Problems

Pick a problem, code in the editor, and watch the judge run real test cases. The archive is open to browse

Under construction

Still being built. Things may change

Total results29,417 problems

Merging Files 2
Medium6
Dynamic programming, Prefix sum
No attempts yet
Time limit
6s
Memory limit
512 MB
Judgeable
Cameras
Medium6
Greedy, Sliding window+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Postman
Medium6
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Tournament Wins
Medium6
Probability, Combinatorics
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Cactus Construction
Medium6
Graph, DFS+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Hard Refactoring
Medium6
Intervals, Sorting+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
List of Primes
Medium6
Number theory, Combinatorics+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
ICPC
Medium6
Math, Simulation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Small Ping Pong Tournament
Medium6
Brute force, Recursion+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Where To Go?
Medium6
String, String matching+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Small PhD Restaurant
Medium6
Greedy, Sorting+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Large PhD Restaurant
Medium6
Greedy, Sorting+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Hungry Fox
Medium6
Greedy, Sorting+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
The Longest Travel Route
Medium6
Dynamic programming, Bit manipulation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Phonomenal Reviews
Medium6
Tree, DFS+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Stupendous Bowties
Medium6
Geometry, Combinatorics+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
O Canada
Medium6
Bit manipulation, Hash map+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Paths in Multigraph
Medium6
Graph, Minimum spanning tree+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Marica
Medium6
Greedy, Sorting+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Bees
Medium6
Bit manipulation, Simulation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Parade
Medium6
Binary search, Graph+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Grayscale Photo
Medium6
Combinatorics, Math+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Mirko's average
Medium6
Math, Implementation+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
RAM
Medium6
Array, Simulation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Magic
Medium6
Math, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Big Table
Medium6
Prefix sum, Math+2
No attempts yet
Time limit
4s
Memory limit
128 MB
Judgeable
Hacker
Medium6
Hash map, Math+1
No attempts yet
Time limit
0.5s
Memory limit
128 MB
Judgeable
Mathematics
Medium6
Math, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Anadrome split
Medium6
Dynamic programming, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Aliens
Medium6
Hash map, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Anthill
Medium6
Graph, BFS+1
No attempts yet
Time limit
0.5s
Memory limit
256 MB
Judgeable
Trokut
Medium6
Math, Geometry
No attempts yet
Time limit
0.5s
Memory limit
256 MB
Judgeable
Multiple Subsequence
Medium6
Dynamic programming, Sorting
No attempts yet
Time limit
2.5s
Memory limit
256 MB
Judgeable
The Walk to School
Medium6
Matrix, Simulation+2
No attempts yet
Time limit
6s
Memory limit
128 MB
Judgeable
Sharing the Candy
Medium6
Number theory, Math+2
No attempts yet
Time limit
2s
Memory limit
64 MB
Judgeable
Architect
Medium6
Geometry, Array+2
No attempts yet
Time limit
1s
Memory limit
64 MB
Judgeable
Guard dog
Medium6
Geometry, Brute force+2
No attempts yet
Time limit
1s
Memory limit
64 MB
Judgeable
Pero the Baker
Medium6
Greedy, Binary search+1
No attempts yet
Time limit
1s
Memory limit
64 MB
Judgeable
Connecting switches to bulbs
Medium6
Combinatorics, Dynamic programming+2
No attempts yet
Time limit
1s
Memory limit
64 MB
Judgeable
Cow Checklist
Medium6
Dynamic programming, Geometry
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Array Characteristic
Medium6
Array, Prefix sum
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Electoral College
Medium6
Dynamic programming, Probability
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Halting Machine
Medium6
Graph, Dynamic programming+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Oland must not fall
Medium6
Graph, BFS+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Circular Board Game
Medium6
Number theory, Math+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Minions and the rooms
Medium6
Combinatorics, Intervals+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Sort the Table
Medium6
Sorting, Implementation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Red button, blue button
Medium6
Math, Greedy+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Water Tank
Medium6
Binary search, Prefix sum+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Plane Game
Medium6
Geometry, Brute force+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
The Jewel Thief
Medium6
Number theory, Greedy
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Attendance Record
Medium6
Greedy, Brute force+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Attendance Record 2
Medium6
Greedy, String+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
XOR
Medium6
Binary search, Prefix sum+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
XOR Equation
Medium6
Math, Bit manipulation
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
XOR Groups
Medium6
Union-find, Simulation+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Key Rearrangement 2
Medium6
Dynamic programming, Bit manipulation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Hold off the enemy
Medium6
Graph, Shortest path+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Armistice Negotiation
Medium6
Geometry, Divide and conquer+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Grid Game
Medium6
Simulation, BFS+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Adding edges one by one
Medium6
Union-find, Greedy+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Cutting edges 2
Medium6
Minimum spanning tree, Graph+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Partitioning Balls into Buckets
Medium6
Dynamic programming, Math+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Partitioning Number (Large)
Medium6
Dynamic programming, Combinatorics+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Monster Path (Small)
Medium6
Dynamic programming, Bit manipulation+1
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Sherlock and Parentheses (Large)
Medium6
String, Greedy+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Rain (Large)
Medium6
Heap, BFS+1
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Jane's Flower Shop (Small)
Medium6
Binary search, Math+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Impromptu Outdoor Gallery
Medium6
Geometry, Brute force
No attempts yet
Time limit
Not set
Memory limit
1024 MB
Judgeable
Counting Distinct Subsequences
Medium6
Dynamic programming, String+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Coggle
Medium6
Backtracking, Trie+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Go++ (Small)
Medium6
Implementation, Simulation+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Rather Perplexing Showdown (Small)
Medium6
Divide and conquer, Recursion+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Fashion Police (Small)
Medium6
Greedy, Brute force+2
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Fractiles (Small)
Medium6
Recursion, Math+1
No attempts yet
Time limit
5s
Memory limit
512 MB
Judgeable
Whitespace
Medium6
Dynamic programming, Greedy+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Sequence Permutations
Medium6
Dynamic programming, Combinatorics+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Two Operations
Medium6
BFS, Graph+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Fortune telling with sticks
Medium6
Brute force, Implementation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Foehn Phenomena
Medium6
Array, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Sequence and Queries 16
Medium6
Segment tree, Array+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Prime Village
Medium6
Graph, Shortest path+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Sequence and Queries 17
Medium6
Segment tree, Array+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Break Walls and Move 2
Medium6
BFS, Graph+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Hoof, Paper, Scissors (Gold)
Medium6
Dynamic programming, Greedy+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Secret Cow Code
Medium6
Recursion, Divide and conquer+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Why Did the Cow Cross the Road 12
Medium6
Divide and conquer, Sorting+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Why Did the Cow Cross the Road 7
Medium6
Graph, Shortest path+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Why Did the Cow Cross the Road 9
Medium6
Array, Hash map+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Why Did the Cow Cross the Road 4
Medium6
Greedy, Sorting+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Ridge
Medium6
Graph, DFS+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Snake JOI
Medium6
Shortest path, Graph+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Assembly Required
Medium6
Heap, Greedy
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Ground Defense
Medium6
Prefix sum, Implementation+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Junan's Rampage
Medium6
BFS, Graph+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Trapezoid puzzle
Medium6
Backtracking, Greedy+2
No attempts yet
Time limit
0.5s
Memory limit
1024 MB
Judgeable
Bovine Genomics (Gold)
Medium6
String, Hash map+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Paired Up
Medium6
Greedy, Two pointers+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Where's Bessie?
Medium6
Implementation, Brute force+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
The Triangle Game
Medium6
Brute force, Backtracking+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Merging Files 2Given the sizes of K consecutive chapter files, find the minimum total cost of merging them two at a time into one file, where each merge costs the sum of the two sizes.	Medium6	Dynamic programmingPrefix sum	No attempts yet	6s	512 MB	Judgeable
CamerasGiven houses that already have cameras, add the minimum number of cameras so every window of r consecutive houses holds at least two cameras.	Medium6	GreedySliding window+1	No attempts yet	1s	512 MB	Judgeable
PostmanDeliver m_i letters to house i at position x_i from the origin, carrying at most k letters per trip, and return to the origin each time; minimize total distance.	Medium6	GreedySorting+1	No attempts yet	1s	512 MB	Judgeable
Tournament WinsIn a random single elimination bracket of 2^k players, you are ranked r; find your expected number of wins.	Medium6	ProbabilityCombinatorics	No attempts yet	1s	512 MB	Judgeable
Cactus ConstructionGiven a cactus as edge-disjoint paths, simulate the fixed recursive procedure that emits join, recolor, and connect operations assembling it with four colors.	Medium6	GraphDFS+2	No attempts yet	2s	512 MB	Judgeable
Hard RefactoringMerge a union of integer intervals given as comparisons, then reprint the merged ranges using the fewest possible constants, with special handling for saturated ends and all-true or all-false cases.	Medium6	IntervalsSorting+2	No attempts yet	2s	512 MB	Judgeable
List of PrimesGiven positions a to b in an infinite notebook listing all finite non-empty sets of distinct primes by sum, then lexicographically, print those characters.	Medium6	Number theoryCombinatorics+2	No attempts yet	2s	512 MB	Judgeable
ICPCTwo batteries alternate powering a phone whose drain rate A exceeds the recharge rate B; find how many whole seconds the system lasts.	Medium6	MathSimulation+2	No attempts yet	2s	512 MB	Judgeable
Small Ping Pong TournamentGiven the total points each of 2^N players scored, decide whether Dudu (first score) can be the champion.	Medium6	Brute forceRecursion+2	No attempts yet	2s	512 MB	Judgeable
Where To Go?A note string uses upper case letters and each station name uses lower case letters, so a match between them is an equality-pattern match between two windows of different alphabets.	Medium6	StringString matching+2	No attempts yet	2s	512 MB	Judgeable
Small PhD RestaurantGiven N challenges with cost A_i and payoff B_i, starting money M, choose an order to maximize final money while affording each cost.	Medium6	GreedySorting+1	No attempts yet	2s	512 MB	Judgeable
Large PhD RestaurantGiven N tasks each with a cost and a reward, and starting money M, choose an order to run tasks (paying cost first, then gaining reward) that maximizes the final money.	Medium6	GreedySorting+2	No attempts yet	2s	512 MB	Judgeable
Hungry FoxGiven cracker temperatures and a starting water temperature, order eating and water sips to minimize and maximize the total of absolute differences.	Medium6	GreedySorting+1	No attempts yet	2s	512 MB	Judgeable
The Longest Travel RouteGiven a directed weighted graph with at most 18 cities, find the maximum total length of a simple path from city 0 to city n-1.	Medium6	Dynamic programmingBit manipulation+2	No attempts yet	2s	512 MB	Judgeable
Phonomenal ReviewsGiven a tree and a set of M marked nodes, find the minimum number of edges Jo must walk to visit every marked node, starting anywhere.	Medium6	TreeDFS+2	No attempts yet	2s	512 MB	Judgeable
Stupendous BowtiesGiven N distinct integer points, count unordered pairs of axis-aligned right triangles that share only the right-angle vertex.	Medium6	GeometryCombinatorics+2	No attempts yet	2s	512 MB	Judgeable
O CanadaEach move flips a 2x2 block of an N x N red/white grid. Count pairs of given grids that can reach each other by such moves.	Medium6	Bit manipulationHash map+2	No attempts yet	1s	512 MB	Judgeable
Paths in MultigraphFind the minimum number of edges to delete from an undirected multigraph so the remaining graph becomes disconnected.	Medium6	GraphMinimum spanning tree+1	No attempts yet	2s	512 MB	Judgeable
MaricaPick target counts for baskets so every value in [A,B] appears, minimizing total plum additions and removals.	Medium6	GreedySorting+1	No attempts yet	1s	512 MB	Judgeable
BeesGiven an n by m hexagonal honeycomb's initial honey pattern, apply the rule that each cell fills next day exactly when an odd number of its neighbors were filled, and print the state after k days.	Medium6	Bit manipulationSimulation+2	No attempts yet	1s	512 MB	Judgeable
ParadeFind the largest tank count T so that a path from junction 1 to N costs at most K, where each road costs C_i*(T - T_i)^2 when T exceeds T_i.	Medium6	Binary searchGraph+1	No attempts yet	2s	512 MB	Judgeable
Grayscale PhotoCount the color photos (RGB triples) whose floor average matches each given gray value, modulo 10007.	Medium6	CombinatoricsMath+1	No attempts yet	1s	512 MB	Judgeable
Mirko's averageAfter each pair of position updates, report whether Mirko's repeated pairwise average increased, decreased, or stayed the same.	Medium6	MathImplementation+1	No attempts yet	2s	512 MB	Judgeable
RAMProcess files one by one; after each, count how many times a given letter appears in the last K characters seen so far.	Medium6	ArraySimulation+2	No attempts yet	2s	512 MB	Judgeable
MagicGiven Y, count natural numbers X whose decimal digits reversed and added back to X give exactly Y.	Medium6	MathImplementation	No attempts yet	1s	128 MB	Judgeable
Big TableEach row of a huge table repeats a short digit period; answer rectangle-sum queries without materializing the table.	Medium6	Prefix sumMath+2	No attempts yet	4s	128 MB	Judgeable
HackerFind the first string t such that the strings from S to t contain exactly K strings sharing t's rolling-hash value, then print those K strings.	Medium6	Hash mapMath+1	No attempts yet	0.5s	128 MB	Judgeable
MathematicsCount how many starting integers, under a sequence of at most 10 add, subtract, multiply by x, or truncating divide by x operations, land on a given final result.	Medium6	MathBrute force+2	No attempts yet	1s	128 MB	Judgeable
Anadrome splitSplit a lowercase word into the fewest substrings that are each anagrams of some palindrome, breaking ties by the lexicographically smallest printed line.	Medium6	Dynamic programmingGreedy+1	No attempts yet	1s	128 MB	Judgeable
AliensGiven N points, choose an integer axis value s minimizing new points needed so the set is symmetric about x = s/2, then output those points. Ties go to the smallest s, output sorted by x then y.	Medium6	Hash mapSorting+2	No attempts yet	1s	128 MB	Judgeable
AnthillIn a grid of free cells and walls, find every 2x2-seeded connected room and report each room's size and how many rooms touch it directly.	Medium6	GraphBFS+1	No attempts yet	0.5s	256 MB	Judgeable
TrokutGiven two numbers in this triangular arrangement, list every third number that completes an equilateral triangle with sides parallel to the 1-2-3 grid.	Medium6	MathGeometry	No attempts yet	0.5s	256 MB	Judgeable
Multiple SubsequenceGiven a sequence, find the longest subsequence where each element is a larger multiple of the previous one.	Medium6	Dynamic programmingSorting	No attempts yet	2.5s	256 MB	Judgeable
The Walk to SchoolCount ordered pairs of grass cells where a fixed three-segment path (east, south, east) stays entirely on grass cells.	Medium6	MatrixSimulation+2	No attempts yet	6s	128 MB	Judgeable
Sharing the CandyFor each X in [A,B], the number of even splits equals the number of divisors of X; find the maximum divisor count and all X achieving it.	Medium6	Number theoryMath+2	No attempts yet	2s	64 MB	Judgeable
ArchitectGiven N tree points and Q axis-aligned polygons of at most 12 vertices, count for each polygon how many trees lie inside it, border included.	Medium6	GeometryArray+2	No attempts yet	1s	64 MB	Judgeable
Guard dogFind an integer lattice point on a square roof where a chain can be anchored so it reaches every hatch center without leaving the roof, choosing the smallest coordinates.	Medium6	GeometryBrute force+2	No attempts yet	1s	64 MB	Judgeable
Pero the BakerAssign loaves of P sizes to P ovens so all finish as fast as possible; each round bakes everything in an oven and takes five minutes.	Medium6	GreedyBinary search+1	No attempts yet	1s	64 MB	Judgeable
Connecting switches to bulbsCount the number of functions from A numbered switches onto B numbered bulbs, modulo 1000000007, i.e. B! times Stirling number of the second kind S(A, B).	Medium6	CombinatoricsDynamic programming+2	No attempts yet	1s	64 MB	Judgeable
Cow ChecklistFind the cheapest path that visits all Holsteins in order and all Guernseys in order, starting at Holstein 1 and ending at Holstein H.	Medium6	Dynamic programmingGeometry	No attempts yet	2s	512 MB	Judgeable
Array CharacteristicMove one element to any position and maximize the weighted sum of A_i times its new index.	Medium6	ArrayPrefix sum	No attempts yet	2s	512 MB	Judgeable
Electoral CollegeGiven each state's win probability and electoral votes, find the probability that Jenabkhan gets more than half of the total electoral votes.	Medium6	Dynamic programmingProbability	No attempts yet	2s	512 MB	Judgeable
Halting MachineParse N goto statements, build a directed graph, and print the longest path length from line 0 to line N, or infinity if a cycle is reachable on some path to N.	Medium6	GraphDynamic programming+2	No attempts yet	2s	512 MB	Judgeable
Oland must not fallGiven hospital supplies, demands, and an undirected tunnel graph with unit edge costs, find the minimum total cost to balance every hospital, or -1 if impossible.	Medium6	GraphBFS+2	No attempts yet	2s	512 MB	Judgeable
Circular Board GameFor each query with S, M, N, compute the final cell after advancing expo(S) steps on a circular board of N cells, using modular reduction of a huge power tower.	Medium6	Number theoryMath+1	No attempts yet	2s	512 MB	Judgeable
Minions and the roomsRooms flip between available and unavailable over range updates; after each flip, count set partitions of N minions into the k currently available rooms, mod 880803841.	Medium6	CombinatoricsIntervals+1	No attempts yet	2s	512 MB	Judgeable
Sort the TableGiven an N by M grid holding a permutation of 1 to N*M, decide whether swapping whole rows and whole columns can make the row-major reading order sorted ascending.	Medium6	SortingImplementation+2	No attempts yet	2s	512 MB	Judgeable
Red button, blue buttonGiven (a,b), reach (c,d) using +1 on both coordinates or doubling both, with the fewest presses, or report -1.	Medium6	MathGreedy+2	No attempts yet	2s	512 MB	Judgeable
Water TankFind the smallest constant drain rate R so the tank never exceeds capacity C while inflow runs through n phases.	Medium6	Binary searchPrefix sum+1	No attempts yet	2s	512 MB	Judgeable
Plane GameGiven N points, rotate and translate them arbitrarily so that as many points as possible lie on the two coordinate axes; output that maximum count.	Medium6	GeometryBrute force+2	No attempts yet	2s	512 MB	Judgeable
The Jewel ThiefFactor k into the largest possible count of integers greater than 1 whose product is k, and list them in ascending order.	Medium6	Number theoryGreedy	No attempts yet	2s	512 MB	Judgeable
Attendance RecordRearrange the letters of a record over A, B, C so the result is valid (B needs one rest day, C needs two) and lexicographically smallest.	Medium6	GreedyBrute force+2	No attempts yet	2s	512 MB	Judgeable
Attendance Record 2Given a string of A, B, C, rearrange its letters into the lexicographically smallest valid schedule where B needs a rest day after working and C needs two.	Medium6	GreedyString+2	No attempts yet	2s	512 MB	Judgeable
XORMaintain an array under range XOR updates and point queries, printing each queried element in order.	Medium6	Binary searchPrefix sum+2	No attempts yet	2s	512 MB	Judgeable
XOR EquationCount ordered pairs of positive integers A and B with A+B=S and A xor B=X.	Medium6	MathBit manipulation	No attempts yet	2s	512 MB	Judgeable
XOR GroupsErase cells from an N by M grid in increasing value order and after each erasure report the maximum sum of XOR values of the connected groups.	Medium6	Union-findSimulation+1	No attempts yet	2s	512 MB	Judgeable
Key Rearrangement 2Given n keys with lists of compatible keyholes and a time limit k, decide whether a perfect matching exists with total \|i-j\| cost at most k.	Medium6	Dynamic programmingBit manipulation+2	No attempts yet	2s	512 MB	Judgeable
Hold off the enemyGiven troop costs on strongholds, decide whether k troops can block every path from node n to node 1 before the invasion reaches the capital.	Medium6	GraphShortest path+1	No attempts yet	2s	512 MB	Judgeable
Armistice NegotiationGiven two sets of points, decide whether a straight line exists that keeps each country's cities strictly on opposite sides.	Medium6	GeometryDivide and conquer+2	No attempts yet	2s	512 MB	Judgeable
Grid GameEach cell becomes alive if it or an edge neighbor was alive, so the live region grows by repeated dilation; count live cells after K steps.	Medium6	SimulationBFS+2	No attempts yet	2s	512 MB	Judgeable
Adding edges one by oneAdd the given weighted edges one at a time in any order and stop once s and t become connected; maximize the total weight of added edges at that moment.	Medium6	Union-findGreedy+2	No attempts yet	2s	512 MB	Judgeable
Cutting edges 2Given a weighted undirected graph and two vertices s and t, find the minimum total weight of edges to delete so that s and t end up disconnected, choosing the deletion order.	Medium6	Minimum spanning treeGraph+2	No attempts yet	2s	512 MB	Judgeable
Partitioning Balls into BucketsCount the ways to split N balls into buckets whose sizes are non-decreasing, span at most 2, and start with a value divisible by D.	Medium6	Dynamic programmingMath+2	No attempts yet	5s	512 MB	Judgeable
Partitioning Number (Large)Count non-decreasing partitions of N whose first part is divisible by D and whose parts span a range of at most 2.	Medium6	Dynamic programmingCombinatorics+2	No attempts yet	5s	512 MB	Judgeable
Monster Path (Small)Given a small grid, a start cell, and a fixed step count, choose a walk maximizing the expected number of distinct monsters caught.	Medium6	Dynamic programmingBit manipulation+1	No attempts yet	5s	512 MB	Judgeable
Sherlock and Parentheses (Large)Given L opening and R closing parentheses, arrange a string of length L+R that maximizes the number of non-empty balanced substrings; output that maximum.	Medium6	StringGreedy+2	No attempts yet	5s	512 MB	Judgeable
Rain (Large)Given an island grid, compute the total rise in water level after rain, where water fills each basin up to its lowest surrounding edge.	Medium6	HeapBFS+1	No attempts yet	5s	512 MB	Judgeable
Jane's Flower Shop (Small)Find the internal rate of return r that makes the net present value of a monthly cash flow sequence equal zero, then print it to 12 decimals.	Medium6	Binary searchMath+2	No attempts yet	5s	512 MB	Judgeable
Impromptu Outdoor GalleryGiven N points in general position, find twice the smallest area of a simple quadrilateral formed by four of them.	Medium6	GeometryBrute force	No attempts yet	Not set	1024 MB	Judgeable
Counting Distinct SubsequencesCount the distinct subsequences of a string, including the empty string, for up to 10,000 test cases.	Medium6	Dynamic programmingString+1	No attempts yet	1s	512 MB	Judgeable
CoggleGiven a 5x5 letter grid and a dictionary, count how many dictionary words can be traced through adjacent cells without reusing a cell.	Medium6	BacktrackingTrie+1	No attempts yet	1s	512 MB	Judgeable
Go++ (Small)Given bad string B of all 1s and a set G of length-L binary strings, decide whether two interleavable Go++ programs can output all of G but never B.	Medium6	ImplementationSimulation+2	No attempts yet	5s	512 MB	Judgeable
Rather Perplexing Showdown (Small)Find the alphabetically smallest left-to-right lineup of R rocks, P papers, and S scissors so that a single-elimination bracket never pairs identical moves.	Medium6	Divide and conquerRecursion+2	No attempts yet	5s	512 MB	Judgeable
Fashion Police (Small)Choose the largest set of distinct (jacket, pants, shirt) outfits so no two-garment pair repeats more than K times, and output it lexicographically smallest.	Medium6	GreedyBrute force+2	No attempts yet	5s	512 MB	Judgeable
Fractiles (Small)Choose at most S tile positions to inspect so that, for any original K-tile sequence, you can decide whether some gold tile exists.	Medium6	RecursionMath+1	No attempts yet	5s	512 MB	Judgeable
WhitespaceGiven the line lengths of a Whitespace program and a RETURN key that duplicates the current line's spaces, find the minimum key presses to build the text from a single newline.	Medium6	Dynamic programmingGreedy+1	No attempts yet	2s	512 MB	Judgeable
Sequence PermutationsCount how many distinct permutations of 1..N are reachable from the sorted order by exactly M adjacent swaps, modulo 1,000,000,009.	Medium6	Dynamic programmingCombinatorics+2	No attempts yet	2s	512 MB	Judgeable
Two OperationsStarting from X = Y = 1, repeatedly add one variable to the other, and find the shortest (then lexicographically smallest) operation string that makes N appear.	Medium6	BFSGraph+2	No attempts yet	2s	512 MB	Judgeable
Fortune telling with sticksGiven an n by m letter grid and p query words, find for each word the longest contiguous substring that can be placed along a row or column in one of four directions.	Medium6	Brute forceImplementation+2	No attempts yet	2s	512 MB	Judgeable
Foehn PhenomenaAfter each range add to altitudes, report the wind temperature at spot N, where the total depends on the altitude differences between adjacent spots.	Medium6	ArrayPrefix sum+1	No attempts yet	1s	256 MB	Judgeable
Sequence and Queries 16Maintain an array under point updates and range queries that ask for the leftmost index of the minimum value in a subarray.	Medium6	Segment treeArray+2	No attempts yet	2s	512 MB	Judgeable
Prime VillageGiven 2D points, find the shortest path from a start to a target where every edge must have a prime truncated Euclidean distance.	Medium6	GraphShortest path+2	No attempts yet	2s	256 MB	Judgeable
Sequence and Queries 17Maintain an array under point updates and answer range-minimum queries over subarrays.	Medium6	Segment treeArray+2	No attempts yet	2s	512 MB	Judgeable
Break Walls and Move 2Find the shortest path length from the top-left to the bottom-right of an N by M grid, where you may break at most K walls along the way.	Medium6	BFSGraph+2	No attempts yet	2s	512 MB	Judgeable
Hoof, Paper, Scissors (Gold)Given John's sequence of N gestures and at most K gesture switches, find the maximum number of games Bessie can win.	Medium6	Dynamic programmingGreedy+2	No attempts yet	2s	512 MB	Judgeable
Secret Cow CodeAn infinite code string grows by doubling: each step appends the current string rotated right by one. Find the N-th character.	Medium6	RecursionDivide and conquer+1	No attempts yet	2s	512 MB	Judgeable
Why Did the Cow Cross the Road 12Given the left and right orderings of N breeds along a road, count pairs whose segments cross and whose breed numbers differ by more than K.	Medium6	Divide and conquerSorting+2	No attempts yet	2s	512 MB	Judgeable
Why Did the Cow Cross the Road 7On an N x N grid, find the fastest route from the top-left to the bottom-right cell when every third move forces Bessie to spend that cell's eating time.	Medium6	GraphShortest path+2	No attempts yet	2s	512 MB	Judgeable
Why Did the Cow Cross the Road 9Given a circular sequence where each cow label appears exactly twice, count pairs of cows whose chords necessarily cross.	Medium6	ArrayHash map+2	No attempts yet	2s	512 MB	Judgeable
Why Did the Cow Cross the Road 4Match chickens, each available at a single time, to cows whose interval covers that time, so that as many cows as possible get help.	Medium6	GreedySorting+2	No attempts yet	2s	512 MB	Judgeable
RidgeCount grid cells where rain falling on that cell alone eventually drains to more than one local minimum.	Medium6	GraphDFS+1	No attempts yet	2s	512 MB	Judgeable
Snake JOIFind the shortest travel time from room 1 to room N where entering a hot room requires X minutes since last leaving a cold room, and vice versa.	Medium6	Shortest pathGraph+1	No attempts yet	2s	512 MB	Judgeable
Assembly RequiredGiven several lists of piece values, output the k smallest sums of picking one value from each list.	Medium6	HeapGreedy	No attempts yet	2s	512 MB	Judgeable
Ground DefenseHandle updates that add an arithmetic sequence of troops along a line of cities in one direction, and answer queries for a city's running total.	Medium6	Prefix sumImplementation+2	No attempts yet	2s	512 MB	Judgeable
Junan's RampageEach jump clears all friends in the four straight rays from Junan's cell until the first friend in each direction; find the fewest jumps to clear the culprit's cell.	Medium6	BFSGraph+2	No attempts yet	2s	512 MB	Judgeable
Trapezoid puzzleTile a triangular-grid hexagon of shaded cells with 3-triangle trapezoids, backtracking in a fixed canonical order and colouring pieces greedily so no two equal colours share an edge.	Medium6	BacktrackingGreedy+2	No attempts yet	0.5s	1024 MB	Judgeable
Bovine Genomics (Gold)Given N spotted and N plain DNA strings of length M, find the shortest window of consecutive positions whose substrings separate every spotted string from every plain one.	Medium6	StringHash map+2	No attempts yet	2s	512 MB	Judgeable
Paired UpPair up M cows with given milk outputs to minimize the maximum sum in any pair, where each pair's time is A+B. Input gives counts and output values in compressed form.	Medium6	GreedyTwo pointers+2	No attempts yet	2s	512 MB	Judgeable
Where's Bessie?Given an N x N grid of colors (N up to 20), count the rectangular sub-grids where exactly two colors appear, one forming one connected region and the other forming two or more, and that are not contained in any other such rectangle.	Medium6	ImplementationBrute force+1	No attempts yet	2s	512 MB	Judgeable
The Triangle GameGiven six numbered triangles, arrange all of them into a legal hexagon where touching edges match, and maximize the sum of the six outer edge numbers.	Medium6	Brute forceBacktracking+2	No attempts yet	2s	512 MB	Judgeable