Problems

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Total results29,413 problems

Mine Shaft Expression
Medium6
Dynamic programming, String+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Elevator Hall Number
Medium6
Brute force, Hash map+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Pattern Language
Medium6
Union-find, Math+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Wave Attack
Medium6
Geometry, Math+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Almost Same Substring
Medium6
String, String matching+2
No attempts yet
Time limit
4s
Memory limit
512 MB
Judgeable
Save Your Privacy!
Medium6
Implementation, Brute force+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Treasure Hunt
Medium6
Sorting, Binary search+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
The Long and Narrow Place
Medium6
Simulation, Brute force
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
House Moving
Medium6
Dynamic programming, Sorting+2
No attempts yet
Time limit
3s
Memory limit
512 MB
Judgeable
Zero Division Checker
Medium6
Stack, Brute force+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
A Two Floors Dungeon
Medium6
BFS, Bit manipulation+1
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Dangerous Tower
Medium6
Dynamic programming, Sorting+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Power of Power
Medium6
Greedy, Math+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Rabbit Party
Medium6
Graph, Brute force+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Palindrome Generator
Medium6
Graph, BFS+1
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
White Bird
Medium6
Geometry, Brute force+1
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Differential Pulse Code Modulation
Medium6
Dynamic programming, Implementation+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
HullMarathon
Medium6
Geometry, Greedy+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Bicube
Medium6
Simulation, Implementation+1
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Sightseeing Tour
Medium6
Graph, Dynamic programming+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Tampopo Machine
Medium6
Math, Number theory
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Approximate Circle
Medium6
Math, Geometry+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Earn Big
Medium6
Combinatorics, Dynamic programming+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Laser Puzzle
Medium6
Brute force, Simulation+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Testing Sorting Networks
Medium6
Sorting, Bit manipulation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Train King
Medium6
Graph, BFS
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Tree Construction
Medium6
Geometry, Greedy
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Matsuzaki Number
Medium6
Number theory, Math+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Brave Princess Revisited
Medium6
Graph, Shortest path+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Mirror Cave
Medium6
BFS, Graph+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Defend the Bases
Medium6
Binary search, Greedy+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Strange String Manipulation
Medium6
Brute force, Math+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Marked Ancestor
Medium6
Union-find, Tree+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Reverse a Road
Medium6
Graph, Shortest path+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Vending Machine
Medium6
Dynamic programming, Greedy+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Adaptive Time Slicing Quantization
Medium6
Dynamic programming, Prefix sum+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Magical Island
Medium6
Geometry, Binary search+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Dance Dance Revolution
Medium6
Greedy, Implementation+1
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Hit and Blow
Medium6
Brute force, Implementation+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Election
Medium6
Simulation, Implementation+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Jaggie Spheres
Medium6
Math, Implementation+1
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Private Teacher
Medium6
Greedy, Implementation+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Triangles
Medium6
Geometry, Math+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Defend the Nation
Medium6
Math, Geometry+1
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Life Game
Medium6
Matrix, Math
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Magical Dungeon
Medium6
Shortest path, Graph
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Land Mark
Medium6
Geometry, Implementation
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Alien Pianist
Medium6
Greedy, Sorting+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Japanese Style Pub
Medium6
Dynamic programming, Combinatorics+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Text Justification
Medium6
Dynamic programming, Prefix sum+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
X-Ray Screening System
Medium6
Implementation, Brute force+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Sort that Queue
Medium6
BFS, Queue+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Tetrahedra
Medium6
Brute force, Geometry+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
International Party
Medium6
Brute force, Combinatorics+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
TV Watching
Medium6
Intervals, Dynamic programming+1
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Make Friendships
Medium6
Graph, BFS+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Reading Brackets in English
Medium6
String, Dynamic programming+1
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
The Family Tree of ACM Cells
Medium6
Tree, DFS+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Hills
Medium6
Geometry, Brute force+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Safe Packing
Medium6
Greedy, Sorting+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Make Purse Light
Medium6
Brute force, Dynamic programming+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Area Separation
Medium6
Geometry, Implementation+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Gather the Maps!
Medium6
Graph, BFS+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Painting
Medium6
Backtracking, Brute force+1
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Building Bridges
Medium6
Minimum spanning tree, Union-find+1
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Opened-up Die
Medium6
Brute force, Implementation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
The Revolution of the Ants
Medium6
Simulation, Graph
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Minimum Coin Exchange Problem
Medium6
Dynamic programming, Shortest path
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Walk an Equation
Medium6
Backtracking, DFS+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
The Secret Number
Medium6
Dynamic programming, Array+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Square Carpets
Medium6
Backtracking, Brute force+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Missing Numbers
Medium6
Math, Graph+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Pump up Batteries
Medium6
Simulation, Queue+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Ether Geometry
Medium6
Geometry, Shortest path
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Walking Ant
Medium6
BFS, Graph+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Folder Cleanup (large)
Medium6
Tree, Simulation+2
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Farthest Place
Medium6
Graph, Shortest path+2
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Walk (small)
Medium6
Graph, BFS+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Reversort Engineering
Medium6
Greedy, Implementation+2
No attempts yet
Time limit
10s
Memory limit
1024 MB
Judgeable
Append Sort
Medium6
Greedy, String+2
No attempts yet
Time limit
10s
Memory limit
1024 MB
Judgeable
Closest Pick
Medium6
Greedy, Sorting+2
No attempts yet
Time limit
10s
Memory limit
1024 MB
Judgeable
Roaring Years
Medium6
Math, Brute force+2
No attempts yet
Time limit
30s
Memory limit
1024 MB
Judgeable
Orange Island Trip
Medium6
Number theory, Graph+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Growing Oranges
Medium6
Greedy, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Matrygons
Medium6
Dynamic programming, Number theory+2
No attempts yet
Time limit
Not set
Memory limit
1024 MB
Judgeable
Build-A-Pair
Medium6
Greedy, Sorting+1
No attempts yet
Time limit
5s
Memory limit
1024 MB
Judgeable
Divisible Divisions
Medium6
Dynamic programming, Number theory+1
No attempts yet
Time limit
60s
Memory limit
1024 MB
Judgeable
Mountainous Palindromic Subarray
Medium6
Array, Two pointers+2
No attempts yet
Time limit
2s
Memory limit
2048 MB
Judgeable
Data Checker
Medium6
Sorting, Intervals+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Team Building
Medium6
Array, Two pointers+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Cloud Bridge
Medium6
Tree, Graph+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Jump Hide-and-Seek
Medium6
Math, Greedy+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Patching with Colored Paper
Medium6
Matrix, Prefix sum+1
No attempts yet
Time limit
4s
Memory limit
512 MB
Judgeable
Human Pipeline
Medium6
Greedy, Sorting+2
No attempts yet
Time limit
1.5s
Memory limit
1024 MB
Judgeable
Recycling Campaign
Medium6
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Sudden Attack 3
Medium6
Greedy, Sorting+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
L Shaped Plots
Medium6
Array, Implementation+2
No attempts yet
Time limit
60s
Memory limit
1024 MB
Judgeable
Rabbit House
Medium6
Graph, Greedy+2
No attempts yet
Time limit
Not set
Memory limit
1024 MB
Judgeable
Longest Progression
Medium6
Array, Two pointers+2
No attempts yet
Time limit
30s
Memory limit
1024 MB
Judgeable
Alien Generator
Medium6
Math, Number theory+2
No attempts yet
Time limit
30s
Memory limit
1024 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Mine Shaft ExpressionGiven a single-digit arithmetic expression with + and -, add parentheses to maximize its value and print the maximum.	Medium6	Dynamic programmingString+1	No attempts yet	2s	512 MB	Judgeable
Elevator Hall NumberCount how many distinct decimal strings can be formed by concatenating one chosen floor from each of N elevators, where each floor is between 1 and 99.	Medium6	Brute forceHash map+2	No attempts yet	8s	512 MB	Judgeable
Pattern LanguageEach of M letters takes a digit up to its own limit u_i; count assignments that make the whole string a palindrome, where positions paired by mirror symmetry must get equal digits.	Medium6	Union-findMath+2	No attempts yet	5s	512 MB	Judgeable
Wave AttackCount how many reflected shockwave paths from the launcher reach the Count within t seconds, where simultaneous arrivals from different directions each count.	Medium6	GeometryMath+2	No attempts yet	2s	512 MB	Judgeable
Almost Same SubstringCount the length-\|T'\| substrings of S that differ from T' in exactly one character.	Medium6	StringString matching+2	No attempts yet	4s	512 MB	Judgeable
Save Your Privacy!Given which members each member knows and the set of leaked records, find the unique member whose knowledge could explain exactly that leak set, or -1.	Medium6	ImplementationBrute force+2	No attempts yet	8s	512 MB	Judgeable
Treasure HuntGiven n treasure points and m axis-aligned rectangles, count how many points fall inside each rectangle (boundaries included).	Medium6	SortingBinary search+2	No attempts yet	5s	512 MB	Judgeable
The Long and Narrow PlaceGiven a road of length dist, n carriages with speeds S_i, and m passing spots at distances D_i, find the minimum time until all carriages reach the goal.	Medium6	SimulationBrute force	No attempts yet	3s	512 MB	Judgeable
House MovingGiven a permutation of weights, move pieces to any position at cost equal to the piece's weight so the final order is sorted; minimize total cost.	Medium6	Dynamic programmingSorting+2	No attempts yet	3s	512 MB	Judgeable
Zero Division CheckerGiven variable ranges, decide whether some assignment causes a division by zero in an 8-bit reverse Polish notation evaluation.	Medium6	StackBrute force+2	No attempts yet	2s	512 MB	Judgeable
A Two Floors DungeonFind the fewest steps from the start to the exit on a two-floor grid where switches flip cells between floors, with up to 10 switches.	Medium6	BFSBit manipulation+1	No attempts yet	5s	512 MB	Judgeable
Dangerous TowerEach block is 1 x Ai x Bi and can be placed with either Ai or Bi as its height; a block must be strictly narrower than the block below it. Maximize the total tower height.	Medium6	Dynamic programmingSorting+2	No attempts yet	2s	512 MB	Judgeable
Power of PowerGiven N integers, rearrange them so the power tower B1^(B2^(...^BN)) is maximized, and print the lexicographically smallest optimal order.	Medium6	GreedyMath+1	No attempts yet	2s	512 MB	Judgeable
Rabbit PartyChoose a subset of rabbits to maximize the sum over guests of the minimum friendliness toward any other guest; uninvited pairs have friendliness 0.	Medium6	GraphBrute force+2	No attempts yet	5s	512 MB	Judgeable
Palindrome GeneratorFind the longest palindrome made of dictionary words where each consecutive word pair is an allowed transition. Print 0 if none exists and -1 if the length is unbounded.	Medium6	GraphBFS+1	No attempts yet	5s	512 MB	Judgeable
White BirdGiven rectangular obstacles and a launch speed, decide whether the white bird can fly past them and drop an egg bomb onto the pig at (X, Y).	Medium6	GeometryBrute force+1	No attempts yet	5s	512 MB	Judgeable
Differential Pulse Code ModulationGiven a codebook of step values and a signal, choose a code per sample so the reconstructed signal stays within 0 to 255 and minimizes the sum of squared errors against the input.	Medium6	Dynamic programmingImplementation+2	No attempts yet	8s	512 MB	Judgeable
HullMarathonGiven N speeds, each rabbit runs up to r_i in any direction for one minute; maximize the convex hull area of the final positions.	Medium6	GeometryGreedy+2	No attempts yet	8s	512 MB	Judgeable
BicubeDecide whether eight unit cubes folded from a painted paper sheet can form a 2x2x2 bicube with black inner faces and distinct uniform outer faces.	Medium6	SimulationImplementation+1	No attempts yet	8s	512 MB	Judgeable
Sightseeing TourOrient every edge of a complete undirected graph at minimum cost so that the resulting digraph has a Hamiltonian path visiting all N areas.	Medium6	GraphDynamic programming+2	No attempts yet	8s	512 MB	Judgeable
Tampopo MachineGiven package width W, gap D, N magic hands spaced M apart, and a tampopo interval T, find the fraction of packages that receive no tampopo.	Medium6	MathNumber theory	No attempts yet	8s	512 MB	Judgeable
Approximate CircleFind the circle that minimizes the sum of squared algebraic residuals over n points by solving the resulting 3x3 normal equations.	Medium6	MathGeometry+2	No attempts yet	2s	512 MB	Judgeable
Earn BigGiven N boxes and N names in a random permutation, compute the probability that every element lies in a cycle of length at most M.	Medium6	CombinatoricsDynamic programming+2	No attempts yet	2s	512 MB	Judgeable
Laser PuzzleDecide whether John can leave through the door by pushing at most two mirrors or crystals so the laser hits every statue.	Medium6	Brute forceSimulation+1	No attempts yet	2s	512 MB	Judgeable
Testing Sorting NetworksGiven a layered circuit of N/2 sorters joined by fixed wiring, decide whether every 0-1 input ends up sorted after all stages.	Medium6	SortingBit manipulation+2	No attempts yet	2s	512 MB	Judgeable
Train KingFind the maximum units of material Roland can move from station A to station B, given train timetables with car counts and possibly backward time jumps.	Medium6	GraphBFS	No attempts yet	2s	512 MB	Judgeable
Tree ConstructionGiven n points with x increasing and y decreasing, find the minimum total length of axis-aligned edges that go right or up and connect all points.	Medium6	GeometryGreedy	No attempts yet	2s	512 MB	Judgeable
Matsuzaki NumberFor each query N and P, list all sums of two primes greater than N (with repetition, duplicates counted separately) in increasing order and report the P-th sum, where P is at most 100.	Medium6	Number theoryMath+2	No attempts yet	8s	512 MB	Judgeable
Brave Princess RevisitedGiven a weighted undirected graph with a budget L, find a path from node 1 to node N minimizing total enemies encountered, where the budget constrains the maximum sum of guard costs.	Medium6	GraphShortest path+2	No attempts yet	8s	512 MB	Judgeable
Mirror CaveTwo people move on two W by H grids with mirrored directions, one blocked mover stays put, and the task asks whether they can occupy the two destination cells at the same time.	Medium6	BFSGraph+2	No attempts yet	8s	512 MB	Judgeable
Defend the BasesGiven troops with positions and speeds and a set of bases, find the minimum time so every base is reached by at least one troop, or report it is impossible.	Medium6	Binary searchGreedy+2	No attempts yet	8s	512 MB	Judgeable
Strange String ManipulationGiven a byte string, search all 4096 parameter triples of a fixed LCG and output the one whose shift minimizes the output string's entropy.	Medium6	Brute forceMath+2	No attempts yet	8s	512 MB	Judgeable
Marked AncestorOn a rooted tree, process mark and query operations where each query asks for the nearest marked ancestor of a node, then report the sum of all query answers.	Medium6	Union-findTree+2	No attempts yet	8s	512 MB	Judgeable
Reverse a RoadGiven a directed graph, allow reversing at most one edge and report the shortest S to T distance and the smallest-numbered edge to reverse (0 if none helps).	Medium6	GraphShortest path+2	No attempts yet	8s	512 MB	Judgeable
Vending MachineGiven up to 10 coin denominations and a target M up to 100000, find the minimum number of operations where each operation outputs at most one coin of each denomination.	Medium6	Dynamic programmingGreedy+2	No attempts yet	8s	512 MB	Judgeable
Adaptive Time Slicing QuantizationSplit a sequence into M frames of at least two elements each to minimize the total squared quantization error under a 2L-level quantizer.	Medium6	Dynamic programmingPrefix sum+2	No attempts yet	8s	512 MB	Judgeable
Magical IslandFour crystals at the corners of a W by H rectangle each project a same-radius circular shield; find the minimum radius so the four circles cover area S, and output 4R^2.	Medium6	GeometryBinary search+2	No attempts yet	8s	512 MB	Judgeable
Dance Dance RevolutionDecide whether a sequence of arrow steps can be played alternating feet, never repeating a panel, body facing forward, and legs never crossing.	Medium6	GreedyImplementation+1	No attempts yet	8s	512 MB	Judgeable
Hit and BlowGiven prior guesses with hit and blow counts, find the unique secret, the smallest guess that would pin it down next turn, or ???? if neither holds.	Medium6	Brute forceImplementation+2	No attempts yet	8s	512 MB	Judgeable
ElectionGiven parties with list candidates and party votes plus constituency results, apply MMP seat allocation including overhang seats, then print all elected names in ASCII order.	Medium6	SimulationImplementation+2	No attempts yet	8s	512 MB	Judgeable
Jaggie SpheresGiven n, count the faces of the smallest union of unit cubes that covers every point closer than sqrt(n) to the origin.	Medium6	MathImplementation+1	No attempts yet	8s	512 MB	Judgeable
Private TeacherGiven each pupil's required lesson count and the weekdays they are available, decide whether all lessons can be scheduled within W weeks with at most one lesson per pupil per day.	Medium6	GreedyImplementation+2	No attempts yet	8s	512 MB	Judgeable
TrianglesFor each n up to 1000, find the area of the union of n unit equilateral triangles sharing a centroid, each rotated by 360/n degrees.	Medium6	GeometryMath+2	No attempts yet	8s	512 MB	Judgeable
Defend the NationGiven the projectile's launch speed and angle, find the interceptor angle and the earliest time it can destroy the projectile before the projectile lands.	Medium6	MathGeometry+1	No attempts yet	8s	512 MB	Judgeable
Life GameViruses spread across a hexagonal grid each period with counts reduced mod M, and the task asks for the grand total after L periods.	Medium6	MatrixMath	No attempts yet	8s	512 MB	Judgeable
Magical DungeonFind the maximum hit points Arthur can have when reaching room t from room s, where HP is capped at H and must stay above zero along the way.	Medium6	Shortest pathGraph	No attempts yet	8s	512 MB	Judgeable
Land MarkGiven landmarks in the order a person sees them on a counterclockwise turn, find the area of the region where that person can be, or report Infinity or No area.	Medium6	GeometryImplementation	No attempts yet	8s	512 MB	Judgeable
Alien PianistGiven a sequence of notes (sets of keys) and N fingers, decide whether the alien can play every note while keeping fingers uncrossed during overlaps.	Medium6	GreedySorting+2	No attempts yet	8s	512 MB	Judgeable
Japanese Style PubGiven a confusion matrix of drink delivery probabilities and order counts, compute the natural log of the probability that the delivered multiset matches the ordered multiset.	Medium6	Dynamic programmingCombinatorics+2	No attempts yet	8s	512 MB	Judgeable
Text JustificationSplit a sequence of word widths into lines no wider than the paper, minimizing a per-line cost that is absolute except on the last line.	Medium6	Dynamic programmingPrefix sum+2	No attempts yet	8s	512 MB	Judgeable
X-Ray Screening SystemGiven an X-ray projection grid of at most 7 labeled materials, decide whether every material region is a solid rectangle, otherwise report SUSPICIOUS.	Medium6	ImplementationBrute force+2	No attempts yet	8s	512 MB	Judgeable
Sort that QueueGiven a queue holding 0 to N-1 in random order and two empty stacks, find the fewest block operations that leave the queue sorted in ascending order.	Medium6	BFSQueue+2	No attempts yet	8s	512 MB	Judgeable
TetrahedraGiven up to 15 stick lengths, choose 6 sticks to form the edges of a tetrahedron and maximize its volume.	Medium6	Brute forceGeometry+2	No attempts yet	8s	512 MB	Judgeable
International PartyFind the smallest set of at most five languages such that every pair of students shares a common language in the set, or report Impossible.	Medium6	Brute forceCombinatorics+2	No attempts yet	8s	512 MB	Judgeable
TV WatchingPick each program to watch live or record so that the live picks and the recorded picks each have no time overlap, maximizing the total score.	Medium6	IntervalsDynamic programming+1	No attempts yet	8s	512 MB	Judgeable
Make FriendshipsGiven Isaac's available days and each friend's available days, find the largest set of friends he can date on distinct days.	Medium6	GraphBFS+2	No attempts yet	8s	512 MB	Judgeable
Reading Brackets in EnglishGiven an English phrase describing nested lists, output the S-expression it encodes, or AMBIGUOUS if the phrase has more than one reading.	Medium6	StringDynamic programming+1	No attempts yet	8s	512 MB	Judgeable
The Family Tree of ACM CellsGiven offspring counts that define a family tree in numbering order, count how many queries ask whether one cell is an ancestor of another.	Medium6	TreeDFS+2	No attempts yet	2s	512 MB	Judgeable
HillsCount the triangles formed by segments in each picture that no other segment cuts through.	Medium6	GeometryBrute force+1	No attempts yet	2s	512 MB	Judgeable
Safe PackingEach day, choose boxes from the Fibonacci sizes so that every non-Fibonacci item's box is filled with the limited daily filling, packing as many items as possible.	Medium6	GreedySorting+2	No attempts yet	2s	512 MB	Judgeable
Make Purse LightGiven his coin counts and an amount to pay, find which coins to hand over so that the total number of coins he keeps is minimized, accounting for optimal change.	Medium6	Brute forceDynamic programming+2	No attempts yet	8s	512 MB	Judgeable
Area SeparationGiven lines that each cut a fixed square, count how many regions the square is divided into.	Medium6	GeometryImplementation+2	No attempts yet	8s	512 MB	Judgeable
Gather the Maps!Each person is free on some subset of days 1 to 30; find the earliest day by which repeated pairwise meetings can collect all map fragments at one person.	Medium6	GraphBFS+2	No attempts yet	8s	512 MB	Judgeable
PaintingGiven a triangle of white and black circles, find the fewest lines parallel to the edges that cover every white circle without touching any black circle.	Medium6	BacktrackingBrute force+1	No attempts yet	8s	512 MB	Judgeable
Building BridgesFind the minimum total length of new bridges that connect all islands without crossing other islands or bridges.	Medium6	Minimum spanning treeUnion-find+1	No attempts yet	8s	512 MB	Judgeable
Opened-up DieGiven a partially filled die net (six faces, some unknown), assign distinct digits 1 to 6 to the unknown faces to minimize the sum of absolute differences along the net's five edges.	Medium6	Brute forceImplementation+2	No attempts yet	2s	512 MB	Judgeable
The Revolution of the AntsGiven com-ants that cycle along smell-path routes and swap messages when they meet, decide whether the news from com-ant 1 reaches every com-ant.	Medium6	SimulationGraph	No attempts yet	2s	512 MB	Judgeable
Minimum Coin Exchange ProblemGiven coin values 1 and a_1 to a_n, find the largest minimum number of coins (counting change) needed to pay any amount p with 1 < p < a_n.	Medium6	Dynamic programmingShortest path	No attempts yet	2s	512 MB	Judgeable
Walk an EquationFind every path from the first row to the last row that reads as a valid equation with exactly one =, joining adjacent digits into numbers of up to four digits.	Medium6	BacktrackingDFS+2	No attempts yet	2s	512 MB	Judgeable
The Secret NumberIn a grid of digits and letters, find the largest number spelled by a path of digits that only moves right or down, ignoring paths with letters.	Medium6	Dynamic programmingArray+2	No attempts yet	2s	512 MB	Judgeable
Square CarpetsFind the fewest overlapping square carpets that cover every scratched panel in a grid of up to 10 by 10 and no flawless panel.	Medium6	BacktrackingBrute force+1	No attempts yet	2s	512 MB	Judgeable
Missing NumbersGiven a sales table with some entries missing but all row and column totals intact, decide whether the missing values are uniquely determined and print them in order, otherwise print NO.	Medium6	MathGraph+2	No attempts yet	2s	512 MB	Judgeable
Pump up BatteriesSimulate guards cycling through consumption and charging phases, queueing for one charger, and report total waiting time within the given duration.	Medium6	SimulationQueue+2	No attempts yet	2s	512 MB	Judgeable
Ether GeometryFind the shortest cable route from hub to terminal inside a rectilinear polygonal study and print its turning points.	Medium6	GeometryShortest path	No attempts yet	2s	512 MB	Judgeable
Walking AntOn a grid up to 8 by 8, an ant with 6 HP that refills on food tiles must reach the hole; find the minimum number of moves, or -1.	Medium6	BFSGraph+2	No attempts yet	2s	512 MB	Judgeable
Folder Cleanup (large)Given a folder tree, move subtrees between folders where identical names merge or overwrite, then answer queries counting distinct file names and total files under a folder.	Medium6	TreeSimulation+2	No attempts yet	1.5s	1024 MB	Judgeable
Farthest PlaceOn a weighted undirected graph, find the vertex whose distance to the nearest of three given friends is largest, breaking ties by smallest index.	Medium6	GraphShortest path+2	No attempts yet	1.5s	1024 MB	Judgeable
Walk (small)Given an undirected unweighted graph, find the sum of the shortest S-to-E path (lexicographically smallest) and the shortest E-to-S path that avoids all vertices used on the forward trip.	Medium6	GraphBFS+2	No attempts yet	1s	1024 MB	Judgeable
Reversort EngineeringGiven N and a target cost C, construct a permutation of 1..N whose Reversort cost equals C, or report that none exists.	Medium6	GreedyImplementation+2	No attempts yet	10s	1024 MB	Judgeable
Append SortGiven a fixed list of integers, append digits to the right of each number so the list becomes strictly increasing, using the fewest total append operations.	Medium6	GreedyString+2	No attempts yet	10s	1024 MB	Judgeable
Closest PickGiven N sold tickets with values in 1..K, pick two integers to maximize the fraction of values in 1..K that your tickets are strictly closest to.	Medium6	GreedySorting+2	No attempts yet	10s	1024 MB	Judgeable
Roaring YearsFor each given year Y, find the smallest year strictly greater than Y whose decimal digits split into two or more distinct consecutive integers written in increasing order.	Medium6	MathBrute force+2	No attempts yet	30s	1024 MB	Judgeable
Orange Island TripGiven N, find a walk along trees whose numbers are coprime at each step, eating the oranges on every tree (phi(k) on tree k), or report -1.	Medium6	Number theoryGraph+1	No attempts yet	1s	1024 MB	Judgeable
Growing OrangesGiven N planting spots on a line and a ripening time K, find the minimum total time to plant one orange at each spot and eat all of them.	Medium6	GreedyDynamic programming+1	No attempts yet	2s	1024 MB	Judgeable
MatrygonsFor each target total N, find the maximum number of regular polygons that can be nested so that each polygon has strictly fewer sides than its container and the side counts sum to N.	Medium6	Dynamic programmingNumber theory+2	No attempts yet	Not set	1024 MB	Judgeable
Build-A-PairGiven a string of decimal digits, split every digit into two positive integers with no leading zeros and find the minimum possible absolute difference between them.	Medium6	GreedySorting+1	No attempts yet	5s	1024 MB	Judgeable
Divisible DivisionsCount the ways to split digit string S into contiguous pieces so that every two adjacent pieces include one number divisible by D, modulo 10^9+7.	Medium6	Dynamic programmingNumber theory+1	No attempts yet	60s	1024 MB	Judgeable
Mountainous Palindromic SubarrayFind the longest subarray that is both strictly increasing then strictly decreasing and a palindrome, or report -1 if none exists.	Medium6	ArrayTwo pointers+2	No attempts yet	2s	2048 MB	Judgeable
Data CheckerGiven N circles centered on the x-axis, decide whether every pair is either disjoint or nested, so no two circles intersect.	Medium6	SortingIntervals+2	No attempts yet	1s	1024 MB	Judgeable
Team BuildingGiven N developers in a line with powers, pick two so that the gap between them times the smaller power is maximized.	Medium6	ArrayTwo pointers+2	No attempts yet	1s	1024 MB	Judgeable
Cloud BridgeGiven a tree with N nodes, add at most N-1 edges to minimize the resulting graph's diameter, and output the number of edges, the diameter, and the edges.	Medium6	TreeGraph+2	No attempts yet	1s	1024 MB	Judgeable
Jump Hide-and-SeekStarting at 0, each jump doubles the previous one (1, 2, 4, ...); find the minimum number of jumps to land exactly on K, or report -1.	Medium6	MathGreedy+2	No attempts yet	1s	512 MB	Judgeable
Patching with Colored PaperCount the paper sizes (height and width) that, placed only on uncolored cells, cover every uncolored cell in an N by M grid.	Medium6	MatrixPrefix sum+1	No attempts yet	4s	512 MB	Judgeable
Human PipelineSplit N people into two nonempty teams so the larger of the two team times ceil(K / (min speed times team size)) is minimized.	Medium6	GreedySorting+2	No attempts yet	1.5s	1024 MB	Judgeable
Recycling CampaignGiven N containers each holding some amount up to capacity X, repeatedly merge two containers into one holding min(A+B+X/2, X); find the maximum number of full containers obtainable.	Medium6	GreedySorting+2	No attempts yet	1s	1024 MB	Judgeable
Sudden Attack 3Given attack powers where a winner absorbs the loser's power, decide whether player 1 can be the last survivor under some order of fights.	Medium6	GreedySorting+2	No attempts yet	2s	1024 MB	Judgeable
L Shaped PlotsCount L-shapes in a binary grid, where an L-shape is a perpendicular pair of all-1 segments sharing an endpoint, each at least length 2, with the longer exactly twice the shorter.	Medium6	ArrayImplementation+2	No attempts yet	60s	1024 MB	Judgeable
Rabbit HouseGiven a grid of heights, add the fewest boxes so that every pair of side-adjacent cells differs in height by at most 1.	Medium6	GraphGreedy+2	No attempts yet	Not set	1024 MB	Judgeable
Longest ProgressionGiven an array, replace at most one element and find the length of the longest contiguous arithmetic subarray.	Medium6	ArrayTwo pointers+2	No attempts yet	30s	1024 MB	Judgeable
Alien GeneratorCount how many starting values K make the running sum K + (K+1) + ... hit exactly G before it would exceed G.	Medium6	MathNumber theory+2	No attempts yet	30s	1024 MB	Judgeable