Problems

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Total results1,787 problems

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
PeriodFor every prefix of a string, find the largest exponent K such that the prefix equals some string A repeated K times, using KMP failure function.	Medium4	String matchingString+1	No attempts yet	1s	128 MB	Judgeable
Common SubsequenceCompute the length of the longest common subsequence of two given strings for multiple test cases.	Medium4	Dynamic programmingString	No attempts yet	1s	128 MB	Judgeable
Guess the NumbersDetermine whether some permutation of up to 5 given values assigned to the unknowns in a fully parenthesized arithmetic expression makes it evaluate to a target result.	Medium4	Brute forceRecursion+1	No attempts yet	1s	128 MB	Judgeable
Molecular FormulaParse a nested molecular formula with repetition counts and atomic weight lookups to compute total molecular weight, or report UNKNOWN.	Medium4	RecursionString+1	No attempts yet	3s	128 MB	Judgeable
Pizza HawaiiFor each local ingredient and native ingredient, output the pair when the two words appear on exactly the same set of pizza names.	Medium4	Hash mapSorting+2	No attempts yet	1s	128 MB	Judgeable
Touchscreen KeyboardGiven a typed word and a list of same-length dictionary words, print each with its keyboard Manhattan distance, sorted by distance then lexicographically.	Medium4	StringSorting+2	No attempts yet	1s	128 MB	Judgeable
DigitsGiven a huge decimal number, repeatedly replace it with its digit count and report the first step where the value stops changing.	Medium4	MathImplementation+2	No attempts yet	1s	128 MB	Judgeable
TautologyGiven propositional formulas in Polish notation, decide for each whether it is a tautology by parsing and evaluating it over every truth assignment.	Medium4	StringRecursion+2	No attempts yet	1s	128 MB	Judgeable
Basic ModuloRead base-b numbers p and m, with p up to 1000 digits, and print the remainder of p divided by m in base b.	Medium4	MathNumber theory+2	No attempts yet	1s	128 MB	Judgeable
System of Linear EquationsParse two linear equations and report each unknown as a reduced fraction, or as don't know when it is not uniquely determined.	Medium4	MathImplementation+1	No attempts yet	1s	128 MB	Judgeable
Crypt Kicker IIOne input line is the pangram 'the quick brown fox jumps over the lazy dog' encrypted by a letter substitution; find it, build the table, and decrypt every line.	Medium4	StringHash map+2	No attempts yet	1s	128 MB	Judgeable
A Smart Brain is a Tasty BrainParse each of up to 10000 Boolean expressions, evaluate it, and report whether the brain's given answer matches.	Medium4	StringStack+2	No attempts yet	1s	128 MB	Judgeable
Symbolic Logic MechanizationParse a prefix logic formula, report the first syntax error left to right, then classify it as a tautology, contradiction, or contingent.	Medium4	StringRecursion+2	No attempts yet	1s	128 MB	Judgeable
Tribute (Editor)Simulate a buggy modal editor: given keystrokes, apply insert, delete, duplicate, reverse, and cursor commands, then print the buffer with a caret marking the cursor position.	Medium4	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
Grade School MultiplicationFormat a grade-school multiplication display column by column, handling zero digits in the second operand and single-line answers.	Medium4	StringSimulation+2	No attempts yet	1s	128 MB	Judgeable
Linear PachinkoFor each linear Pachinko string, compute the percentage chance that a ball dropped on a uniformly random character exits through a hole or off an end, truncated to an integer.	Medium4	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
Frugal SearchGiven a word list and queries of bar-separated terms with unsigned, plus, and minus letters, output the lexicographically smallest matching word or NONE for each query.	Medium4	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
Instruens FabulamRead a header specifying each column's alignment, then print each table with borders, sized columns, and aligned cells.	Medium4	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
Automatic EditingApply a fixed list of find-and-replace rules in order, repeatedly replacing the first occurrence of each find string until it no longer appears, and print the final text.	Medium4	StringSimulation+2	No attempts yet	1s	128 MB	Judgeable
Equation ElationRepeatedly reduce an arithmetic expression on the left of an equals sign by performing one operation at a time in precedence order, printing each intermediate line.	Medium4	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
DNA TranslationFor each DNA strand, try all four readings (forward, reverse, complement, reverse complement), translate the first AUG to the first stop codon, and print the lexicographically greatest valid protein or a failure message.	Medium4	StringSimulation+2	No attempts yet	1s	128 MB	Judgeable
Letter Sequence AnalysisRead a text block to EOF and, for each sequence length 1 to 5, list the five most frequent letter sequences with alphabetized ties.	Medium4	StringHash map+2	No attempts yet	1s	128 MB	Judgeable
Witness Redaction PlanReplace every character of each sentence that contains a sensitive word (case-insensitive) with @, keeping the rest of the message unchanged.	Medium4	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
Shrew-ologyGiven per-trait dominance rules and adult shrews with sex and trait bits, list every mother-father pair that could produce each juvenile.	Medium4	Brute forceImplementation+2	No attempts yet	1s	128 MB	Judgeable
User NamesGenerate unique lowercase user names from full names using fixed truncation and numeric suffix collision rules, printing each result.	Medium4	StringHash map+2	No attempts yet	3s	256 MB	Judgeable
Set-Theoretic Number NotationParse two numbers given as von Neumann ordinal sets, add their values, and print the sum in the same nested-brace notation.	Medium4	StringRecursion+1	No attempts yet	1s	128 MB	Judgeable
Shortest PrefixesFor each word in a list, find the shortest prefix that matches only that word, counting an exact match as unique even if longer words share it.	Medium4	TrieString+2	No attempts yet	1s	128 MB	Judgeable
Shake, Rattle and RollFill a square grid with an uppercase message plus padding letters, then apply the key's sequence of shake, rattle, and roll operations and print the final flat string.	Medium4	SimulationMatrix+2	No attempts yet	1s	128 MB	Judgeable
CompressGiven pairs F and R with F < R, print F and the shortest compressed form C that decodes back to R.	Medium4	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
Spreadsheet Circular ReferenceGiven spreadsheet cell formulas as lines, decide for each defined cell whether evaluating it leads to a circular reference, printing the cell name and circular or ok.	Medium4	GraphDFS+1	No attempts yet	1s	128 MB	Judgeable
Stable StringGiven a string of braces, find the minimum number of single-character flips that make all brackets correctly balanced.	Medium4	StackGreedy+2	No attempts yet	1s	128 MB	Judgeable
A Tale from the Dark Side of the MoonReimplement a lost text filter that applies four ordered string rules per line, including conditional ei to ie and dd to p replacements, stopping at a line reading EOF.	Medium4	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
Wooden BlocksGiven a string of digit pieces, check whether it forms a valid interlocking arrangement starting with piece 1, ending with piece 2, and matching every adjacent edge pair.	Medium4	ImplementationString+2	No attempts yet	1s	128 MB	Judgeable
Flatten the ExpressionParse a recursively repeated bracketed expression and print its flattened string without spaces.	Medium4	StringRecursion+1	No attempts yet	1s	128 MB	Judgeable
Phone ListGiven a list of distinct phone numbers, decide whether any number is a prefix of another.	Medium4	TrieString+1	No attempts yet	1s	256 MB	Judgeable
Web PagesFor each line of HTML-looking text, decide whether every opening tag has a matching closing tag and all tags nest properly.	Medium4	StackString+2	No attempts yet	1s	128 MB	Judgeable
Risk AssessmentScore each company from text by applying sentence modifiers to quality words and attributing words to the most recent company name.	Medium4	StringSimulation+1	No attempts yet	1s	128 MB	Judgeable
Presentation ErrorNormalize two strings by case, spacing around special symbols, bracket and comma/semicolon equivalence, then decide if they match.	Medium4	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
Stump SpeechGiven scored key phrases and a speech, sum each phrase's score times its number of occurrences in the speech.	Medium4	StringString matching+1	No attempts yet	1s	128 MB	Judgeable
Breaking the Vigenère CipherFrom a ciphertext, collect all repeated 3-letter groups and their occurrence distances, then report every key length from 4 to 20 dividing at least 90% of those distances.	Medium4	StringHash map+2	No attempts yet	1s	128 MB	Judgeable
Next PermutationGiven an integer A, find the smallest permutation of its digits that is strictly greater than A, or print USELESS if none exists.	Medium4	ArrayString+2	No attempts yet	1s	128 MB	Judgeable
SignboardCount how many of the given strings contain the store name as an equally spaced subsequence, where each string counts at most once.	Medium4	StringBrute force+1	No attempts yet	1s	256 MB	Judgeable
Product Order TotalsSum the order quantities for each distinct product name, then print each product with its total sorted by name length, then alphabetically.	Medium4	Hash mapSorting+2	No attempts yet	1s	128 MB	Judgeable
Car Plates CompetitionDecide whether Isa's 7-character plate is a legal plate newer than Martin's by at most C positions ahead in the ACM sequence.	Medium4	ImplementationMath+2	No attempts yet	1s	128 MB	Judgeable
ScrabbleGiven a tray of T letters (some blanks that score 0) and an alphabetized dictionary, pick the highest-scoring dictionary word formable from the tray, breaking ties alphabetically.	Medium4	StringGreedy+2	No attempts yet	1s	128 MB	Judgeable
Word PowerFor each of N cow names, count how many of M good strings appear as a case-insensitive subsequence of the name.	Medium4	StringTwo pointers+2	No attempts yet	1s	128 MB	Judgeable
Word GamesGiven a rack of up to 10 letters with wildcards and a dictionary of up to 50000 words, print every dictionary word whose letters can be covered by the rack, in input order.	Medium4	ImplementationBrute force+2	No attempts yet	1s	128 MB	Judgeable
L-I-N-G-OGiven a secret five-letter word and guesses, print one feedback line per guess using upper-case for exact matches, lower-case for misplaced letters, and periods otherwise.	Medium4	StringHash map+2	No attempts yet	1s	128 MB	Judgeable
Number Base ConversionConvert a number given in one base to another base, where digits run 0-9, A-Z, a-z, and print a blank line after each conversion.	Medium4	MathString+2	No attempts yet	1s	128 MB	Judgeable
Mutilated Morse Code CipherApply Ohaver's symmetric Morse cipher: encode each message to dot-dash with a length string, reverse the lengths, and decode back to text.	Medium4	StringHash map+2	No attempts yet	1s	128 MB	Judgeable
Microprocessor SimulationSimulate a 4-bit microprocessor from a 256-word hex memory dump and print the final memory state when the stop instruction runs.	Medium4	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
Scramble SortSort words case-insensitively and integers numerically within each comma-separated list while keeping each element's original type position.	Medium4	SortingString+2	No attempts yet	1s	128 MB	Judgeable
KeywordsGiven keyword profiles with a gap threshold and a list of titles, report for each profile the numbers of titles where some pair of its distinct keywords appears within the threshold.	Medium4	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
Numerically SpeakingTranslate between lowercase words of length 1 to 20 and their bijective base-26 numbers, printing output in a padded two-column format.	Medium4	MathString+2	No attempts yet	1s	128 MB	Judgeable
Octal FractionsRead octal fractions from 0 to 1 and print each one's exact decimal value, with trailing zeros stripped.	Medium4	MathString+2	No attempts yet	1s	128 MB	Judgeable
Volleyball StatsParse volleyball play-by-play lines, track kills, errors, hits, blocks, and digs per player and team, and print formatted reports on demand.	Medium4	ImplementationSimulation+2	No attempts yet	1s	128 MB	Judgeable
Excuses, Excuses!Find the excuses containing the most keyword occurrences, where keywords match case-insensitively and only as whole words.	Medium4	StringHash map+2	No attempts yet	1s	128 MB	Judgeable
Identifying Legal Pascal Real ConstantsClassify each candidate line as a legal Pascal real constant or not, following the syntax rules for digits, decimal points, scale factors, and signs.	Medium4	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
CowculationsFor each tablet, simulate three operations (add, shift right, shift left, or null) on a five-symbol cow number and check the padded result equals the eight-symbol line.	Medium4	ImplementationSimulation+2	No attempts yet	1s	128 MB	Judgeable
Bingo, Really?!Split the input into letter-only words, count distinct words per game ending at BULLSHIT, and print the running average as an irreducible fraction.	Medium4	StringHash map+2	No attempts yet	1s	128 MB	Judgeable
Etaoin ShrdluConcatenate each sample's lines, count overlapping adjacent character pairs, then print the five most frequent digrams with their counts and rounded relative frequencies.	Medium4	StringHash map+2	No attempts yet	1s	128 MB	Judgeable
CompromiseFor each pair of word lists terminated by #, print the lexicographically smallest longest common subsequence of words.	Medium4	Dynamic programmingString	No attempts yet	1s	128 MB	Judgeable
Digital DisplayRender each input time as a seven-segment digital clock face 29 characters wide and 7 rows tall, then print end after all times.	Medium4	ImplementationSimulation+2	No attempts yet	1s	128 MB	Judgeable
Intriguing IdentifiersValidate each given identifier as a Czech Personal ID for a birth between 1920 and 2009, and report the gender or mark it invalid.	Medium4	ImplementationString+2	No attempts yet	1s	256 MB	Judgeable
Emag eht htiw Em PlehGiven White and Black piece lists, print the 8x8 chess board as ASCII art with alternating light and dark square fills.	Medium4	ImplementationSimulation+2	No attempts yet	1s	128 MB	Judgeable
English Number TranslatorParse English number words such as 'one thousand five hundred' into their integer value, handling negatives and an empty-line terminator.	Medium4	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
R.Ø.L.P. Code WheelFor each encoded message, try all 42 wheel shifts and print every decoding that contains the substring RØLP.	Medium4	StringBrute force+2	No attempts yet	1s	128 MB	Judgeable
Parsing Real NumbersGiven T lines, decide whether each line is a valid real number with optional sign, decimal point, and exponent, allowing surrounding blanks.	Medium4	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
Expression EvaluatorEvaluate a C-style expression of letter variables with binary + and -, plus pre and post ++ and --, then report the result and each used variable's final value.	Medium4	StringSimulation+2	No attempts yet	1s	128 MB	Judgeable
From Prefix to PostfixTranslate each prefix arithmetic expression over + and - into its equivalent postfix form, stopping at the terminating 0.	Medium4	StackTree+2	No attempts yet	1s	128 MB	Judgeable
Attack of the CipherTextsGiven one plaintext/ciphertext pair, invert the letter substitution to decrypt a second ciphertext, printing a period for undetermined characters.	Medium4	Hash mapString+1	No attempts yet	1s	128 MB	Judgeable
Year 2000Read n lines of text and expand the two-digit year in every date that matches one of three fixed formats, leaving all other characters unchanged.	Medium4	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
Common WordsFor each data set, count word frequencies, find the k-th most common words, and print them alphabetically after a title line.	Medium4	Hash mapSorting+2	No attempts yet	1s	128 MB	Judgeable
LotteryInsert parentheses into arithmetic expressions so that multiplication is grouped before addition and subtraction, keeping the original spaces.	Medium4	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
Divisibility by 11Apply Dodgson's divisibility-by-11 test to numbers up to 50 digits, printing each intermediate value and the final verdict.	Medium4	MathImplementation+2	No attempts yet	1s	128 MB	Judgeable
When in Rome...Parse two Roman numerals, add them, and print the sum as a Roman numeral, or CONCORDIA CUM VERITATE when the sum exceeds 1000.	Medium4	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
Where's Waldorf?Given a grid of letters and a list of words, find the first-letter position of each word along any of eight straight directions, or the bottom-right cell if absent.	Medium4	ArrayString+2	No attempts yet	1s	128 MB	Judgeable
Double TroubleGiven an encrypted ciphertext formed by shifting letters and reversing blocks of size m, find the shift s and block size m that make a given crib appear.	Medium4	StringBrute force+2	No attempts yet	1s	128 MB	Judgeable
Weather ForecastingParse four weather forecast lines, score each sentence by phenomenon and qualifier, weight forecasts by day, and test whether the total is under 0.25.	Medium4	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
GeopeitusExpand each variable's value list, substitute every combination into the coordinate formula, and print each resulting coordinate in the specified digit order.	Medium4	ImplementationBrute force+2	No attempts yet	1s	1024 MB	Judgeable
Meli kalikamakaApply syllable and letter substitution rules to convert a lowercase text into a Polynesian-style pronunciation.	Medium4	StringSimulation+2	No attempts yet	1s	1024 MB	Judgeable
Substring ReversalGiven an original string and the result of reversing one substring of length at least two, find the reversed segment, preferring the smallest start then end.	Medium4	StringTwo pointers	No attempts yet	1s	1024 MB	Judgeable
Ancient CipherGiven two equal-length strings of capital letters, decide whether the first can be obtained from the second by a substitution cipher followed by a permutation.	Medium4	StringSorting+2	No attempts yet	2s	128 MB	Judgeable
Chemical ReactionsParse chemical formulas with nested parentheses and multipliers, then compare element counts between the left side and each candidate right side.	Medium4	StringStack+1	No attempts yet	1s	128 MB	Judgeable
Buffer ManagerGiven buffer states (free, digit worthiness, or locked) in a string, find the starting position of the K-length window without locked buffers whose digit sum is smallest.	Medium4	Sliding windowPrefix sum+2	No attempts yet	1s	128 MB	Judgeable
ImprovisationGiven a chord progression and a melody with pauses, remap each played note to the nearest note in the current chord's scale, advancing the chord every fourth position.	Medium4	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
ROT13Given a list of lowercase words, count ordered pairs (w1, w2) from the list where w2 equals the ROT13 encoding of w1.	Medium4	Hash mapString+2	No attempts yet	1s	128 MB	Judgeable
Summing JaśAdd up to 100 signed decimal numbers with up to 100 digits on each side of the comma and print the shortest form of the sum.	Medium4	StringMath+1	No attempts yet	1s	512 MB	Judgeable
Guess the WordGiven each uppercase word, output the next distinct arrangement of its letters in dictionary order, or the word itself when it is already last.	Medium4	StringSorting	No attempts yet	1s	128 MB	Judgeable
OulipoCount overlapping occurrences of a pattern W in a text T over uppercase letters for each test case.	Medium4	String matchingString	No attempts yet	1s	128 MB	Judgeable
Mixing WordsDecide whether the third word interleaves the first two words while keeping each word's letter order.	Medium4	Dynamic programmingString	No attempts yet	1s	256 MB	Judgeable
Special JudgeDecide whether the given string appears as a contiguous block in both A and B.	Medium4	String matchingString	No attempts yet	1s	128 MB	Judgeable
Password ValidationDecide whether each password meets length, character mix, repeat, palindrome, and forbidden subsequence rules.	Medium4	ImplementationString+1	No attempts yet	1s	128 MB	Judgeable
CasinoFind every longest palindromic substring of length at least 2 in each string and print them rightmost first.	Medium4	StringString matching	No attempts yet	1s	128 MB	Judgeable
CalculatorEvaluate up to 100 polynomials given as compact strings with omitted coefficients at integer X and print each result.	Medium4	StringMath+1	No attempts yet	1s	128 MB	Judgeable
Exact Sum of Real NumbersAdd each group of decimal numbers with up to 30 digits exactly and print the unrounded sum with trailing zeros removed.	Medium4	ImplementationString+1	No attempts yet	1s	128 MB	Judgeable
Word ExtractionClean each input line by lowercasing it, joining or splitting words at punctuation by neighbor rules, then print the sorted unique words per line.	Medium4	StringSorting+1	No attempts yet	1s	128 MB	Judgeable
Fib InverseGiven Fibonacci numbers, find each one's index, taking the larger index when two match.	Medium4	MathHash map+1	No attempts yet	1s	512 MB	Judgeable
Uncompressing Compressed WordsExpand each nested compressed word by concatenating its parts and repeating the group n times.	Medium4	RecursionStack+1	No attempts yet	1s	256 MB	Judgeable
RunesFind the smallest digit that replaces every question mark so the addition, subtraction, or multiplication equation holds.	Medium4	Brute forceString+1	No attempts yet	5s	256 MB	Judgeable