Problems

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Total results29,478 problems

Walking Route
Easy3
Array, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Flag Recognition
Easy3
Brute force, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
IPv6
Easy3
String, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Radio
Easy3
Graph, Shortest path+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
Phone Bill
Easy3
Simulation, Implementation
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
Luka
Easy3
Simulation, Array
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Unreachable Functions
Easy3
Graph, BFS+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Rhyme Pattern
Easy3
String, Implementation
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
Sum of Two Numbers
Easy3
Hash map, Two pointers+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
Most Visited Domains
Easy3
String, Hash map+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Dollars
Easy3
Greedy, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hotel Room Assignment
Easy3
Simulation, Queue+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
DECODE
Easy3
String, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hal's Calculator
Easy3
Stack, Simulation+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
Game
Easy3
Matrix, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Reaux! Sham! Beaux!
Easy3
String, Hash map+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bug King
Easy3
Stack, String
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Character Recognition
Easy3
String, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Easy Task
Easy3
Hash map, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Gates
Easy3
Simulation, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hotline
Easy3
Hash map, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 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
Whitespace King: Aligning Columns
Easy3
String, 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
Building for the UN
Easy3
Implementation, Simulation+1
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
Water Main Break
Easy3
Array, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 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
Java vs C++
Easy3
String, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Building a Swimming Pool
Easy3
Array, Greedy+1
No attempts yet
Time limit
2.5s
Memory limit
128 MB
Judgeable
Roots Intervals
Easy3
Implementation, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Control Points
Easy3
Greedy, Sorting+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
Networking
Easy3
Minimum spanning tree, Graph+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Mowing the Lawn
Easy3
Sorting, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Working at the Restaurant
Easy3
Stack, Simulation+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
Unreliable Messengers
Easy3
String, Simulation+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
My Brother's Diary
Easy3
String, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Roll Cake
Easy3
Simulation, Array+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Chain of Fools
Easy3
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Windows
Easy3
Array, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
LCR
Easy3
Simulation, Implementation+1
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
Words
Easy3
String, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Profit
Easy3
Array, Dynamic programming+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Euclid
Easy3
Geometry, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Modulo Solitaire
Easy3
BFS, Graph
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Subset Sum
Easy3
Brute force, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Memorable Phone Numbers
Easy3
String, Hash map+2
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
Exact Change
Easy3
Dynamic programming, Array+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Snakes and Ladders
Easy3
Simulation, Implementation+1
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
Conformity Prize
Easy3
Hash map, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
To and Fro
Easy3
String, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Ferry Loading IV
Easy3
Simulation, Queue
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
Traditional BINGO
Easy3
Simulation, Array+2
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
Major Scales
Easy3
Implementation, String+2
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
Ecology
Easy3
Hash map, String+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Forests
Easy3
Hash map, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Stack 'em Up
Easy3
Simulation, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Average Speed
Easy3
Simulation, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Zipf's Law
Easy3
Hash map, String+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
Minesweeper
Easy3
Simulation, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Soundex
Easy3
String, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Election
Easy3
Hash map, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Request for Proposal
Easy3
Hash map, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Elf's Sword
Easy3
Implementation, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
ROT13
Easy3
Implementation, String+2
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

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
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
Flag RecognitionGiven a 6x9 letter grid, compute the minimum edits needed to make it a valid three-stripe flag, either horizontal (2-row bands) or vertical (3-column bands) with the middle band's color differing from both outer bands.	Easy3	Brute forceImplementation+1	No attempts yet	1s	128 MB	Judgeable
IPv6Given a shortened IPv6 address with omitted leading zeros and possibly one '::' run, expand it into eight full 4-digit hex groups.	Easy3	StringImplementation	No attempts yet	1s	128 MB	Judgeable
RadioGiven a start and target frequency plus up to 5 preset shortcut buttons, find the minimum presses using +1, -1, or jump to a preset to reach the target.	Easy3	GraphShortest path+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
Phone BillGiven N calls with a start time and duration under 60 minutes, sum the cost by charging 10 won per minute in 07:00-19:00 and 5 won otherwise, splitting calls that cross the boundary.	Easy3	SimulationImplementation	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
LukaSimulate a walker's path on a grid and output every time step when the walker is within Chebyshev distance 1 of a fixed point.	Easy3	SimulationArray	No attempts yet	1s	128 MB	Judgeable
Unreachable FunctionsGiven a control flow graph built from three instruction types with fall-through or jump edges, count how many functions are unreachable from the first one.	Easy3	GraphBFS+1	No attempts yet	1s	128 MB	Judgeable
Rhyme PatternGiven verses of four lines, extract each line's last syllable from its final word and classify the rhyme pattern as perfect, even, cross, shell, or free.	Easy3	StringImplementation	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
Sum of Two NumbersCount pairs of distinct integers in an array that sum exactly to a given value x.	Easy3	Hash mapTwo pointers+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
Most Visited DomainsParse a list of URLs to extract each domain suffix and print the maximum visit count along with all domains that reach it, sorted alphabetically.	Easy3	StringHash map+1	No attempts yet	1s	128 MB	Judgeable
DollarsSimulate converting between dollars and marks daily using given rates to maximize final dollar amount, truncated to two decimals.	Easy3	GreedySimulation+1	No attempts yet	1s	128 MB	Judgeable
Hotel Room AssignmentSimulate assigning arriving groups to hotel rooms with two beds each, filling empty rooms first then pairing singles, and output the final occupancy per room.	Easy3	SimulationQueue+1	No attempts yet	1s	128 MB	Judgeable
DECODEBuild a substitution cipher table from a key word placed at a given offset, then decode a given ciphertext using it.	Easy3	StringSimulation+1	No attempts yet	1s	128 MB	Judgeable
Hal's CalculatorSimulate a stack-like list of expressions under six commands (HASH, DOLLAR, SWAP, DROP, DUP, ROT), enforcing size and availability constraints, and output the final list or ERROR.	Easy3	StackSimulation+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
GameGiven many filled 5x5 tic-tac-toe boards, determine for each whether A, B, or neither has three consecutive same marbles in a row, column, or diagonal.	Easy3	MatrixSimulation+1	No attempts yet	1s	128 MB	Judgeable
Reaux! Sham! Beaux!Parse rock-paper-scissors rounds given in multiple languages per player, tally wins, and print each game's score and winner.	Easy3	StringHash map+1	No attempts yet	1s	128 MB	Judgeable
Bug KingRepeatedly remove all occurrences of the substring "BUG" from each input line, using a stack-like scan since removals can form new matches, until none remain.	Easy3	StackString	No attempts yet	1s	128 MB	Judgeable
Character RecognitionRead multi-line text blocks separated by blank lines, count '#' as unrecognized characters, and print the recognition percentage formatted with rounding rules.	Easy3	StringImplementation	No attempts yet	1s	128 MB	Judgeable
Easy TaskProcess a list of contest submissions to compute, for each of nine problems, the number of teams that solved it and the average submissions and solve time.	Easy3	Hash mapSimulation+1	No attempts yet	1s	128 MB	Judgeable
GatesGiven an acyclic NAND-gate circuit whose inputs are all tied to one variable x, decide whether the overall output depends on x (answer 1) or is constant (answer 0).	Easy3	SimulationGraph+1	No attempts yet	1s	128 MB	Judgeable
HotlineAnswer yes, no, or maybe questions about one-word subjects and verb-object activities using the statements heard earlier in each dialogue.	Easy3	Hash mapSimulation+1	No attempts yet	1s	128 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
Whitespace King: Aligning ColumnsReformat text lines so that words in each column line up to a width equal to the longest word in that column, with single spaces separating columns.	Easy3	StringImplementation+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
Building for the UNPrint a fixed two-floor n by n grid where the lower floor's rows and upper floor's columns each represent a labeled country, satisfying a connectivity and adjacency construction.	Easy3	ImplementationSimulation+1	No attempts yet	3s	128 MB	Judgeable
Water Main BreakGiven several water main breaks with start, end, and flow rate, sum the gallons leaked during each second of a given query interval.	Easy3	ArraySimulation+1	No attempts yet	1s	128 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
Java vs C++Detect whether a name follows Java camelCase or C++ snake_case rules and convert it to the other style, or print an error if invalid.	Easy3	StringImplementation	No attempts yet	1s	128 MB	Judgeable
Building a Swimming PoolCompute the minimum cost to convert a grid into grass/hole cells, forcing the border to be grass and charging per boundary edge between grass and hole.	Easy3	ArrayGreedy+1	No attempts yet	2.5s	128 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
Control PointsGiven sorted coordinates of control points, find the minimum number of length-1 half-open intervals needed to cover all points using a greedy sweep.	Easy3	GreedySorting+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
NetworkingGiven points and weighted candidate cable routes, compute the minimum total cable length needed to connect all points (minimum spanning tree).	Easy3	Minimum spanning treeGraph+1	No attempts yet	1s	128 MB	Judgeable
Mowing the LawnDetermine if sorted mower path coordinates with a given strip width fully cover a 75x100 rectangle in both directions, across multiple test cases until a terminator line.	Easy3	SortingSimulation+1	No attempts yet	1s	128 MB	Judgeable
Working at the RestaurantSimulate a two-pile plate stacking strategy that always drops on pile 2 and serves from pile 1, moving plates when pile 1 runs out, and output the exact operation transcript.	Easy3	StackSimulation+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
Unreliable MessengersGiven a sequence of reversible string transformations and the final message, undo each transformation in reverse order to recover the original message.	Easy3	StringSimulation+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
My Brother's DiaryFind the Caesar shift whose most frequent ciphertext letter maps to E, print the smallest valid shift and the decrypted text, or NOT POSSIBLE if several shifts work.	Easy3	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
Roll CakeGiven N interval requests over pieces 1..L, find the member with the largest requested length, then the member who actually receives the most pieces when earlier requests get priority.	Easy3	SimulationArray+1	No attempts yet	1s	128 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
WindowsGiven windows in opening order, answer clicks by returning the most recently opened window covering each click point, or background if none does.	Easy3	ArrayBrute force+2	No attempts yet	1s	128 MB	Judgeable
LCRSimulate the dice game LCR turn by turn with the given rolls, then print the final chip counts for each player and the center.	Easy3	SimulationImplementation+1	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
WordsRead lines until a line with a single #, and output each line with the characters of every word reversed, keeping spaces fixed.	Easy3	StringImplementation	No attempts yet	1s	128 MB	Judgeable
ProfitGiven a sequence of daily profits, find the maximum total over any non-empty stretch of consecutive days, across several test cases.	Easy3	ArrayDynamic programming+1	No attempts yet	1s	256 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
Modulo SolitaireGiven a modulus m, up to 10 affine maps, and a start s0, find the fewest moves to reach 0.	Easy3	BFSGraph	No attempts yet	1s	128 MB	Judgeable
Subset SumGiven up to 20 bag sizes and a target n, pick each bag at most once to reach at least n with the smallest possible total.	Easy3	Brute forceBit manipulation+1	No attempts yet	1s	128 MB	Judgeable
Memorable Phone NumbersNormalize each listed phone number to seven digits and report those appearing more than once, sorted, with their counts.	Easy3	StringHash map+2	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
Exact ChangeGiven a price and a multiset of up to 100 coin values, pick a subset summing to at least the price; minimize the sum first, then the number of coins.	Easy3	Dynamic programmingArray+1	No attempts yet	1s	128 MB	Judgeable
Snakes and LaddersSimulate a Snakes and Ladders game with a players and a list of die rolls, applying snakes and ladders after each move, and print each token's final square.	Easy3	SimulationImplementation+1	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
Conformity PrizeCanonicalize each frosh's five courses, count how many frosh share each set, then output the total over all sets with the maximum count.	Easy3	Hash mapSorting+2	No attempts yet	1s	128 MB	Judgeable
To and FroDecode a message written row by row in alternating left-to-right and right-to-left order back into column-major plaintext.	Easy3	StringSimulation+2	No attempts yet	1s	128 MB	Judgeable
Ferry Loading IVSimulate a ferry of given length that repeatedly crosses between two banks, loading waiting cars in arrival order.	Easy3	SimulationQueue	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
Traditional BINGOFor each card, find how many announced numbers are needed before some row, column, or diagonal of five spaces is fully marked, with the center free.	Easy3	SimulationArray+2	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
Major ScalesFor each sequence of notes, list the keys whose major scale contains every note, ordered C through B.	Easy3	ImplementationString+2	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
EcologyCount how many times each tree species line appears, then print each species in lexicographic order with its share of the total, rounded to four decimals.	Easy3	Hash mapString+1	No attempts yet	1s	256 MB	Judgeable
ForestsCount how many distinct nonempty sets of trees appear among the (person, tree) pairs; people who heard nothing are excluded.	Easy3	Hash mapSorting+2	No attempts yet	1s	128 MB	Judgeable
Stack 'em UpApply a sequence of fixed 52-card permutation shuffles to a new deck, printing the deck after each shuffle.	Easy3	SimulationImplementation+1	No attempts yet	1s	128 MB	Judgeable
Average SpeedTrack a car's speed changes over time and answer queries asking the total distance travelled up to a given elapsed time.	Easy3	SimulationImplementation+1	No attempts yet	1s	128 MB	Judgeable
Zipf's LawFor each test case, count the words in a book body and print the words that appear exactly n times, in lowercase alphabetical order.	Easy3	Hash mapString+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
MinesweeperGiven an n×n mine layout and which cells are currently opened, print the board: mine counts for opened safe cells, asterisks for all mines if any mine was opened, and dots elsewhere.	Easy3	SimulationImplementation+1	No attempts yet	1s	128 MB	Judgeable
SoundexConvert each uppercase word into its Soundex digit code, collapsing adjacent letters that share a digit.	Easy3	StringImplementation	No attempts yet	1s	128 MB	Judgeable
ElectionCount the votes each candidate receives in one riding, ignore unknown names, and report the winner's party or independent, or tie if there is no strict winner.	Easy3	Hash mapImplementation+2	No attempts yet	1s	128 MB	Judgeable
Request for ProposalGiven a set of requirements, score each proposal by how many requirements it meets, then pick the best one by compliance and price.	Easy3	Hash mapString+2	No attempts yet	1s	128 MB	Judgeable
The Elf's SwordFor each input n, find the smallest k such that the digits 0 through 9 all appear across the multiples n, 2n, ..., kn.	Easy3	ImplementationSimulation+2	No attempts yet	1s	128 MB	Judgeable
ROT13Decode lines of text by reversing the ROT13 cipher: each vowel shifts three places back in a fixed vowel order, each consonant ten back in a consonant order.	Easy3	ImplementationString+2	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