Problems

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Total results29,461 problems

Enclosing the Grid Points
Medium4
Geometry, Math
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
The Mountain of Gold?
Medium4
Shortest path, Graph
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Switch toggling instruction
Medium4
Simulation, Tree
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
This Too Shall Pass
Medium4
Geometry, Brute force
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Counting Substhreengs
Medium4
Prefix sum, Math
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Plane Ticket Pricing
Medium4
Dynamic programming
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Complete the multiplication grid
Medium4
Brute force, Math+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Algorithms Final Exam
Medium4
Segment tree, Prefix sum
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Fib Inverse
Medium4
Math, Hash map+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Quento
Medium4
Backtracking, DFS
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Exploration Team
Medium4
Graph, Queue
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Uncompressing Compressed Words
Medium4
Recursion, Stack+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Human Cannonball
Medium4
Shortest path, Graph
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Units
Medium4
Graph, Sorting+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Ternarian Weights
Medium4
Math, Implementation
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Trapezoid Walkway
Medium4
Shortest path, Graph
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Stacking Curvy Blocks
Medium4
Math
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Radar Coverage
Medium4
Geometry
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Euclidean TSP
Medium4
Binary search, Math
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Flowery Trails
Medium4
Shortest path, Graph
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Book Club
Medium4
Graph, BFS+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Runes
Medium4
Brute force, String+1
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
Push-Ups
Medium4
Dynamic programming
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Wormholes
Medium4
Shortest path, Graph+1
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
Diamonds
Medium4
Dynamic programming
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
Ranked Choice
Medium4
Simulation, Array
No attempts yet
Time limit
60s
Memory limit
256 MB
Judgeable
Elevators
Medium4
Shortest path, Graph
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Ambiguous Encodings
Medium4
Dynamic programming, String
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Broken Audio Signal
Medium4
Intervals, Implementation
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Shipura
Medium4
Stack, Recursion+1
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
NIKO
Medium4
Graph
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Silk Road
Medium4
Dynamic programming
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Train Travel
Medium4
Prefix sum, Greedy
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Binary Mobile Width
Medium4
Tree, DFS
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Pangaea 1
Medium4
Minimum spanning tree, Union-find+1
No attempts yet
Time limit
20s
Memory limit
256 MB
Judgeable
XOR triplets 2
Medium4
Brute force, Bit manipulation
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
ACM
Medium4
Prefix sum, Brute force
No attempts yet
Time limit
1s
Memory limit
64 MB
Judgeable
Cow Hopscotch
Medium4
Dynamic programming, Matrix
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Bessie Goes Moo
Medium4
Math, Brute force+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Airport
Medium4
Union-find, Greedy
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Network
Medium4
Tree, DFS+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Exact a to the power b
Medium4
Implementation, Math+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Frodo's Gift Wrapping
Medium4
Brute force, Geometry
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
MD5
Medium4
Implementation, Bit manipulation
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
SHA-1
Medium4
Implementation, Simulation+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
RIPEMD-160
Medium4
Implementation, Bit manipulation
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
SHA-1 Hash
Medium4
Implementation, Bit manipulation
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Palindrome?
Medium4
Dynamic programming, Intervals
No attempts yet
Time limit
0.5s
Memory limit
256 MB
Judgeable
Next permutation
Medium4
Array, Two pointers
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Previous Permutation
Medium4
Array
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Dormitory Reassignment
Medium4
Combinatorics, Dynamic programming
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Remainder Subarray Count
Medium4
Prefix sum, Hash map
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Star Pattern 18
Medium4
Recursion, Matrix+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Range Add and Range Sum
Medium4
Segment tree
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Classroom assignment
Medium4
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Sliding Window Minimum
Medium4
Sliding window, Queue
No attempts yet
Time limit
2.4s
Memory limit
512 MB
Judgeable
Drinks
Medium4
Probability, Dynamic programming+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Study Time Allocation
Medium4
Dynamic programming
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Josephus Problem 3
Medium4
Math, Dynamic programming
No attempts yet
Time limit
1s
Memory limit
16 MB
Judgeable
Matrix chain multiplication order
Medium4
Dynamic programming, Matrix
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Longest Increasing Subsequence
Medium4
Dynamic programming, Binary search
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Shortest string containing both
Medium4
Dynamic programming, String
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Jump Jump
Medium4
Dynamic programming, Greedy
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Card Game
Medium4
Dynamic programming, Game theory
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Talking Money
Medium4
Implementation, String
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Diana and the Golden Apples
Medium4
Dynamic programming
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Decimal to Fraction
Medium4
Math, Number theory+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
The Knight's Scouting Mission
Medium4
BFS, Dynamic programming
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Troop Movement
Medium4
Minimum spanning tree, Union-find+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Torn to Pieces
Medium4
Graph, BFS
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
City Planning
Medium4
Graph, Matrix+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Scorched Earth
Medium4
Math
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Robotic Encryption
Medium4
Simulation, Stack
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Nurikabe
Medium4
BFS, Matrix+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Travelling Tom
Medium4
Shortest path, Graph
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Civilization
Medium4
Brute force, Bit manipulation
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Candy Store
Medium4
Dynamic programming
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
C.S.I.: P15
Medium4
DFS, String matching
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Kindergarten Excursion
Medium4
Sorting, Prefix sum
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Coast Length
Medium4
BFS, Graph+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
OPS
Medium4
Number theory, Brute force
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
VeryEasy
Medium4
Brute force, Matrix+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Goods Market
Medium4
Heap, Simulation
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
The Party That Never Ends
Medium4
Shortest path, Graph
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Articulation points
Medium4
DFS, Graph
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
2-SAT Assignment
Medium4
Brute force, Bit manipulation
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Black Jack
Medium4
Simulation, Implementation
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
SV Filters
Medium4
Graph, BFS+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Two Jugs
Medium4
Number theory, Math
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Serves Me Right
Medium4
Simulation, Hash map+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
One Stroke Drawing
Medium4
Graph, Union-find
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Horn Blowing
Medium4
Dynamic programming, Probability
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Frame by Frame
Medium4
Simulation, Implementation
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Job Assignment
Medium4
Graph, DFS
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Job Assignment 2
Medium4
Graph, BFS+1
No attempts yet
Time limit
4s
Memory limit
256 MB
Judgeable
Job Assignment 3
Medium4
Graph
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Graph bridges
Medium4
DFS, Graph
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Binomial Coefficient 3
Medium4
Combinatorics, Number theory
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Floyd
Medium4
Shortest path, Graph+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Buying Books 2
Medium4
Graph
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Enclosing the Grid PointsCompute the shortest perimeter of a lattice polygon with axis-aligned and diagonal sides that encloses all given grid points strictly inside.	Medium4	GeometryMath	No attempts yet	5s	256 MB	Judgeable
The Mountain of Gold?Decide whether portal hops from mountain 0 can return to mountain 0 at a strictly earlier time.	Medium4	Shortest pathGraph	No attempts yet	1s	256 MB	Judgeable
Switch toggling instructionSimulate trains arriving over time through a binary switch tree and emit the fewest latest possible toggles routing each train to its platform.	Medium4	SimulationTree	No attempts yet	2s	256 MB	Judgeable
This Too Shall PassFind every teammate joined to player 1 by a straight segment that touches no guarded square.	Medium4	GeometryBrute force	No attempts yet	3s	256 MB	Judgeable
Counting SubsthreengsCount the contiguous digit-only substrings of S whose value is a multiple of 3.	Medium4	Prefix sumMath	No attempts yet	3s	256 MB	Judgeable
Plane Ticket PricingSet each week's ticket price from that week's demand estimates to maximize total revenue over the remaining seats and weeks.	Medium4	Dynamic programming	No attempts yet	2s	256 MB	Judgeable
Complete the multiplication gridCount pairs of multiplicand and multiplier whose partial products and final product use only the allowed nonzero digits with the given lengths.	Medium4	Brute forceMath+1	No attempts yet	3s	256 MB	Judgeable
Algorithms Final ExamGiven the final order listed by midterm rank, print for each student how many midterm superiors they passed minus how many inferiors passed them.	Medium4	Segment treePrefix sum	No attempts yet	1s	256 MB	Judgeable
Fib InverseGiven Fibonacci numbers, find each one's index, taking the larger index when two match.	Medium4	MathHash map+1	No attempts yet	1s	512 MB	Judgeable
QuentoFind a no-revisit path using exactly M digits on the fixed 3x3 board whose left-to-right value equals N and print the lexicographically smallest one.	Medium4	BacktrackingDFS	No attempts yet	1s	256 MB	Judgeable
Exploration TeamFind the size of the largest group where every member has at least k friends inside the group.	Medium4	GraphQueue	No attempts yet	1s	256 MB	Judgeable
Uncompressing Compressed WordsExpand each nested compressed word by concatenating its parts and repeating the group n times.	Medium4	RecursionStack+1	No attempts yet	1s	256 MB	Judgeable
Human CannonballFind the fastest route from start to target by running at 5 m/s and chaining optional 50-meter cannon shots that cost 2 seconds each.	Medium4	Shortest pathGraph	No attempts yet	1s	256 MB	Judgeable
UnitsGiven N-1 pairwise conversion relations, sort the units from largest to smallest and print the chain with the largest unit set to 1.	Medium4	GraphSorting+1	No attempts yet	3s	256 MB	Judgeable
Ternarian WeightsConvert each decimal weight to balanced ternary and list which powers of three go on each pan.	Medium4	MathImplementation	No attempts yet	2s	256 MB	Judgeable
Trapezoid WalkwayFind the cheapest chain of trapezoid stones joining two given widths, where each stone links its two edge lengths at a cost tied to its area.	Medium4	Shortest pathGraph	No attempts yet	2s	256 MB	Judgeable
Stacking Curvy BlocksGiven two cubic edges on [0,1], lower the upper curve until it touches the lower one and report the largest vertical gap between them.	Medium4	Math	No attempts yet	2s	256 MB	Judgeable
Radar CoverageFind the center of the smallest circle enclosing three given points for each test case.	Medium4	Geometry	No attempts yet	1s	256 MB	Judgeable
Euclidean TSPPick c to minimize the sum of the approximation runtime and the lengthened tour flight time, and print the best time and c.	Medium4	Binary searchMath	No attempts yet	1s	256 MB	Judgeable
Flowery TrailsAdd twice the length of every trail that lies on some shortest route from point 0 to point P-1.	Medium4	Shortest pathGraph	No attempts yet	2s	256 MB	Judgeable
Book ClubDecide whether each of N members can receive a distinct liked book, given M like declarations.	Medium4	GraphBFS+1	No attempts yet	2s	256 MB	Judgeable
RunesFind the smallest digit that replaces every question mark so the addition, subtraction, or multiplication equation holds.	Medium4	Brute forceString+1	No attempts yet	5s	256 MB	Judgeable
Push-UpsGiven a push-up total equal to the sum of running scores, find the largest final score reachable with the allowed scoring plays.	Medium4	Dynamic programming	No attempts yet	1s	256 MB	Judgeable
WormholesGiven planet coordinates and directed zero-cost wormholes, report the shortest travel distance for each queried planet pair.	Medium4	Shortest pathGraph+1	No attempts yet	5s	256 MB	Judgeable
DiamondsFind the longest subsequence of diamonds in input order with strictly rising weight and strictly falling clarity.	Medium4	Dynamic programming	No attempts yet	5s	256 MB	Judgeable
Ranked ChoiceSimulate ranked-choice runoff with batch elimination and print each round until a majority winner emerges or no winner remains.	Medium4	SimulationArray	No attempts yet	60s	256 MB	Judgeable
ElevatorsFind the shortest total ride distance from the start floor to the target floor by switching between elevators that each serve only certain floors.	Medium4	Shortest pathGraph	No attempts yet	2s	256 MB	Judgeable
Ambiguous EncodingsCount how many letter strings map to each digit string when A is 1 through Z at 26.	Medium4	Dynamic programmingString	No attempts yet	1s	256 MB	Judgeable
Broken Audio SignalThe program finds the one integer that fills every x and makes odd positions valleys and even positions peaks, or reports ambiguous or none.	Medium4	IntervalsImplementation	No attempts yet	8s	512 MB	Judgeable
ShipuraEvaluate expressions that combine floor division by powers of two with squaring modulo 1,000,000,007 and nested brackets.	Medium4	StackRecursion+1	No attempts yet	8s	512 MB	Judgeable
NIKODecide for each listed O-V-N lineup whether 10 of the M candidates can cover its lines using only positions each player accepts.	Medium4	Graph	No attempts yet	1s	256 MB	Judgeable
Silk RoadChoose N of M days in order for the eastward moves so the sum of distance times daily badness is smallest.	Medium4	Dynamic programming	No attempts yet	1s	256 MB	Judgeable
Train TravelCount how many times each rail is crossed and pay the cheaper of single tickets or a discount card plus cheap fares for every rail.	Medium4	Prefix sumGreedy	No attempts yet	1s	256 MB	Judgeable
Binary Mobile WidthCompute the horizontal width of a balanced binary mobile from rod lengths and bead weights using torque balance.	Medium4	TreeDFS	No attempts yet	1s	256 MB	Judgeable
Pangaea 1After each added road, compute the cheapest total length connecting all cities and XOR the m totals per test case.	Medium4	Minimum spanning treeUnion-find+1	No attempts yet	20s	256 MB	Judgeable
XOR triplets 2Pick the largest block of consecutive integers from 1 to N with no three distinct elements xoring to zero, breaking ties by smallest start.	Medium4	Brute forceBit manipulation	No attempts yet	5s	256 MB	Judgeable
ACMSplit the task list into three nonempty consecutive blocks and assign one member to each block to minimize the summed difficulty estimates.	Medium4	Prefix sumBrute force	No attempts yet	1s	64 MB	Judgeable
Cow HopscotchCount paths from the top-left cell to the bottom-right cell that move strictly down and right onto cells of the opposite color.	Medium4	Dynamic programmingMatrix	No attempts yet	1s	256 MB	Judgeable
Bessie Goes MooCount assignments of listed values to seven variables that make (B+E+S+S+I+E)(G+O+E+S)(M+O+O) a multiple of 7.	Medium4	MathBrute force+1	No attempts yet	1s	256 MB	Judgeable
AirportEach arriving plane takes the largest free gate up to its limit gi, and the count stops at the first plane with no free gate.	Medium4	Union-findGreedy	No attempts yet	1s	256 MB	Judgeable
NetworkAdd the fewest edges to a tree so it stays connected after any single edge breaks, pairing leaves in the prescribed DFS order.	Medium4	TreeDFS+1	No attempts yet	1s	256 MB	Judgeable
Exact a to the power bPrint the exact value of a to the power b for a decimal base without rounding or dropping digits.	Medium4	ImplementationMath+1	No attempts yet	1s	256 MB	Judgeable
Frodo's Gift WrappingThree rotatable rectangles must be packed axis-aligned into one enclosing rectangle of smallest area.	Medium4	Brute forceGeometry	No attempts yet	1s	256 MB	Judgeable
MD5Read a short alphanumeric string and print its MD5 hash as 32 lowercase hex digits.	Medium4	ImplementationBit manipulation	No attempts yet	1s	256 MB	Judgeable
SHA-1Given an alphanumeric string of length 1 to 50, print its SHA-1 hash as 40 lowercase hex digits.	Medium4	ImplementationSimulation+1	No attempts yet	1s	256 MB	Judgeable
RIPEMD-160Compute the RIPEMD-160 hash of an alphanumeric string of length at most 50 and print it as 40 lowercase hexadecimal digits.	Medium4	ImplementationBit manipulation	No attempts yet	1s	256 MB	Judgeable
SHA-1 HashPrint the SHA-1 hash of the given alphanumeric string as lowercase hexadecimal.	Medium4	ImplementationBit manipulation	No attempts yet	1s	256 MB	Judgeable
Palindrome?Answer up to a million queries asking whether a given range of the number sequence is a palindrome.	Medium4	Dynamic programmingIntervals	No attempts yet	0.5s	256 MB	Judgeable
Next permutationGiven a permutation of 1 to N, print the next permutation in lexicographic order, or -1 when the given one is the last.	Medium4	ArrayTwo pointers	No attempts yet	1s	256 MB	Judgeable
Previous PermutationGiven a permutation of 1 to N, print the permutation that comes just before it in lexicographic order, or -1 when it is the first.	Medium4	Array	No attempts yet	1s	256 MB	Judgeable
Dormitory ReassignmentCount the permutations of N students to rooms in which no student keeps the same room.	Medium4	CombinatoricsDynamic programming	No attempts yet	1s	128 MB	Judgeable
Remainder Subarray CountCount contiguous intervals whose sum is divisible by M using prefix remainder frequencies.	Medium4	Prefix sumHash map	No attempts yet	1s	256 MB	Judgeable
Star Pattern 18Print the size N star figure of nested triangles with alternating orientation defined recursively.	Medium4	RecursionMatrix+1	No attempts yet	1s	256 MB	Judgeable
Range Add and Range SumProcess range additions on a sequence and print the sum of each queried range in order.	Medium4	Segment tree	No attempts yet	2s	256 MB	Judgeable
Classroom assignmentGiven N class time intervals, find the smallest number of rooms so overlapping classes never share a room.	Medium4	GreedySorting+2	No attempts yet	1s	256 MB	Judgeable
Sliding Window MinimumPrint the minimum of each window of length L ending at every position of the array.	Medium4	Sliding windowQueue	No attempts yet	2.4s	512 MB	Judgeable
DrinksTwo players alternately draw balls without replacement until the first red ball appears, and you compute the chance the first player draws it.	Medium4	ProbabilityDynamic programming+1	No attempts yet	2s	256 MB	Judgeable
Study Time AllocationDistribute up to H study hours among courses with tiered grade costs to maximize the average grade points.	Medium4	Dynamic programming	No attempts yet	1s	256 MB	Judgeable
Josephus Problem 3Find the number of the last person remaining after removing every K-th of N people seated in a circle.	Medium4	MathDynamic programming	No attempts yet	1s	16 MB	Judgeable
Matrix chain multiplication orderFind the parenthesization of N given matrices that minimizes the total number of scalar multiplications.	Medium4	Dynamic programmingMatrix	No attempts yet	1s	256 MB	Judgeable
Longest Increasing SubsequenceFind the length of the longest strictly increasing subsequence of the given sequence.	Medium4	Dynamic programmingBinary search	No attempts yet	1s	256 MB	Judgeable
Shortest string containing bothFind the length of the shortest string that has both given strings as subsequences.	Medium4	Dynamic programmingString	No attempts yet	1s	256 MB	Judgeable
Jump JumpStarting from the first cell, find the fewest rightward jumps bounded by each cell value to reach the last cell, or -1 when unreachable.	Medium4	Dynamic programmingGreedy	No attempts yet	1s	256 MB	Judgeable
Card GameBoth players alternately take the left or right end card to maximize their own sum, and you compute the first player best total score.	Medium4	Dynamic programmingGame theory	No attempts yet	1s	256 MB	Judgeable
Talking MoneyConvert one currency amount from -$999999999999.99 to $999999999999.99 into English words under the given hyphen, and-placement, and plural rules.	Medium4	ImplementationString	No attempts yet	2s	256 MB	Judgeable
Diana and the Golden ApplesPick the apples with the greatest total weight so the extra carrying time stays strictly below her lead over Humperdonkey.	Medium4	Dynamic programming	No attempts yet	2s	256 MB	Judgeable
Decimal to FractionConvert a decimal with an optional parenthesized repeating part into its irreducible numerator/denominator form.	Medium4	MathNumber theory+1	No attempts yet	2s	256 MB	Judgeable
The Knight's Scouting MissionFind the shortest knight distance from (1,1) to (r,c) on an r by c board, count those routes modulo 1000000009, and report None when unreachable.	Medium4	BFSDynamic programming	No attempts yet	2s	256 MB	Judgeable
Troop MovementFind the route between two cities whose narrowest road is as wide as possible and report that width.	Medium4	Minimum spanning treeUnion-find+1	No attempts yet	2s	256 MB	Judgeable
Torn to PiecesRebuild the subway graph from the torn map pieces and print the stations on the path from the start to the destination, or no route found.	Medium4	GraphBFS	No attempts yet	2s	256 MB	Judgeable
City PlanningRebuild the smallest one-way road network matching a given reachability matrix, with cycles inside mutually reachable groups and cover edges between groups.	Medium4	GraphMatrix+1	No attempts yet	2s	256 MB	Judgeable
Scorched EarthGiven a fixed firing angle, wind, and both tank positions, compute the smallest launch speed up to 300 m/s that lands the shell on the target.	Medium4	Math	No attempts yet	1s	256 MB	Judgeable
Robotic EncryptionSimulate a robot that runs nested-loop command lines on a character grid and read the square it stops on after each line to decode the message.	Medium4	SimulationStack	No attempts yet	1s	256 MB	Judgeable
NurikabeCheck whether each numbered island has the required size, all water cells connect, and no 2 by 2 block is all water.	Medium4	BFSMatrix+1	No attempts yet	1s	256 MB	Judgeable
Travelling TomFind the cheapest route that starts at the first listed city, visits every city in the given order using any connecting flights, then returns to the start.	Medium4	Shortest pathGraph	No attempts yet	1s	256 MB	Judgeable
CivilizationPick the smallest subset of at most 18 regions whose total workforce, tax income, and farm count all reach the required thresholds, or print game over.	Medium4	Brute forceBit manipulation	No attempts yet	1s	256 MB	Judgeable
Candy StoreCount the subsets of candy prices whose total is at least C for each test case, modulo 65537.	Medium4	Dynamic programming	No attempts yet	1s	256 MB	Judgeable
C.S.I.: P15Count ground-connected 8-connected flower components and isolated /\/\ bird patterns in each ASCII picture.	Medium4	DFSString matching	No attempts yet	1s	256 MB	Judgeable
Kindergarten ExcursionCount the minimum adjacent swaps needed to reorder a string of 0s, 1s, and 2s into sorted order.	Medium4	SortingPrefix sum	No attempts yet	1s	256 MB	Judgeable
Coast LengthCount the total length of borders between land and sea connected to the outside of the grid, excluding enclosed lakes.	Medium4	BFSGraph+1	No attempts yet	1s	256 MB	Judgeable
OPSFor each odd M, write it as a sum of three odd primes so the largest prime is as large as possible, and print that prime.	Medium4	Number theoryBrute force	No attempts yet	1s	256 MB	Judgeable
VeryEasyFind the highest-scoring legal placement of VERY or EASY on a 15x15 board using tiles from a 7-tile rack.	Medium4	Brute forceMatrix+1	No attempts yet	1s	256 MB	Judgeable
Goods MarketProcess insertions, global rent hikes, and cheapest-shop evictions, then report how many shops remain and their total rent.	Medium4	HeapSimulation	No attempts yet	1s	256 MB	Judgeable
The Party That Never EndsFor each query, decide whether the shortest travel time from hall A to hall B fits within C using all-pairs shortest paths.	Medium4	Shortest pathGraph	No attempts yet	2s	256 MB	Judgeable
Articulation pointsFind and list in increasing order every vertex whose removal increases the number of connected components in an undirected graph.	Medium4	DFSGraph	No attempts yet	1s	256 MB	Judgeable
2-SAT AssignmentDetermine whether a 2-CNF formula with up to 20 variables is satisfiable and output the lexicographically smallest satisfying assignment.	Medium4	Brute forceBit manipulation	No attempts yet	1s	256 MB	Judgeable
Black JackSimulate fixed-rule blackjack games from a given deck order and tally wins for each player and the dealer.	Medium4	SimulationImplementation	No attempts yet	1s	256 MB	Judgeable
SV FiltersCompute the max flow between nodes 0 and 1, then remove the size-P edges reachable from node 0 and compute the max flow again.	Medium4	GraphBFS+1	No attempts yet	1s	256 MB	Judgeable
Two JugsGiven two jug capacities and a target volume, decide whether fill, empty, and pour operations can leave exactly that volume in one jug.	Medium4	Number theoryMath	No attempts yet	2s	256 MB	Judgeable
Serves Me RightReplay logins, logouts, restarts, and session timeouts to count distinct users and the highest number logged in at once.	Medium4	SimulationHash map+1	No attempts yet	2s	256 MB	Judgeable
One Stroke DrawingDecide whether given line segments form a shape drawable in one stroke without retracing any segment.	Medium4	GraphUnion-find	No attempts yet	2s	256 MB	Judgeable
Horn BlowingCompute the probability that the summed start-up delays of N vehicles with given discrete distributions total at most T seconds.	Medium4	Dynamic programmingProbability	No attempts yet	2s	256 MB	Judgeable
Frame by FrameParse bowling notation for ten frames and compute the total score with spare and strike bonuses.	Medium4	SimulationImplementation	No attempts yet	1s	256 MB	Judgeable
Job AssignmentAssign each of N employees at most one job they can do so the number of finished jobs is as large as possible.	Medium4	GraphDFS	No attempts yet	2s	256 MB	Judgeable
Job Assignment 2Assign each of M jobs to one of N employees who can do it with at most two jobs per employee to handle as many jobs as possible.	Medium4	GraphBFS+1	No attempts yet	4s	256 MB	Judgeable
Job Assignment 3Each worker takes jobs only from a given eligible list, with K workers allowed two jobs, to finish as many of M jobs as possible.	Medium4	Graph	No attempts yet	3s	256 MB	Judgeable
Graph bridgesFind every bridge in a connected undirected graph and print them sorted by endpoint.	Medium4	DFSGraph	No attempts yet	1s	256 MB	Judgeable
Binomial Coefficient 3Compute the binomial coefficient C(N, K) modulo 1,000,000,007 for N up to 4,000,000.	Medium4	CombinatoricsNumber theory	No attempts yet	1s	256 MB	Judgeable
FloydFor every pair of n cities, compute the cheapest directed bus fare from up to 100,000 routes and print 0 where no route connects them.	Medium4	Shortest pathGraph+1	No attempts yet	1s	256 MB	Judgeable
Buying Books 2Find the maximum number of book copies N buyers can purchase from M stores under per-pair purchase limits.	Medium4	Graph	No attempts yet	1s	256 MB	Judgeable