Problems

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Total results21,491 problems

Cutting CornersEasy2
Math, Geometry +2No attempts yetTime limit1sMemory limit512 MB
Judgeable
Count Down Up 2020Easy2
Array, Implementation +1No attempts yetTime limit2sMemory limit512 MB
Judgeable
ArchivistEasy2
Implementation, Brute forceNo attempts yetTime limit2sMemory limit512 MB
Judgeable
BicycleEasy2
Math, Implementation +1No attempts yetTime limit2sMemory limit512 MB
Judgeable
Right-Coupled NumbersEasy2
Brute force, Math +1No attempts yetTime limit1sMemory limit1024 MB
Judgeable
Moderate PaceEasy2
Array, Sorting +1No attempts yetTime limit2sMemory limit512 MB
Judgeable
Big MoneyEasy2
Math, Implementation +1No attempts yetTime limit1sMemory limit512 MB
Judgeable
Counting MonumentsEasy2
Hash map, String +1No attempts yetTime limit2sMemory limit512 MB
Judgeable
A Colorful ProblemEasy2
Implementation, Brute force +2No attempts yetTime limit1sMemory limit512 MB
Judgeable
VCR++ CodesEasy2
Bit manipulation, Implementation +2No attempts yetTime limit1sMemory limit512 MB
Judgeable
Operation: Save the Raffle Prize! (Easy)Easy2
Brute force, Math +1No attempts yetTime limit1sMemory limit512 MB
Judgeable
TaxEasy2
Math, Implementation +1No attempts yetTime limit1sMemory limit1024 MB
Judgeable
ElevatorsEasy2
Implementation, Brute force +1No attempts yetTime limit1sMemory limit1024 MB
Judgeable
Buffon's NeedleEasy2
Geometry, Implementation +1No attempts yetTime limit4sMemory limit1024 MB
Judgeable
PizzaEasy2
Hash map, Implementation +1No attempts yetTime limit1sMemory limit512 MB
Judgeable
Safe SquaresEasy2
Array, Implementation +1No attempts yetTime limit2sMemory limit512 MB
Judgeable
Triple TextingEasy2
String, ImplementationNo attempts yetTime limit2sMemory limit512 MB
Judgeable
Fifty Shades of PinkEasy2
String, Implementation +2No attempts yetTime limit1sMemory limit1024 MB
Judgeable
Consonant CollapseEasy2
String, Implementation +1No attempts yetTime limit1sMemory limit1024 MB
Judgeable
GradingEasy2
Implementation, Math +1No attempts yetTime limit1sMemory limit1024 MB
Judgeable
MinigolfEasy2
Implementation, MathNo attempts yetTime limit1sMemory limit1024 MB
Judgeable
Archaeologist YerinEasy2
Math, Implementation +1No attempts yetTime limit1sMemory limit1024 MB
Judgeable
The Second Largest IntegerEasy2
Implementation, SortingNo attempts yetTime limit2sMemory limit1024 MB
Judgeable
JOI SortEasy2
Sorting, Implementation +1No attempts yetTime limit2sMemory limit1024 MB
Judgeable
Common ElementsEasy2
Hash map, Sorting +1No attempts yetTime limit2sMemory limit1024 MB
Judgeable
Simple Operations in MatrixEasy2
Array, Simulation +2No attempts yetTime limit1sMemory limit512 MB
Judgeable
Methodic MultiplicationEasy2
String, Math +2No attempts yetTime limit2sMemory limit1024 MB
Judgeable
New Financial YearEasy2
Math, Implementation +1No attempts yetTime limit1sMemory limit512 MB
Judgeable
Missing NumberEasy2
String, Implementation +1No attempts yetTime limit1sMemory limit512 MB
Judgeable
Rating ProblemsEasy2
Math, Implementation +1No attempts yetTime limit1sMemory limit512 MB
Judgeable
Curve SpeedEasy2
Math, ImplementationNo attempts yetTime limit1sMemory limit1024 MB
Judgeable
Some SumEasy2
Math, Implementation +2No attempts yetTime limit1sMemory limit1024 MB
Judgeable
MeditationEasy2
Sorting, Greedy +1No attempts yetTime limit1sMemory limit512 MB
Judgeable
CakesEasy2
Implementation, Math +1No attempts yetTime limit1sMemory limit512 MB
Judgeable
Comfy DeviationsEasy2
Math, ImplementationNo attempts yetTime limit1sMemory limit512 MB
Judgeable
Mars MessageEasy2
Implementation, String +2No attempts yetTime limit1sMemory limit1024 MB
Judgeable
Contest StrugglesEasy2
Math, ImplementationNo attempts yetTime limit1sMemory limit1024 MB
Judgeable
Count of Numbers 2Easy2
Math, Implementation +1No attempts yetTime limit1sMemory limit128 MB
Judgeable
Air ConditionerEasy2
Implementation, Simulation +2No attempts yetTime limit2sMemory limit1024 MB
Judgeable
Laptop StickerEasy2
Implementation, MathNo attempts yetTime limit1sMemory limit1024 MB
Judgeable
K 2K GameEasy2
Implementation, Math +1No attempts yetTime limit1sMemory limit256 MB
Judgeable
Silent AuctionEasy2
Array, ImplementationNo attempts yetTime limit1sMemory limit1024 MB
Judgeable
Secret InstructionsEasy2
Implementation, Simulation +2No attempts yetTime limit1sMemory limit1024 MB
Judgeable
Crazy FencingEasy2
Math, Geometry +2No attempts yetTime limit1sMemory limit1024 MB
Judgeable
Bank TransferEasy2
Math, Implementation +1No attempts yetTime limit1sMemory limit512 MB
Judgeable
ChessboardEasy2
Math, Implementation +1No attempts yetTime limit2sMemory limit512 MB
Judgeable
Kart RaceEasy2
Implementation, ArrayNo attempts yetTime limit2sMemory limit512 MB
Judgeable
Misha and the NegativeEasy2
Implementation, Array +2No attempts yetTime limit2sMemory limit512 MB
Judgeable
Black and White GraphicsEasy2
Implementation, Array +2No attempts yetTime limit2sMemory limit512 MB
Judgeable
KeyboardEasy2
Array, Implementation +1No attempts yetTime limit2sMemory limit512 MB
Judgeable
MonstersEasy2
Math, Combinatorics +2No attempts yetTime limit1sMemory limit512 MB
Judgeable
PalindromesEasy2
Implementation, Math +1No attempts yetTime limit1sMemory limit512 MB
Judgeable
SplitEasy2
String, ImplementationNo attempts yetTime limit1sMemory limit512 MB
Judgeable
Basalt BreakdownEasy2
Math, Geometry +1No attempts yetTime limit1sMemory limit1024 MB
Judgeable
ScrollEasy2
String, Implementation +1No attempts yetTime limit2sMemory limit1024 MB
Judgeable
GameEasy2
Implementation, Matrix +1No attempts yetTime limit2sMemory limit256 MB
Judgeable
Changyoung and the BusEasy2
Implementation, Array +2No attempts yetTime limit2sMemory limit512 MB
Judgeable
ExamEasy2
Implementation, MathNo attempts yetTime limit2sMemory limit256 MB
Judgeable
Pie ChartEasy2
Math, Implementation +1No attempts yetTime limit2sMemory limit256 MB
Judgeable
TariffsEasy2
Implementation, Brute force +2No attempts yetTime limit2sMemory limit256 MB
Judgeable
Quality-Adjusted Life-YearEasy2
Math, Implementation +2No attempts yetTime limit1sMemory limit512 MB
Judgeable
Splitting the BillEasy2
Implementation, Math +2No attempts yetTime limit8sMemory limit512 MB
Judgeable
Binary DivisionEasy2
Math, String +1No attempts yetTime limit1sMemory limit1024 MB
Judgeable
I Don't Want to Attend a Fifth YearEasy2
Implementation, Greedy +1No attempts yetTime limit1sMemory limit512 MB
Judgeable
Matrix InverseEasy2
Math, Matrix +1No attempts yetTime limit2sMemory limit1024 MB
Judgeable
Does Not ComputeEasy2
Implementation, Math +1No attempts yetTime limit2sMemory limit1024 MB
Judgeable
Formatting TextEasy2
String, Implementation +2No attempts yetTime limit2sMemory limit1024 MB
Judgeable
Knot KnowledgeEasy2
Array, Hash map +1No attempts yetTime limit1sMemory limit1024 MB
Judgeable
Coding BiorhythmEasy2
Implementation, Math +1No attempts yetTime limit1sMemory limit512 MB
Judgeable
Hongik Absolute GradingEasy2
Implementation, Sorting +1No attempts yetTime limit1sMemory limit1024 MB
Judgeable
Hongik Dance PartyEasy2
Implementation, String +2No attempts yetTime limit1sMemory limit1024 MB
Judgeable
JavaScriptEasy2
String, Implementation +2No attempts yetTime limit2sMemory limit1024 MB
Judgeable
Street Coding FighterEasy2
Implementation, Math +1No attempts yetTime limit1sMemory limit512 MB
Judgeable
QuackQuack (Easy)Easy2
String, ImplementationNo attempts yetTime limit1sMemory limit1024 MB
Judgeable
Dickensian DictionaryEasy2
String, ImplementationNo attempts yetTime limit1sMemory limit1024 MB
Judgeable
Kinder SurpriseEasy2
Hash map, StringNo attempts yetTime limit1sMemory limit64 MB
Judgeable
РесторанEasy2
Implementation, String +1No attempts yetTime limit1sMemory limit1024 MB
Judgeable
Drawing Snails - Flipped LEasy2
Implementation, SimulationNo attempts yetTime limit1sMemory limit512 MB
Judgeable
Drawing Snail - ㄴEasy2
Implementation, String +2No attempts yetTime limit1sMemory limit512 MB
Judgeable
Drawing a Snail - ㄷEasy2
Implementation, SimulationNo attempts yetTime limit1sMemory limit512 MB
Judgeable
Drawing a Snail - Rotated RieulEasy2
Implementation, Simulation +1No attempts yetTime limit1sMemory limit512 MB
Judgeable
Drawing Snails - ㅁEasy2
Implementation, SimulationNo attempts yetTime limit1sMemory limit512 MB
Judgeable
Drawing Snails - Flipped KieukEasy2
Implementation, SimulationNo attempts yetTime limit1sMemory limit512 MB
Judgeable
Printing a Snail - ㅌEasy2
Implementation, SimulationNo attempts yetTime limit1sMemory limit512 MB
Judgeable
Drawing Snail - Rotated ㅍEasy2
Implementation, Simulation +1No attempts yetTime limit1sMemory limit512 MB
Judgeable
Let's Make a SASA ModelEasy2
Math, Implementation +2No attempts yetTime limit0.5sMemory limit512 MB
Judgeable
Bishop TourEasy2
Math, Implementation +1No attempts yetTime limit1sMemory limit512 MB
Judgeable
Bike TourEasy2
Array, ImplementationNo attempts yetTime limit10sMemory limit1024 MB
Judgeable
SaturnaliaEasy2
Implementation, String +1No attempts yetTime limit20sMemory limit1024 MB
Judgeable
What Makes 2021 Special?Easy2
Math, Brute forceNo attempts yetTime limit1sMemory limit1024 MB
Judgeable
Bitaro and IOIEasy2
String, Greedy +1No attempts yetTime limit2sMemory limit1024 MB
Judgeable
IOI StringEasy2
String, Implementation +2No attempts yetTime limit2sMemory limit1024 MB
Judgeable
ComparisonEasy2
Brute force, Array +1No attempts yetTime limit2sMemory limit1024 MB
Judgeable
Boxes and KeysEasy2
Hash map, Implementation +1No attempts yetTime limit2sMemory limit1024 MB
Judgeable
Moving BallsEasy2
Array, Simulation +1No attempts yetTime limit2sMemory limit1024 MB
Judgeable
Poster mailingEasy2
Math, Implementation +1No attempts yetTime limit1sMemory limit1024 MB
Judgeable
Hidden WordsEasy2
String, Simulation +1No attempts yetTime limit2sMemory limit1024 MB
Judgeable
Tab HoppingEasy2
Simulation, Implementation +2No attempts yetTime limit2sMemory limit1024 MB
Judgeable
Algorithm Class - Algorithm Runtime 4Easy2
Math, Combinatorics +2No attempts yetTime limit1sMemory limit512 MB
Judgeable
Algorithm Class - Algorithm Runtime 5Easy2
Math, Implementation +2No attempts yetTime limit1sMemory limit512 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Cutting CornersGiven a stained w by h corner, compute how much longer the rectangular cut is than the diagonal cut.	Easy2	MathGeometry+2	No attempts yet	1s	512 MB	Judgeable
Count Down Up 2020Given lists of digits, count how many times the consecutive subsequence 2, 0, 2, 0 appears, including overlaps.	Easy2	ArrayImplementation+1	No attempts yet	2s	512 MB	Judgeable
ArchivistRead a year between 1995 and 2019 and print the contest winner for that year exactly as given in the provided list.	Easy2	ImplementationBrute force	No attempts yet	2s	512 MB	Judgeable
BicycleFor each of two bike rental plans, compute the monthly cost over 21 working days given a daily riding time T and per-minute overage rates.	Easy2	MathImplementation+1	No attempts yet	2s	512 MB	Judgeable
Right-Coupled NumbersFor each x below 215, decide whether x has a factor pair a*b = x with a <= b and a/b >= 0.5, printing 1 or 0.	Easy2	Brute forceMath+1	No attempts yet	1s	1024 MB	Judgeable
Moderate PaceFor each of n days, read three ideal running distances and output the median value of the three.	Easy2	ArraySorting+1	No attempts yet	2s	512 MB	Judgeable
Big MoneySum n decimal amounts given in euros with two cent digits each, and print the exact total in the same format.	Easy2	MathImplementation+1	No attempts yet	1s	512 MB	Judgeable
Counting MonumentsRead n lines, each with a date and a monument name, and output the number of distinct monument names.	Easy2	Hash mapString+1	No attempts yet	2s	512 MB	Judgeable
A Colorful ProblemFor each RGB color after the first 16, print it, the words "maps to", and the target color with the smallest Euclidean distance.	Easy2	ImplementationBrute force+2	No attempts yet	1s	512 MB	Judgeable
VCR++ CodesRead scheduling lines and pack channel, month, day, year, start time, and length into the 32-bit VCR++ code, then print its decimal value.	Easy2	Bit manipulationImplementation+2	No attempts yet	1s	512 MB	Judgeable
Operation: Save the Raffle Prize! (Easy)Given a prime m and three values Seed, X1, X2, find a and c such that X1 = (aSeed + c) mod m and X2 = (aX1 + c) mod m.	Easy2	Brute forceMath+1	No attempts yet	1s	512 MB	Judgeable
TaxGiven a prize amount N, compute what the student keeps when 22% is taxed outright, and when only 22% of the remaining 20% after an 80% expense deduction is taxed.	Easy2	MathImplementation+1	No attempts yet	1s	1024 MB	Judgeable
ElevatorsGiven a zoning district and a floor count between 1 and 20, look up the required number of elevators from a fixed table.	Easy2	ImplementationBrute force+1	No attempts yet	1s	1024 MB	Judgeable
Buffon's NeedleGiven N unit-length needle segments, count how many cross a vertical line x = k, then output 2 divided by that fraction.	Easy2	GeometryImplementation+1	No attempts yet	4s	1024 MB	Judgeable
PizzaGiven n disliked topping labels and m pizzas, each a set of topping labels, count how many pizzas contain none of the disliked toppings.	Easy2	Hash mapImplementation+1	No attempts yet	1s	512 MB	Judgeable
Safe SquaresGiven an 8x8 board of rooks and empty squares, count the empty squares whose row and column both contain no rook.	Easy2	ArrayImplementation+1	No attempts yet	2s	512 MB	Judgeable
Triple TextingGiven a string formed by writing a word three times with at most one letter changed, recover the original word.	Easy2	StringImplementation	No attempts yet	2s	512 MB	Judgeable
Fifty Shades of PinkCount how many of N color names contain "pink" or "rose" ignoring case; if the count is zero, print a fixed excuse string instead.	Easy2	StringImplementation+2	No attempts yet	1s	1024 MB	Judgeable
Consonant CollapseGiven a line of lowercase letters and single spaces, collapse any run of three or more identical consonants down to two, leaving everything else unchanged.	Easy2	StringImplementation+1	No attempts yet	1s	1024 MB	Judgeable
GradingGiven counts of satisfied A, C, and E criteria, print the grade from E up to A using the half-threshold rules for D and B.	Easy2	ImplementationMath+1	No attempts yet	1s	1024 MB	Judgeable
MinigolfGiven strokes per hole, with odd holes par 2 and even holes par 3 and any hole capped at 7 strokes, print the total score relative to par.	Easy2	ImplementationMath	No attempts yet	1s	1024 MB	Judgeable
Archaeologist YerinFor each test case with a and b, compute the return value of the given triple nested loop, which equals (a+b)^2 * (a+b-1) / 2.	Easy2	MathImplementation+1	No attempts yet	1s	1024 MB	Judgeable
The Second Largest IntegerGiven three integers A, B, and C, output the second largest value among them.	Easy2	ImplementationSorting	No attempts yet	2s	1024 MB	Judgeable
JOI SortGiven a string of J, O, and I characters, rearrange it so every J precedes every O, and every O precedes every I.	Easy2	SortingImplementation+1	No attempts yet	2s	1024 MB	Judgeable
Common ElementsGiven two short integer sequences, print every value that occurs in both, once each, in ascending order.	Easy2	Hash mapSorting+1	No attempts yet	2s	1024 MB	Judgeable
Simple Operations in MatrixApply row and column addition queries to a small matrix, then print the total sum, minimum, and maximum of the final values.	Easy2	ArraySimulation+2	No attempts yet	1s	512 MB	Judgeable
Methodic MultiplicationRead two Peano-encoded natural numbers and print their product, also in Peano form.	Easy2	StringMath+2	No attempts yet	2s	1024 MB	Judgeable
New Financial YearGiven the new price P and the percent change C for each flavor, recover the original price O using the formula C = 100(P-O)/O.	Easy2	MathImplementation+1	No attempts yet	1s	512 MB	Judgeable
Missing NumberA string lists the numbers 1 to n in order with one number erased; find the missing value.	Easy2	StringImplementation+1	No attempts yet	1s	512 MB	Judgeable
Rating ProblemsGiven some judges' ratings, find the minimum and maximum possible average once the remaining judges submit ratings between -3 and 3.	Easy2	MathImplementation+1	No attempts yet	1s	512 MB	Judgeable
Curve SpeedRead radius and superelevation pairs until EOF and print the maximum curve speed from the given formula, rounded to the nearest integer.	Easy2	MathImplementation	No attempts yet	1s	1024 MB	Judgeable
Some SumGiven N consecutive positive integers picked from 1 to 100, decide whether their sum is always even, always odd, or can be either.	Easy2	MathImplementation+2	No attempts yet	1s	1024 MB	Judgeable
MeditationGiven n exercise grades, pick k distinct exercises so their sum is as large as possible.	Easy2	SortingGreedy+1	No attempts yet	1s	512 MB	Judgeable
CakesGiven how much of each of N ingredients one cake needs and how much you have, find the largest number of cakes you can bake.	Easy2	ImplementationMath+1	No attempts yet	1s	512 MB	Judgeable
Comfy DeviationsRead 10 temperatures, compute the sample standard deviation with n-1, and print COMFY if it is at most 1.0, otherwise NOT COMFY.	Easy2	MathImplementation	No attempts yet	1s	512 MB	Judgeable
Mars MessageRead N angles, map each to a hex digit by which 22.5 degree sector it falls in, pair them into ASCII codes, and print the decoded text.	Easy2	ImplementationString+2	No attempts yet	1s	1024 MB	Judgeable
Contest StrugglesGiven the average difficulty of all n problems and the average of the k solved ones, find the average of the remaining problems or report it impossible.	Easy2	MathImplementation	No attempts yet	1s	1024 MB	Judgeable
Count of Numbers 2Multiply three positive integers and count how many times each digit 0 through 9 appears in the decimal representation of the product.	Easy2	MathImplementation+1	No attempts yet	1s	128 MB	Judgeable
Air ConditionerGiven the current room temperature, a target temperature, and one of four AC modes, output the temperature after one hour of operation.	Easy2	ImplementationSimulation+2	No attempts yet	2s	1024 MB	Judgeable
Laptop StickerDecide whether a sticker fits on a laptop lid with one centimeter of margin on every side, without rotating it.	Easy2	ImplementationMath	No attempts yet	1s	1024 MB	Judgeable
K 2K GamePrint how many integers from 1 to N have a units digit different from both the units digits of K and 2K, then list those integers.	Easy2	ImplementationMath+1	No attempts yet	1s	256 MB	Judgeable
Silent AuctionGiven bids in the order they were placed, print the name of the highest bidder, breaking ties in favor of the earliest bid.	Easy2	ArrayImplementation	No attempts yet	1s	1024 MB	Judgeable
Secret InstructionsDecode a list of five-digit instructions into left or right turns with step counts, carrying the previous direction when the first two digits sum to zero.	Easy2	ImplementationSimulation+2	No attempts yet	1s	1024 MB	Judgeable
Crazy FencingGiven the left and right heights and the width of each of N trapezoidal boards, output the total area of the fence.	Easy2	MathGeometry+2	No attempts yet	1s	1024 MB	Judgeable
Bank TransferGiven the transfer amount k, compute the commission of 25 tugriks plus 1 percent of k, clamped between 100 and 2000.	Easy2	MathImplementation+1	No attempts yet	1s	512 MB	Judgeable
ChessboardGiven an m by n chessboard and the color of one cell, decide whether black, white, or neither appears more often.	Easy2	MathImplementation+1	No attempts yet	2s	512 MB	Judgeable
Kart RaceEach of n drivers reports m lap times; output the name of any driver whose total time is smallest.	Easy2	ImplementationArray	No attempts yet	2s	512 MB	Judgeable
Misha and the NegativeGiven two binary black-and-white images of the same size, count the pixels where the second image does not equal the negative of the first.	Easy2	ImplementationArray+2	No attempts yet	2s	512 MB	Judgeable
Black and White GraphicsApply a logical operation, given by a four-entry truth table, to two same-size black and white images pixel by pixel and print the result.	Easy2	ImplementationArray+2	No attempts yet	2s	512 MB	Judgeable
KeyboardGiven each key's press limit and a sequence of key presses, report for every key whether it broke.	Easy2	ArrayImplementation+1	No attempts yet	2s	512 MB	Judgeable
MonstersEach monster with k fingers can form 2^k distinct sums by lifting any subset of powers of two; output the sum of 2^ki mod 1e9+7 over all monsters.	Easy2	MathCombinatorics+2	No attempts yet	1s	512 MB	Judgeable
PalindromesRead n integers and print the sum of those that read the same forwards and backwards.	Easy2	ImplementationMath+1	No attempts yet	1s	512 MB	Judgeable
SplitGiven an even-length number, split it into two equal halves and print the two numbers.	Easy2	StringImplementation	No attempts yet	1s	512 MB	Judgeable
Basalt BreakdownGiven the area of a regular hexagon, compute its perimeter, allowing a small floating-point error.	Easy2	MathGeometry+1	No attempts yet	1s	1024 MB	Judgeable
ScrollGiven a string T and an index K, swap the case of every character from position K onward to recover the original string S.	Easy2	StringImplementation+1	No attempts yet	2s	1024 MB	Judgeable
GameGiven an n by n grid of numbers where 0 marks an empty cell, decide whether the grid is good: it has an empty cell or two side-adjacent cells with equal values.	Easy2	ImplementationMatrix+1	No attempts yet	2s	256 MB	Judgeable
Changyoung and the BusGiven a list of buses in the order they are ridden and a matrix of transfer fares, print the sum of the fares between consecutive buses.	Easy2	ImplementationArray+2	No attempts yet	2s	512 MB	Judgeable
ExamGiven the exam start and end times and the minutes Igor needs, decide whether he finishes on time, up to an hour late, or fails.	Easy2	ImplementationMath	No attempts yet	2s	256 MB	Judgeable
Pie ChartGiven n numbers and a radius r, split the circle's area into sectors proportional to each number and print every sector's area.	Easy2	MathImplementation+1	No attempts yet	2s	256 MB	Judgeable
TariffsFor each of n tariffs, compute the monthly cost from the fee plus rounded call charges, and print the index of the cheapest one.	Easy2	ImplementationBrute force+2	No attempts yet	2s	256 MB	Judgeable
Quality-Adjusted Life-YearGiven N periods, each with a quality-of-life value and a duration in years, multiply and sum to get total QALY.	Easy2	MathImplementation+2	No attempts yet	1s	512 MB	Judgeable
Splitting the BillEach of N attendees owes M/N yen; anyone with less pays everything they have. Sum the minimum of each attendee's money and the share.	Easy2	ImplementationMath+2	No attempts yet	8s	512 MB	Judgeable
Binary DivisionGiven a binary string M and an integer K, decide whether M is divisible by 2^K.	Easy2	MathString+1	No attempts yet	1s	1024 MB	Judgeable
I Don't Want to Attend a Fifth YearGiven credits and major credits already earned, plus 10 semesters of course offerings with a 6-course cap per semester, decide whether the 130 total and 66 major credit requirements can be met within 8 semesters.	Easy2	ImplementationGreedy+1	No attempts yet	1s	512 MB	Judgeable
Matrix InverseFor each 2x2 integer matrix, print its inverse over two lines with a case number, guaranteed to have integer entries.	Easy2	MathMatrix+1	No attempts yet	2s	1024 MB	Judgeable
Does Not ComputeRead arithmetic statements of the form A op B = C, check whether each result is correct, and report OKAY or DOES NOT COMPUTE per case.	Easy2	ImplementationMath+1	No attempts yet	2s	1024 MB	Judgeable
Formatting TextRead whitespace-separated tokens until END, printing each normal token followed by a space and a newline for each N token.	Easy2	StringImplementation+2	No attempts yet	2s	1024 MB	Judgeable
Knot KnowledgeGiven n knots to learn and the n-1 already learned, print the one knot still missing.	Easy2	ArrayHash map+1	No attempts yet	1s	1024 MB	Judgeable
Coding BiorhythmFor each of N dates, compute a biorhythm value from the squared digit differences of the birth date and that date, then print the earliest date with the maximum value.	Easy2	ImplementationMath+1	No attempts yet	1s	512 MB	Judgeable
Hongik Absolute GradingGiven N distinct scores, a percentage X, and a cutoff Y, count how many students get an A under relative grading (top X%) and under absolute grading (score at least Y).	Easy2	ImplementationSorting+1	No attempts yet	1s	1024 MB	Judgeable
Hongik Dance PartyGiven five lines of characters forming a 5-column-wide photograph, swap the two characters that mark the Ready to Leap and Leaping states, and print the resulting lines.	Easy2	ImplementationString+2	No attempts yet	1s	1024 MB	Judgeable
JavaScriptRead two short strings and print the JavaScript result of x - y, which is NaN if either string is not a valid number, otherwise their numeric difference.	Easy2	StringImplementation+2	No attempts yet	2s	1024 MB	Judgeable
Street Coding FighterGiven three technique difficulties, read each club's three members' usage counts, compute every club's total score, and print the maximum.	Easy2	ImplementationMath+1	No attempts yet	1s	512 MB	Judgeable
QuackQuack (Easy)Print a string of q's and a's within a 100000 step budget, where the step count depends on the exact characters chosen.	Easy2	StringImplementation	No attempts yet	1s	1024 MB	Judgeable
Dickensian DictionaryGiven a lowercase word, decide whether the hands typing its letters alternate between left and right on every step.	Easy2	StringImplementation	No attempts yet	1s	1024 MB	Judgeable
Kinder SurpriseGiven n hippo statuette names with some repeats, output how many of the n statuettes are still missing, which is n minus the number of distinct names.	Easy2	Hash mapString	No attempts yet	1s	64 MB	Judgeable
РесторанGiven a word of English capital letters that look like Russian ones, print its pronunciation using the seven letters that sound different.	Easy2	ImplementationString+1	No attempts yet	1s	1024 MB	Judgeable
Drawing Snails - Flipped LGiven a cell size N, print a flipped-L shaped snail made of five horizontal and five vertical cells.	Easy2	ImplementationSimulation	No attempts yet	1s	512 MB	Judgeable
Drawing Snail - ㄴGiven an integer N, print a snail-shaped figure made of 5 by 5 cells where each cell is N characters wide.	Easy2	ImplementationString+2	No attempts yet	1s	512 MB	Judgeable
Drawing a Snail - ㄷPrint a ㄷ-shaped snail figure where each of the 5 by 5 cells has side length N.	Easy2	ImplementationSimulation	No attempts yet	1s	512 MB	Judgeable
Drawing a Snail - Rotated RieulGiven a cell size N, print a 5 by 5 grid of cells forming a snail shape that looks like the Korean letter ㄹ rotated 90 degrees counterclockwise.	Easy2	ImplementationSimulation+1	No attempts yet	1s	512 MB	Judgeable
Drawing Snails - ㅁGiven a cell size N, print the character-shaped snail pattern made of cells on a 5 by 5 grid.	Easy2	ImplementationSimulation	No attempts yet	1s	512 MB	Judgeable
Drawing Snails - Flipped KieukGiven a cell size N, print a fixed flipped-Kieuk snail shape built from 5-by-5 cells, each cell drawn N by N.	Easy2	ImplementationSimulation	No attempts yet	1s	512 MB	Judgeable
Printing a Snail - ㅌGiven a cell size N, print a fixed snail shape (the Korean letter ㅌ) where each of the five rows is N lines tall and each cell is N characters wide.	Easy2	ImplementationSimulation	No attempts yet	1s	512 MB	Judgeable
Drawing Snail - Rotated ㅍGiven a cell size N, print a snail drawn as a 90-degree counterclockwise rotated ㅍ shape on a 5 by 5 grid, scaling each cell to N.	Easy2	ImplementationSimulation+1	No attempts yet	1s	512 MB	Judgeable
Let's Make a SASA ModelGiven N S-shaped blocks and M A-shaped blocks, find how many models can be built when each model needs 2 S blocks and 2 A blocks.	Easy2	MathImplementation+2	No attempts yet	0.5s	512 MB	Judgeable
Bishop TourGiven a board and two squares, decide whether a bishop can travel from the start square to the end square using any number of diagonal moves.	Easy2	MathImplementation+1	No attempts yet	1s	512 MB	Judgeable
Bike TourCount interior checkpoints whose height is strictly greater than both neighbors, one output line per test case.	Easy2	ArrayImplementation	No attempts yet	10s	1024 MB	Judgeable
SaturnaliaFor each message, print a case label and a three line box of '+', '-', and '\|' characters with the message padded by one space on each side.	Easy2	ImplementationString+1	No attempts yet	20s	1024 MB	Judgeable
What Makes 2021 Special?Given N, find the smallest number greater than N that is the product of two consecutive primes, such as 43 × 47 = 2021.	Easy2	MathBrute force	No attempts yet	1s	1024 MB	Judgeable
Bitaro and IOIGiven a short string over B, I, T, A, R, O, decide whether it contains the subsequence I, O, I in order.	Easy2	StringGreedy+1	No attempts yet	2s	1024 MB	Judgeable
IOI StringGiven an odd-length uppercase string S, find the minimum number of single-character changes needed to make it an alternating I/O string starting with I.	Easy2	StringImplementation+2	No attempts yet	2s	1024 MB	Judgeable
ComparisonGiven two short sequences A and B, count how many pairs (i, j) satisfy Ai <= Bj.	Easy2	Brute forceArray+1	No attempts yet	2s	1024 MB	Judgeable
Boxes and KeysCount how many of the N box labels appear among the M key labels, since each key can open any number of boxes.	Easy2	Hash mapImplementation+1	No attempts yet	2s	1024 MB	Judgeable
Moving BallsTrack where each ball ends up after a sequence of moves that relocate a named ball to a named box.	Easy2	ArraySimulation+1	No attempts yet	2s	1024 MB	Judgeable
Poster mailingGiven three paper basis weights, compute the total weight in grams of an envelope, two posters, and an info sheet from their dimensions.	Easy2	MathImplementation+1	No attempts yet	1s	1024 MB	Judgeable
Hidden WordsStarting from the first character, each letter tells how many positions ahead the next character is; output every visited character.	Easy2	StringSimulation+1	No attempts yet	2s	1024 MB	Judgeable
Tab HoppingGiven n tabs in a cycle and a sequence of tabs to visit, find the minimum total number of forward or backward steps starting from tab 1.	Easy2	SimulationImplementation+2	No attempts yet	2s	1024 MB	Judgeable
Algorithm Class - Algorithm Runtime 4For a given n, count how many times the inner statement of a nested double loop runs, and report the polynomial degree of that count.	Easy2	MathCombinatorics+2	No attempts yet	1s	512 MB	Judgeable
Algorithm Class - Algorithm Runtime 5Given n, count how many times the innermost statement of a triple nested loop runs, and print the polynomial degree of that count.	Easy2	MathImplementation+2	No attempts yet	1s	512 MB	Judgeable