Problems

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Total results29,478 problems

Laser Turret Maintenance
Easy3
Implementation, Matrix+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Robot Roll Call
Easy3
Hash map, String+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
Car Racing
Easy3
Stack, Simulation+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
Verdis Quo
Easy3
String, Simulation+1
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
Queue Rearrangement
Easy3
Array, Simulation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Defining Moment
Easy3
String, Implementation+2
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
Choose Your Own Adventure
Easy3
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Is the Name of This Problem
Easy3
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
LRU Caching
Easy3
Linked list, Hash map+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Judges' Time Calculation
Easy3
Implementation, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Mad Scientist
Easy3
Array, Prefix sum+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Teleporting Firefly Chase
Easy3
Simulation, Geometry+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Steganography
Easy3
String, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Copier Reduction
Easy3
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Netiquette
Easy3
String, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Symmetric Order
Easy3
Array, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Flow Layout
Easy3
Simulation, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tanning Salon
Easy3
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
W's Cipher
Easy3
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hangover
Easy3
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pronounceable Passwords
Easy3
String, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Loansome Car Buyer
Easy3
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Booklet Printing
Easy3
Array, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Self Numbers
Easy3
Implementation, Math+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Do the Untwist
Easy3
Math, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Word Amalgamation
Easy3
Hash map, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Skew Binary
Easy3
Math, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Snail
Easy3
Implementation, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Polynomial Showdown
Easy3
Implementation, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Semigroups
Easy3
Brute force, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Basically Speaking
Easy3
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Losers Are Winners
Easy3
Hash map, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Close Enough Computations
Easy3
Math, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
I-Soar
Easy3
Intervals, Sorting
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Transposition
Easy3
String, Hash map+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Take Your Vitamins
Easy3
Implementation, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Extrusion
Easy3
Geometry, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Beautiful Triangle
Easy3
Geometry, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Spelling Be
Easy3
Hash map, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Counting Pages
Easy3
Implementation, String+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Post Office
Easy3
Implementation, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Dance
Easy3
Implementation, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Primorial Number System
Easy3
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Look and Say
Easy3
String, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Wavelet Compression
Easy3
Divide and conquer, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bridge Bidding
Easy3
Implementation, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Faulty Odometer
Easy3
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Gold Coins
Easy3
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Gym
Easy3
Math, Matrix+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Seven-Segment Display Addition
Easy3
String, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Relax! It's Just a Game
Easy3
Math, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tetromino Maximum Sum
Easy3
Brute force, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Great Sahara
Easy3
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Casting Out Nines
Easy3
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
A Balanced World
Easy3
Stack, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Number of Islands
Easy3
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Equal Total Scores
Easy3
Brute force, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Dirichlet's Theorem on Arithmetic Progressions
Easy3
Number theory, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
MCXI Numeral System
Easy3
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hanafuda Shuffle
Easy3
Simulation, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Red and Black
Easy3
DFS, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Car Trouble
Easy3
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Skyline
Easy3
Geometry, Intervals+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Carbonated Drinks
Easy3
Math, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Really Good Compression
Easy3
Math, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The God of Parking
Easy3
Math, Greedy+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
When Do We Finish?
Easy3
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Car Park
Easy3
Simulation, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Shirts
Easy3
Sorting, Two pointers+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Archaeological Digs
Easy3
Hash map, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Street Numbers
Easy3
Simulation, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hostel Nights
Easy3
Implementation, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Air Old Zeeland
Easy3
Implementation, Array+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Letter Replacement
Easy3
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sequences
Easy3
Math, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Postman Joe
Easy3
Simulation, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Target
Easy3
Array, Hash map+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Coded Communication
Easy3
String, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Driving the Rover
Easy3
Simulation, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Alarmist
Easy3
Sliding window, Array+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Countdown
Easy3
Implementation, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Weird Currency
Easy3
Math, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Grocery Shopping
Easy3
Hash map, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Subway Fares
Easy3
Array, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Lobbying
Easy3
Implementation, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Gadget Purchases
Easy3
Array, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Toxic Assets
Easy3
Dynamic programming, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
A Fistful of Dollars
Easy3
Implementation, Array+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Fingerprints
Easy3
Array, Bit manipulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Fundraising
Easy3
Hash map, Array+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Sand Castles
Easy3
Geometry, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
School Colors
Easy3
Brute force, Geometry+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Campus Buildings
Easy3
String, Two pointers+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
A Minor and C Major
Easy3
String, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Global Warming
Easy3
Array, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
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
Robot Roll CallGiven a roster of names and a multi-line data stream split on spaces and tabs, report for each roster name whether it appears as an exact token.	Easy3	Hash mapString+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
Car RacingGiven the order in which cars arrive, decide whether a single FIFO bypass lane can reorder them to increasing order.	Easy3	StackSimulation+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
Verdis QuoConvert valid Roman numerals to decimal integers using addition and subtraction rules.	Easy3	StringSimulation+1	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
Queue RearrangementGiven a queue of m items and n simultaneous move operations, apply all moves at once and print the resulting queue order.	Easy3	ArraySimulation	No attempts yet	1s	128 MB	Judgeable
Defining MomentFor each word, strip at most one valid prefix and one valid suffix, then substitute the matching English meaning, expanding the suffix after the prefix.	Easy3	StringImplementation+2	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
Choose Your Own AdventureEach page is a node with two outgoing choices or a terminal ending; print the unique path from page 1 to the single HAPPY ending.	Easy3	GraphDFS+2	No attempts yet	1s	128 MB	Judgeable
Is the Name of This ProblemRead sentences until END and for each decide whether it has the form quote, phrase A, quote, space, A, printing Quine(A) or not a quine.	Easy3	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
LRU CachingSimulate an LRU cache over a sequence of letter accesses and exclamation-mark print requests, outputting cache contents from least to most recently used.	Easy3	Linked listHash map+1	No attempts yet	1s	128 MB	Judgeable
Judges' Time CalculationGiven a 12-hour start time and a contest duration, print a lookup table giving the elapsed minutes formula for each hour block.	Easy3	ImplementationSimulation+1	No attempts yet	1s	128 MB	Judgeable
Mad ScientistRecover a non-decreasing sequence of measurements from its cumulative counts P(j), the number of measurements at most j, for each j from 1 to k.	Easy3	ArrayPrefix sum+1	No attempts yet	1s	128 MB	Judgeable
Teleporting Firefly ChaseSimulate a chase where the chaser repeatedly teleports a fixed distance toward each firefly flash and is caught if distance drops to 1 or less.	Easy3	SimulationGeometry+2	No attempts yet	1s	128 MB	Judgeable
SteganographyDecode hidden bits from odd/even runs of spaces in a text and decode five-bit groups into characters.	Easy3	StringBit manipulation+1	No attempts yet	1s	128 MB	Judgeable
Copier ReductionGiven an image and paper size in millimeters, find the largest integer percentage scale (with optional 90-degree rotation) that still fits on the paper.	Easy3	MathImplementation+2	No attempts yet	1s	128 MB	Judgeable
NetiquetteDecide whether a one-line email breaks any of four netiquette rules about adjacent case, digits, isolated characters, or punctuation.	Easy3	StringImplementation	No attempts yet	1s	128 MB	Judgeable
Symmetric OrderGiven a list of names sorted by length, rearrange them so shorter names sit at the top and bottom and longer ones in the middle, pairing names from the start.	Easy3	ArrayImplementation+2	No attempts yet	1s	128 MB	Judgeable
Flow LayoutPlace rectangles left to right into rows under a max width, wrap when one does not fit, and report the final window width and total height.	Easy3	SimulationImplementation+1	No attempts yet	1s	128 MB	Judgeable
Tanning SalonSimulate a tanning salon with a fixed number of beds, tracking arrivals and departures, and count how many customers leave without a bed.	Easy3	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
W's CipherDecrypt messages by extracting each of three character groups and rotating its subsequence right by the matching key.	Easy3	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
HangoverFor each target overhang c, find the smallest n such that the harmonic sum 1/2 + 1/3 + ... + 1/(n+1) reaches c, and report n.	Easy3	MathImplementation+2	No attempts yet	1s	128 MB	Judgeable
Pronounceable PasswordsFor each lowercase password, check three rules: at least one vowel, no three vowels or consonants in a row, and no double letter except ee and oo.	Easy3	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
Loansome Car BuyerSimulate monthly depreciation and payments on a car loan, and report the first month when the amount owed drops below the car's value.	Easy3	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
Booklet PrintingFor each page count, print which page numbers (or Blank) go on each side of every sheet in fold-over booklet order.	Easy3	ArrayImplementation+1	No attempts yet	1s	128 MB	Judgeable
Self NumbersPrint all self numbers up to 10000, that is, numbers with no generator under d(n) = n + digit sum of n.	Easy3	ImplementationMath+2	No attempts yet	1s	256 MB	Judgeable
Do the UntwistGiven a key and a twisted ciphertext, invert the twisting formula to recover the original plaintext message.	Easy3	MathImplementation	No attempts yet	1s	128 MB	Judgeable
Word AmalgamationFor each scrambled word, print all dictionary words that are anagrams of it in alphabetical order, or NOT A VALID WORD.	Easy3	Hash mapSorting+2	No attempts yet	1s	128 MB	Judgeable
Skew BinaryRead each skew binary string and print its decimal value, stopping at the terminating 0 line.	Easy3	MathString+1	No attempts yet	1s	128 MB	Judgeable
The SnailSimulate a snail that climbs a bit less each day and slides a fixed distance each night, and report whether it escapes or falls back first.	Easy3	ImplementationSimulation+1	No attempts yet	1s	128 MB	Judgeable
Polynomial ShowdownGiven nine polynomial coefficients from degree 8 down to the constant, print each polynomial with signs, exponents, and coefficients formatted to drop all unnecessary characters.	Easy3	ImplementationSimulation+2	No attempts yet	1s	128 MB	Judgeable
SemigroupsGiven a small multiplication table, decide whether it defines a semigroup, report the first counterexample if not, and check commutativity.	Easy3	Brute forceImplementation+2	No attempts yet	1s	128 MB	Judgeable
Basically SpeakingConvert a number from one base to another (bases 2 to 16) and print the result right-justified in a 7-character field, or ERROR if it exceeds 7 digits.	Easy3	MathImplementation+2	No attempts yet	1s	128 MB	Judgeable
Losers Are WinnersGroup contestants into teams of two, compute each team's percentage of combined weight lost, and print the winner with one decimal place.	Easy3	Hash mapImplementation+2	No attempts yet	1s	128 MB	Judgeable
Close Enough ComputationsDecide whether printed grams of fat, carbohydrate, and protein can come from true amounts whose calorie total rounds to the printed calories.	Easy3	MathImplementation+1	No attempts yet	1s	128 MB	Judgeable
I-SoarGiven building intervals along a highway, find the total length of the highway not covered by any building.	Easy3	IntervalsSorting	No attempts yet	1s	128 MB	Judgeable
TranspositionTranspose a list of note names by a given number of semitones, then print each note using the 12 canonical sharp names.	Easy3	StringHash map+2	No attempts yet	1s	128 MB	Judgeable
Take Your VitaminsFor each line of amount, unit, requirement, and name, print the rounded daily-value percentage; collect items under 1% into a trailing list.	Easy3	ImplementationMath+2	No attempts yet	1s	128 MB	Judgeable
ExtrusionGiven the vertices of a polygon in clockwise order and a volume of metal, compute the polygon's area and divide to get the bar length.	Easy3	GeometryMath+2	No attempts yet	1s	128 MB	Judgeable
Beautiful TriangleGiven three vertices, classify the triangle by side lengths and by angles, or report that the points are collinear.	Easy3	GeometryMath+2	No attempts yet	1s	128 MB	Judgeable
Spelling BeRead a dictionary and several emails, then report for each email whether all its words are known and list the unknown words in order.	Easy3	Hash mapString+2	No attempts yet	1s	128 MB	Judgeable
Counting PagesGiven a document's page count and a comma-separated list of page ranges, count the distinct pages that are actually printed, ignoring empty ranges and pages past the end.	Easy3	ImplementationString+2	No attempts yet	1s	256 MB	Judgeable
Post OfficeSort each item's three dimensions into length, height, and thickness, then apply the postal size rules to print one of four classes.	Easy3	ImplementationMath+2	No attempts yet	1s	128 MB	Judgeable
DanceCheck a sequence of dance steps against five textual rules and report which rules it violates, uppercasing any misplaced dip.	Easy3	ImplementationString+1	No attempts yet	1s	128 MB	Judgeable
Primorial Number SystemRepresent each positive integer in the mixed-radix primorial system where the i-th place value is the product of the first i primes.	Easy3	MathNumber theory+2	No attempts yet	1s	128 MB	Judgeable
Look and SayFor each input string of digits, produce the next look-and-say element by counting runs of equal digits and writing each count followed by the digit.	Easy3	StringImplementation	No attempts yet	1s	128 MB	Judgeable
Wavelet CompressionGiven a signal transformed by recursive sum/difference wavelet steps, reconstruct the original samples for each test case.	Easy3	Divide and conquerSimulation+1	No attempts yet	1s	128 MB	Judgeable
Bridge BiddingFor each 13-card bridge hand, compute high card points and suit lengths, then print the first applicable opening bid rule.	Easy3	ImplementationSimulation+1	No attempts yet	1s	128 MB	Judgeable
Faulty OdometerRead odometer values that skip the digit 4 and print the true mileage by treating each reading as a base-9 number.	Easy3	MathImplementation+2	No attempts yet	1s	128 MB	Judgeable
Gold CoinsFor each number of days, add up the gold coins when the knight is paid N coins on each of N consecutive days.	Easy3	MathImplementation+2	No attempts yet	1s	128 MB	Judgeable
GymGiven an N by N matrix of card counts, compute the probability distribution over N baskets for the first 10 steps of a Markov process starting at basket 1.	Easy3	MathMatrix+2	No attempts yet	1s	128 MB	Judgeable
Seven-Segment Display AdditionDecode two seven-segment code strings into integers, add them, then re-encode the sum using the given digit codes.	Easy3	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
Relax! It's Just a GameFor each score (A, B), check whether the binomial coefficient C(A+B, A) equals the sum A+B, and print the comparison.	Easy3	MathCombinatorics+2	No attempts yet	1s	128 MB	Judgeable
Tetromino Maximum SumGiven an N x N grid of integers, place one of the five tetrominoes (with rotations, not flips) so the four covered cells have the largest sum.	Easy3	Brute forceImplementation+2	No attempts yet	1s	128 MB	Judgeable
The Great SaharaOn a fixed 54-triangle hex board, decide whether player one can move one pyramid to trap an opponent's pyramid immediately.	Easy3	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
Casting Out NinesFor each line like a+b=c. or a*b=c., compute digit sums modulo 9 and print PASS if the operation is congruent, otherwise NOT!.	Easy3	MathNumber theory+2	No attempts yet	1s	128 MB	Judgeable
A Balanced WorldFor each line ending in a period, decide whether its round and square brackets are properly matched and nested, printing yes or no.	Easy3	StackString+1	No attempts yet	1s	128 MB	Judgeable
Number of IslandsGiven a grid of land and sea cells with 8-directional adjacency, count the connected land components.	Easy3	GraphDFS+2	No attempts yet	1s	128 MB	Judgeable
Equal Total ScoresFind one card from each person to swap so their total scores match, choosing the pair with the smallest sum, or print -1.	Easy3	Brute forceImplementation+2	No attempts yet	1s	128 MB	Judgeable
Dirichlet's Theorem on Arithmetic ProgressionsFor each dataset, print the n-th prime in the arithmetic progression a, a+d, a+2d, ... , where a and d are coprime.	Easy3	Number theoryMath+1	No attempts yet	1s	128 MB	Judgeable
MCXI Numeral SystemRead two MCXI-strings, add their values, and print the canonical MCXI-string for the sum.	Easy3	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
Hanafuda ShuffleCards 1 to n start from the bottom, and each cut moves a contiguous block of c cards starting at position p to the top; report the top card after all cuts.	Easy3	SimulationImplementation+1	No attempts yet	1s	128 MB	Judgeable
Red and BlackCount how many black tiles are reachable from a start tile in a small grid by moving up, down, left, and right.	Easy3	DFSGraph+1	No attempts yet	1s	128 MB	Judgeable
Car TroubleGiven a directed graph of street ids with ring road 0, report streets that cannot reach 0 and streets that 0 cannot reach, preserving input order.	Easy3	GraphDFS+2	No attempts yet	1s	128 MB	Judgeable
SkylineWe have N trapezoidal buildings listed from nearest to farthest. For each building, we must compute the fraction of its area that remains visible, i.e., the part of the trapezoid not hidden by any closer building. The presence of overlapping sloped roofs makes the computation nontrivial: for a given building we need to determine, for each horizontal coordinate, the maximum roof height among all closer buildings. Then the visible area is the integral, over the building’s own range [x1, x2], of the positive part of the difference between the building's top edge (roof) and that maximum height.For	Easy3	GeometryIntervals+2	No attempts yet	1s	128 MB	Judgeable
Carbonated DrinksGiven starting empties, empties found, and the empties needed per exchange, count how many drinks Junmin can obtain and drink in total.	Easy3	MathSimulation+2	No attempts yet	1s	128 MB	Judgeable
Really Good CompressionGiven N distinct 1000-bit files, decide whether each can be compressed to at most b bits.	Easy3	MathCombinatorics+2	No attempts yet	1s	128 MB	Judgeable
The God of ParkingGiven shop coordinates on a line, pick an integer parking spot and visit all shops, returning to the car, to minimize total walking distance.	Easy3	MathGreedy+2	No attempts yet	1s	128 MB	Judgeable
When Do We Finish?Add each event's duration to its start time and print the resulting clock time, appending the number of days past midnight when the end crosses into later days.	Easy3	MathImplementation+2	No attempts yet	1s	128 MB	Judgeable
Car ParkSimulate a sequence of car entry and exit signals for a car park of capacity S starting with C cars, stopping early if an exit occurs while empty.	Easy3	SimulationImplementation+1	No attempts yet	1s	128 MB	Judgeable
ShirtsMerge two already sorted lists of shirts and print one merged list ordered by size, then by colour letter. Multiple scenarios end with a 0.	Easy3	SortingTwo pointers+2	No attempts yet	1s	128 MB	Judgeable
Archaeological DigsGiven repeated item coordinates on a small grid and a list of query cells, sum how many items fall in those cells.	Easy3	Hash mapImplementation	No attempts yet	1s	128 MB	Judgeable
Street NumbersCount how many times each digit 0 to 9 appears on house numbers from L to H, skipping the given gap ranges.	Easy3	SimulationImplementation+1	No attempts yet	1s	128 MB	Judgeable
Hostel NightsFor each week, apply five nights of elimination rules to 20 rooms and list the students who survive the most nights, ordered by room number.	Easy3	ImplementationSimulation+2	No attempts yet	1s	128 MB	Judgeable
Air Old ZeelandFor each customer, sum the prices of requested products whose shipping delay fits the wait limit, flag customers who miss any product, and count them.	Easy3	ImplementationArray+2	No attempts yet	1s	128 MB	Judgeable
Letter ReplacementReplace each repeated letter in a word with a symbol assigned in the order letters first repeat, comparing case-insensitively.	Easy3	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
SequencesFor each query with a first term, non-zero common difference, and value, print the term index if the value is in the arithmetic sequence, otherwise X.	Easy3	MathImplementation+1	No attempts yet	1s	128 MB	Judgeable
Postman JoeSimulate Joe's walk on 20 houses, flag any out-of-range or repeated house as illegal, else list the houses with no delivery.	Easy3	SimulationImplementation+1	No attempts yet	1s	128 MB	Judgeable
TargetGiven all solution words of a letter puzzle, recover the 9 grid letters and place the letter common to every word in the middle.	Easy3	ArrayHash map+1	No attempts yet	1s	128 MB	Judgeable
Coded CommunicationGiven n binary strings of length b and a received string r, find the minimum Hamming distance from r to any of the n strings.	Easy3	StringBrute force+2	No attempts yet	1s	128 MB	Judgeable
Driving the RoverSimulate a rover that takes one command per second, tracking its speed, heading, and position, then report the final integer coordinates.	Easy3	SimulationImplementation	No attempts yet	1s	128 MB	Judgeable
AlarmistGiven n samples and a window size w, compute the floor of each window average and report the difference between the largest and smallest average.	Easy3	Sliding windowArray+1	No attempts yet	1s	128 MB	Judgeable
CountdownGiven a Maya Long Count date and its Julian Day Number, convert today's Gregorian date to JDN and report the days until 13.0.0.0.0.	Easy3	ImplementationMath+2	No attempts yet	1s	128 MB	Judgeable
Weird CurrencyGiven a chain of denomination conversion rates, convert each vendor's price to the smallest unit and report the difference between the highest and lowest price.	Easy3	MathImplementation+1	No attempts yet	1s	128 MB	Judgeable
Grocery ShoppingFor each grocery item, find its matching store item by case-insensitive name and add the club-card saving on the units actually bought.	Easy3	Hash mapString+1	No attempts yet	1s	128 MB	Judgeable
Subway FaresGiven a per-stop fare table and an ordered list of station names, find the number of stops between two stations and print the corresponding fare.	Easy3	ArrayString+2	No attempts yet	1s	128 MB	Judgeable
LobbyingSum each lawmaker's donations made within 1000 days before the vote, then weight each no vote by 1/(1+D/10000) and add up both sides.	Easy3	ImplementationMath+2	No attempts yet	1s	128 MB	Judgeable
Gadget PurchasesCount how many visits demand each machine, cap each count at its usage limit, and report the machines whose revenue beats purchase plus usage cost.	Easy3	ArrayImplementation+2	No attempts yet	1s	128 MB	Judgeable
Toxic AssetsGiven current values of basic investments and acyclic derivative definitions, compute the current worth of a portfolio made of these investments.	Easy3	Dynamic programmingMath+1	No attempts yet	1s	128 MB	Judgeable
A Fistful of DollarsGiven transaction totals for s people, find the person whose spending exceeds twice that of every other person, or report none.	Easy3	ImplementationArray+1	No attempts yet	1s	128 MB	Judgeable
FingerprintsFor each of K query 5x5 bitmaps, find the database bitmap with the smallest Hamming distance and print all tied indices in increasing order.	Easy3	ArrayBit manipulation+2	No attempts yet	1s	128 MB	Judgeable
FundraisingGiven a sequence of donation transactions, aggregate the amount each donor gave to each candidate and in total, then report every donor whose per-candidate total exceeds $2100 or whose overall total exceeds $40000. The core task is grouping and summing values by keys, then applying two threshold checks.	Easy3	Hash mapArray+1	No attempts yet	1s	128 MB	Judgeable
Sand CastlesGiven a rectangular patch, a perimeter moat, and cylindrical towers, compute how much the flat base level rises or falls so the sand volume stays fixed.	Easy3	GeometryMath+2	No attempts yet	1s	128 MB	Judgeable
School ColorsGiven up to 200 RGB colors, find every pair whose Euclidean distance is maximal and print the index pairs in sorted order.	Easy3	Brute forceGeometry+2	No attempts yet	1s	128 MB	Judgeable
Campus BuildingsGiven building names and an abbreviation, list the names whose letters contain the abbreviation as a case-insensitive subsequence, in input order.	Easy3	StringTwo pointers+1	No attempts yet	1s	128 MB	Judgeable
A Minor and C MajorSplit the score at bar lines, count how many measure-initial notes are A, D, E versus C, F, G, and break ties with the last note.	Easy3	StringImplementation	No attempts yet	1s	128 MB	Judgeable
Global WarmingGiven a small land/sea grid, mark every land cell with three or more sea neighbours as sea simultaneously, then print the tight bounding box of the remaining land.	Easy3	ArraySimulation+2	No attempts yet	1s	128 MB	Judgeable