Problems

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Total results29,466 problems

Search
Medium4
Simulation, Array+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Multi-key Sorting
Medium4
Array, Greedy+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Radio Transmission
Medium4
String matching, String
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Riddle
Medium4
Greedy, Array+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Reducing a Sequence
Medium4
Greedy, Array
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Countries
Medium4
Simulation, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Board Jump
Medium4
Dynamic programming, Matrix+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Calculator Game
Medium4
Math, Brute force+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Division Expression
Medium4
Math, Number theory+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Vow
Medium4
Dynamic programming, String
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Weird Numbers
Medium4
Math, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Piggy-Bank
Medium4
Dynamic programming
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Lifting the Stone
Medium4
Geometry, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Headshot
Medium4
String, Probability+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Dragon's Question
Medium4
Math, Implementation
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Homo or Hetero?
Medium4
Hash map, Implementation+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Large Screen
Medium4
Brute force, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
iSharp
Medium4
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Access Control Lists
Medium4
Bit manipulation, String+2
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Class
Medium4
Math, Greedy+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Deposits
Medium4
Math, Number theory+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Important Wires
Medium4
String, Bit manipulation+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Nearest Common Ancestor
Medium4
Tree, DFS+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Robot Project
Medium4
Two pointers, Sorting+1
No attempts yet
Time limit
5s
Memory limit
256 MB
Judgeable
The Bird Tree
Medium4
Math, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Movie Collection
Medium4
Array, Simulation+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Divisible Contiguous Subarrays
Medium4
Prefix sum, Hash map+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Matchsticks
Medium4
Dynamic programming, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Parking Building
Medium4
Simulation, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Leonardo's Notebook
Medium4
Math, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Laserbox
Medium4
Simulation, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Student ID Numbers
Medium4
Brute force, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Search by template
Medium4
String matching, String+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Table
Medium4
Math, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Calculator
Medium4
String, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Rising Trend
Medium4
Dynamic programming, Binary search+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
John
Medium4
Game theory, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Double Queue
Medium4
Heap, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
KCPC
Medium4
Simulation, Hash map+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Republic of Korea
Medium4
Sorting, Divide and conquer+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Songs
Medium4
Greedy, Sorting
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tour
Medium4
Dynamic programming, Geometry+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Period
Medium4
String matching, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cube Root
Medium4
Math, Binary search+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Booklets
Medium4
Sorting, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Common Subsequence
Medium4
Dynamic programming, String
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cash Machine
Medium4
Dynamic programming, Brute force
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Manager
Medium4
Heap, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Guess the Numbers
Medium4
Brute force, Recursion+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Peer Review
Medium4
Hash map, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Comparing Answers
Medium4
Matrix, Brute force+1
No attempts yet
Time limit
10s
Memory limit
128 MB
Judgeable
Trick or Treat
Medium4
Binary search, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Happy Phone Call
Medium4
Intervals, Sorting+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Society Members
Medium4
Graph, DFS+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Expected Allowance
Medium4
Dynamic programming, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Slim Span
Medium4
Union-find, Sorting+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Lagrange's Four-Square Theorem
Medium4
Brute force, Math+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Molecular Formula
Medium4
Recursion, String+1
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Pen Counts
Medium4
Math, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pizza Hawaii
Medium4
Hash map, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Touchscreen Keyboard
Medium4
String, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Indiana Jones and the Lost Soccer Cup
Medium4
Topological sort, Graph+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Cubelover
Medium4
Math, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Babs’ Box Boutique
Medium4
Dynamic programming, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Flash Mob
Medium4
Sorting, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Condorcet Paradox
Medium4
Array, Simulation+2
No attempts yet
Time limit
5s
Memory limit
128 MB
Judgeable
Wally World
Medium4
Geometry, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Countdown
Medium4
Graph, DFS+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Viva la Diferencia
Medium4
Simulation, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Vampire Numbers
Medium4
Brute force, Implementation+1
No attempts yet
Time limit
10s
Memory limit
128 MB
Judgeable
Knitting
Medium4
Math, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Shoring Up the Levees
Medium4
Geometry, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Combination Lock
Medium4
Math, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Room Painting
Medium4
Sorting, Binary search
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Course Scheduling
Medium4
Hash map, Sorting
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pousse
Medium4
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
CD
Medium4
Two pointers, Sorting+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Alaska
Medium4
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tunnelling the Earth
Medium4
Geometry, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
sqrt log sin
Medium4
Dynamic programming, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Digits
Medium4
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Convex Hull
Medium4
Geometry, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Unique Snowflakes
Medium4
Sliding window, Hash map+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Dominos 2
Medium4
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Dominos
Medium4
Graph, DFS+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
The Dragon of Loowater
Medium4
Greedy, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pseudoprime
Medium4
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Humidex
Medium4
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tree
Medium4
Tree, Recursion+1
No attempts yet
Time limit
1s
Memory limit
192 MB
Judgeable
Tautology
Medium4
String, Recursion+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Rock-Paper-Scissors Tournament
Medium4
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Antiarithmetic?
Medium4
Hash map, Brute force+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Basic Modulo
Medium4
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
System of Linear Equations
Medium4
Math, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tic Tac Toe
Medium4
Implementation, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Subway
Medium4
Shortest path, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Interpreter
Medium4
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Y2K Accounting Bug
Medium4
Brute force, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Airline Hub
Medium4
Geometry, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Trip
Medium4
Greedy, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
SearchTrack all reachable cells on a grid as a car moves in given directions by at least one free cell each step, then mark final possible positions.	Medium4	SimulationArray+1	No attempts yet	1s	128 MB	Judgeable
Multi-key SortingGiven a sequence of stable column sorts, output the shortest equivalent sequence by keeping only the last occurrence of each column value in the order that determines the final effect.	Medium4	ArrayGreedy+1	No attempts yet	2s	128 MB	Judgeable
Radio TransmissionGiven a received string that is part of a repeated broadcast, find the length of the shortest repeating unit using KMP failure function.	Medium4	String matchingString	No attempts yet	1s	128 MB	Judgeable
The RiddleFind the minimum prefix length of a coin sequence so that all values from 1 to K are achievable as subset sums, using the classic greedy reachable-range extension, or report -1.	Medium4	GreedyArray+1	No attempts yet	1s	128 MB	Judgeable
Reducing a SequenceGiven a sequence, find the minimum total cost of repeatedly merging adjacent elements where cost equals the max of the pair, until one element remains.	Medium4	GreedyArray	No attempts yet	1s	128 MB	Judgeable
CountriesFor each city, compute which other city exerts the strongest gravity-like influence on it, then label it king, democracy, or trace the chain of surrender to find its ultimate capital.	Medium4	SimulationMath+1	No attempts yet	1s	128 MB	Judgeable
Board JumpCount distinct paths from top-left to bottom-right of an N×N grid where each cell's digit fixes the exact jump length right or down, using big-integer DP.	Medium4	Dynamic programmingMatrix+1	No attempts yet	1s	128 MB	Judgeable
Calculator GameGiven K up to 999, find the smallest multiple of K whose decimal digits are all identical, printing the digit and its count or 'Impossible'.	Medium4	MathBrute force+1	No attempts yet	1s	128 MB	Judgeable
Division ExpressionGiven a left-to-right division expression of n positive integers, decide if some parenthesization yields an integer value, which reduces to checking if x1 times the product of x3..xn is divisible by x2.	Medium4	MathNumber theory+1	No attempts yet	1s	128 MB	Judgeable
The VowDetermine, for each word and up to length 50000, whether it can be split into a sequence of one or two letter chemical element symbols using DP.	Medium4	Dynamic programmingString	No attempts yet	1s	128 MB	Judgeable
Weird NumbersConvert numbers between decimal and a given negative base representation, in both directions, for multiple queries until an end marker.	Medium4	MathImplementation+1	No attempts yet	1s	128 MB	Judgeable
Piggy-BankGiven empty and full weights of a piggy bank and coin value/weight pairs, find the minimum possible total coin value achieving the exact weight difference, using unbounded knapsack.	Medium4	Dynamic programming	No attempts yet	1s	128 MB	Judgeable
Lifting the StoneCompute the centroid (area centre) of a simple polygon given up to a million vertices, with careful half-up rounding to two decimals.	Medium4	GeometryMath+1	No attempts yet	1s	128 MB	Judgeable
HeadshotGiven a circular string of loaded/empty chambers, decide whether shooting immediately or re-spinning gives a lower chance of firing given the previous chamber was empty.	Medium4	StringProbability+1	No attempts yet	1s	128 MB	Judgeable
Dragon's QuestionFind the smallest n-digit number (no leading zero) divisible by d, or report no solution, for n up to 1000.	Medium4	MathImplementation	No attempts yet	3s	256 MB	Judgeable
Homo or Hetero?Maintain a list under insert and delete-first-occurrence operations and classify it after each step as homogeneous, heterogeneous, both, or neither.	Medium4	Hash mapImplementation+1	No attempts yet	3s	256 MB	Judgeable
Large ScreenGiven a target resolution and physical size, pick a monitor type and orientation and find the minimum-cost grid multiple that meets both requirements.	Medium4	Brute forceMath+1	No attempts yet	1s	128 MB	Judgeable
iSharpParse a C-like multi-variable type declaration with pointer, reference, and array symbols, then print each variable on its own line with its symbols moved to the front in reversed order.	Medium4	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
Access Control ListsParse an ordered ACL of allow/deny IP network rules and, for each query IP, output whether the first matching rule grants or denies access.	Medium4	Bit manipulationString+2	No attempts yet	3s	256 MB	Judgeable
ClassGiven n students and an r by c grid of desks, find the maximum achievable value k such that some row and some column can each have k occupied desks.	Medium4	MathGreedy+1	No attempts yet	3s	256 MB	Judgeable
DepositsCount pairs of deposits and requests where the deposit amount is divisible by the request length, using frequency counts and divisor enumeration up to 10^6.	Medium4	MathNumber theory+1	No attempts yet	3s	256 MB	Judgeable
Important WiresParse boolean formulas over up to 11 wires and count distinct output tuples across all wire assignments by brute-force enumeration.	Medium4	StringBit manipulation+1	No attempts yet	3s	256 MB	Judgeable
Nearest Common AncestorGiven a rooted tree and two nodes, find their nearest common ancestor for each test case.	Medium4	TreeDFS+1	No attempts yet	1s	128 MB	Judgeable
Robot ProjectGiven a target length and up to a million rod lengths, find two rods summing exactly to the target with the maximum length difference, or report impossibility.	Medium4	Two pointersSorting+1	No attempts yet	5s	256 MB	Judgeable
The Bird TreeGiven a reduced fraction, reconstruct its path of L/R moves in the Stern-Brocot style Bird tree using a Euclidean-like process.	Medium4	MathGreedy+1	No attempts yet	1s	128 MB	Judgeable
Movie CollectionGiven a stack of DVDs and a sequence of watched movie numbers, output for each watch how many DVDs sat above it before moving it to the top.	Medium4	ArraySimulation+1	No attempts yet	1s	256 MB	Judgeable
Divisible Contiguous SubarraysCount contiguous subarrays whose sum is divisible by a given d, using prefix sums modulo d and counting equal remainders.	Medium4	Prefix sumHash map+1	No attempts yet	1s	128 MB	Judgeable
MatchsticksGiven a number of matchsticks, find the smallest and largest positive numbers (no leading zero) that can be formed using exactly that many matchsticks based on per-digit costs.	Medium4	Dynamic programmingGreedy+1	No attempts yet	1s	128 MB	Judgeable
Parking BuildingSimulate an elevator and rotating conveyor belts to compute total retrieval time for cars fetched in customer order.	Medium4	SimulationImplementation+1	No attempts yet	1s	128 MB	Judgeable
Leonardo's NotebookDetermine whether a given permutation of the alphabet can be expressed as some permutation applied twice (its functional square).	Medium4	MathCombinatorics+1	No attempts yet	1s	128 MB	Judgeable
LaserboxSimulate a laser beam bouncing off right-turning mirrors on a grid until it exits the board or loops forever.	Medium4	SimulationImplementation	No attempts yet	1s	128 MB	Judgeable
Student ID NumbersGiven up to 300 distinct student IDs under 10^6, find the smallest modulus m so that all IDs have distinct remainders mod m.	Medium4	Brute forceMath+1	No attempts yet	1s	128 MB	Judgeable
Search by templateParse a pattern with literal letters, wildcards, and allow/forbid letter groups, then find all positions where it matches inside a large text.	Medium4	String matchingString+1	No attempts yet	2s	128 MB	Judgeable
TableGiven an N by M table, compute each column's product and output the column index (largest index on tie) with the maximum product, handling big products across up to 1000 rows.	Medium4	MathSimulation+1	No attempts yet	1s	128 MB	Judgeable
CalculatorParse and evaluate fully parenthesized arithmetic expressions with big integers up to 90 digits, printing Error on overflow, negative results, or division by zero.	Medium4	StringMath+2	No attempts yet	1s	128 MB	Judgeable
Rising TrendFor each test case, compute the length of the longest strictly increasing subsequence in a sequence of up to 100000 prices.	Medium4	Dynamic programmingBinary search+1	No attempts yet	1s	128 MB	Judgeable
JohnDetermine the winner of a Nim-like misère game where players remove same-colored candies from piles and taking the last candy loses.	Medium4	Game theoryBit manipulation+1	No attempts yet	1s	128 MB	Judgeable
Double QueueProcess a stream of add/serve commands maintaining a dynamic set to pop and remove either the maximum or minimum priority client each query.	Medium4	HeapSorting+1	No attempts yet	1s	128 MB	Judgeable
KCPCFrom a submission log, compute each team's best-per-problem total score, break ties by submission count then last submission time, and output a given team's rank.	Medium4	SimulationHash map+1	No attempts yet	1s	128 MB	Judgeable
Republic of KoreaCount crossing pairs among K straight highways linking numbered east and west coast cities, using inversion counting.	Medium4	SortingDivide and conquer+1	No attempts yet	1s	128 MB	Judgeable
SongsGiven songs with lengths and play frequencies, sort them by length-to-frequency ratio (stable on ties) to minimize expected access time and report the song at a queried position.	Medium4	GreedySorting	No attempts yet	1s	128 MB	Judgeable
TourGiven points sorted by x-coordinate, compute the shortest bitonic tour that goes strictly left-to-right then strictly right-to-left, using classic O(n^2) DP.	Medium4	Dynamic programmingGeometry+1	No attempts yet	1s	128 MB	Judgeable
PeriodFor every prefix of a string, find the largest exponent K such that the prefix equals some string A repeated K times, using KMP failure function.	Medium4	String matchingString+1	No attempts yet	1s	128 MB	Judgeable
Cube RootCompute the cube root of very large integers (up to 150 digits) truncated to 10 decimal places, for multiple test cases.	Medium4	MathBinary search+1	No attempts yet	1s	128 MB	Judgeable
BookletsGiven booklets sorted by page count split among schools using floor/ceiling division with a strict serving order, find the first booklet's page count given to a specified school.	Medium4	SortingMath+1	No attempts yet	1s	128 MB	Judgeable
Common SubsequenceCompute the length of the longest common subsequence of two given strings for multiple test cases.	Medium4	Dynamic programmingString	No attempts yet	1s	128 MB	Judgeable
Cash MachineGiven a cash target and limited counts of several bill denominations, find the maximum total not exceeding the target using a bounded-knapsack style search.	Medium4	Dynamic programmingBrute force	No attempts yet	1s	128 MB	Judgeable
ManagerSimulate a priority-based queue manager that adds costs, removes min or max cost per current policy, and prints results only for specified removal request indices.	Medium4	HeapSimulation+1	No attempts yet	1s	128 MB	Judgeable
Guess the NumbersDetermine whether some permutation of up to 5 given values assigned to the unknowns in a fully parenthesized arithmetic expression makes it evaluate to a target result.	Medium4	Brute forceRecursion+1	No attempts yet	1s	128 MB	Judgeable
Peer ReviewGiven each author's institution and their K assigned papers to review, count how many papers violate review-count, self-review, collaborator, or duplicate-review rules.	Medium4	Hash mapSimulation+1	No attempts yet	1s	128 MB	Judgeable
Comparing AnswersGiven an adjacency matrix with edge counts, verify whether a provided matrix correctly gives the number of length-2 paths between every ordered pair (essentially checking a matrix multiplication), for large n up to 1000 requiring fast I/O.	Medium4	MatrixBrute force+1	No attempts yet	10s	128 MB	Judgeable
Trick or TreatFind the point on the x-axis minimizing the maximum distance to a set of given points, an application of ternary search on a convex function.	Medium4	Binary searchMath+1	No attempts yet	1s	128 MB	Judgeable
Happy Phone CallFor each query time window, count how many given phone-call intervals overlap it by at least one second, across multiple test cases.	Medium4	IntervalsSorting+1	No attempts yet	2s	128 MB	Judgeable
Society MembersGiven nested society membership definitions with possible society-name references, compute the total number of distinct human members in the first listed society.	Medium4	GraphDFS+1	No attempts yet	1s	128 MB	Judgeable
Expected AllowanceGiven n m-sided dice and a cutback k, compute the exact reduced fraction for the expected value of max(1, sum of dice - k).	Medium4	Dynamic programmingMath+1	No attempts yet	1s	128 MB	Judgeable
Slim SpanGiven a weighted graph, find the spanning tree that minimizes the difference between its largest and smallest edge weight, or report -1 if disconnected.	Medium4	Union-findSorting+1	No attempts yet	2s	128 MB	Judgeable
Lagrange's Four-Square TheoremFor each input number, count the unordered ways to express it as a sum of one to four positive perfect squares.	Medium4	Brute forceMath+1	No attempts yet	2s	128 MB	Judgeable
Molecular FormulaParse a nested molecular formula with repetition counts and atomic weight lookups to compute total molecular weight, or report UNKNOWN.	Medium4	RecursionString+1	No attempts yet	3s	128 MB	Judgeable
Pen CountsCount the number of triangles with integer side lengths summing to N, where rotations count as the same and reflections differ.	Medium4	MathCombinatorics+1	No attempts yet	1s	128 MB	Judgeable
Pizza HawaiiFor each local ingredient and native ingredient, output the pair when the two words appear on exactly the same set of pizza names.	Medium4	Hash mapSorting+2	No attempts yet	1s	128 MB	Judgeable
Touchscreen KeyboardGiven a typed word and a list of same-length dictionary words, print each with its keyboard Manhattan distance, sorted by distance then lexicographically.	Medium4	StringSorting+2	No attempts yet	1s	128 MB	Judgeable
Indiana Jones and the Lost Soccer CupGiven precedence constraints between levers, decide whether the order is unique; print the unique order, or report no order or multiple orders.	Medium4	Topological sortGraph+2	No attempts yet	1s	256 MB	Judgeable
CubeloverGiven a sequence, decide whether real coefficients a, b, c, d exist so that x_i equals ai^3 + bi^2 + c*i + d for every position i.	Medium4	MathImplementation+1	No attempts yet	1s	128 MB	Judgeable
Babs’ Box BoutiqueGiven up to 10 boxes, each orientable in 3 ways, find the largest subset that can be stacked with each base fitting inside the one below.	Medium4	Dynamic programmingSorting+2	No attempts yet	1s	128 MB	Judgeable
Flash MobGiven n grid points, find the intersection minimizing the total Manhattan distance, breaking ties by smallest x then smallest y.	Medium4	SortingMath+2	No attempts yet	1s	128 MB	Judgeable
Condorcet ParadoxGiven b ranked ballots over c candidates, find the candidate who beats every other candidate head to head on more than half the ballots.	Medium4	ArraySimulation+2	No attempts yet	5s	128 MB	Judgeable
Wally WorldTwo points in a plane must meet while a single axis-parallel wall segment blocks the straight path; compute the minimum meeting time.	Medium4	GeometryMath+2	No attempts yet	1s	128 MB	Judgeable
CountdownGiven one family tree per test case, count for each person how many descendants sit exactly d generations below, then rank the top holders.	Medium4	GraphDFS+1	No attempts yet	1s	128 MB	Judgeable
Viva la DiferenciaGiven four positive integers, repeatedly replace them with the absolute differences of cyclic neighbours until all four are equal, and count the steps.	Medium4	SimulationMath+1	No attempts yet	1s	128 MB	Judgeable
Vampire NumbersGiven X, find the smallest vampire number at or above X, where a vampire number splits into two factors whose combined digits match its own digits.	Medium4	Brute forceImplementation+1	No attempts yet	10s	128 MB	Judgeable
KnittingGiven a starting stitch count, a row total, and a repeating pattern of row change values, compute the sum of all row stitch counts for each project until the 0 0 0 terminator.	Medium4	MathPrefix sum+1	No attempts yet	1s	128 MB	Judgeable
Shoring Up the LeveesGiven a convex quadrilateral, order its four corner triangles by area and print each triangle's area and perimeter rounded to three decimals.	Medium4	GeometrySorting+2	No attempts yet	1s	128 MB	Judgeable
Combination LockFor each lock, find the largest total number of ticks turned over the three stages, maximized over all possible starting positions of the dial.	Medium4	MathSimulation+1	No attempts yet	1s	128 MB	Judgeable
Room PaintingGiven n can sizes and m paint requirements, sum the waste from picking for each colour the smallest can whose size is at least the requirement.	Medium4	SortingBinary search	No attempts yet	1s	128 MB	Judgeable
Course SchedulingGiven n course requests as (first name, last name, course) triples, count the distinct students per course and print courses in ASCII order.	Medium4	Hash mapSorting	No attempts yet	1s	128 MB	Judgeable
PousseSimulate the push game on an N by N board and report which color first has more complete rows or columns, or a tie at QUIT.	Medium4	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
CDGiven two sorted lists of distinct CD numbers, count how many numbers appear in both lists.	Medium4	Two pointersSorting+1	No attempts yet	1s	256 MB	Judgeable
AlaskaGiven charging station positions along a 1422-mile highway and a 200-mile range, decide whether the round trip Dawson Creek to Delta Junction and back is possible.	Medium4	GreedySorting+2	No attempts yet	1s	128 MB	Judgeable
Tunnelling the EarthFor each pair of points given by latitude and longitude, print the difference between the great-circle surface distance and the straight-line tunnel distance, rounded to the nearest metre.	Medium4	GeometryMath+1	No attempts yet	1s	128 MB	Judgeable
sqrt log sinPrecompute x_i for all i up to 10^6 using the given recurrence with floating point floors, then answer each query modulo 10^6.	Medium4	Dynamic programmingMath+2	No attempts yet	1s	128 MB	Judgeable
DigitsGiven a huge decimal number, repeatedly replace it with its digit count and report the first step where the value stops changing.	Medium4	MathImplementation+2	No attempts yet	1s	128 MB	Judgeable
Convex HullGiven points already labeled as hull or non-hull, output only the hull points in counterclockwise order starting from the lexicographically smallest one.	Medium4	GeometrySorting+2	No attempts yet	1s	128 MB	Judgeable
Unique SnowflakesGiven a stream of integer snowflake ids, find the length of the longest contiguous block in which every value is distinct.	Medium4	Sliding windowHash map+2	No attempts yet	1s	128 MB	Judgeable
Dominos 2Given directed edges between dominos and a set of manually pushed dominos, count how many dominos end up falling.	Medium4	GraphDFS+2	No attempts yet	1s	128 MB	Judgeable
DominosGiven a directed graph of domino toppling relations, find the minimum number of blocks to push by hand so that all blocks fall.	Medium4	GraphDFS+1	No attempts yet	1s	256 MB	Judgeable
The Dragon of LoowaterMatch the smallest knight to each dragon head so that every head is cut by a tall enough knight, minimizing total height paid; report failure if impossible.	Medium4	GreedySorting+2	No attempts yet	1s	128 MB	Judgeable
PseudoprimeFor each pair p and a, decide whether p is composite and satisfies a^p mod p == a, printing yes or no.	Medium4	MathNumber theory+2	No attempts yet	1s	128 MB	Judgeable
HumidexGiven any two of temperature, dew point, and humidex per line, compute and print the third rounded to one decimal.	Medium4	MathImplementation+2	No attempts yet	1s	128 MB	Judgeable
TreeGiven the preorder and inorder traversals of a binary tree, reconstruct the tree and print its postorder traversal.	Medium4	TreeRecursion+1	No attempts yet	1s	192 MB	Judgeable
TautologyGiven propositional formulas in Polish notation, decide for each whether it is a tautology by parsing and evaluating it over every truth assignment.	Medium4	StringRecursion+2	No attempts yet	1s	128 MB	Judgeable
Rock-Paper-Scissors TournamentCount wins and losses for each player across all games, then print each player's win average w/(w+l) to three decimals, or - if the denominator is 0.	Medium4	SimulationImplementation+2	No attempts yet	1s	256 MB	Judgeable
Antiarithmetic?Given a permutation of 0 to n-1, decide whether any three positions contain values forming an arithmetic progression.	Medium4	Hash mapBrute force+1	No attempts yet	1s	128 MB	Judgeable
Basic ModuloRead base-b numbers p and m, with p up to 1000 digits, and print the remainder of p divided by m in base b.	Medium4	MathNumber theory+2	No attempts yet	1s	128 MB	Judgeable
System of Linear EquationsParse two linear equations and report each unknown as a reduced fraction, or as don't know when it is not uniquely determined.	Medium4	MathImplementation+1	No attempts yet	1s	128 MB	Judgeable
Tic Tac ToeGiven a 3x3 Tic Tac Toe grid, decide whether some legal sequence of moves could produce exactly that position.	Medium4	ImplementationSimulation+2	No attempts yet	1s	128 MB	Judgeable
SubwayFind the shortest travel time from home to school using walking and subway lines, rounding the answer to the nearest minute.	Medium4	Shortest pathGraph+2	No attempts yet	1s	128 MB	Judgeable
InterpreterSimulate a 10-register, 1000-word RAM machine that executes encoded 3-digit instructions, and count how many instructions run before the halt.	Medium4	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
Y2K Accounting BugGiven monthly surplus s and deficit d, find the maximum yearly total over all 12 months given that every 5-month block is negative, or report Deficit.	Medium4	Brute forceGreedy+1	No attempts yet	1s	128 MB	Judgeable
Airline HubGiven up to 1000 airports by latitude and longitude, pick the one minimizing the largest great-circle distance to any other airport, breaking ties by earliest input order.	Medium4	GeometryBrute force+2	No attempts yet	1s	128 MB	Judgeable
The TripGiven what each student spent, find the minimum total money that must change hands so every student ends up paying the same amount within one cent.	Medium4	GreedyMath+2	No attempts yet	1s	128 MB	Judgeable