Interview warm-up

Short whiteboard warmups

Under construction

Still being built. Things may change

Total results4,880 problems

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
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
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
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
Matrix Inverse
Easy2
Math, Matrix+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
Hongik Absolute Grading
Easy2
Implementation, Sorting+1
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
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
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
What Makes 2021 Special?
Easy2
Math, Brute force
No attempts yet
Time limit
1s
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
Food Delivery
Easy2
Implementation, Matrix+1
No attempts yet
Time limit
8s
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
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
Algorithm Class - Asymptotic Notation 4
Easy2
Math, Implementation+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Algorithm Class - Asymptotic Notation 6
Easy2
Math, Implementation+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Three Matches
Easy2
Implementation, Sorting+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Eye of Sauron
Easy2
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Piano Competition
Easy2
Array, Implementation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Library 2
Easy2
Stack, Simulation+1
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Fergusonball Ratings
Easy2
Implementation, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Espresso!
Easy2
Simulation, Implementation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Scaling Recipe
Easy2
Math, Implementation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Double Password
Easy2
Math, Combinatorics+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Average Character
Easy2
String, Math+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Pooling PCR Tests
Easy2
Math, Brute force
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Transporting Spaghetti
Easy2
Math, Brute force
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Beehives
Easy2
Brute force, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Saving Princess Peach
Easy2
Array, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Math Homework
Easy2
Brute force, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Friendly Rooks
Easy2
Implementation, Greedy
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Calendar of Alpha Centauri
Easy2
Math, Implementation
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Patchwork
Easy2
Simulation, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Organizing SWERC
Easy2
Array, Implementation
No attempts yet
Time limit
2s
Memory limit
2048 MB
Judgeable
Searching for Sogang's History
Easy2
Implementation, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Cake slices
Easy2
Brute force, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
November 11
Easy2
Implementation, Simulation
No attempts yet
Time limit
2s
Memory limit
1024 MB
Judgeable
Cutline
Easy2
Sorting, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Multi-Field Preference Survey (Small)
Easy2
Implementation, Brute force
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Simple Problem (Small)
Easy2
Brute force, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
AirPods
Easy2
Simulation, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Navigation
Easy2
Implementation, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Puang and Jongyun
Easy2
Math, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Odd-Even Sequence
Easy2
Sorting, Implementation
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Palindrome Sotteok-Sotteok
Easy2
String, Two pointers
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Minigames with Ims
Easy2
Hash map, Math
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Number Maximization
Easy2
Sorting, String
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Easy-to-Pronounce Words
Easy2
String, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Decimal XOR
Easy2
Implementation, Math
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Odd/Even Strings
Easy2
String, Hash map
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Presidential Election
Easy2
Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Digit Count
Easy2
Implementation, Brute force
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
A Game Called Mind
Easy2
Sorting, Array
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Parity of Strings
Easy2
Array, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
HI-ARC
Easy2
String, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Similar Phone Numbers
Easy2
String, Implementation
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Redistributing the Setting Fees
Easy2
Array, Implementation
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
HCPC 2022 Problem Setting
Easy2
Brute force, Implementation
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Finding Maximal Non-Trivial Monotones
Easy2
String, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Mentors and Mentees
Easy2
Sorting, String
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Soccer Standings
Easy2
Brute force, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Are We Stopping Again?
Easy2
Math, Implementation
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
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
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
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
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
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
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
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
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
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
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
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
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
Food DeliveryFind the weighted balance point row and column from a grid of food weights.	Easy2	ImplementationMatrix+1	No attempts yet	8s	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
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
Algorithm Class - Asymptotic Notation 4Given a quadratic f(n) and constants c, n0, decide whether f(n) <= c*n^2 holds for every n >= n0.	Easy2	MathImplementation+1	No attempts yet	1s	512 MB	Judgeable
Algorithm Class - Asymptotic Notation 6Given a quadratic f(n)=a2n^2+a1n+a0 and constants c1, c2, n0, decide whether c1n^2 <= f(n) <= c2n^2 holds for every n >= n0.	Easy2	MathImplementation+1	No attempts yet	1s	512 MB	Judgeable
Three MatchesGiven three matches on a line, find the minimum number to light so fire spreads to all, and report the shortest and longest lengths.	Easy2	ImplementationSorting+2	No attempts yet	1s	1024 MB	Judgeable
Eye of SauronGiven a string of bars surrounding a single matched pair of parentheses, decide whether the bar counts on the left and right sides are equal.	Easy2	StringImplementation+1	No attempts yet	1s	1024 MB	Judgeable
Piano CompetitionGiven N distinct judge scores, output the sum of all scores except the highest and the lowest.	Easy2	ArrayImplementation+1	No attempts yet	2s	1024 MB	Judgeable
Library 2Process a sequence of push and pop actions on a stack of book titles, printing the title each time a READ pop occurs.	Easy2	StackSimulation+1	No attempts yet	2s	1024 MB	Judgeable
Fergusonball RatingsFor each player, compute 5 times points minus 3 times fouls, count how many exceed 40, and mark the team gold if all do.	Easy2	ImplementationMath+1	No attempts yet	1s	1024 MB	Judgeable
Espresso!Given orders of 1 to 4 shots (latte adds one ounce) and a tank of s ounces, count refills needed to serve all orders in order.	Easy2	SimulationImplementation+1	No attempts yet	1s	1024 MB	Judgeable
Scaling RecipeScale each ingredient amount from a recipe that makes x portions so it makes y portions instead.	Easy2	MathImplementation+1	No attempts yet	1s	1024 MB	Judgeable
Double PasswordGiven two four-digit passwords, count how many four-digit sequences match at least one password in every digit position.	Easy2	MathCombinatorics+2	No attempts yet	1s	1024 MB	Judgeable
Average CharacterGiven a printable ASCII string, output the character whose ASCII value is the floor of the average of all characters' ASCII values.	Easy2	StringMath+1	No attempts yet	1s	1024 MB	Judgeable
Pooling PCR TestsGiven the chance p that one person tests positive, find the pool size N (2 to 16) that minimizes expected PCR tests per person, or print 1.	Easy2	MathBrute force	No attempts yet	1s	1024 MB	Judgeable
Transporting SpaghettiFind the fewest full trucks from Milan so that Mestre keeps exactly D tons and the rest, shipped in full boats, is at least C tons for Venice.	Easy2	MathBrute force	No attempts yet	1s	1024 MB	Judgeable
BeehivesGiven hive coordinates and a distance d, count the hives within d of another hive (sour) and the hives with no such neighbor (sweet).	Easy2	Brute forceMath	No attempts yet	1s	1024 MB	Judgeable
Saving Princess PeachGiven N obstacles and Mario's list of finds with repeats, print the numbers he missed in increasing order, then the count of distinct obstacles he found.	Easy2	ArrayImplementation	No attempts yet	1s	1024 MB	Judgeable
Math HomeworkGiven the leg counts b, d, c of three animal types and a total of l legs, list every count triple whose legs add up to l, or print impossible.	Easy2	Brute forceImplementation	No attempts yet	1s	1024 MB	Judgeable
Friendly RooksPlace k rooks on an n by m board so that no two rooks share a row or column, or report Impossible when that cannot be done.	Easy2	ImplementationGreedy	No attempts yet	1s	512 MB	Judgeable
Calendar of Alpha CentauriGiven a calendar with m months of d days each and a w-day week labeled a to the w-th letter, find the weekday letter for day i of month j in year k.	Easy2	MathImplementation	No attempts yet	1s	512 MB	Judgeable
PatchworkGiven an R by C quilt and a sequence of patch placements, print the final grid after each patch is stamped on and clipped at the edges.	Easy2	SimulationImplementation	No attempts yet	1s	1024 MB	Judgeable
Organizing SWERCFor each test, take the most beautiful problem at each difficulty 1 to 10 and sum the beauty, or print MOREPROBLEMS if one is missing.	Easy2	ArrayImplementation	No attempts yet	2s	2048 MB	Judgeable
Searching for Sogang's HistoryGiven current and freshman-era facility scores for campus places, find the largest increase in total score from restoring at most one place.	Easy2	ImplementationArray	No attempts yet	1s	1024 MB	Judgeable
Cake slicesGiven up to 10 cake slices, where slice i is 1/c_i of a cake, count the subsets whose total size is between 99/100 and 101/100 of a cake.	Easy2	Brute forceMath	No attempts yet	1s	1024 MB	Judgeable
November 11For each year and month, find the date that is m days before month m, day m of that year, using the calendar with leap-year rules.	Easy2	ImplementationSimulation	No attempts yet	2s	1024 MB	Judgeable
CutlineGiven N student scores, find the k-th highest score, which is the lowest score among the top k students.	Easy2	SortingArray	No attempts yet	1s	1024 MB	Judgeable
Multi-Field Preference Survey (Small)Given n student preference triples and m queries with wildcards, count the students matching each query's subject, fruit, and color.	Easy2	ImplementationBrute force	No attempts yet	1s	512 MB	Judgeable
Simple Problem (Small)Count tuples (x, y, z) within the bounds 1 to a, 1 to b, and 1 to c where x mod y, y mod z, and z mod x are all equal.	Easy2	Brute forceImplementation	No attempts yet	1s	1024 MB	Judgeable
AirPodsSimulate the AirPods battery use across N phone connections, doubling the cost on a repeat connection and resetting at 100 percent, then print the current level.	Easy2	SimulationImplementation	No attempts yet	1s	1024 MB	Judgeable
NavigationGiven N routes that pass through ordered intermediate points, find the route number with the smallest total Manhattan distance from start to end.	Easy2	ImplementationArray	No attempts yet	1s	1024 MB	Judgeable
Puang and JongyunGiven two two-digit numbers, compute their product with the Vedic method, printing the intermediate values a, b, c, d, q, r and the product's two halves.	Easy2	MathImplementation	No attempts yet	1s	1024 MB	Judgeable
Odd-Even SequenceDecide whether the sequence can be rearranged so odd positions hold sorted odd values and even positions hold sorted even values.	Easy2	SortingImplementation	No attempts yet	1s	512 MB	Judgeable
Palindrome Sotteok-SotteokGiven a string of 's' and 't', find the minimum number of single-character changes needed to make it a palindrome.	Easy2	StringTwo pointers	No attempts yet	1s	512 MB	Judgeable
Minigames with ImsCount the distinct names, then divide by the other players each game needs: 1 for Yut Nori, 2 for Find the Same Picture, 3 for One Card.	Easy2	Hash mapMath	No attempts yet	1s	512 MB	Judgeable
Number MaximizationGiven an integer of up to six digits, rearrange its digits to form the largest number possible.	Easy2	SortingString	No attempts yet	1s	1024 MB	Judgeable
Easy-to-Pronounce WordsGiven a lowercase word, print 1 if its vowels and consonants strictly alternate, and 0 otherwise.	Easy2	StringImplementation	No attempts yet	1s	1024 MB	Judgeable
Decimal XORGiven two integers up to 999,999, compute their digit-wise DEXOR, where each digit pair gives 0 if both digits are at most 2 or both are at least 7, otherwise 9.	Easy2	ImplementationMath	No attempts yet	1s	1024 MB	Judgeable
Odd/Even StringsGiven a lowercase string, decide whether every letter appears an even number of times, every letter an odd number of times, or neither.	Easy2	StringHash map	No attempts yet	1s	1024 MB	Judgeable
Presidential ElectionGiven each state's electoral votes and both candidates' vote counts, decide who wins the popular vote and who wins the electoral vote.	Easy2	Implementation	No attempts yet	1s	1024 MB	Judgeable
Digit CountGiven a range of 4-digit integers and a digit from 0 to 9, count how many times that digit appears across all numbers in the range.	Easy2	ImplementationBrute force	No attempts yet	1s	1024 MB	Judgeable
A Game Called MindGiven each player's sorted cards, print the player letter for every card in ascending order of card value.	Easy2	SortingArray	No attempts yet	1s	1024 MB	Judgeable
Parity of StringsGiven a lowercase string, decide whether every letter appears an even number of times, every letter appears an odd number of times, or neither.	Easy2	ArrayImplementation	No attempts yet	1s	1024 MB	Judgeable
HI-ARCGiven a string of uppercase letters, find how many complete sets of H, I, A, R, and C can be taken to make HI-ARC emojis.	Easy2	StringImplementation	No attempts yet	1s	1024 MB	Judgeable
Similar Phone NumbersCount the space-separated phone numbers in A that start with B and are not equal to B.	Easy2	StringImplementation	No attempts yet	1s	512 MB	Judgeable
Redistributing the Setting FeesGiven each setter's fee and the amounts they hand to others, compute the final money of all N+M staff members.	Easy2	ArrayImplementation	No attempts yet	1s	256 MB	Judgeable
HCPC 2022 Problem SettingGiven the fee for each difficulty from 1 to 5, find the maximum total fee under two limits on the weighted sum of chosen problems.	Easy2	Brute forceImplementation	No attempts yet	1s	512 MB	Judgeable
Finding Maximal Non-Trivial MonotonesGiven a string of a and b characters, count the a characters that lie in maximal runs of equal letters with length at least 2.	Easy2	StringImplementation	No attempts yet	1s	1024 MB	Judgeable
Mentors and MenteesSort mentor-mentee pairs by mentor in dictionary order, and break ties by mentee in reverse dictionary order.	Easy2	SortingString	No attempts yet	2s	256 MB	Judgeable
Soccer StandingsGiven each team's games played and points, list every win-tie-loss record that produces those points, sorted by wins in descending order.	Easy2	Brute forceImplementation	No attempts yet	1s	1024 MB	Judgeable
Are We Stopping Again?Given the trip length and the gas and food intervals in miles, count the stops made before the destination, with a shared mile counted once.	Easy2	MathImplementation	No attempts yet	1s	1024 MB	Judgeable