Curated sets
Interview warm-up
Short whiteboard tasks to get the rust off.
Total results2,493 problems
| Topics | Judge | |||||
|---|---|---|---|---|---|---|
| MarathonerCount the listed students who finished within 6 hours and report the fastest one, breaking ties by race result order. | Easy2 | ImplementationHash map | No attempts yet | 2s | 64 MB | Judgeable |
| Sequence Folding GameRepeatedly fold the list by adding symmetric pairs until two numbers remain, then Alice wins when the first is larger. | Easy2 | SimulationArray | No attempts yet | 1s | 128 MB | Judgeable |
| Triangle ClassificationFor each of T triples of side lengths, output whether it is equilateral, isosceles, scalene, or not a triangle. | Easy2 | Implementation | No attempts yet | 1s | 128 MB | Judgeable |
| Arbiter LoginGiven the original and entered passwords, report login success or hint at a caps lock or num lock mistake. | Easy2 | StringImplementation | No attempts yet | 1s | 128 MB | Judgeable |
| Zombie InvasionProcess villages east to west, moving half of each village west and leaving at most one behind, with everything gathering on the west coast. | Easy2 | SimulationMath | No attempts yet | 2s | 128 MB | Judgeable |
| Arrangement of ContestCount the titles that form the longest unbroken run from A onward, using each title's first letter and stopping at the first missing letter. | Easy2 | GreedyString+1 | No attempts yet | 2s | 256 MB | Judgeable |
| BoxesBoxes fall straight down in each column of a grid, and the program sums how many cells all boxes move. | Easy2 | SimulationMatrix | No attempts yet | 1s | 256 MB | Judgeable |
| Text RollSimulate a ball that rolls right over non-space characters and drops down through spaces until it falls off the last line, then report its exit column. | Easy2 | Simulation | No attempts yet | 1s | 128 MB | Judgeable |
| Perfect Number CheckDecide whether each given integer equals the sum of its proper divisors and print the equation or a negative verdict. | Easy2 | Number theoryImplementation | No attempts yet | 2s | 128 MB | Judgeable |
| I Love CroatiaTrack the 210 seconds of answers and pass the bomb left on each correct answer to find who holds it when it explodes. | Easy2 | Simulation | No attempts yet | 1s | 128 MB | Judgeable |
| Roman Catholic MassThe program seats the latecomer in the empty spot with the most occupied neighbors and counts every adjacent occupied pair once. | Easy2 | Brute forceMatrix+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Presidential ElectionEach voter ranks all candidates, and the program counts first-choice votes and then a top-two runoff to report the winner and the deciding round. | Easy2 | SimulationImplementation | No attempts yet | 1s | 128 MB | Judgeable |
| Contest Venue SetupCount the schools that have two of their teams seated in king-adjacent cells of an N by M grid with empty seats. | Easy2 | MatrixImplementation | No attempts yet | 1s | 128 MB | Judgeable |
| Combination LockCount distinct triples of dial positions within circular distance 2 of either of two given combinations. | Easy2 | Brute forceMath | No attempts yet | 1s | 128 MB | Judgeable |
| VicinityFor each query, count how many of the n points lie within distance d_v of the chosen base point, excluding the base point itself. | Easy2 | Brute forceGeometry | No attempts yet | 1s | 128 MB | Judgeable |
| Stone Game 5Two players alternately take 1 or 3 stones from a pile of N, and the program prints SK or CY for optimal play. | Easy2 | Game theoryMath | No attempts yet | 1s | 128 MB | Judgeable |
| Show Me The OperatorsEvaluate each space-separated expression in two left-to-right sweeps and print the operators in execution order with the final value. | Easy2 | SimulationImplementation | No attempts yet | 1s | 128 MB | Judgeable |
| Anti-Arithmetic PermutationFor each permutation of 0 to n-1, decide whether any three terms in order form an arithmetic progression. | Easy2 | Brute forceMath | No attempts yet | 1s | 128 MB | Judgeable |
| Fibonacci remainderFor each test case, compute the P-th Fibonacci number of the sequence starting 1, 1 modulo Q and print it as Case #x: M. | Easy2 | MathSimulation | No attempts yet | 1s | 128 MB | Judgeable |
| Word SearchingCount case-sensitive overlapping occurrences of a given word, each fully inside one line of the following text. | Easy2 | String matchingString | No attempts yet | 1s | 128 MB | Judgeable |
| Jane's First WordsCheck each input word against the pattern da+dd?(i|y) and print whether Jane called for daddy or is cooing. | Easy2 | String matchingString | No attempts yet | 1s | 128 MB | Judgeable |
| Rectangle intersectionCompute the area shared by all n axis-aligned rectangles, or 0 when they do not all overlap. | Easy2 | GeometryIntervals | No attempts yet | 2s | 512 MB | Judgeable |
| CipherDecrypt a Caesar-shifted message by trying all 26 shifts and picking the one where both CHIPMUNKS and LIVE appear. | Easy2 | Brute forceString | No attempts yet | 2s | 512 MB | Judgeable |
| EuclidRead two positive integers up to 32767 and print their greatest common divisor. | Easy2 | Number theory | No attempts yet | 2s | 512 MB | Judgeable |
| LampGuards patrol in roster order, each toggling the lamps in one arithmetic progression, and you report how many lamps stay on. | Easy2 | SimulationArray | No attempts yet | 1s | 128 MB | Judgeable |
| Maximum FrequencyGiven N integers, count how many times each value appears and print the largest count. | Easy2 | Hash mapArray | No attempts yet | 2s | 1024 MB | Judgeable |
| Zeros in a FactorialCount how many zero digits appear in the decimal representation of n factorial for a given n below 100. | Easy2 | MathImplementation | No attempts yet | 1s | 128 MB | Judgeable |
| RouteCount the maximal runs of level, uphill, and downhill metre sections along the looped jogging route starting at pole 1. | Easy2 | ArrayImplementation | No attempts yet | 2s | 1024 MB | Judgeable |
| The Euclidean AlgorithmCount how many subtraction steps the original Euclidean algorithm needs to find the gcd of two integers up to 32767. | Easy2 | SimulationMath | No attempts yet | 1s | 128 MB | Judgeable |
| Word PuzzleDecide for each pair of strings whether the gathered letters can be rearranged to form the original word. | Easy2 | Hash mapString | No attempts yet | 3s | 256 MB | Judgeable |
| Cedric's cypherDecrypt each Caesar-ciphered line using the trailing encrypted A to recover the shift and drop that marker. | Easy2 | StringImplementation | No attempts yet | 1s | 128 MB | Judgeable |
| The Hardest Problem EverDecode each START/END block by shifting every uppercase letter five places back and leaving other characters unchanged. | Easy2 | StringImplementation | No attempts yet | 1s | 128 MB | Judgeable |
| VoteEach judge votes for the most interesting game they can afford, and the game with the most votes wins. | Easy2 | SimulationArray | No attempts yet | 1s | 128 MB | Judgeable |
| Party InvitationSimulate m rounds of removing every person at a multiple of ri from the ordered list and print the survivors in order. | Easy2 | SimulationArray | No attempts yet | 2s | 256 MB | Judgeable |
| Mirror TenderDecide for each test case whether one workshop's width and height ranges contain every other workshop's ranges. | Easy2 | Intervals | No attempts yet | 1s | 256 MB | Judgeable |
| Microwave ButtonsPress the 5-minute, 1-minute, and 10-second buttons to total exactly T seconds with the fewest presses, or print -1 when impossible. | Easy2 | GreedyMath | No attempts yet | 1s | 64 MB | Judgeable |
| Palindrome LinesDecide for each of n short lines whether it reads the same forward and backward, ignoring letter case. | Easy2 | Two pointersString | No attempts yet | 1s | 256 MB | Judgeable |
| Magic SquaresCheck each test case square by comparing every row, column, and both diagonal sums and report whether it is magic. | Easy2 | MatrixSimulation | No attempts yet | 1s | 256 MB | Judgeable |
| Clean UpRecompute each of the nine batting averages after adding the new series and reorder the lineup around the new best average. | Easy2 | SimulationImplementation | No attempts yet | 1s | 256 MB | Judgeable |
| Odysseus and the SirensThe program scores every melody under each candidate key by summing note penalties and prints the numbered key with the smallest total. | Easy2 | ImplementationString+1 | No attempts yet | 1s | 256 MB | Judgeable |
| Milo of Croton and the CalfSimulate Milo lifting the calf as it gains a pound a day, with strength gains after 3 days and soreness lasting 2 days, and report the first failure day. | Easy2 | Simulation | No attempts yet | 1s | 256 MB | Judgeable |
| Dice GameEach player rolls two dice with consecutive face ranges and the larger total wins, so compute both win probabilities from the four ranges. | Easy2 | ProbabilityBrute force | No attempts yet | 1s | 256 MB | Judgeable |
| Train PassengersDecide if per-station counts of passengers leaving, boarding, and left waiting fit the train capacity and boarding rules. | Easy2 | SimulationImplementation | No attempts yet | 1s | 256 MB | Judgeable |
| HeadshotAfter a click on a circular cylinder, compare firing at once against spinning first and print which choice is safer. | Easy2 | ProbabilityString | No attempts yet | 1s | 64 MB | Judgeable |
| Radix 32 ConversionConvert each base-32 string of up to 8 digits to its decimal value and to binary by expanding every digit to 5 bits. | Easy2 | MathString | No attempts yet | 1s | 64 MB | Judgeable |
| Alarm ClockPrint the earliest hh:mm time whose four digits use exactly n lit segments, or Impossible when no such time exists. | Easy2 | Brute forceImplementation | No attempts yet | 2s | 256 MB | Judgeable |
| Pangram CheckerCount how many times each English letter appears in every sentence and print its pangram grade. | Easy2 | StringHash map | No attempts yet | 3s | 256 MB | Judgeable |
| Queens on Bad TermsCheck an 8x8 board holding eight queens and print valid only when no two queens share a row, column, or diagonal. | Easy2 | ImplementationMatrix | No attempts yet | 1s | 256 MB | Judgeable |
| Hitting the TargetsCount, for each of up to 100 shot points, how many of up to 30 given rectangles and circles contain it, boundaries included. | Easy2 | GeometryImplementation | No attempts yet | 2s | 256 MB | Judgeable |
| The Wet KeypadGiven a permuted phone keypad, encode a message of up to 100 letters into multi-tap presses with # separators. | Easy2 | ImplementationSimulation | No attempts yet | 1s | 32 MB | Judgeable |
| Most Chosen NumberPick the number that appears most often in each test case, breaking ties by the smaller number. | Easy2 | ArrayImplementation | No attempts yet | 5s | 256 MB | Judgeable |
| Closest Web Color NameThe program maps each RGB triple to the closest of 16 named HTML colors by Euclidean distance, breaking ties by table order. | Easy2 | Brute forceMath | No attempts yet | 2s | 256 MB | Judgeable |
| Crossword Clue NumberingScan the grid for empty cells that begin a word of at least three cells across or down and print them in reading order. | Easy2 | ImplementationMatrix | No attempts yet | 1s | 256 MB | Judgeable |
| Cow RoutingFind the cheapest single flight route on which city A appears before city B, or report -1 when none exists. | Easy2 | ImplementationArray | No attempts yet | 1s | 256 MB | Judgeable |
| Paprika ID CardsSimulate one left-to-right pass of conditional card swaps, then count paprikas whose final card matches their goal. | Easy2 | SimulationArray | No attempts yet | 1s | 256 MB | Judgeable |
| Weather ForecasterClouds drift east one cell per minute, and each cell reports how many minutes until a cloud first arrives, or -1 if none ever does. | Easy2 | SimulationArray | No attempts yet | 1s | 256 MB | Judgeable |
| Canteen CheckoutChoose the number of fixed-price 4-item set menus that minimizes the total bill for the tray. | Easy2 | Brute forceMath | No attempts yet | 1s | 64 MB | Judgeable |
| Wait TimeReconstruct message timestamps from the log and sum each friend reply wait time, reporting -1 for a friend with an unanswered message. | Easy2 | SimulationHash map | No attempts yet | 1s | 256 MB | Judgeable |
| Rotating the basket orderPerform M given segment rotations on baskets numbered 1 to N and print the final left-to-right order. | Easy2 | SimulationArray | No attempts yet | 1s | 256 MB | Judgeable |
| BeltsGiven each belt rotation ratio and twist, compute the last wheel speed and direction when the first wheel turns clockwise once per minute. | Easy2 | SimulationMath | No attempts yet | 1s | 256 MB | Judgeable |
| Counting FriendsCount the friends of each of N students from M mutual friendship pairs and print the N totals. | Easy2 | GraphArray | No attempts yet | 1s | 256 MB | Judgeable |
| Divide the land into trianglesSort all pegs by x then y, split the order into consecutive triples, and print each triple's input numbers in increasing order. | Easy2 | Sorting | No attempts yet | 1s | 16 MB | Judgeable |
| Veni, vidi, viciDrop the last letter of each odd-length ciphertext, then decode every letter pair into one plain letter with the given key. | Easy2 | StringMath | No attempts yet | 1s | 256 MB | Judgeable |
| Best guess in the random gamePick the number from 1 to N whose interval of radius K covers the most hidden values and report its coverage count. | Easy2 | MathIntervals | No attempts yet | 1s | 256 MB | Judgeable |
| Base Conversion 2Convert the decimal number N to base B, writing digits above 9 as uppercase letters. | Easy2 | MathImplementation | No attempts yet | 0.5s | 256 MB | Judgeable |
| Inverse Move-to-Front TransformReconstruct the lowercase string from its move-to-front code by simulating the 26-letter list. | Easy2 | SimulationArray | No attempts yet | 2s | 256 MB | Judgeable |
| Spring 2005: Arriving at USCFilter the building list to names that hold the abbreviation letters as a case-insensitive subsequence and print the matches in input order. | Easy2 | Two pointersString matching | No attempts yet | 1s | 256 MB | Judgeable |
| Sieve of EratosthenesSimulate the sieve of Eratosthenes as described and print the K-th crossed-out number for each N and K pair. | Easy2 | SimulationImplementation | No attempts yet | 1s | 256 MB | Judgeable |
| ICPC CalculatorEvaluate a dot-indented prefix expression where + sums its operands and * multiplies them. | Easy2 | RecursionTree+1 | No attempts yet | 1s | 256 MB | Judgeable |
| Pattern Word BankingAdd the PIN digits picked by lowercase pattern letters and print non sequitur if the letter values do not match the PIN length. | Easy2 | SimulationString | No attempts yet | 2s | 256 MB | Judgeable |
| Secret MessagePad each message with asterisks to a square, rotate the square 90 degrees clockwise, then read it row by row without asterisks. | Easy2 | MatrixSimulation | No attempts yet | 2s | 256 MB | Judgeable |
| Letter CookiesGiven the letters in a box, decide for each query word whether its letters can all be taken from the box. | Easy2 | Hash mapString | No attempts yet | 1s | 256 MB | Judgeable |
| Negative People in Da HouseGiven each test case's sequence of entries and exits, compute the smallest initial occupancy that keeps the count nonnegative throughout. | Easy2 | Prefix sumSimulation | No attempts yet | 1s | 256 MB | Judgeable |
| ElectionFor each test case, count how many coins overlap each coin and print the top name or TIE on ties. | Easy2 | GeometryBrute force+1 | No attempts yet | 1s | 256 MB | Judgeable |
| Reverse the Binary DigitsRead N, write it in binary without leading zeros, reverse the digits, and print the reversed string as a decimal number. | Easy2 | Bit manipulationMath | No attempts yet | 1s | 256 MB | Judgeable |
| Toilet Seat PoliciesCount seat moves under leave-up, leave-down, and leave-as-preferred policies given the initial seat position and each person in order. | Easy2 | Simulation | No attempts yet | 1s | 256 MB | Judgeable |
| Flag QuizPrint the alternatives whose maximum position-wise difference to any other alternative is smallest. | Easy2 | Brute forceArray | No attempts yet | 1s | 256 MB | Judgeable |
| Choosing an Exam SetYou compare exam sets by random-guess expected score and pick the highest, preferring fewer questions then the smaller number. | Easy2 | ImplementationMath | No attempts yet | 1s | 256 MB | Judgeable |
| ITAI VirusCount the initially infected cities plus every city directly joined to one by a single road. | Easy2 | GraphImplementation | No attempts yet | 1s | 256 MB | Judgeable |
| Creature Number SystemsConvert each given decimal number up to 5000 into the creature's base between 2 and 20, using letters A to J for digits above 9. | Easy2 | MathImplementation | No attempts yet | 1s | 256 MB | Judgeable |
| CypherDecrypt each message line by shifting its lowercase letters back by the Caesar shift computed from its date. | Easy2 | StringMath | No attempts yet | 1s | 256 MB | Judgeable |
| SolitaireSimulate token moves on cells 0 to N with a repeating six-roll generator and sum landed values until reaching N. | Easy2 | Simulation | No attempts yet | 1s | 256 MB | Judgeable |
| Coverity CrosswordDecide whether every listed word appears horizontally, vertically, or diagonally in an 8 by 8 letter grid. | Easy2 | String matchingMatrix+1 | No attempts yet | 2s | 256 MB | Judgeable |
| Eakspay igpay atinlay?Translate each phrase into Pig Latin by moving each leading consonant cluster to the end with ay, or adding yay after vowel-initial words. | Easy2 | StringImplementation | No attempts yet | 1s | 256 MB | Judgeable |
| Crushing ConfectionsFind the lexicographically smallest row or column triple of equal candies in each grid and print its positions. | Easy2 | MatrixImplementation | No attempts yet | 1s | 256 MB | Judgeable |
| The Big Eye in the SkyFor each point in the first quadrant, print its angle from the positive x-axis in degrees, rounded to the nearest integer. | Easy2 | MathGeometry | No attempts yet | 1s | 256 MB | Judgeable |
| Mr. Gorbachev, Tear Down This Wall!Add up the lengths of the axis-aligned wall segments and report the total work hours split across the workers, rounded up. | Easy2 | MathImplementation | No attempts yet | 1s | 256 MB | Judgeable |
| Distribution in MetagoniaRepeatedly peel off 2^a times the largest power of 3 fitting the odd part of the remainder until it hits zero, then print the pieces sorted. | Easy2 | SimulationMath+1 | No attempts yet | 2s | 256 MB | Judgeable |
| Lucky ChancesCount over every grid cell how many of the four directions contain only smaller numbers or reach the edge. | Easy2 | Brute forceMatrix+1 | No attempts yet | 2s | 256 MB | Judgeable |
| Spin the number wheelCount the wheel positions where the M digits read clockwise form a number between X and Y. | Easy2 | Brute forceString | No attempts yet | 1s | 256 MB | Judgeable |
| Hidden PasswordDecide if scanning the message and skipping letters outside the remaining password set reproduces the password in order. | Easy2 | SimulationString | No attempts yet | 1s | 256 MB | Judgeable |
| D as in DaedalusGiven each round budget and the cards played, compute the extra points the first player could have won by playing the best card each round. | Easy2 | Simulation | No attempts yet | 3s | 256 MB | Judgeable |
| Base ConversionConvert the given number written in base A into base B and print its digits separated by spaces. | Easy2 | MathImplementation | No attempts yet | 2s | 256 MB | Judgeable |
| Marko's T9 inputCount how many dictionary words map letter by letter to the given T9 digit string. | Easy2 | StringHash map | No attempts yet | 2s | 64 MB | Judgeable |
| Egg Drop LogFrom the logged safe and broken drops, compute the lowest floor that could break and the highest floor that could stay safe. | Easy2 | IntervalsImplementation | No attempts yet | 2s | 256 MB | Judgeable |
| Stand on ZanzibarThe program adds yearly increases beyond twice the previous count to bound the number of imported turtles. | Easy2 | MathImplementation | No attempts yet | 1s | 256 MB | Judgeable |
| Cities Alice has visitedCount how many different city names appear in each trip log. | Easy2 | Hash map | No attempts yet | 1s | 256 MB | Judgeable |
| Identifying Map TilesConvert a map tile quadkey into its zoom level and x and y coordinates. | Easy2 | Bit manipulationString | No attempts yet | 1s | 256 MB | Judgeable |
| Dice CupFind the most likely sums of an N-sided and an M-sided die, printing every tied sum from lowest to highest. | Easy2 | Brute forceMath | No attempts yet | 1s | 256 MB | Judgeable |
| Easy ProblemsetSimulate judges proposing problems in turn and keep each proposal whose hardness reaches the running total until k problems are chosen. | Easy2 | Simulation | No attempts yet | 1s | 256 MB | Judgeable |