Math and counting

Number theory, combinatorics, and geometry

Under construction

Still being built. Things may change

Total results13,160 problems

Card 2
Easy3
Queue, Simulation+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Polygon Area
Easy3
Geometry, Math+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Diagonal Across Tiles
Easy3
Math, Number theory
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pinary Numbers
Easy3
Dynamic programming, Math+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Sum Decomposition
Easy3
Dynamic programming, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Decomposition Sum
Easy3
Brute force, Math+1
No attempts yet
Time limit
2s
Memory limit
192 MB
Judgeable
Repeated Sequence
Easy3
Simulation, Hash map+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Making Equal-Length Sticks
Easy3
Math, Greedy+1
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Combination
Easy3
Math, Combinatorics+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Integer Square Root
Easy3
Binary search, Math
No attempts yet
Time limit
0.4s
Memory limit
128 MB
Judgeable
Greatest Common Divisor and Least Common Multiple
Easy3
Number theory, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Melon Field
Easy3
Geometry, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Rice Cakes for the Tiger
Easy3
Math, Brute force+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pancake Love
Easy3
Math, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Remainder Sequence Cycle
Easy3
Simulation, Hash map+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Rectangle Overlap Type
Easy3
Geometry, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Student Who Raises Both Averages
Easy3
Array, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Representative Natural Number
Easy3
Sorting, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Two Representative Natural Numbers
Easy3
Math, Sorting+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Prime Numbers
Easy3
Math, Number theory+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Roman Numerals
Easy3
String, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Making Triangles with Matchsticks
Easy3
Math, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Paper Cutting
Easy3
Sorting, Array+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Nim Sum
Easy3
Math, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Darts
Easy3
Geometry, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Spreadsheet Cell Names
Easy3
Math, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bicycle Speed
Easy3
Math, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Apartment Residents
Easy3
Dynamic programming, Math+1
No attempts yet
Time limit
0.5s
Memory limit
128 MB
Judgeable
Keypad Passwords
Easy3
Dynamic programming, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Contest or Internship
Easy3
Greedy, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Chocolate Lunch
Easy3
Bit manipulation, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sangbeom's Game
Easy3
Math, Array+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Non-Alcoholic Cocktail
Easy3
Math, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Midpoint Displacement Algorithm
Easy3
Math, Simulation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Candy Purchase
Easy3
Math, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Ruler and Protractor
Easy3
Number theory, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Noise
Easy3
Math, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Apple Distribution Methods
Easy3
Number theory, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Turtle
Easy3
Brute force, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sieve of Eratosthenes
Easy3
Simulation, Math
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Doyoung's Delicious Food
Easy3
Brute force, Math
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Three Numbers
Easy3
Brute force, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pascal Loop Output
Easy3
Math, Number theory+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Aggressive Dogs
Easy3
Math, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Fourth Number
Easy3
Math, Brute force+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Completing a League Table
Easy3
Math, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Rings
Easy3
Math, Number theory+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Polygon Diagonal Intersections
Easy3
Combinatorics, Math
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Visible Poster Area
Easy3
Geometry, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Heart Number System
Easy3
Math, Number theory+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cutting Chocolate
Easy3
Math, Number theory+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Walking Route
Easy3
Array, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Date Validation
Easy3
Implementation, Math
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Worm Turns
Easy3
Math, Simulation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pizza
Easy3
Greedy, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Multiply
Easy3
Brute force, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Comport
Easy3
Simulation, Brute force+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
ICONS
Easy3
Math, Brute force+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
N-Queens
Easy3
Math, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Towers of Coins
Easy3
Dynamic programming, Game theory
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Polygon
Easy3
Greedy, Math
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Darts
Easy3
Math, Implementation+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Adding Reversed Numbers
Easy3
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Turing Arithmetic Expressions
Easy3
Math, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Binary Encoding
Easy3
Bit manipulation, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Alien Communication Masterclass
Easy3
Math, Implementation+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Holes
Easy3
Greedy, Math
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Beer Refrigerator
Easy3
Brute force, Math
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
iChess
Easy3
Binary search, Math+1
No attempts yet
Time limit
2s
Memory limit
64 MB
Judgeable
Journey with Pigs
Easy3
Greedy, Sorting+1
No attempts yet
Time limit
2s
Memory limit
64 MB
Judgeable
Roots Intervals
Easy3
Implementation, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Build Your Home
Easy3
Geometry, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Internet Service Providers
Easy3
Math, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Count on Cantor
Easy3
Math, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Gray Area
Easy3
Array, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
And Then There Was One
Easy3
Simulation, Queue+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Prime Gap Sequence
Easy3
Math, Number theory+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
How I Wonder What You Are!
Easy3
Geometry, Brute force+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hailstone Sequence
Easy3
Simulation, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Remainder Calculation
Easy3
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Chain of Fools
Easy3
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
CIVIC DILL MIX
Easy3
String, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Euclid
Easy3
Geometry, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Alien Base Conversion
Easy3
Math, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Fibonacci Number
Easy3
Dynamic programming, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Smeech
Easy3
Recursion, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Word Ratios
Easy3
String, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Brownie Points I
Easy3
Geometry, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Ants
Easy3
Math, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Guess the Number
Easy3
Implementation, Math
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Blocks
Easy3
Brute force, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Jolly Jumpers
Easy3
Array, Hash map+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Carry Count
Easy3
Implementation, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tales from DeCrypt
Easy3
Simulation, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Laser Turret Maintenance
Easy3
Implementation, Matrix+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pencils from the 19th Century
Easy3
Math, Brute force+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Geek Challenge [SKRZAT] (Base Minus Two)
Easy3
Math, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Patterns and Pictures
Easy3
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Rout 66
Easy3
Simulation, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
It's My Derivative
Easy3
String, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Card 2Simulate the Josephus-style card elimination process to find which card number remains last for a given N.	Easy3	QueueSimulation+1	No attempts yet	2s	128 MB	Judgeable
Polygon AreaGiven the ordered vertices of a simple polygon, compute its area using the shoelace formula, rounded to one decimal place.	Easy3	GeometryMath+1	No attempts yet	2s	128 MB	Judgeable
Diagonal Across TilesGiven a grid of x by y unit tiles, count how many tiles a diagonal from corner to corner passes through using the gcd formula.	Easy3	MathNumber theory	No attempts yet	1s	128 MB	Judgeable
Pinary NumbersCount binary strings of length N that start with 1 and have no two consecutive 1s, using Fibonacci-style counting with big integers up to N=90.	Easy3	Dynamic programmingMath+1	No attempts yet	2s	128 MB	Judgeable
Sum DecompositionCount ordered sequences of K integers from 0 to N whose sum equals N, modulo 1,000,000,000.	Easy3	Dynamic programmingCombinatorics+1	No attempts yet	2s	128 MB	Judgeable
Decomposition SumGiven N up to 1,000,000, find the smallest number M such that M plus its digit sum equals N, or print 0 if none exists.	Easy3	Brute forceMath+1	No attempts yet	2s	192 MB	Judgeable
Repeated SequenceSimulate a digit-power sequence until it cycles, then output how many distinct values appear before the repetition starts.	Easy3	SimulationHash map+1	No attempts yet	2s	256 MB	Judgeable
Making Equal-Length SticksGiven piece lengths, find the smallest stick length such that all pieces can be regrouped into sticks of that equal length (the sum divided by a suitable divisor, bounded by the maximum piece).	Easy3	MathGreedy+1	No attempts yet	3s	128 MB	Judgeable
CombinationGiven n and m within 100, compute the exact value of the binomial coefficient C(n, m).	Easy3	MathCombinatorics+1	No attempts yet	2s	128 MB	Judgeable
Integer Square RootGiven an integer n up to 2^63-1, compute the smallest nonnegative integer q whose square is at least n.	Easy3	Binary searchMath	No attempts yet	0.4s	128 MB	Judgeable
Greatest Common Divisor and Least Common MultipleGiven the gcd and lcm of two unknown natural numbers, find the pair with the smallest sum satisfying both conditions.	Easy3	Number theoryMath+1	No attempts yet	1s	128 MB	Judgeable
Melon FieldGiven an L-shaped rectilinear hexagon described by six directional side lengths, compute its area and multiply by a melon density constant.	Easy3	GeometryMath+1	No attempts yet	1s	128 MB	Judgeable
Rice Cakes for the TigerGiven the day index D and Fibonacci-like combination coefficients, find starting values A and B (A ≤ B) so the D-th term equals K.	Easy3	MathBrute force+1	No attempts yet	1s	128 MB	Judgeable
Pancake LoveGiven raw ingredient counts, compute the maximum batter portions (limited by a scaling factor) and topping-based pancake counts, then output the minimum of total toppings possible and batter portions.	Easy3	MathGreedy+1	No attempts yet	1s	128 MB	Judgeable
Remainder Sequence CycleGiven N and P, simulate the sequence a_{i+1} = a_i*N mod P and output the length of the eventual repeating cycle.	Easy3	SimulationHash map+1	No attempts yet	1s	128 MB	Judgeable
Rectangle Overlap TypeFor four pairs of axis-aligned rectangles, determine whether their intersection is a rectangle, a line segment, a point, or empty, printing a code letter per case.	Easy3	GeometryImplementation	No attempts yet	1s	128 MB	Judgeable
Student Who Raises Both AveragesGiven two groups' IQ lists, count students in the first group whose IQ is below that group's average but above the second group's average.	Easy3	ArrayMath+1	No attempts yet	1s	128 MB	Judgeable
Representative Natural NumberFind the smallest integer minimizing the sum of absolute differences to a list of numbers, which is the lower median.	Easy3	SortingMath+1	No attempts yet	1s	128 MB	Judgeable
Two Representative Natural NumbersGiven up to 5,000,000 integers from 1 to 10,000, output the median (smallest if tie) and the rounded mean as representatives.	Easy3	MathSorting+1	No attempts yet	2s	256 MB	Judgeable
Prime NumbersGiven a range M to N up to 10,000, find all primes in it and print their sum plus the smallest one, or -1 if none exist.	Easy3	MathNumber theory+1	No attempts yet	1s	128 MB	Judgeable
Roman NumeralsConvert two Roman numerals to integers, sum them, and output the sum as both an Arabic and a Roman numeral.	Easy3	StringMath+1	No attempts yet	1s	128 MB	Judgeable
Making Triangles with MatchsticksGiven n identical matchsticks, count the number of non-congruent integer-sided triangles whose perimeter equals n.	Easy3	MathCombinatorics+1	No attempts yet	1s	128 MB	Judgeable
Paper CuttingGiven a rectangular sheet and a series of horizontal or vertical cuts along grid lines, compute the area of the largest resulting piece.	Easy3	SortingArray+1	No attempts yet	1s	128 MB	Judgeable
Nim SumCompute a generalized digit-wise sum of two numbers in base B, adding digits modulo B, for multiple test cases.	Easy3	MathImplementation	No attempts yet	1s	128 MB	Judgeable
DartsFor each test case, sum dartboard scores from coordinates for two players and print the winner or a tie.	Easy3	GeometrySimulation+1	No attempts yet	1s	128 MB	Judgeable
Spreadsheet Cell NamesConvert given row and column numbers into spreadsheet-style cell names like A1 or BC23, stopping at R0C0.	Easy3	MathString+1	No attempts yet	1s	128 MB	Judgeable
Bicycle SpeedGiven wheel diameter, rotation count, and elapsed time per line, compute total distance in miles and average speed in mph until a zero-rotation terminator.	Easy3	MathImplementation+1	No attempts yet	1s	128 MB	Judgeable
Apartment ResidentsCompute the resident count in room n on floor k, defined by repeated prefix sums starting from room i having i residents on floor 0.	Easy3	Dynamic programmingMath+1	No attempts yet	0.5s	128 MB	Judgeable
Keypad PasswordsCount length-N digit sequences on a phone keypad where consecutive digits must be adjacent keys, modulo 1,234,567, for up to N=1000.	Easy3	Dynamic programmingGraph+1	No attempts yet	1s	128 MB	Judgeable
Contest or InternshipGiven female and male student counts and a number who must leave for internship, decide who to remove to maximize teams of 2 females and 1 male each.	Easy3	GreedyMath+1	No attempts yet	1s	128 MB	Judgeable
Chocolate LunchGiven K, find the smallest power-of-two chocolate bar size and the minimum number of halving splits needed to obtain exactly K unit pieces.	Easy3	Bit manipulationMath+1	No attempts yet	1s	128 MB	Judgeable
Sangbeom's GameGiven a grid with two players' king pieces, compute for each player the sum over all pairs of their kings of the Chebyshev distance between them.	Easy3	MathArray+1	No attempts yet	1s	128 MB	Judgeable
Non-Alcoholic CocktailGiven amounts of three juices and a mixing ratio, compute the leftover of each juice after making the maximum possible cocktail.	Easy3	MathImplementation	No attempts yet	1s	128 MB	Judgeable
Midpoint Displacement AlgorithmGiven N iterations of a midpoint-displacement grid subdivision starting from a square, compute the number of distinct grid points, which reduces to a closed-form formula based on the (2^N+1) x (2^N+1) grid size.	Easy3	MathSimulation	No attempts yet	1s	128 MB	Judgeable
Candy PurchaseGiven a price and a bill denomination that is a power of ten, round the price to the nearest multiple of that denomination, rounding up on ties.	Easy3	MathImplementation	No attempts yet	1s	128 MB	Judgeable
Ruler and ProtractorGiven N base angles closable under addition/subtraction mod 360, determine for K query angles whether each is reachable, which reduces to checking divisibility by gcd of the base angles and 360.	Easy3	Number theoryMath+1	No attempts yet	1s	128 MB	Judgeable
NoiseGiven two powers of ten with up to 100 digits and an operator, compute their sum or product using big-number arithmetic.	Easy3	MathString+1	No attempts yet	1s	128 MB	Judgeable
Apple Distribution MethodsGiven R and G, list every common divisor N of both, printing N along with R/N and G/N as red and green apples per player.	Easy3	Number theoryMath+1	No attempts yet	1s	128 MB	Judgeable
TurtleGiven four positive integers as segment lengths for a path with three right-angle turns, find the maximum rectangle area that can be enclosed (requires opposite sides equal).	Easy3	Brute forceMath+1	No attempts yet	1s	128 MB	Judgeable
Sieve of EratosthenesSimulate the Sieve of Eratosthenes and output which number gets crossed out on the K-th removal step.	Easy3	SimulationMath	No attempts yet	1s	128 MB	Judgeable
Doyoung's Delicious FoodGiven up to 10 ingredients with sourness and bitterness, choose a non-empty subset minimizing the absolute difference between the product of sourness and sum of bitterness, using brute force over all subsets.	Easy3	Brute forceMath	No attempts yet	1s	128 MB	Judgeable
Three NumbersGiven three numbers in order, insert one arithmetic operator and one equals sign to form a valid equation like a op b = c or a = b op c.	Easy3	Brute forceMath+1	No attempts yet	1s	128 MB	Judgeable
Pascal Loop OutputGiven N up to 1e9, simulate finding the largest divisor of N smaller than N by scanning downward, and output how many steps that takes without brute force.	Easy3	MathNumber theory+1	No attempts yet	1s	128 MB	Judgeable
Aggressive DogsGiven two dogs' attack/rest cycle lengths, determine for three given minute timestamps how many dogs are attacking at that minute.	Easy3	MathSimulation+1	No attempts yet	1s	128 MB	Judgeable
The Fourth NumberGiven three integers from a 4-term arithmetic progression (order unspecified), find the missing fourth integer.	Easy3	MathBrute force+1	No attempts yet	1s	128 MB	Judgeable
Completing a League TableFill in missing values (marked ?) in each football league row using matches=wins+draws+losses and points=3*wins+draws, with a unique solution guaranteed.	Easy3	MathImplementation	No attempts yet	1s	128 MB	Judgeable
RingsGiven radii of N touching rings, compute how many rotations each ring after the first makes as a reduced fraction when the first ring completes one rotation.	Easy3	MathNumber theory+1	No attempts yet	1s	128 MB	Judgeable
Polygon Diagonal IntersectionsGiven N, a convex N-gon with no three diagonals concurrent, compute the number of interior diagonal intersection points using the combinatorial formula C(N,4).	Easy3	CombinatoricsMath	No attempts yet	1s	128 MB	Judgeable
Visible Poster AreaGiven two axis-aligned rectangles, compute the visible area of the first rectangle after subtracting its overlap with the second.	Easy3	GeometryImplementation+1	No attempts yet	1s	128 MB	Judgeable
Heart Number SystemConvert a decimal integer to balanced ternary notation using digits 1, 0, and - for -1, without leading zeros.	Easy3	MathNumber theory+1	No attempts yet	1s	128 MB	Judgeable
Cutting ChocolateGiven an N by M chocolate bar, find the minimum number of square pieces obtained by repeatedly cutting it fully along rows or columns.	Easy3	MathNumber theory+1	No attempts yet	1s	128 MB	Judgeable
Walking RouteGiven N vectors forming a walking route, output the total displacement and the minimum distance from the start after removing exactly one segment.	Easy3	ArrayMath+1	No attempts yet	1s	128 MB	Judgeable
Date ValidationRead day, month, year triples until a terminator and print whether each represents a real calendar date, accounting for leap years.	Easy3	ImplementationMath	No attempts yet	1s	128 MB	Judgeable
Worm TurnsGiven an M by N grid eaten in a clockwise spiral, compute how many times the direction changes before the whole grid is consumed.	Easy3	MathSimulation	No attempts yet	1s	128 MB	Judgeable
PizzaGiven each friend's pizza appetite of 1/4, 1/2, or 3/4, compute the minimum number of whole pizzas needed to serve exact slices to all.	Easy3	GreedyMath+1	No attempts yet	1s	128 MB	Judgeable
MultiplyFor each test case, find the smallest base from 2 to 16 in which the digit strings p, q, r satisfy p times q equals r, or output 0 if none works.	Easy3	Brute forceMath+1	No attempts yet	1s	128 MB	Judgeable
ComportFind the smallest step size K (1 to N) so repeatedly moving K fields clockwise from field 1 reaches field Z without landing on any obstacle field along the way.	Easy3	SimulationBrute force+1	No attempts yet	1s	128 MB	Judgeable
ICONSGiven N, find rows R and columns C with R<=C, R*C>=N, minimizing R+C, and output the most balanced such pair.	Easy3	MathBrute force+1	No attempts yet	1s	128 MB	Judgeable
N-QueensGiven N, print a specific N-queens placement built by a fixed construction rule based on N mod 6, rather than searching for any valid solution.	Easy3	MathImplementation+1	No attempts yet	1s	128 MB	Judgeable
Towers of CoinsGiven move options 1, K, or L coins in a Nim-like turn game, determine for each pile size whether the first player wins under optimal play.	Easy3	Dynamic programmingGame theory	No attempts yet	1s	128 MB	Judgeable
PolygonDecide whether N given segment lengths can form the sides of some convex polygon, which reduces to checking that the largest length is smaller than the sum of the rest.	Easy3	GreedyMath	No attempts yet	1s	128 MB	Judgeable
DartsFor each dart throw coordinate, determine the score based on concentric circle radius bands and sum the scores per test case.	Easy3	MathImplementation+1	No attempts yet	1s	256 MB	Judgeable
Adding Reversed NumbersReverse two given numbers, add them, then output the sum reversed with leading zeros dropped.	Easy3	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
Turing Arithmetic ExpressionsGiven up to nine large integers and an arithmetic expression using them, evaluate the expression under mod-10 addition and multiplication with normal precedence and print the result digit.	Easy3	MathString+1	No attempts yet	1s	128 MB	Judgeable
Binary EncodingGiven m, output the truncated binary code for each integer from 0 to m-1 following the standard truncated binary encoding rules.	Easy3	Bit manipulationImplementation+1	No attempts yet	1s	128 MB	Judgeable
Alien Communication MasterclassGiven true bases and false bases, output a fixed-form product-of-factors equation that holds only for the true bases in that numeral system.	Easy3	MathImplementation+1	No attempts yet	3s	256 MB	Judgeable
HolesFind the smallest non-negative integer without leading zeros whose digits produce exactly h holes, where 0,4,6,9 give one hole and 8 gives two.	Easy3	GreedyMath	No attempts yet	3s	256 MB	Judgeable
Beer RefrigeratorGiven n, find integer dimensions a,b,c with abc=n that minimize the box surface area 2(ab+bc+ca).	Easy3	Brute forceMath	No attempts yet	1s	128 MB	Judgeable
iChessGiven counts of black and white tiles, find the largest square side length whose checkerboard pattern fits within those tile counts, or report impossibility.	Easy3	Binary searchMath+1	No attempts yet	2s	64 MB	Judgeable
Journey with PigsGiven pig weights and per-village net price coefficients, assign pigs to villages one-to-one to maximize total revenue (sort and multiply greedily).	Easy3	GreedySorting+1	No attempts yet	2s	64 MB	Judgeable
Roots IntervalsGiven interval [a,b] split into nb equal subintervals, count subintervals where f(x)=1-x^2 has a sign change or zero at endpoints.	Easy3	ImplementationSimulation+1	No attempts yet	1s	128 MB	Judgeable
Build Your HomeCompute and round the area of each given simple polygon, including degenerate cases with fewer than three vertices, until a terminating zero.	Easy3	GeometryImplementation+1	No attempts yet	1s	128 MB	Judgeable
Internet Service ProvidersGiven N and C, find the smallest integer T minimizing/maximizing the quadratic profit NT(C-T*N), handling N=0 edge case.	Easy3	MathImplementation+1	No attempts yet	1s	128 MB	Judgeable
Count on CantorFor given indices n, find the n-th fraction a/b in Cantor's diagonal enumeration of positive rationals and print it in a fixed format.	Easy3	MathImplementation+1	No attempts yet	1s	128 MB	Judgeable
Gray AreaCompute weighted ink used by a histogram where each bar contributes its normalized height times a linearly decreasing darkness, plus a fixed constant.	Easy3	ArraySimulation+1	No attempts yet	1s	128 MB	Judgeable
And Then There Was OneSimulate a Josephus-style circle elimination game with a custom starting removal point and report the last remaining stone for each test case.	Easy3	SimulationQueue+1	No attempts yet	1s	128 MB	Judgeable
Prime Gap SequenceGiven a number k, find the gap length between the two consecutive primes surrounding it if k is composite, otherwise output 0.	Easy3	MathNumber theory+1	No attempts yet	1s	128 MB	Judgeable
How I Wonder What You Are!For each dataset, count how many of the given stars fall within the angular radius of at least one of several telescopes all located at the origin.	Easy3	GeometryBrute force+1	No attempts yet	1s	128 MB	Judgeable
Hailstone SequenceFor each of up to 100,000 starting values, simulate the Collatz sequence until it reaches 1 and report the maximum value seen.	Easy3	SimulationImplementation+1	No attempts yet	1s	128 MB	Judgeable
Remainder CalculationFor each test case, find the remainder when a base-B number D with up to ten million digits is divided by B-1.	Easy3	MathNumber theory+2	No attempts yet	1s	256 MB	Judgeable
Chain of FoolsGiven sprocket prongs, chain links, and start positions of a broken prong and bent link, find when they first meet at location 0, printing revolutions and fraction or Never.	Easy3	MathNumber theory+2	No attempts yet	1s	128 MB	Judgeable
CIVIC DILL MIXRead groups of valid Roman numerals, add each group, and print the sum and case number back in standard Roman form.	Easy3	StringMath+1	No attempts yet	1s	128 MB	Judgeable
EuclidFor each case, find G and H so that ABGH is a parallelogram, H sits on ray AC, and the parallelogram's area equals triangle DEF's area.	Easy3	GeometryMath+1	No attempts yet	1s	128 MB	Judgeable
Alien Base ConversionConvert a number written in base x into the same value written in base y, where both bases are between 2 and 36 and the value fits in four billion.	Easy3	MathImplementation+1	No attempts yet	1s	128 MB	Judgeable
Fibonacci NumberGiven n, print the n-th Fibonacci number, where the sequence starts 1, 1 and each later term is the sum of the previous two.	Easy3	Dynamic programmingMath+2	No attempts yet	1s	128 MB	Judgeable
SmeechParse a prefix Smeech expression with probabilistic plus or minus operators and compute its expected value to two decimals.	Easy3	RecursionMath+2	No attempts yet	1s	128 MB	Judgeable
Word RatiosFor each line of three equal-length lowercase words, apply the per-letter alphabet shift from the first word to the second onto the third, and output all four words.	Easy3	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
Brownie Points IGiven a fixed crossing point, split the remaining brownie points into the four quadrants and count Stan's two quadrants versus Ollie's two.	Easy3	GeometryImplementation	No attempts yet	1s	128 MB	Judgeable
AntsGiven ant positions on a rod of length l, choose each ant's initial direction to minimize and maximize the time for all ants to fall off.	Easy3	MathGreedy+1	No attempts yet	1s	128 MB	Judgeable
Guess the NumberFor each guessing game, decide whether some integer from 1 to 10 fits all of Stan's answers, or the answers contradict each other.	Easy3	ImplementationMath	No attempts yet	1s	128 MB	Judgeable
BlocksGiven N unit cubes, find positive integers a, b, c with abc = N that minimize the surface area 2(ab+bc+ca).	Easy3	Brute forceMath+2	No attempts yet	1s	128 MB	Judgeable
Jolly JumpersFor each sequence, check whether the absolute differences of adjacent elements are exactly the set 1 to n-1.	Easy3	ArrayHash map+2	No attempts yet	1s	128 MB	Judgeable
Carry CountFor each pair of non-negative integers, count how many carries occur while adding them column by column from the right. Stop at the 0 0 line.	Easy3	ImplementationMath+1	No attempts yet	1s	128 MB	Judgeable
Tales from DeCryptRead three LCG parameters, then walk the ciphertext byte by byte, advancing the generator only on printable ASCII, and apply the inverse rotation to each such byte.	Easy3	SimulationMath+2	No attempts yet	1s	128 MB	Judgeable
Laser Turret MaintenanceGiven a conflict-free n-queens configuration as a column vector, output the eight rotations and reflections in a fixed order with three-character right-justified fields.	Easy3	ImplementationMatrix+2	No attempts yet	1s	128 MB	Judgeable
Pencils from the 19th CenturyFor each N, find all triples (a, b, c) of positive counts of 4-cent, 2-for-1, and 4-for-1 pencils with a+b+c = N and 4a + b/2 + c/4 = N.	Easy3	MathBrute force+1	No attempts yet	1s	128 MB	Judgeable
Geek Challenge [SKRZAT] (Base Minus Two)Convert numbers between decimal and base -2 (Weird Binary), echoing each query with its formatted result.	Easy3	MathImplementation+1	No attempts yet	1s	128 MB	Judgeable
Patterns and PicturesFor each data set, compute the total area of one full set, then find how many full sets fit in one, two, and three square yards.	Easy3	MathImplementation+2	No attempts yet	1s	128 MB	Judgeable
Rout 66Simulate an invader whose strength drops after each stronghold it breaks, processing strongholds nearest first, and report whether all fall.	Easy3	SimulationSorting+1	No attempts yet	1s	128 MB	Judgeable
It's My DerivativeFor each polynomial, print its derivative and the step-by-step evaluation of that derivative at a given x, matching the input's terse notation.	Easy3	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable