Curated sets
Interview warm-up
Short whiteboard tasks to get the rust off.
Total results2,493 problems
| Topics | Judge | |||||
|---|---|---|---|---|---|---|
| Polynomial Derivative (Small)Given the nonzero terms of a polynomial, compute the value of its derivative at x = 1. | Easy1 | MathImplementation+1 | No attempts yet | 1s | 128 MB | Judgeable |
| FizzBuzzPrint the numbers 1 through N, writing Fizz for multiples of X, Buzz for multiples of Y, and FizzBuzz for multiples of both. | Easy1 | ImplementationMath+2 | No attempts yet | 1s | 512 MB | Judgeable |
| Final ScoreGiven the rosters of two teams and the names of the goal scorers, count each team's goals and decide which team scored more. | Easy1 | Hash mapImplementation+1 | No attempts yet | 2s | 512 MB | Judgeable |
| Sim CardFor each student, compute the smallest total cost of call minutes and data across the three fixed operator price plans. | Easy1 | ImplementationBrute force+1 | No attempts yet | 2s | 512 MB | Judgeable |
| Vera's FashionGiven N tops and N bottoms colored 1 to N, count how many top and bottom pairs have different colors. | Easy1 | MathCombinatorics+1 | No attempts yet | 2s | 256 MB | Judgeable |
| Helmet and VestGiven a list of helmet defense values and a list of vest values, print the sum of the best helmet and the best vest. | Easy1 | ArrayImplementation+2 | No attempts yet | 1s | 512 MB | Judgeable |
| What Is Your Name Score?Given an uppercase name, sum the alphabetical position of each letter and print the total. | Easy1 | StringImplementation | No attempts yet | 1s | 128 MB | Judgeable |
| Command PromptGiven N equal-length file names, output a pattern where each position is the common character if all names agree there, or a question mark otherwise. | Easy2 | StringImplementation | No attempts yet | 2s | 128 MB | Judgeable |
| Hansu NumbersCount integers from 1 to N (N up to 1000) whose digits form an arithmetic sequence. | Easy2 | ImplementationBrute force+1 | No attempts yet | 2s | 128 MB | Judgeable |
| Make It DivisibleFind the smallest two-digit replacement (00-99) for the last two digits of N that makes N divisible by F. | Easy2 | Brute forceMath+1 | No attempts yet | 2s | 128 MB | Judgeable |
| White SquaresGiven an 8x8 board marked with pieces and empty cells, count how many pieces sit on the white squares of the standard alternating coloring. | Easy2 | ArrayImplementation+1 | No attempts yet | 2s | 128 MB | Judgeable |
| Word CountCount the number of space-separated words in a string that may have leading or trailing spaces. | Easy2 | StringImplementation | No attempts yet | 2s | 128 MB | Judgeable |
| Most Frequent LetterCount letter frequencies in a string, case-insensitively, and print the most common letter in uppercase or a question mark on ties. | Easy2 | Hash mapString+1 | No attempts yet | 2s | 128 MB | Judgeable |
| Basketball GameGiven N surnames, count first letters and print all letters (in order) that start at least five surnames, or PREDAJA if none does. | Easy2 | Hash mapImplementation+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Word SortingDeduplicate a list of words and sort them first by length, then lexicographically. | Easy2 | SortingString | No attempts yet | 2s | 256 MB | Judgeable |
| Sign of Integer SumsFor three separate lists of integers, compute each sum and print whether it is positive, negative, or zero, handling values up to 64-bit signed range. | Easy2 | ImplementationMath | No attempts yet | 2s | 256 MB | Judgeable |
| Splitting a WordSplit a lowercase word into three nonempty parts, reverse each part, and find the lexicographically smallest concatenation among all splits. | Easy2 | StringBrute force+1 | No attempts yet | 2s | 128 MB | Judgeable |
| Mobile Phone BillGiven up to 20 call durations, compute total cost under two per-block billing plans and print the cheaper one with its cost. | Easy2 | SimulationImplementation+1 | No attempts yet | 2s | 128 MB | Judgeable |
| House Number SignCompute the total width of a house-number sign given fixed per-digit widths and 1 cm margins between digits and at both ends, for each input number until 0 appears. | Easy2 | ImplementationString+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Easy Sequence SumGiven a sequence where each integer k repeats k times, compute the sum of terms between positions A and B. | Easy2 | MathSimulation+1 | No attempts yet | 2s | 128 MB | Judgeable |
| Choosing a Team NameCount letters L,O,V,E across a fixed name plus each candidate string, compute a formula mod 100, and print the candidate with the highest value, breaking ties by lexicographic order. | Easy2 | StringImplementation+1 | No attempts yet | 2s | 128 MB | Judgeable |
| TV SizeGiven a TV's diagonal length and height-to-width ratio, compute the actual height and width, flooring non-integer results. | Easy2 | MathImplementation | No attempts yet | 2s | 128 MB | Judgeable |
| Group Word CheckerCount how many of up to 100 lowercase words have every repeated character forming a single contiguous block. | Easy2 | StringImplementation | No attempts yet | 2s | 128 MB | Judgeable |
| Year Progress BarGiven a date and time string, compute what percentage of the current year (accounting for leap years) has elapsed. | Easy2 | ImplementationMath | No attempts yet | 2s | 128 MB | Judgeable |
| Actual Disk SpaceGiven N file sizes and a cluster size, compute total disk space used by rounding each file up to the nearest cluster multiple and summing. | Easy2 | MathImplementation+1 | No attempts yet | 2s | 128 MB | Judgeable |
| Yujin NumberGiven an integer up to about 2.1 billion, determine whether some split of its digits into a left and right part yields equal digit products. | Easy2 | StringBrute force+1 | No attempts yet | 2s | 128 MB | Judgeable |
| Reversed AdditionReverse the digits of two numbers up to 1000, add the reversed values, then reverse the sum and print the result. | Easy2 | MathImplementation | No attempts yet | 2s | 128 MB | Judgeable |
| PetSimulate feeding and exercising a pet's weight across scenarios and report whether it ends happy, sad, or dead based on simple weight thresholds. | Easy2 | SimulationImplementation | No attempts yet | 1s | 128 MB | Judgeable |
| Most Frequent LettersCount lowercase letter frequencies across up to 50 lines of text and print all letters tied for the highest frequency in alphabetical order. | Easy2 | Hash mapString+1 | No attempts yet | 2s | 128 MB | Judgeable |
| EarringsGiven girl names and 2n-1 confiscation/return records tagged with a number and a letter, find the girl whose number appears only once and thus never got her earring back. | Easy2 | Hash mapArray+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Floor DecorationCount the number of wooden planks by counting maximal runs of consecutive '-' in each row and '|' in each column of a grid. | Easy2 | MatrixImplementation+1 | No attempts yet | 2s | 128 MB | Judgeable |
| Song ScoresGiven cumulative durations of N song scores, answer Q queries asking which score is being sung at a given time using prefix sums and search. | Easy2 | Prefix sumBinary search+1 | No attempts yet | 2s | 128 MB | Judgeable |
| 24-Hour MissionGiven the current time and a start time in HH:MM:SS, compute the time remaining until the start time next occurs within a 24-hour cycle. | Easy2 | MathImplementation | No attempts yet | 2s | 128 MB | Judgeable |
| Sort Digits DescendingRearrange the digits of a given natural number so they appear in descending order and print the result. | Easy2 | SortingString+1 | No attempts yet | 2s | 128 MB | Judgeable |
| Organizing BooksSimulate packing books into boxes in order, sealing a box once the next book no longer fits, and sum the leftover capacity of every box. | Easy2 | SimulationImplementation+1 | No attempts yet | 2s | 128 MB | Judgeable |
| Time MachineGiven three two-digit numbers from a digital clock, count how many of the 6 permutations form a valid HH:MM:SS time. | Easy2 | CombinatoricsBrute force+1 | No attempts yet | 2s | 128 MB | Judgeable |
| Internet Cafe Seat RequestsGiven a sequence of seat requests for 100 computers, count how many requests are rejected because the requested seat is already taken. | Easy2 | SimulationArray+1 | No attempts yet | 2s | 128 MB | Judgeable |
| Room NumberGiven a room number, count how many plastic digit sets (0-9 each) are needed, treating 6 and 9 as interchangeable when flipped. | Easy2 | MathImplementation | No attempts yet | 2s | 128 MB | Judgeable |
| Adjusted AverageGiven N exam scores, rescale each by dividing by the maximum score and multiplying by 100, then output the average of the rescaled scores. | Easy2 | ArrayMath+1 | No attempts yet | 2s | 128 MB | Judgeable |
| BallTrack which of three cups covers a ball as cups swap positions M times, then output the cup number holding it. | Easy2 | SimulationImplementation | No attempts yet | 2s | 128 MB | Judgeable |
| Sequence TransformationRepeatedly replace a sequence with its adjacent differences K times and print the resulting shorter sequence. | Easy2 | ArraySimulation+1 | No attempts yet | 2s | 128 MB | Judgeable |
| Manhattan Distance on a Four-Row Number BoardGiven two numbers placed column by column in a 4-row grid, compute the Manhattan distance between their cell positions. | Easy2 | MathImplementation | No attempts yet | 2s | 128 MB | Judgeable |
| Find Places to Lie DownCount maximal horizontal and vertical runs of at least two consecutive empty cells in an N x N grid. | Easy2 | MatrixSimulation | No attempts yet | 2s | 128 MB | Judgeable |
| Trophy DisplayCount how many trophies form a visible prefix-maximum sequence when scanning the row from the left and separately from the right. | Easy2 | ArrayImplementation | No attempts yet | 2s | 128 MB | Judgeable |
| Chicken CouponsGiven n chicken coupons and a stamp-to-coupon exchange rate k, compute the maximum chickens obtainable by repeatedly redeeming stamps for new coupons. | Easy2 | MathSimulation+1 | No attempts yet | 2s | 128 MB | Judgeable |
| Growth PointsSimulate a tree that multiplies its leaves by a yearly factor then subtracts pruned branches, and report the final leaf count. | Easy2 | SimulationMath | No attempts yet | 1s | 128 MB | Judgeable |
| Next Term in a SequenceGiven a sequence that is either arithmetic or geometric, determine which type it is and output its next term. | Easy2 | MathImplementation | No attempts yet | 2s | 128 MB | Judgeable |
| Fraction SumAdd two given fractions and output the sum reduced to lowest terms using GCD. | Easy2 | MathNumber theory+1 | No attempts yet | 2s | 128 MB | Judgeable |
| Concatenating Numbers 1Compute the total digit count when integers from 1 to N are written consecutively without spaces. | Easy2 | MathImplementation | No attempts yet | 0.15s | 128 MB | Judgeable |
| Packing Books into BoxesGiven book weights in order and a per-box weight limit, compute the minimum number of boxes needed by greedily filling each box in sequence. | Easy2 | GreedyArray+1 | No attempts yet | 2s | 128 MB | Judgeable |
| Numbers With Equal Remainder and QuotientGiven N, find the sum of all positive integers x whose quotient and remainder are equal when divided by N. | Easy2 | Math | No attempts yet | 2s | 256 MB | Judgeable |
| Octopus NumbersConvert base-8 strings using nine special symbols (including one for digit -1) into their decimal integer values until a terminator line appears. | Easy2 | StringMath+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Good License PlatesFor each license plate, compute a base-26 value from the three letters and compare it to the four-digit number, printing whether their difference is within 100. | Easy2 | StringImplementation+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Fourth PointGiven two adjacent sides of a parallelogram as endpoint coordinates, compute and print the fourth vertex for each line of input. | Easy2 | GeometryMath+1 | No attempts yet | 2s | 128 MB | Judgeable |
| Making AnagramsGiven two lowercase words, compute how many letters must be deleted in total so their remaining letters match as multisets (anagrams). | Easy2 | Hash mapString | No attempts yet | 2s | 128 MB | Judgeable |
| Year 2007Given a month and day in 2007, compute and print the corresponding day of the week starting from Monday, Jan 1. | Easy2 | MathImplementation | No attempts yet | 2s | 128 MB | Judgeable |
| Least Common MultipleFor each of up to 1000 pairs of numbers, compute and print the least common multiple. | Easy2 | MathNumber theory | No attempts yet | 1s | 128 MB | Judgeable |
| Counting Pentagon PointsCompute the total pentagonal points after N steps using a simple arithmetic formula, modulo 45678. | Easy2 | MathImplementation | No attempts yet | 2s | 256 MB | Judgeable |
| Perfect SquaresGiven two numbers M and N up to 10000, sum all perfect squares in that inclusive range and print the smallest one, or -1 if none exist. | Easy2 | MathBrute force+1 | No attempts yet | 2s | 128 MB | Judgeable |
| Counting PrimesCount how many of up to 100 given numbers (each at most 1000) are prime. | Easy2 | MathBrute force | No attempts yet | 2s | 128 MB | Judgeable |
| PlugsGiven N power strips each with a plug capacity, compute the max number of computers powered when strips are chained from one wall outlet. | Easy2 | MathGreedy+1 | No attempts yet | 2s | 256 MB | Judgeable |
| Self-Replicating NumberCheck whether squaring an integer N reproduces N as the trailing digits of N squared. | Easy2 | MathImplementation | No attempts yet | 2s | 128 MB | Judgeable |
| Day of the YearGiven day, month, year, compute the day's ordinal number within that year accounting for leap years, until a 0 0 0 terminator. | Easy2 | ImplementationMath | No attempts yet | 1s | 128 MB | Judgeable |
| Number GameRepeatedly sum decimal digits of each number until one digit remains, processing lines until a terminating zero. | Easy2 | MathImplementation | No attempts yet | 2s | 128 MB | Judgeable |
| Prime WordSum letter values (a-z=1-26, A-Z=27-52) for a word and print whether the sum is prime (with 1 counted as prime). | Easy2 | StringMath+1 | No attempts yet | 2s | 128 MB | Judgeable |
| Dobby's Case-Insensitive Word TestFor each test case, output the original-cased word that is smallest in dictionary order when comparisons ignore letter case. | Easy2 | StringSorting+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Restoring NumbersFor each given integer up to 100,000, output its prime factorization as prime-exponent pairs in increasing order. | Easy2 | MathNumber theory+1 | No attempts yet | 2s | 128 MB | Judgeable |
| Sum of Consecutive IntegersGiven two integers, print the sum of all integers in the closed range between them, handling either order. | Easy2 | MathImplementation | No attempts yet | 0.25s | 128 MB | Judgeable |
| Weather Intern's Temperature SumGiven N daily temperatures, find the maximum sum over any contiguous window of exactly K days. | Easy2 | Sliding windowArray | No attempts yet | 1s | 128 MB | Judgeable |
| Right-Aligned StarsPrint N lines of right-aligned stars, where line i has i stars padded with leading spaces to align the right edge. | Easy2 | ImplementationSimulation | No attempts yet | 1s | 128 MB | Judgeable |
| Star Printing - 6Print a centered triangle of stars whose width decreases by 2 each line from 2N-1 down to 1. | Easy2 | ImplementationSimulation | No attempts yet | 1s | 128 MB | Judgeable |
| Star Printing - 8Print a diamond-like star pattern of width 2N where side star counts rise from 1 to N then fall back to 1, with spaces filling the middle. | Easy2 | ImplementationSimulation | No attempts yet | 1s | 128 MB | Judgeable |
| Intelligent TrainSimulate passengers getting off and on at four stations and output the maximum train occupancy at any point. | Easy2 | SimulationImplementation | No attempts yet | 1s | 128 MB | Judgeable |
| Intelligent Train 2Given boarding and alighting counts at 10 stations, simulate the running passenger total and print its maximum value. | Easy2 | SimulationArray | No attempts yet | 1s | 128 MB | Judgeable |
| Dice GameFor each player's three dice rolls, compute a prize using given rules and print the maximum prize among all players. | Easy2 | SimulationImplementation | No attempts yet | 1s | 128 MB | Judgeable |
| Three DiceGiven three dice values from 1 to 6, compute a prize following fixed rules for triples, pairs, or all different values. | Easy2 | Implementation | No attempts yet | 1s | 128 MB | Judgeable |
| Longest Digit RunFor three given eight-digit numbers, print the length of the longest run of identical consecutive digits in each. | Easy2 | StringImplementation | No attempts yet | 1s | 128 MB | Judgeable |
| Find the K-th DivisorGiven N and K, find and print the K-th smallest divisor of N, or 0 if it doesn't exist. | Easy2 | MathBrute force | No attempts yet | 1s | 128 MB | Judgeable |
| Score CalculationCompute a total score from a 0/1 sequence where consecutive correct answers score an increasing running count. | Easy2 | ArraySimulation+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Card GameSimulate 10 rounds of card comparisons between two players, scoring points, and determine the overall winner using the most recent non-tied round as a tiebreaker. | Easy2 | SimulationArray | No attempts yet | 1s | 128 MB | Judgeable |
| AI Oven ClockGiven a start time in hours, minutes, seconds and a duration in seconds, compute the finishing time on a 24-hour clock that wraps around. | Easy2 | MathImplementation | No attempts yet | 1s | 128 MB | Judgeable |
| Candy Teacher Go ChangyoungCheck whether the total number of candies among N students can be evenly divided among them (sum divisible by N). | Easy2 | MathImplementation | No attempts yet | 1s | 128 MB | Judgeable |
| Maximum ValueGiven a 9x9 grid of numbers, find the maximum value and print its row and column position. | Easy2 | ArrayImplementation | No attempts yet | 1s | 128 MB | Judgeable |
| Digit Counts in a ProductGiven three 3-digit natural numbers, compute their product and count how many times each digit 0 to 9 appears in it. | Easy2 | MathImplementation | No attempts yet | 1s | 128 MB | Judgeable |
| Average and ModeGiven ten natural numbers, compute and print their average and the most frequently occurring value. | Easy2 | ArrayImplementation | No attempts yet | 1s | 128 MB | Judgeable |
| VirusCount how many computers other than computer 1 lie in computer 1's connected component of a small undirected graph. | Easy2 | GraphBFS+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Greatest Common Divisor and Least Common MultipleGiven two natural numbers up to 10000, output their greatest common divisor and least common multiple. | Easy2 | MathNumber theory | No attempts yet | 1s | 128 MB | Judgeable |
| Coin GameCount occurrences of each of 8 possible length-3 head/tail patterns among all consecutive triples in a 40-character coin toss string, for multiple test cases. | Easy2 | StringImplementation | No attempts yet | 1s | 128 MB | Judgeable |
| Third Largest NumberFor each test case of 10 positive integers, output the third largest distinct-position value in the array. | Easy2 | SortingArray | No attempts yet | 1s | 32 MB | Judgeable |
| CryptoquoteDecode each ciphertext message by substituting letters using a given 26-letter mapping while preserving spaces. | Easy2 | StringImplementation | No attempts yet | 1s | 128 MB | Judgeable |
| U.S. Unit ConversionConvert given values between kilograms/pounds and liters/gallons using fixed conversion factors, rounding to four decimal places. | Easy2 | ImplementationMath | No attempts yet | 1s | 128 MB | Judgeable |
| Laundry Owner DonghyukGiven a number of cents, output the minimum count of quarters, dimes, nickels, and pennies using a greedy coin breakdown. | Easy2 | GreedyMath+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Binary AdditionAdd two binary strings up to length 80 for multiple test cases and print the sum without leading zeros. | Easy2 | StringSimulation+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Matrix MultiplicationRead two matrices of bounded size and print their standard matrix product. | Easy2 | MatrixImplementation | No attempts yet | 1s | 128 MB | Judgeable |
| Base ConversionConvert a number given in an arbitrary base (2 to 36, using letters for digits above 9) into its decimal value. | Easy2 | MathImplementation+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Fibonacci Number 2Compute the nth Fibonacci number for n up to 90. | Easy2 | Dynamic programmingMath | No attempts yet | 1s | 128 MB | Judgeable |
| What Is This Semester's GPA?Compute a weighted GPA from a list of courses, credits, and letter grades, rounded to two decimal places. | Easy2 | ImplementationMath | No attempts yet | 1s | 128 MB | Judgeable |
| Triangular Gimbap Price ComparisonGiven several price rates for gimbap, compute the cheapest cost to buy exactly 1000 grams using the best per-gram rate among all stores. | Easy2 | MathGreedy+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Score CalculationGiven 8 distinct problem scores, output the sum of the top 5 and their original indices in increasing order. | Easy2 | SortingArray+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Sugar DeliveryFind the minimum number of 3kg and 5kg bags that sum to exactly N kilograms, or -1 if impossible. | Easy2 | GreedyMath | No attempts yet | 1s | 128 MB | Judgeable |