Strings and text

Parsing, matching, and tries

Under construction

Still being built. Things may change

Total results3,615 problems

Cipher
Easy3
String, Simulation+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Number Word Sort
Easy3
Sorting, String+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Password Generation
Easy3
Backtracking, Brute force+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Common Names
Easy3
Hash map, Sorting+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Multiple of Three
Easy3
String, Math+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Cipher
Easy3
Simulation, Matrix+2
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Broken Odometer
Easy3
Math, Implementation+1
No attempts yet
Time limit
0.5s
Memory limit
128 MB
Judgeable
Carbon Compounds
Easy3
Brute force, String+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Postfix Expression Evaluation 2
Easy3
Stack, String+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
DNA
Easy3
String, Greedy+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Surprising String
Easy3
String, Brute force+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Overtaking
Easy3
Dynamic programming, Array+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Text Message
Easy3
Simulation, String+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
DNA Decoding 2
Easy3
String, Simulation+1
No attempts yet
Time limit
1s
Memory limit
2 MB
Judgeable
Distinguishing Files
Easy3
String, Brute force+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Sascha
Easy3
String, Brute force+1
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Secret Letter
Easy3
String, Brute force+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Similar Words
Easy3
Hash map, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Roman Numerals
Easy3
String, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Spreadsheet Cell Names
Easy3
Math, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Window Blinds
Easy3
Simulation, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Make a Crossword
Easy3
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Math Homework
Easy3
String, Sorting+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Machine Code
Easy3
Greedy, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Rock-Paper-Scissors Score
Easy3
Simulation, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Noise
Easy3
Math, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Croatian Alphabet
Easy3
String, Greedy+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Three Parts
Easy3
Brute force, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Secret Email
Easy3
Matrix, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Lexicographically Smallest Crossword Word
Easy3
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
IPv6
Easy3
String, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Rhyme Pattern
Easy3
String, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Most Visited Domains
Easy3
String, Hash map+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
DECODE
Easy3
String, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Reaux! Sham! Beaux!
Easy3
String, Hash map+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Bug King
Easy3
Stack, String
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Character Recognition
Easy3
String, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Adding Reversed Numbers
Easy3
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Turing Arithmetic Expressions
Easy3
Math, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Whitespace King: Aligning Columns
Easy3
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Alien Communication Masterclass
Easy3
Math, Implementation+1
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Java vs C++
Easy3
String, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Unreliable Messengers
Easy3
String, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Remainder Calculation
Easy3
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
My Brother's Diary
Easy3
String, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
CIVIC DILL MIX
Easy3
String, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Words
Easy3
String, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Memorable Phone Numbers
Easy3
String, Hash map+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Alien Base Conversion
Easy3
Math, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
To and Fro
Easy3
String, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Word Ratios
Easy3
String, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Major Scales
Easy3
Implementation, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Ecology
Easy3
Hash map, String+1
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Zipf's Law
Easy3
Hash map, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Soundex
Easy3
String, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Election
Easy3
Hash map, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Request for Proposal
Easy3
Hash map, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
ROT13
Easy3
Implementation, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tales from DeCrypt
Easy3
Simulation, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Robot Roll Call
Easy3
Hash map, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Verdis Quo
Easy3
String, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Defining Moment
Easy3
String, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
It's My Derivative
Easy3
String, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Choose Your Own Adventure
Easy3
Graph, DFS+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Is the Name of This Problem
Easy3
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Steganography
Easy3
String, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Netiquette
Easy3
String, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tanning Salon
Easy3
Simulation, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
W's Cipher
Easy3
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pronounceable Passwords
Easy3
String, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Word Amalgamation
Easy3
Hash map, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Skew Binary
Easy3
Math, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Polynomial Showdown
Easy3
Implementation, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Basically Speaking
Easy3
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Transposition
Easy3
String, Hash map+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Take Your Vitamins
Easy3
Implementation, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Spelling Be
Easy3
Hash map, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Counting Pages
Easy3
Implementation, String+2
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Dance
Easy3
Implementation, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Look and Say
Easy3
String, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Seven-Segment Display Addition
Easy3
String, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Casting Out Nines
Easy3
Math, Number theory+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
A Balanced World
Easy3
Stack, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
MCXI Numeral System
Easy3
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Car Park
Easy3
Simulation, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Shirts
Easy3
Sorting, Two pointers+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Letter Replacement
Easy3
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Target
Easy3
Array, Hash map+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Coded Communication
Easy3
String, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Grocery Shopping
Easy3
Hash map, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Subway Fares
Easy3
Array, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Campus Buildings
Easy3
String, Two pointers+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
A Minor and C Major
Easy3
String, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Base K
Easy3
Math, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Longest Decreasing Suffix
Easy3
String, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Mining Maps
Easy3
Hash map, Graph+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Parity Bit
Easy3
Implementation, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
PLU Count
Easy3
Greedy, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Duplicate SSN
Easy3
Hash map, Sorting+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Decoder
Easy3
String, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
CipherEncrypt a lowercase text by shifting each letter backward in the alphabet by the position value of a repeating key letter, leaving spaces unchanged but still consuming a key character.	Easy3	StringSimulation+1	No attempts yet	2s	256 MB	Judgeable
Number Word SortSort integers from M to N by comparing their digits spelled out as English words rather than by numeric value, then print 10 per line.	Easy3	SortingString+1	No attempts yet	2s	128 MB	Judgeable
Password GenerationGenerate all length-L increasing letter combinations from a given set of C letters that contain at least one vowel and two consonants, printed in lexicographic order.	Easy3	BacktrackingBrute force+1	No attempts yet	2s	128 MB	Judgeable
Common NamesGiven two lists of unique lowercase names, find and print the count and sorted list of names common to both.	Easy3	Hash mapSorting+1	No attempts yet	2s	256 MB	Judgeable
Multiple of ThreeGiven a huge number as a digit string, repeatedly sum its digits until one digit remains, then report how many steps it took and whether the number is divisible by 3.	Easy3	StringMath+1	No attempts yet	2s	128 MB	Judgeable
CipherGiven an encrypted string built by zigzag row reading of a column-filled table, reconstruct the original string for a given number of columns.	Easy3	SimulationMatrix+2	No attempts yet	2s	128 MB	Judgeable
Broken OdometerConvert an odometer reading that skips the digit 4 back into the real distance traveled, using a base-9-like digit mapping.	Easy3	MathImplementation+1	No attempts yet	0.5s	128 MB	Judgeable
Carbon CompoundsParse three molecules of C,H,O atoms and find coefficients 1 to 10 for each side that balance atom counts, lexicographically smallest.	Easy3	Brute forceString+1	No attempts yet	2s	128 MB	Judgeable
Postfix Expression Evaluation 2Evaluate a postfix expression using given operand values and print the result rounded to two decimal places.	Easy3	StackString+1	No attempts yet	2s	128 MB	Judgeable
DNAGiven N DNA strings of length M, construct the string minimizing total Hamming distance to all, breaking ties lexicographically, and output that distance.	Easy3	StringGreedy+1	No attempts yet	2s	128 MB	Judgeable
Surprising StringFor each string, check for every gap size whether all pairs of letters at that fixed distance are distinct, and report if the string is 'surprising'.	Easy3	StringBrute force+1	No attempts yet	2s	128 MB	Judgeable
OvertakingGiven entry and exit orders of N cars, count how many cars are not part of the longest common subsequence, meaning they overtook someone.	Easy3	Dynamic programmingArray+1	No attempts yet	2s	128 MB	Judgeable
Text MessageSimulate typing a message on a numeric keypad, summing key press costs and extra wait times when consecutive characters share a key (except spaces).	Easy3	SimulationString+1	No attempts yet	2s	128 MB	Judgeable
DNA Decoding 2Given a DNA string up to 20 million bases, repeatedly collapse the rightmost two characters using a lookup table until one base remains.	Easy3	StringSimulation+1	No attempts yet	1s	2 MB	Judgeable
Distinguishing FilesGiven N files as sequences padded with zeros, find the minimum prefix length K that makes all files pairwise distinct.	Easy3	StringBrute force+1	No attempts yet	2s	128 MB	Judgeable
SaschaGiven a pronounced word and a dictionary of same-length words, find the dictionary word with the minimum Hamming distance, breaking ties by input order.	Easy3	StringBrute force+1	No attempts yet	2s	128 MB	Judgeable
Secret LetterDecode a binary string into 6-bit chunks matching a fixed 8-letter code table by Hamming distance at most 1, printing the first unidentifiable chunk's position if any.	Easy3	StringBrute force+1	No attempts yet	1s	128 MB	Judgeable
Similar WordsCount how many words differ from the first word's letter multiset by at most one insertion, deletion, or substitution.	Easy3	Hash mapString+1	No attempts yet	1s	128 MB	Judgeable
Roman NumeralsConvert two Roman numerals to integers, sum them, and output the sum as both an Arabic and a Roman numeral.	Easy3	StringMath+1	No attempts yet	1s	128 MB	Judgeable
Spreadsheet Cell NamesConvert given row and column numbers into spreadsheet-style cell names like A1 or BC23, stopping at R0C0.	Easy3	MathString+1	No attempts yet	1s	128 MB	Judgeable
Window BlindsParse a grid of ASCII-drawn window blinds and count how many of the M×N windows show each of five possible blind heights.	Easy3	SimulationImplementation+1	No attempts yet	1s	128 MB	Judgeable
Make a CrosswordBuild a grid where word A is placed horizontally and word B vertically, crossing at the first shared letter following a defined scan rule, filling the rest with dots.	Easy3	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
Math HomeworkExtract every maximal run of digits from up to 100 strings, strip leading zeros, and print all extracted numbers sorted nondecreasing.	Easy3	StringSorting+1	No attempts yet	1s	128 MB	Judgeable
Machine CodeGiven a sequence of instructions with parameters, compute the minimum NOPs needed so each instruction starts at an address divisible by 4.	Easy3	GreedySimulation+1	No attempts yet	1s	128 MB	Judgeable
Rock-Paper-Scissors ScoreGiven a player's rock-paper-scissors choices against several friends over multiple rounds, compute the actual score and the best possible score with foreknowledge each round.	Easy3	SimulationGreedy+1	No attempts yet	1s	128 MB	Judgeable
NoiseGiven two powers of ten with up to 100 digits and an operator, compute their sum or product using big-number arithmetic.	Easy3	MathString+1	No attempts yet	1s	128 MB	Judgeable
Croatian AlphabetParse a string left to right, greedily matching multi-character Croatian letter codes (like c=, dz=, lj), and count total letters.	Easy3	StringGreedy+1	No attempts yet	1s	128 MB	Judgeable
Three PartsSplit a short lowercase string into three contiguous non-empty parts, reverse each part, and find the split that yields the lexicographically smallest concatenation.	Easy3	Brute forceString+1	No attempts yet	1s	128 MB	Judgeable
Secret EmailGiven an encrypted string, find matrix dimensions R<=C with R*C=N and largest R, then reverse a row-major-write column-major-read transposition to recover the original message.	Easy3	MatrixString+1	No attempts yet	1s	128 MB	Judgeable
Lexicographically Smallest Crossword WordExtract all horizontal and vertical maximal letter sequences of length at least 2 from a grid and output the lexicographically smallest one.	Easy3	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
IPv6Given a shortened IPv6 address with omitted leading zeros and possibly one '::' run, expand it into eight full 4-digit hex groups.	Easy3	StringImplementation	No attempts yet	1s	128 MB	Judgeable
Rhyme PatternGiven verses of four lines, extract each line's last syllable from its final word and classify the rhyme pattern as perfect, even, cross, shell, or free.	Easy3	StringImplementation	No attempts yet	1s	128 MB	Judgeable
Most Visited DomainsParse a list of URLs to extract each domain suffix and print the maximum visit count along with all domains that reach it, sorted alphabetically.	Easy3	StringHash map+1	No attempts yet	1s	128 MB	Judgeable
DECODEBuild a substitution cipher table from a key word placed at a given offset, then decode a given ciphertext using it.	Easy3	StringSimulation+1	No attempts yet	1s	128 MB	Judgeable
Reaux! Sham! Beaux!Parse rock-paper-scissors rounds given in multiple languages per player, tally wins, and print each game's score and winner.	Easy3	StringHash map+1	No attempts yet	1s	128 MB	Judgeable
Bug KingRepeatedly remove all occurrences of the substring "BUG" from each input line, using a stack-like scan since removals can form new matches, until none remain.	Easy3	StackString	No attempts yet	1s	128 MB	Judgeable
Character RecognitionRead multi-line text blocks separated by blank lines, count '#' as unrecognized characters, and print the recognition percentage formatted with rounding rules.	Easy3	StringImplementation	No attempts yet	1s	128 MB	Judgeable
Adding Reversed NumbersReverse two given numbers, add them, then output the sum reversed with leading zeros dropped.	Easy3	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
Turing Arithmetic ExpressionsGiven up to nine large integers and an arithmetic expression using them, evaluate the expression under mod-10 addition and multiplication with normal precedence and print the result digit.	Easy3	MathString+1	No attempts yet	1s	128 MB	Judgeable
Whitespace King: Aligning ColumnsReformat text lines so that words in each column line up to a width equal to the longest word in that column, with single spaces separating columns.	Easy3	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
Alien Communication MasterclassGiven true bases and false bases, output a fixed-form product-of-factors equation that holds only for the true bases in that numeral system.	Easy3	MathImplementation+1	No attempts yet	3s	256 MB	Judgeable
Java vs C++Detect whether a name follows Java camelCase or C++ snake_case rules and convert it to the other style, or print an error if invalid.	Easy3	StringImplementation	No attempts yet	1s	128 MB	Judgeable
Unreliable MessengersGiven a sequence of reversible string transformations and the final message, undo each transformation in reverse order to recover the original message.	Easy3	StringSimulation+1	No attempts yet	1s	128 MB	Judgeable
Remainder CalculationFor each test case, find the remainder when a base-B number D with up to ten million digits is divided by B-1.	Easy3	MathNumber theory+2	No attempts yet	1s	256 MB	Judgeable
My Brother's DiaryFind the Caesar shift whose most frequent ciphertext letter maps to E, print the smallest valid shift and the decrypted text, or NOT POSSIBLE if several shifts work.	Easy3	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
CIVIC DILL MIXRead groups of valid Roman numerals, add each group, and print the sum and case number back in standard Roman form.	Easy3	StringMath+1	No attempts yet	1s	128 MB	Judgeable
WordsRead lines until a line with a single #, and output each line with the characters of every word reversed, keeping spaces fixed.	Easy3	StringImplementation	No attempts yet	1s	128 MB	Judgeable
Memorable Phone NumbersNormalize each listed phone number to seven digits and report those appearing more than once, sorted, with their counts.	Easy3	StringHash map+2	No attempts yet	1s	128 MB	Judgeable
Alien Base ConversionConvert a number written in base x into the same value written in base y, where both bases are between 2 and 36 and the value fits in four billion.	Easy3	MathImplementation+1	No attempts yet	1s	128 MB	Judgeable
To and FroDecode a message written row by row in alternating left-to-right and right-to-left order back into column-major plaintext.	Easy3	StringSimulation+2	No attempts yet	1s	128 MB	Judgeable
Word RatiosFor each line of three equal-length lowercase words, apply the per-letter alphabet shift from the first word to the second onto the third, and output all four words.	Easy3	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
Major ScalesFor each sequence of notes, list the keys whose major scale contains every note, ordered C through B.	Easy3	ImplementationString+2	No attempts yet	1s	128 MB	Judgeable
EcologyCount how many times each tree species line appears, then print each species in lexicographic order with its share of the total, rounded to four decimals.	Easy3	Hash mapString+1	No attempts yet	1s	256 MB	Judgeable
Zipf's LawFor each test case, count the words in a book body and print the words that appear exactly n times, in lowercase alphabetical order.	Easy3	Hash mapString+2	No attempts yet	1s	128 MB	Judgeable
SoundexConvert each uppercase word into its Soundex digit code, collapsing adjacent letters that share a digit.	Easy3	StringImplementation	No attempts yet	1s	128 MB	Judgeable
ElectionCount the votes each candidate receives in one riding, ignore unknown names, and report the winner's party or independent, or tie if there is no strict winner.	Easy3	Hash mapImplementation+2	No attempts yet	1s	128 MB	Judgeable
Request for ProposalGiven a set of requirements, score each proposal by how many requirements it meets, then pick the best one by compliance and price.	Easy3	Hash mapString+2	No attempts yet	1s	128 MB	Judgeable
ROT13Decode lines of text by reversing the ROT13 cipher: each vowel shifts three places back in a fixed vowel order, each consonant ten back in a consonant order.	Easy3	ImplementationString+2	No attempts yet	1s	128 MB	Judgeable
Tales from DeCryptRead three LCG parameters, then walk the ciphertext byte by byte, advancing the generator only on printable ASCII, and apply the inverse rotation to each such byte.	Easy3	SimulationMath+2	No attempts yet	1s	128 MB	Judgeable
Robot Roll CallGiven a roster of names and a multi-line data stream split on spaces and tabs, report for each roster name whether it appears as an exact token.	Easy3	Hash mapString+2	No attempts yet	1s	128 MB	Judgeable
Verdis QuoConvert valid Roman numerals to decimal integers using addition and subtraction rules.	Easy3	StringSimulation+1	No attempts yet	1s	128 MB	Judgeable
Defining MomentFor each word, strip at most one valid prefix and one valid suffix, then substitute the matching English meaning, expanding the suffix after the prefix.	Easy3	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
It's My DerivativeFor each polynomial, print its derivative and the step-by-step evaluation of that derivative at a given x, matching the input's terse notation.	Easy3	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
Choose Your Own AdventureEach page is a node with two outgoing choices or a terminal ending; print the unique path from page 1 to the single HAPPY ending.	Easy3	GraphDFS+2	No attempts yet	1s	128 MB	Judgeable
Is the Name of This ProblemRead sentences until END and for each decide whether it has the form quote, phrase A, quote, space, A, printing Quine(A) or not a quine.	Easy3	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
SteganographyDecode hidden bits from odd/even runs of spaces in a text and decode five-bit groups into characters.	Easy3	StringBit manipulation+1	No attempts yet	1s	128 MB	Judgeable
NetiquetteDecide whether a one-line email breaks any of four netiquette rules about adjacent case, digits, isolated characters, or punctuation.	Easy3	StringImplementation	No attempts yet	1s	128 MB	Judgeable
Tanning SalonSimulate a tanning salon with a fixed number of beds, tracking arrivals and departures, and count how many customers leave without a bed.	Easy3	SimulationImplementation+2	No attempts yet	1s	128 MB	Judgeable
W's CipherDecrypt messages by extracting each of three character groups and rotating its subsequence right by the matching key.	Easy3	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
Pronounceable PasswordsFor each lowercase password, check three rules: at least one vowel, no three vowels or consonants in a row, and no double letter except ee and oo.	Easy3	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
Word AmalgamationFor each scrambled word, print all dictionary words that are anagrams of it in alphabetical order, or NOT A VALID WORD.	Easy3	Hash mapSorting+2	No attempts yet	1s	128 MB	Judgeable
Skew BinaryRead each skew binary string and print its decimal value, stopping at the terminating 0 line.	Easy3	MathString+1	No attempts yet	1s	128 MB	Judgeable
Polynomial ShowdownGiven nine polynomial coefficients from degree 8 down to the constant, print each polynomial with signs, exponents, and coefficients formatted to drop all unnecessary characters.	Easy3	ImplementationSimulation+2	No attempts yet	1s	128 MB	Judgeable
Basically SpeakingConvert a number from one base to another (bases 2 to 16) and print the result right-justified in a 7-character field, or ERROR if it exceeds 7 digits.	Easy3	MathImplementation+2	No attempts yet	1s	128 MB	Judgeable
TranspositionTranspose a list of note names by a given number of semitones, then print each note using the 12 canonical sharp names.	Easy3	StringHash map+2	No attempts yet	1s	128 MB	Judgeable
Take Your VitaminsFor each line of amount, unit, requirement, and name, print the rounded daily-value percentage; collect items under 1% into a trailing list.	Easy3	ImplementationMath+2	No attempts yet	1s	128 MB	Judgeable
Spelling BeRead a dictionary and several emails, then report for each email whether all its words are known and list the unknown words in order.	Easy3	Hash mapString+2	No attempts yet	1s	128 MB	Judgeable
Counting PagesGiven a document's page count and a comma-separated list of page ranges, count the distinct pages that are actually printed, ignoring empty ranges and pages past the end.	Easy3	ImplementationString+2	No attempts yet	1s	256 MB	Judgeable
DanceCheck a sequence of dance steps against five textual rules and report which rules it violates, uppercasing any misplaced dip.	Easy3	ImplementationString+1	No attempts yet	1s	128 MB	Judgeable
Look and SayFor each input string of digits, produce the next look-and-say element by counting runs of equal digits and writing each count followed by the digit.	Easy3	StringImplementation	No attempts yet	1s	128 MB	Judgeable
Seven-Segment Display AdditionDecode two seven-segment code strings into integers, add them, then re-encode the sum using the given digit codes.	Easy3	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
Casting Out NinesFor each line like a+b=c. or a*b=c., compute digit sums modulo 9 and print PASS if the operation is congruent, otherwise NOT!.	Easy3	MathNumber theory+2	No attempts yet	1s	128 MB	Judgeable
A Balanced WorldFor each line ending in a period, decide whether its round and square brackets are properly matched and nested, printing yes or no.	Easy3	StackString+1	No attempts yet	1s	128 MB	Judgeable
MCXI Numeral SystemRead two MCXI-strings, add their values, and print the canonical MCXI-string for the sum.	Easy3	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
Car ParkSimulate a sequence of car entry and exit signals for a car park of capacity S starting with C cars, stopping early if an exit occurs while empty.	Easy3	SimulationImplementation+1	No attempts yet	1s	128 MB	Judgeable
ShirtsMerge two already sorted lists of shirts and print one merged list ordered by size, then by colour letter. Multiple scenarios end with a 0.	Easy3	SortingTwo pointers+2	No attempts yet	1s	128 MB	Judgeable
Letter ReplacementReplace each repeated letter in a word with a symbol assigned in the order letters first repeat, comparing case-insensitively.	Easy3	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
TargetGiven all solution words of a letter puzzle, recover the 9 grid letters and place the letter common to every word in the middle.	Easy3	ArrayHash map+1	No attempts yet	1s	128 MB	Judgeable
Coded CommunicationGiven n binary strings of length b and a received string r, find the minimum Hamming distance from r to any of the n strings.	Easy3	StringBrute force+2	No attempts yet	1s	128 MB	Judgeable
Grocery ShoppingFor each grocery item, find its matching store item by case-insensitive name and add the club-card saving on the units actually bought.	Easy3	Hash mapString+1	No attempts yet	1s	128 MB	Judgeable
Subway FaresGiven a per-stop fare table and an ordered list of station names, find the number of stops between two stations and print the corresponding fare.	Easy3	ArrayString+2	No attempts yet	1s	128 MB	Judgeable
Campus BuildingsGiven building names and an abbreviation, list the names whose letters contain the abbreviation as a case-insensitive subsequence, in input order.	Easy3	StringTwo pointers+1	No attempts yet	1s	128 MB	Judgeable
A Minor and C MajorSplit the score at bar lines, count how many measure-initial notes are A, D, E versus C, F, G, and break ties with the last note.	Easy3	StringImplementation	No attempts yet	1s	128 MB	Judgeable
Base KConvert each n to base k and report whether every digit from 0 to k-1 appears, formatting the output line exactly as specified.	Easy3	MathImplementation+2	No attempts yet	1s	128 MB	Judgeable
Longest Decreasing SuffixFor each string, print its longest suffix whose characters strictly decrease from left to right.	Easy3	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
Mining MapsParse each graph block, count distinct node names, and count distinct undirected tunnels including self-loops.	Easy3	Hash mapGraph+2	No attempts yet	1s	128 MB	Judgeable
Parity BitSplit each line into 8-bit blocks, check whether the parity bit matches the parity of the first 7 bits, and count the mismatches.	Easy3	ImplementationString+2	No attempts yet	1s	128 MB	Judgeable
PLU CountFor each text string, find the largest k such that PLU repeated k times is a subsequence, ignoring case.	Easy3	GreedyString+1	No attempts yet	1s	128 MB	Judgeable
Duplicate SSNRead a list of Social Security numbers until the sentinel 000-00-0000, then print every number that appears more than once in ascending order.	Easy3	Hash mapSorting+2	No attempts yet	1s	128 MB	Judgeable
DecoderEach word contributes one letter: the first letter of the first word, then the k-th letter of each word where k is the previous word's length; spaces appear when the previous word is too long.	Easy3	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable