find the pair with the longest common prefix, breaking ties by input order.	Medium5	StringSorting+1	No attempts yet	2s	128 MB	Judgeable
Letter BoardCount the number of paths on an N by M letter grid that spell a given word, moving 1 to K cells in one straight direction per step.	Medium5	Dynamic programmingMatrix+1	No attempts yet	2s	128 MB	Judgeable
Field Mouse EscapeGiven mouse and tunnel coordinates plus a max travel distance, compute the minimum number of mice that cannot be matched to a distinct tunnel using bipartite matching.	Medium5	GraphGreedy+1	No attempts yet	2s	128 MB	Judgeable
Moving a UnitFind the minimum BFS moves to slide an A by B rectangular unit across an N by M grid with obstacles from a start to a goal cell.	Medium5	BFSMatrix+1	No attempts yet	2s	128 MB	Judgeable
String CopyFind the minimum number of substring-copy operations from S needed to reconstruct P using greedy/DP over matching positions.	Medium5	Dynamic programmingString+1	No attempts yet	2s	128 MB	Judgeable
Move by Breaking One WallFind the shortest path in a grid from top-left to bottom-right where you may break at most one wall along the way.	Medium5	BFSGraph+1	No attempts yet	2s	192 MB	Judgeable
Marbles in BoxesGiven two marble sequences and a pairwise score table, choose a sequence of pop/pop/pop-both operations to maximize total matched-pair score, using LCS-like DP with reconstruction.	Medium5	Dynamic programmingArray+1	No attempts yet	2s	128 MB	Judgeable
Checking CausalityGiven send/receive events across computers with local clocks, detect whether the induced ordering constraints form a cycle indicating a causality violation.	Medium5	GraphTopological sort+1	No attempts yet	1s	128 MB	Judgeable
Team FormationPartition an age-ordered score sequence into contiguous groups to maximize the sum of each group's max-minus-min score.	Medium5	Dynamic programmingArray+1	No attempts yet	2s	128 MB	Judgeable
Sequence ReductionDecide if repeatedly merging adjacent elements as A[i]-A[i+1] can reduce the sequence to a single target value T.	Medium5	Dynamic programmingRecursion	No attempts yet	2s	128 MB	Judgeable
Plum TreeGiven a sequence of falling trees over T seconds, find the max plums caught starting at tree 1 with at most W moves between trees.	Medium5	Dynamic programming	No attempts yet	2s	128 MB	Judgeable
Proper Divisor SumGiven n up to 200 million, compute the cumulative sum of proper divisor sums from 1 to n modulo 1,000,000 efficiently.	Medium5	MathNumber theory	No attempts yet	2s	128 MB	Judgeable
Tree Height and WidthGiven a binary tree's parent-child structure, place nodes on a grid by binary tree layout rules and find the level with the maximum column width, breaking ties by smallest level.	Medium5	TreeBFS+1	No attempts yet	2s	128 MB	Judgeable
Water JugsGiven three jug capacities with the third jug initially full, find all possible water amounts in the third jug when the first jug is empty, using pour-until-full-or-empty moves.	Medium5	BFSSimulation+1	No attempts yet	2s	128 MB	Judgeable
JumpFind the minimum number of jumps from stone 1 to stone N where jump lengths change by at most 1 each step and some stones are blocked.	Medium5	Dynamic programmingBFS+1	No attempts yet	2s	128 MB	Judgeable
Recover Tree PreorderGiven a tree's inorder and postorder sequences, reconstruct the tree and output its preorder traversal.	Medium5	TreeRecursion+1	No attempts yet	5s	128 MB	Judgeable
SequenceFind the K-th lexicographically smallest non-decreasing sequence of N positive integers summing to M.	Medium5	BacktrackingCombinatorics+1	No attempts yet	2s	128 MB	Judgeable
Sum of Three NumbersGiven up to 1000 distinct integers, find the largest set element expressible as a sum of three elements (repeats allowed).	Medium5	Two pointersSorting+1	No attempts yet	1s	128 MB	Judgeable
Theater SeatsCount permutations where each ticket holder sits in their own or adjacent seat, with VIP seats fixed and splitting the row into independent segments counted by a Fibonacci-like recurrence.	Medium5	Dynamic programmingCombinatorics+1	No attempts yet	2s	128 MB	Judgeable
Buying JewelsFor each of n rows pick a contiguous non-empty subarray maximizing summed total value, breaking ties by fewest jewels then lexicographically smallest index sequence.	Medium5	Dynamic programmingArray+1	No attempts yet	2s	128 MB	Judgeable
Tree CuttingGiven a tree with n vertices, find the minimum number of edges to cut so some resulting piece has exactly m vertices, or report impossibility.	Medium5	TreeDynamic programming+1	No attempts yet	2s	128 MB	Judgeable
Fax CompressionChoose a quantization of a sequence into 4 levels with run-length style bit encoding to minimize error plus weighted code length.	Medium5	Dynamic programmingString+1	No attempts yet	2s	128 MB	Judgeable
Dance Pad Minimum EnergyGiven a sequence of dance pad moves, compute the minimum total energy to press each in order by choosing which of two feet to move each time.	Medium5	Dynamic programmingSimulation	No attempts yet	2s	128 MB	Judgeable
Placing a Basketball HoopFind the integer point minimizing the sum of weighted Manhattan distances to given weighted points, breaking ties by smallest x then smallest y.	Medium5	MathSorting+1	No attempts yet	2s	128 MB	Judgeable
Polygon PartitionsCount noncrossing dissections of a regular N-gon into all triangles or all quadrilaterals, modulo 1e9, using Catalan-like combinatorics.	Medium5	CombinatoricsDynamic programming+1	No attempts yet	2s	128 MB	Judgeable
Number of PermutationsGiven a permutation's up-down pattern, count permutations of size n sharing the same pattern, modulo 1,000,000,000.	Medium5	Dynamic programmingCombinatorics	No attempts yet	2s	128 MB	Judgeable
Pipe CuttingGiven M long pipes and N required short pipe lengths, compute the maximum number of short pipes that can be cut from the long pipes.	Medium5	GreedySorting	No attempts yet	2s	128 MB	Judgeable
Sum of Powers of TwoCount the ways to write N as an unordered sum of powers of two, modulo one billion.	Medium5	Dynamic programmingMath+1	No attempts yet	2s	128 MB	Judgeable
Star Printing - 10Recursively draw a Sierpinski-like N x N star pattern where N is a power of 3, replicating the base 3x3 block with blank centers at every scale.	Medium5	RecursionMatrix+1	No attempts yet	1s	256 MB	Judgeable