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Total results2,362 problems

Operation: Save the Raffle Prize! (Easy)
Easy2
Brute force, Math+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Tax
Easy2
Math, Implementation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Elevators
Easy2
Implementation, Brute force+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Buffon's Needle
Easy2
Geometry, Implementation+1
No attempts yet
Time limit
4s
Memory limit
1024 MB
Judgeable
Pizza
Easy2
Hash map, Implementation+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Safe Squares
Easy2
Array, Implementation+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Triple Texting
Easy2
String, Implementation
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Fifty Shades of Pink
Easy2
String, Implementation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Consonant Collapse
Easy2
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Grading
Easy2
Implementation, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Volleyball Match
Easy2
Simulation, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Minigolf
Easy2
Implementation, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Archaeologist Yerin
Easy2
Math, Implementation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
The Second Largest Integer
Easy2
Implementation, Sorting
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
JOI Sort
Easy2
Sorting, Implementation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Common Elements
Easy2
Hash map, Sorting+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Simple Operations in Matrix
Easy2
Array, Simulation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Methodic Multiplication
Easy2
String, Math+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
New Financial Year
Easy2
Math, Implementation+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Missing Number
Easy2
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Rating Problems
Easy2
Math, Implementation+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Curve Speed
Easy2
Math, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Some Sum
Easy2
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Meditation
Easy2
Sorting, Greedy+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Cakes
Easy2
Implementation, Math+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Comfy Deviations
Easy2
Math, Implementation
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Mars Message
Easy2
Implementation, String+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Contest Struggles
Easy2
Math, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Making a Cipher
Easy2
String, Implementation
No attempts yet
Time limit
0.5s
Memory limit
256 MB
Judgeable
Count of Numbers 2
Easy2
Math, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Air Conditioner
Easy2
Implementation, Simulation+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Laptop Sticker
Easy2
Implementation, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
K 2K Game
Easy2
Implementation, Math+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Silent Auction
Easy2
Array, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Secret Instructions
Easy2
Implementation, Simulation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Crazy Fencing
Easy2
Math, Geometry+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Bank Transfer
Easy2
Math, Implementation+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Chessboard
Easy2
Math, Implementation+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Kart Race
Easy2
Implementation, Array
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Misha and the Negative
Easy2
Implementation, Array+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Black and White Graphics
Easy2
Implementation, Array+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Keyboard
Easy2
Array, Implementation+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Monsters
Easy2
Math, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Palindromes
Easy2
Implementation, Math+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Split
Easy2
String, Implementation
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Basalt Breakdown
Easy2
Math, Geometry+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Scroll
Easy2
String, Implementation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Game
Easy2
Implementation, Matrix+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Changyoung and the Bus
Easy2
Implementation, Array+2
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Exam
Easy2
Implementation, Math
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Pie Chart
Easy2
Math, Implementation+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Tariffs
Easy2
Implementation, Brute force+2
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Quality-Adjusted Life-Year
Easy2
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Splitting the Bill
Easy2
Implementation, Math+2
No attempts yet
Time limit
8s
Memory limit
512 MB
Judgeable
Binary Division
Easy2
Math, String+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
I Don't Want to Attend a Fifth Year
Easy2
Implementation, Greedy+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Matrix Inverse
Easy2
Math, Matrix+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Does Not Compute
Easy2
Implementation, Math+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Formatting Text
Easy2
String, Implementation+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Knot Knowledge
Easy2
Array, Hash map+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Coding Biorhythm
Easy2
Implementation, Math+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Hongik Absolute Grading
Easy2
Implementation, Sorting+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Hongik Dance Party
Easy2
Implementation, String+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
JavaScript
Easy2
String, Implementation+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Street Coding Fighter
Easy2
Implementation, Math+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
QuackQuack (Easy)
Easy2
String, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Dickensian Dictionary
Easy2
String, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Kinder Surprise
Easy2
Hash map, String
No attempts yet
Time limit
1s
Memory limit
64 MB
Judgeable
Ресторан
Easy2
Implementation, String+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Drawing Snails - Flipped L
Easy2
Implementation, Simulation
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Drawing Snail - ㄴ
Easy2
Implementation, String+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Drawing a Snail - ㄷ
Easy2
Implementation, Simulation
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Drawing a Snail - Rotated Rieul
Easy2
Implementation, Simulation+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Drawing Snails - ㅁ
Easy2
Implementation, Simulation
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Drawing Snails - Flipped Kieuk
Easy2
Implementation, Simulation
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Printing a Snail - ㅌ
Easy2
Implementation, Simulation
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Drawing Snail - Rotated ㅍ
Easy2
Implementation, Simulation+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Let's Make a SASA Model
Easy2
Math, Implementation+2
No attempts yet
Time limit
0.5s
Memory limit
512 MB
Judgeable
Bishop Tour
Easy2
Math, Implementation+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Bike Tour
Easy2
Array, Implementation
No attempts yet
Time limit
10s
Memory limit
1024 MB
Judgeable
Saturnalia
Easy2
Implementation, String+1
No attempts yet
Time limit
20s
Memory limit
1024 MB
Judgeable
What Makes 2021 Special?
Easy2
Math, Brute force
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Bitaro and IOI
Easy2
String, Greedy+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
IOI String
Easy2
String, Implementation+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Comparison
Easy2
Brute force, Array+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Boxes and Keys
Easy2
Hash map, Implementation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Moving Balls
Easy2
Array, Simulation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Poster mailing
Easy2
Math, Implementation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Hidden Words
Easy2
String, Simulation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Tab Hopping
Easy2
Simulation, Implementation+2
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Algorithm Class - Algorithm Runtime 4
Easy2
Math, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Algorithm Class - Algorithm Runtime 5
Easy2
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Algorithm Class - Algorithm Runtime 6
Easy2
Math, Combinatorics+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Numbers Between Characters
Easy2
String, Implementation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
ПЪТУВАНЕ
Easy2
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Algorithm Class - Asymptotic Notation 1
Easy2
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Making Change
Easy2
Greedy, Math+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Meeting of Friends
Easy2
Math, Intervals+1
No attempts yet
Time limit
0.1s
Memory limit
1024 MB
Judgeable
Clock
Easy2
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Minesweeper
Easy2
Implementation, Array+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
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
Volleyball MatchGiven the winner of each rally, simulate a best-of-3 volleyball match with win-by-2 set rules and print the number of sets each team won.	Easy2	SimulationImplementation	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
Making a CipherGiven strings A and P, find a string B of length at most 100 so that P is the only length-\|P\| substring that A and B share.	Easy2	StringImplementation	No attempts yet	0.5s	256 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
Algorithm Class - Algorithm Runtime 6Count how many times the triple nested loop runs for a given n, then report the polynomial degree of that count.	Easy2	MathCombinatorics+1	No attempts yet	1s	512 MB	Judgeable
Numbers Between CharactersRead an integer N and a four-character string, then print N times each digit found, or N/A if there are no digits.	Easy2	StringImplementation+1	No attempts yet	2s	1024 MB	Judgeable
ПЪТУВАНЕGiven a conference start time and fixed activity durations, compute the latest departure time so the group arrives at least 10 minutes early.	Easy2	MathImplementation+2	No attempts yet	1s	1024 MB	Judgeable
Algorithm Class - Asymptotic Notation 1Given f(n) = a1n + a0 and constants c and n0, decide whether f(n) <= cn holds for every n >= n0.	Easy2	MathImplementation+2	No attempts yet	1s	512 MB	Judgeable
Making ChangeFor each pair of cost and payment amounts, compute the change and break it into the fewest $50, $20, $10, $5, and $1 bills.	Easy2	GreedyMath+2	No attempts yet	1s	1024 MB	Judgeable
Meeting of FriendsGiven two available time intervals and one minute when the second friend is busy, count the minutes both are free at the same time.	Easy2	MathIntervals+1	No attempts yet	0.1s	1024 MB	Judgeable
ClockGiven a start time and an end time on a 24-hour clock, compute the elapsed minutes (less than a day) and the number of full 30-minute laps.	Easy2	MathImplementation+2	No attempts yet	1s	1024 MB	Judgeable
MinesweeperGiven a 3x3 grid marking bombs with 9, replace each non-bomb cell with the count of bombs in its up to eight neighboring cells.	Easy2	ImplementationArray+2	No attempts yet	1s	1024 MB	Judgeable