Problems
Pick a problem and write your solution in the built-in editor. The judge runs it against real test cases while you watch, and the wider archive is open to read whenever you like.
Total results2,994 problems
| Title | Level | Topics | Solved | Time limit | Memory limit | Judge |
|---|---|---|---|---|---|---|
| HardwareExpand each house-number order into individual numbers, count how many times each digit 0-9 appears, and print the per-digit totals plus the grand total. | Easy3 | SimulationImplementation+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Add Backward NumbersAdd two numbers whose digits are given in reverse order, printing the sum with its digits also reversed and no leading zeroes. | Easy3 | MathString+2 | No attempts yet | 1s | 128 MB | Judgeable |
| Chances of WinningGiven results of some games among four teams, count the outcomes of the remaining games where team T ends with strictly more points than every other team. | Easy3 | Brute forceImplementation+2 | No attempts yet | 1s | 128 MB | Judgeable |
| Who Has Seen the WindGiven humidity h and a time limit M, evaluate the quartic altitude formula hour by hour and report the first hour the balloon's altitude drops to zero or below. | Easy3 | MathSimulation+2 | No attempts yet | 2s | 512 MB | Judgeable |
| Up and DownTwo walkers repeat a forward/backward step cycle; after s steps, report whose distance from the start is greater, or Tied. | Easy3 | SimulationMath+2 | No attempts yet | 2s | 512 MB | Judgeable |
| PunchySimulate a tiny two-variable language, running the given instructions in order until a stop opcode, and print each requested variable value. | Easy3 | SimulationImplementation+1 | No attempts yet | 2s | 512 MB | Judgeable |
| SignageGiven a sign width, lay out a fixed sentence into lines, justifying each line so spaces are spread as evenly as possible, and print dots for spaces. | Easy3 | StringSimulation+2 | No attempts yet | 1s | 128 MB | Judgeable |
| GPS Text EntryGiven a fixed 5x6 letter grid, compute the total cursor moves to type a string starting from 'A' and then reach 'enter'. | Easy3 | ImplementationSimulation+2 | No attempts yet | 1s | 128 MB | Judgeable |
| Cell-Phone MessagingGiven words, compute the typing time on a phone keypad where each press takes 1 second and switching between letters on the same key adds a 2-second pause. | Easy3 | ImplementationString+2 | No attempts yet | 1s | 128 MB | Judgeable |
| MaternityGiven the two alleles each parent carries for five genes, decide for each baby whether its five visible traits could result from that pairing. | Easy3 | ImplementationCombinatorics+2 | No attempts yet | 1s | 128 MB | Judgeable |
| Returning HomeReverse a short list of turn directions and street names, flipping each left or right turn, to produce the route from school back home. | Easy3 | ImplementationSimulation+2 | No attempts yet | 1s | 128 MB | Judgeable |
| TopYodellerCompute each yodeller's cumulative score after every round, find who ends with the highest total, and report their worst rank. | Easy3 | ArraySimulation+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Snakes and LaddersSimulate a Snakes and Ladders game with a fixed 100-square board, applying three given ladders and three given snakes after each dice roll until the piece reaches 100 or the player quits. | Easy3 | SimulationImplementation | No attempts yet | 1s | 128 MB | Judgeable |
| PoetryFor each four-line verse, extract the last syllable of the final word on every line and print which rhyme scheme it matches. | Easy3 | StringImplementation+2 | No attempts yet | 1s | 128 MB | Judgeable |
| BFedInterpret a Brainfuck program read from stdin up to '#', supporting the seven pointer, arithmetic, loop, and output commands on a 30000-cell byte tape. | Easy3 | SimulationStack+2 | No attempts yet | 1s | 128 MB | Judgeable |
| Keeping ScoreParse a 13-card hand grouped by suit, score high cards and short suits, and print each suit with points right-aligned in a fixed table. | Easy3 | StringImplementation+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Slot MachinesSimulate a gambler who cycles through three slot machines with fixed payout periods and stops when she runs out of quarters, and report the total number of plays. | Easy3 | SimulationImplementation+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Babbling BrooksSimulate a sequence of splits and joins on a list of streams and print the resulting flows after each split divides flow by a percentage and each join merges neighbors. | Easy3 | ImplementationSimulation+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Card GameSimulate a 52-card game where players alternate turning cards; award points when a high card is followed by enough non-high cards, then print each score. | Easy3 | SimulationImplementation+2 | No attempts yet | 1s | 128 MB | Judgeable |
| CensorRead n lines of space-separated words and replace every word of exactly four letters with ****, printing a blank line between consecutive output lines. | Easy3 | StringImplementation+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Dynamic Dictionary CodingCompress each text set by replacing repeated words with their 1-based dictionary positions, leaving first occurrences unchanged, and preserve all spacing. | Easy3 | StringHash map+2 | No attempts yet | 1s | 128 MB | Judgeable |
| Guessing Game ICompare a 4-digit secret and a guess digit by digit, count exact-position matches as circles and remaining cross-position matches as squares, with duplicates matched once. | Easy3 | ImplementationHash map+2 | No attempts yet | 1s | 128 MB | Judgeable |
| MillenniumGiven a birthdate in a fictional 10-month calendar with alternating 19 and 20 day months, find days until year 1000, month 1, day 1. | Easy3 | MathImplementation+2 | No attempts yet | 1s | 128 MB | Judgeable |
| RectangleRepeatedly cut the largest possible square from an n by m rectangle and count how many squares result. | Easy3 | MathImplementation+1 | No attempts yet | 1s | 128 MB | Judgeable |
| ClassGiven a grid of digits, sum each cell's average absolute difference from its up to four orthogonal neighbors, and print the total with four decimals. | Easy3 | ImplementationMatrix+2 | No attempts yet | 1s | 1024 MB | Judgeable |
| Word Problem (TEKSTER)Parse variable values embedded in a word problem, then evaluate the student's step-by-step arithmetic and print the last step's result. | Easy3 | ImplementationString+2 | No attempts yet | 1s | 1024 MB | Judgeable |
| Harmony: Parallel FifthsGiven N pairs of simultaneous two-voice pitches, list every position i where the voices form a perfect fifth (interval 5 mod 12) at both i and i+1 and both voices move. | Easy3 | ImplementationArray+2 | No attempts yet | 3s | 1024 MB | Judgeable |
| Attendance CheckGiven a permutation forming one cycle, find the student who responds last when the calling chain starts at student k. | Easy3 | ImplementationSimulation+2 | No attempts yet | 1s | 1024 MB | Judgeable |
| ShampooGiven N days and a sorted list of holidays, count how many days residents wash their hair under the stated daily rules. | Easy3 | ImplementationSimulation | No attempts yet | 1s | 1024 MB | Judgeable |
| SledSimulate a sled whose speed changes by a_i on each segment and drops by 1 at junctions whenever it exceeds S; report the final speed. | Easy3 | SimulationImplementation+1 | No attempts yet | 1s | 1024 MB | Judgeable |
| CouriersSimulate two couriers who each take an incoming order if free, preferring the faster one, and total each courier's earnings. | Easy3 | SimulationImplementation+1 | No attempts yet | 1s | 1024 MB | Judgeable |
| BusTrack how many passengers are on the bus after each stop and report the largest number of them that exceeds the seat count K. | Easy3 | ImplementationSimulation+1 | No attempts yet | 1s | 1024 MB | Judgeable |
| Ancient KeyboardSimulate a keyboard where each of up to 26 keys toggles an LED at two given times, and output the letter matching the LED count at each time step until all intervals end. | Easy3 | SimulationImplementation+2 | No attempts yet | 1s | 128 MB | Judgeable |
| Scrabble ScoringScore each Scrabble play by parsing its start square and direction, applying letter and word bonus multipliers from the fixed 15x15 board. | Easy3 | ImplementationSimulation+2 | No attempts yet | 1s | 128 MB | Judgeable |
| Web NavigationSimulate browser back and forward navigation using two stacks, printing the current URL after each command. | Easy3 | StackSimulation+1 | No attempts yet | 1s | 128 MB | Judgeable |
| UndercutScore a five-round card game where players reveal numbered cards each round, applying undercut and tie rules, and print both totals. | Easy3 | ImplementationSimulation+2 | No attempts yet | 1s | 128 MB | Judgeable |
| Currency ExchangeGiven a 5x5 exchange-rate table where every conversion rounds to the nearest hundredth, simulate each trip and report the final dollar amount rounded to cents. | Easy3 | SimulationImplementation+2 | No attempts yet | 1s | 128 MB | Judgeable |
| Easy TradingGiven daily prices, compute moving averages over the last m and n days and print a buy or sell signal whenever the trend between them reverses. | Easy3 | ArrayPrefix sum+2 | No attempts yet | 2s | 128 MB | Judgeable |
| Kick-TippGiven each participant's predicted scores and the actual results over several rounds, compute total points, award round dots to top scorers, and print the sorted standings. | Easy3 | ImplementationSorting+1 | No attempts yet | 1s | 128 MB | Judgeable |
| StrategiesGiven contest time and problem times, simulate three orderings (input, ascending, descending) and pick the winner by problems solved, then score, then Steve. | Easy3 | SimulationSorting+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Ancient PlatesApply given PERM and SHIFT rules to lines, words, or characters of a block of text, then print the result. | Easy3 | ImplementationSimulation+1 | No attempts yet | 1s | 128 MB | Judgeable |
| On the BusTrack passengers boarding and alighting over a series of stops, never exceeding the bus capacity, and report the final count. | Easy3 | SimulationImplementation | No attempts yet | 1s | 128 MB | Judgeable |
| Noughts & CrossesReplay each game from its recorded moves and report the winner (X or O) or Draw, ignoring moves after the win. | Easy3 | SimulationImplementation+1 | No attempts yet | 1s | 128 MB | Judgeable |
| TennisRead a sequence of tennis points (A/B), split it into completed games using the 15-30-40-deuce rules, and output the final game count. | Easy3 | SimulationImplementation | No attempts yet | 1s | 128 MB | Judgeable |
| OutfitsGiven two wardrobes numbered from opposite ends with at most one removal each, report for each day whether both girls picked the same physical outfit. | Easy3 | ArrayImplementation+1 | No attempts yet | 1s | 128 MB | Judgeable |
| ElectionSimulate instant-runoff voting over at most 5 candidates and 20 preference groups, eliminating the lowest scorer each round. | Easy3 | SimulationImplementation+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Pseudographical RecognizerGiven a small grid of line and dot characters, decide whether the drawn characters form exactly one connected straight segment. | Easy3 | ImplementationSimulation+1 | No attempts yet | 1s | 128 MB | Judgeable |
| In QueriesMaintain a 5-column table with seeded initial rows and process insert, remove, max, min, and range-count queries over the columns. | Easy3 | ArrayImplementation+2 | No attempts yet | 1s | 128 MB | Judgeable |
| Email from the ProfessorWrite each message row by row into a grid of width k, then read columns in the order given by a permutation key, dropping padding cells. | Easy3 | ImplementationArray+2 | No attempts yet | 1s | 128 MB | Judgeable |
| Circle DrawingPaint circles onto a grid, later circles overwriting earlier ones, then print the final color of every pixel. | Easy3 | SimulationGeometry+1 | No attempts yet | 3s | 128 MB | Judgeable |
| Rectilinear Polygon With Area Equal to Its Vertex CountGiven n, print a canonical rectilinear polygon outline with n vertices and area n, or NIE when n is odd or below 4. | Easy3 | ImplementationGeometry+2 | No attempts yet | 5s | 128 MB | Judgeable |
| SticksGiven stick lengths, repeatedly merge pairs of equal length into doubled sticks and report how many distinct sticks remain. | Easy3 | Hash mapArray+1 | No attempts yet | 1s | 128 MB | Judgeable |
| NecklacesSplit each circular necklace string into runs of equal size and shade and report the longest and shortest run, preferring larger then lighter beads on ties. | Easy3 | SimulationString | No attempts yet | 1s | 512 MB | Judgeable |
| GrasshopperThe grasshopper crosses width x with the fewest jumps, starting at length s and halving each later jump rounded down, with 1 always allowed. | Easy3 | GreedySimulation+1 | No attempts yet | 1s | 128 MB | Judgeable |
| CardsApply k top-to-bottom card moves in order and report the number on top of the deck. | Easy3 | QueueSimulation | No attempts yet | 1s | 128 MB | Judgeable |
| KonduktorCount how many times each of N compartments is visited during the first K steps of a back-and-forth walk starting at compartment 1. | Easy3 | MathSimulation | No attempts yet | 2s | 128 MB | Judgeable |
| Hektor's Test AnswersFor each N, print the N-th letter of Hektor's 12-letter cycle over A to D formed by two steps forward and one step back. | Easy3 | SimulationMath | No attempts yet | 1s | 128 MB | Judgeable |
| Ducci SequenceRepeatedly replace each entry with the absolute difference of adjacent entries and report whether the tuple reaches all zeros or loops. | Easy3 | SimulationHash map | No attempts yet | 1s | 128 MB | Judgeable |
| LagnoCount the most white pieces a single black move flips on an 8 by 8 Othello board. | Easy3 | SimulationMatrix+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Recovering the Input NumbersReconstruct the original array that produces the given output when replayed through the circular skip-and-zero traversal. | Easy3 | SimulationArray | No attempts yet | 1s | 32 MB | Judgeable |
| Cross CountryFrom the finishing order, score only six-runner teams by their top four places and pick the lowest total, breaking ties with the fifth runner. | Easy3 | SimulationHash map | No attempts yet | 1s | 128 MB | Judgeable |
| Iris (Password)Count case-insensitive subsequence occurrences of a word in a text with the prescribed greedy scan and print the count with up to the first three end positions. | Easy3 | GreedySimulation+1 | No attempts yet | 1s | 128 MB | Judgeable |
| The Candy-Sharing GameEach round passes half of each candy pile to the right and tops odd counts to even until every child holds the same number. | Easy3 | SimulationArray | No attempts yet | 1s | 128 MB | Judgeable |
| 6174For each four-digit number, repeat the Kaprekar digit-sort subtraction until 6174 appears and report the step count. | Easy3 | SimulationSorting | No attempts yet | 1s | 128 MB | Judgeable |
| ACM-UCPCPick 60 finalists by scanning ranked teams under per-school caps and rank-band limits, then fill leftovers in rank order. | Easy3 | SimulationImplementation | No attempts yet | 1s | 128 MB | Judgeable |
| The Dean's DirectiveProcess bank commands that create, reset, deposit to, withdraw from, transfer between, and report on up to 10000 accounts with exact formatting. | Easy3 | SimulationHash map+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Number That CountApply the digit-inventory operation up to 15 times and report whether the number is self-inventorying, reaches one, loops, or stays unclassified. | Easy3 | SimulationArray | No attempts yet | 1s | 128 MB | Judgeable |
| The Brave Sir Robin's cAsE cOrReCtOrThe program uppercases each letter after terminal punctuation seen across spaces and parentheses, decimal points excluded, and lowercases the rest. | Easy3 | StringSimulation | No attempts yet | 1s | 128 MB | Judgeable |
| ICPC RankingSimulate the ICPC log to score each team by solved problems and penalty time, then print the ordered ranking with ties marked. | Easy3 | SimulationSorting+1 | No attempts yet | 1s | 128 MB | Judgeable |
| False Sense of SecurityDecode each line by turning it into pause-free Morse code, reversing the per-character length digits, and re-splitting the code into text. | Easy3 | StringSimulation+1 | No attempts yet | 2s | 128 MB | Judgeable |
| Back and ForthSimulate every player stepping and turning on a small grid for R rounds, then report the non-it player nearest to it. | Easy3 | SimulationImplementation | No attempts yet | 3s | 128 MB | Judgeable |
| The real messageDecide whether a received uppercase message could result from duplicating every third occurrence of each letter. | Easy3 | SimulationString | No attempts yet | 1s | 256 MB | Judgeable |
| Paying Off the DebtSimulate monthly interest rounded to the cent with a fixed payment to count months until the debt clears or report impossible. | Easy3 | Simulation | No attempts yet | 2s | 128 MB | Judgeable |
| It Is ColdFrom the farthest fan inward, add matching flows and subtract opposing ones, resetting on outward flow, to find the speed reaching the team. | Easy3 | SimulationArray | No attempts yet | 1s | 128 MB | Judgeable |
| String LDCount how many times the first character can be stripped from every word before a word empties or two words match. | Easy3 | StringSimulation+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Effective Infection TimeGiven each zone infection month and strike month, compute its Effective Infection Time under the half-weight first-year rule, rounded to four decimals. | Easy3 | SimulationMath+1 | No attempts yet | 2s | 128 MB | Judgeable |
| ZombdarReassemble fragmented sensor lines into semicolon-terminated entries and report each entry with the second its closing semicolon arrived. | Easy3 | SimulationString | No attempts yet | 2s | 128 MB | Judgeable |
| Round RobinSimulate rounds of T turns around the circle, remove the player who takes the last turn, and report the survivors and their shared count when the rest tie. | Easy3 | Simulation | No attempts yet | 1s | 128 MB | Judgeable |
| Islands in the Data StreamCount the nested islands, contiguous blocks higher than both neighbors, in each 15-number stream that starts and ends at zero. | Easy3 | SimulationStack | No attempts yet | 1s | 128 MB | Judgeable |
| Pisano PeriodThe program finds the period length of Fibonacci remainders modulo M for each test case. | Easy3 | SimulationMath | No attempts yet | 1s | 128 MB | Judgeable |
| Picking a device for the movieGiven a movie resolution, pick the cheapest of eight listed devices that maximizes the full-screen usage ratio in either orientation. | Easy3 | SimulationMath+1 | No attempts yet | 1s | 128 MB | Judgeable |
| The Sultan's ChapatiFollow the prescribed flip procedure to sort each stack largest on the bottom and print the flip positions ending with 0. | Easy3 | SimulationArray+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Charles Babbage's Difference EngineGiven the first values of a low-degree polynomial, extend its finite-difference table forward and report the value at x = 50. | Easy3 | SimulationMath+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Surface AreaGiven column heights on a grid, compute the total exposed surface area of the solid, including top, sides, and floor. | Easy3 | SimulationMatrix | No attempts yet | 1s | 128 MB | Judgeable |
| Candy FactoryEach parent in a heap-ordered binary tree makes as many candies as the smaller child count, and the total subtracts consumed ingredients from all made candies. | Easy3 | TreeRecursion+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Cracking Tree CodesGiven a tree and its leaf-stripping code with some entries erased, the program replays the encoding to recover the missing numbers. | Easy3 | SimulationTree+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Cabric NumberSimulate the Kaprekar digit routine to 6174 or 0 for each input and print every subtraction step. | Easy3 | SimulationSorting | No attempts yet | 1s | 128 MB | Judgeable |
| Quantity of White MiceSimulate monthly mouse pairs with age-based births, death after month n, and newborn removal past 100 survivors to find the month k count. | Easy3 | SimulationImplementation | No attempts yet | 1s | 128 MB | Judgeable |
| Color Change of Go StonesRepeat k times the rule that replaces each circular gap with the xor of its two neighbors, then count the white stones. | Easy3 | SimulationArray | No attempts yet | 1s | 128 MB | Judgeable |
| Selecting the Ten Best TeachersTally valid ballots into weighted place scores and print the top ten teachers with vote breakdowns in fixed-width columns. | Easy3 | SimulationSorting+1 | No attempts yet | 1s | 128 MB | Judgeable |
| LVMSimulate the stack machine program and print the value shown by the first DONE instruction. | Easy3 | SimulationStack | No attempts yet | 2s | 512 MB | Judgeable |
| Playing Fair with CryptographyGiven a key and a plaintext, build the 5x5 Playfair grid and encrypt the text into digraphs with cycling filler letters. | Easy3 | SimulationImplementation+2 | No attempts yet | 2s | 128 MB | Judgeable |
| Calling All ProgrammersCount around n callers in a circle with step m and report the position of the k-th caller removed. | Easy3 | Simulation | No attempts yet | 1s | 128 MB | Judgeable |
| RockyA horse walks straight across a grid and turns by fixed rules when a rock blocks it; report the exit square and the number of stepped squares. | Easy3 | SimulationMatrix | No attempts yet | 1s | 128 MB | Judgeable |
| Mystery Graph ColoringColor vertices 0 to V-1 with the smallest color unused by colored neighbors, then print the color count, the colors, and the loop counter. | Easy3 | GraphGreedy+1 | No attempts yet | 1s | 128 MB | Judgeable |
| Bree's pantrySort the cans by height with a case-insensitive code tiebreak, then place them alternately left and right from the middle and print the row. | Easy3 | SortingSimulation | No attempts yet | 1s | 128 MB | Judgeable |
| Paula's dress searchCount how many middle-shop visits Paula needs to reach the shop holding her dress. | Easy3 | SimulationBinary search | No attempts yet | 1s | 128 MB | Judgeable |
| Reversing WordsReverse the letters of each word on every input line while keeping punctuation, spaces, and the capital pattern in place. | Easy3 | StringSimulation | No attempts yet | 1s | 128 MB | Judgeable |
| Word CrossesFor each set of four words, print both leading word crosses side by side on one shared row. | Easy3 | StringSimulation | No attempts yet | 1s | 128 MB | Judgeable |
| Byte Me!Simulate the dealer's fixed hitting rules in binary blackjack and report each hit and whether the dealer wins, busts, or loses. | Easy3 | SimulationImplementation | No attempts yet | 1s | 128 MB | Judgeable |