Strings and text

Parsing, matching, and tries

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Still being built. Things may change

Total results3,614 problems

Always Follow the Rules in Zombieland
Easy2
Array, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Refrigerator Magnets
Easy2
Implementation, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Voting
Easy2
Implementation, String
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Mirror Image
Easy2
String, Hash map+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Rock, Paper, Scissors
Easy2
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Parity
Easy2
String, Bit manipulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Seven Percent Solution
Easy2
String, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Quicksum
Easy2
String, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Haiku Review
Easy2
String, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cantor Set
Easy2
Recursion, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Tire Dimensions
Easy2
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Being Smarty!
Easy2
Math, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Ah!
Easy2
String, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Death Knight Hero
Easy2
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Card Cutting
Easy2
Implementation, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Travelling Salesman
Easy2
Hash map, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Jean and Joe's Clothes
Easy2
Implementation, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
DVDs
Easy2
Implementation, Simulation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Alphabet Distance
Easy2
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
String Transformations
Easy2
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Vigenère Cipher
Easy2
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Secret Location
Easy2
String, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Letter Triangles
Easy2
Implementation, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Dedupe
Easy2
String, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Football Team
Easy2
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Garbled Message
Easy2
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Yoda
Easy2
String, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Total Count
Easy2
Hash map, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Which Way
Easy2
Bit manipulation, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Caesar Cipher
Easy2
String, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Comparison Operators
Easy2
Implementation, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pangram
Easy2
String, Hash map+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Jingle Composing
Easy2
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Roll-call in Woop Woop High
Easy2
Implementation, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
String Function Encoding
Easy2
String, Simulation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Odd or Even
Easy2
String, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Barn Echoes
Easy2
String, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
IBM Minus One
Easy2
String, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Deli Deli
Easy2
String, Hash map+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Hard to Believe, but True!
Easy2
String, Math+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Rotating Letters
Easy2
String, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Icon Scaling
Easy2
String, Implementation
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Big Bang Secrets
Easy2
Implementation, String+1
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
English or French?
Easy2
String, Implementation
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
It's Cold Here!
Easy2
Implementation, Array+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
I Speak TXTMSG
Easy2
Hash map, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Anagram Checker
Easy2
Hash map, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Snow Calls
Easy2
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Smile with Similes
Easy2
Implementation, Brute force+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Simple Encryption
Easy2
String, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Trident
Easy2
Implementation, String+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
0123456789
Easy2
Implementation, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
AmeriCanadian
Easy2
String, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Dressing Up
Easy2
Implementation, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Shift Letters
Easy2
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Anagrams
Easy2
String, Hash map+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
String
Easy2
String, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Nonogram
Easy2
Implementation, Array+2
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Hidden Roman Numerals
Easy2
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
1024 MB
Judgeable
Counting Sheep
Easy2
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Entropy
Easy2
Hash map, Math+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Expression
Easy2
String, Implementation+2
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Programming Contest Passwords
Easy2
Implementation, Array+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Stacked Bowls
Easy2
String, Simulation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Jumbled Words
Easy2
String, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
MP3 Songs
Easy2
Sorting, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
How Many Distinct Letters
Easy2
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Divisibility
Easy2
Math, Number theory+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Joke
Easy2
String, Implementation
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Huffman Tree
Easy2
Tree, String+1
No attempts yet
Time limit
3s
Memory limit
128 MB
Judgeable
A Cat on a Keyboard
Easy2
String, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Ant Names
Easy2
String, Implementation+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Rhyming Verses
Easy2
String, Implementation
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Hidden Number
Easy2
String, Implementation
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable
Caesar Cipher
Easy2
String, Array+1
No attempts yet
Time limit
1s
Memory limit
512 MB
Judgeable
Karaoke
Easy2
Sliding window, String
No attempts yet
Time limit
2s
Memory limit
128 MB
Judgeable
Palindrome Coloring
Easy2
String, Two pointers
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Molar Mass
Easy2
String, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Careless Addition
Easy2
Implementation, String
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Decryption
Easy2
Array, String
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
War Game
Easy2
String, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Addition in Different Bases
Easy2
Implementation, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Air speed of a fully laden swallow
Easy2
Implementation, String+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Pig Latin
Easy2
String, Simulation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
W**h y**r mouth out with s**p
Easy2
String, Simulation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Word Ladder
Easy2
String, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Morse Code
Easy2
Hash map, String
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Arbiter Login
Easy2
String, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Arrangement of Contest
Easy2
Greedy, String+1
No attempts yet
Time limit
2s
Memory limit
256 MB
Judgeable
Word Searching
Easy2
String matching, String
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Jane's First Words
Easy2
String matching, String
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Easy Encryption
Easy2
String, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Length and Frequency of Sentences
Easy2
String, Hash map+1
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Form Guide
Easy2
Implementation, String
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Cipher
Easy2
Brute force, String
No attempts yet
Time limit
2s
Memory limit
512 MB
Judgeable
Mingyun's Password
Easy2
String, Brute force
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Word Puzzle
Easy2
Hash map, String
No attempts yet
Time limit
3s
Memory limit
256 MB
Judgeable
Cedric's cypher
Easy2
String, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
The Hardest Problem Ever
Easy2
String, Implementation
No attempts yet
Time limit
1s
Memory limit
128 MB
Judgeable
Finding Nemo
Easy2
String
No attempts yet
Time limit
1s
Memory limit
256 MB
Judgeable

Title	Level	Topics	Solved	Time limit	Memory limit	Judge
Always Follow the Rules in ZombielandRead q quotes in order, then answer r lookups by printing the quote at that 1-based index, or "No such rule" if out of range.	Easy2	ArrayImplementation+1	No attempts yet	1s	128 MB	Judgeable
Refrigerator MagnetsRead lines until END and print each line that contains no repeated letter, ignoring spaces.	Easy2	ImplementationString+2	No attempts yet	1s	128 MB	Judgeable
VotingFor each recorded vote, check quorum and compare yes and no counts to print the outcome.	Easy2	ImplementationString	No attempts yet	1s	128 MB	Judgeable
Mirror ImageFor each word until the terminator '#', print the string reversed with each letter replaced by its mirror image, or INVALID if any letter lacks a mirror.	Easy2	StringHash map+1	No attempts yet	1s	128 MB	Judgeable
Rock, Paper, ScissorsGiven two equal-length strings of R, P, S moves, count the rounds each player wins.	Easy2	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
ParityRead bit strings whose last bit is missing plus a parity letter, and append the 0 or 1 that makes the parity match.	Easy2	StringBit manipulation+1	No attempts yet	1s	128 MB	Judgeable
The Seven Percent SolutionRead lines until a line with only '#', replacing the seven reserved characters in each with their given percent-encodings.	Easy2	StringImplementation	No attempts yet	1s	128 MB	Judgeable
QuicksumCompute a weighted checksum for each input line: sum each character's 1-based position times its letter value, where spaces count as 0, until a line with only #.	Easy2	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
Haiku ReviewCount vowel runs per haiku line and report whether each line has 5, 7, 5 syllables or the first line that fails.	Easy2	StringImplementation	No attempts yet	1s	128 MB	Judgeable
Cantor SetFor each N, print a line of 3^N characters following the Cantor set rule: each third-level block of size 3^k has its middle third blanked, dashes elsewhere.	Easy2	RecursionImplementation+2	No attempts yet	1s	128 MB	Judgeable
Tire DimensionsParse a tire size code and compute its overall circumference from the section width, aspect ratio, and rim diameter.	Easy2	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
Being Smarty!Given row R and block size N, decide whether the alternating style property P1 or P2 applies to that row.	Easy2	MathImplementation+1	No attempts yet	1s	128 MB	Judgeable
Ah!Compare two strings of the form a...ah and print go if the first has at least as many a characters as the second.	Easy2	StringImplementation	No attempts yet	1s	128 MB	Judgeable
Death Knight HeroCount how many of the given ability strings avoid the forbidden substring "CD".	Easy2	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
Card CuttingRead each game line of card values up to '*', count odd values for Cheryl and even values for Tania, and print the winner or Draw.	Easy2	ImplementationString+1	No attempts yet	1s	128 MB	Judgeable
Travelling SalesmanCount the distinct town names in each week's list and report the total for that week.	Easy2	Hash mapString+1	No attempts yet	1s	128 MB	Judgeable
Jean and Joe's ClothesRead clothing sizes and count how many items go to Joe, Jean, Jane, James, or no one, per visit until N equals 0.	Easy2	ImplementationSimulation+2	No attempts yet	1s	128 MB	Judgeable
DVDsApply a series of clamped sale and restock transactions to each DVD title's stock and report the final count.	Easy2	ImplementationSimulation+2	No attempts yet	1s	128 MB	Judgeable
Alphabet DistanceFor each test case, read two equal-length uppercase words and print the alphabet distance between the paired letters at every position.	Easy2	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
String TransformationsApply each letter-to-two-letters rule to the first occurrence of its letter in every word, updating the word after each rule.	Easy2	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
Vigenère CipherEncrypt each given plaintext with the Vigenère cipher, shifting every letter by the aligned repeated keyword letter modulo 26.	Easy2	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
Secret LocationEach of six lines encodes one number by its character count; print the first three as Latitude and the last three as Longitude in the given format.	Easy2	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
Letter TrianglesFor each data set, print a triangle of N lines where line i repeats the ith letter in sequence, starting from a given letter and wrapping Z to A.	Easy2	ImplementationString+1	No attempts yet	1s	128 MB	Judgeable
DedupeFor each of several strings, collapse every run of consecutive identical letters into a single letter and print the result.	Easy2	StringImplementation	No attempts yet	1s	128 MB	Judgeable
Football TeamRead names one per line and swap every i with e and every I with E in each name.	Easy2	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
Garbled MessageRead lines of garbled text until EOF and replace every occurrence of the substring "iiing" with "th", preserving all other characters and line breaks.	Easy2	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
YodaFor each sentence, move its first two words to the end and print the result.	Easy2	StringImplementation	No attempts yet	1s	128 MB	Judgeable
Total CountRead fighter names until a line with 0, print each name with its kill count in first-appearance order, then the grand total.	Easy2	Hash mapImplementation+2	No attempts yet	1s	128 MB	Judgeable
Which WayFor each positive integer, convert it to binary and print left, straight, or right depending on whether it has more 0s, equal 0s and 1s, or more 1s.	Easy2	Bit manipulationImplementation+1	No attempts yet	1s	128 MB	Judgeable
Caesar CipherGiven an uppercase word encrypted by shifting each letter forward three positions, shift every letter back by three to recover the original.	Easy2	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
Comparison OperatorsRead C comparison expressions with integer operands, evaluate each, and print "Case N: true" or "Case N: false" until a line with operator E ends input.	Easy2	ImplementationString+1	No attempts yet	1s	128 MB	Judgeable
PangramRead sentences until a line holding a single asterisk, and print Y if a sentence contains all 26 lowercase letters, otherwise N.	Easy2	StringHash map+1	No attempts yet	1s	128 MB	Judgeable
Jingle ComposingSplit a slash-delimited composition into measures and count how many note durations sum exactly to 1.	Easy2	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
Roll-call in Woop Woop HighRead each class's answers and count pupils into four groups: correct first try, correct late, never correct, and absent.	Easy2	ImplementationString+1	No attempts yet	1s	128 MB	Judgeable
String Function EncodingApply the given suffix-plus-string operation C times to each input string and print the results.	Easy2	StringSimulation	No attempts yet	1s	128 MB	Judgeable
Odd or EvenRead N large integers up to 10^60 and print odd or even for each, judging parity from the last digit.	Easy2	StringMath+2	No attempts yet	1s	128 MB	Judgeable
Barn EchoesGiven two lowercase strings, find the length of the longest string that is a prefix of one and a suffix of the other.	Easy2	StringBrute force+2	No attempts yet	1s	128 MB	Judgeable
IBM Minus OneFor each of n uppercase names, shift every letter to the next letter of the alphabet, wrapping Z to A, and print the result with numbered headers.	Easy2	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
Deli DeliFor each of N words, apply the first matching pluralization rule from a list of irregular forms and four suffix rules, then print the result.	Easy2	StringHash map+2	No attempts yet	1s	128 MB	Judgeable
Hard to Believe, but True!Read the numbers in each equation backwards, add them, and check whether the sum equals the backwards-read result.	Easy2	StringMath+1	No attempts yet	1s	128 MB	Judgeable
Rotating LettersGiven a single uppercase word, decide whether every letter belongs to the set of seven letters that look the same after a 180-degree rotation.	Easy2	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
Icon ScalingRead scaling factor k and print the fixed 3x3 icon with every character expanded into a k-by-k block.	Easy2	StringImplementation	No attempts yet	2s	512 MB	Judgeable
Big Bang SecretsDecode an uppercase word by shifting each letter backward by S = 3P + K positions, where P is the letter's 1-based position.	Easy2	ImplementationString+1	No attempts yet	2s	512 MB	Judgeable
English or French?Count the letters t and T against s and S across N lines and print English if t wins, otherwise French.	Easy2	StringImplementation	No attempts yet	2s	512 MB	Judgeable
It's Cold Here!Read city names with integer temperatures, one per line, and print the name of the city with the lowest temperature.	Easy2	ImplementationArray+2	No attempts yet	1s	128 MB	Judgeable
I Speak TXTMSGRead lines until TTYL, map each known short form through a fixed table, and echo other lines unchanged.	Easy2	Hash mapString+1	No attempts yet	1s	128 MB	Judgeable
Anagram CheckerDecide whether two phrases are anagrams, ignoring spaces and letters only.	Easy2	Hash mapString+1	No attempts yet	1s	128 MB	Judgeable
Snow CallsConvert each alphanumeric phone number to digits, keep the first 10 digits, and print them in xxx-xxx-xxxx form.	Easy2	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
Smile with SimilesGiven up to five adjectives and five nouns, print every phrase of the form "<adjective> as <noun>" in nested input order.	Easy2	ImplementationBrute force+2	No attempts yet	1s	128 MB	Judgeable
Simple EncryptionRemove non-letters from a message and shift each letter within its column by the alphabet position of the keyword letter above it.	Easy2	StringSimulation+1	No attempts yet	1s	128 MB	Judgeable
TridentPrint an ASCII trident with t tine rows, a crossbar, and h handle rows, using spacing s between the tines.	Easy2	ImplementationString+2	No attempts yet	1s	128 MB	Judgeable
0123456789Read one digit from 0 to 9 and print it as a seven-segment display drawn with asterisks, three per segment, with no trailing whitespace.	Easy2	ImplementationSimulation+1	No attempts yet	1s	128 MB	Judgeable
AmeriCanadianRead words one per line until the line quit!, and for each word rewrite a trailing consonant followed by or as our when the word has at least five letters.	Easy2	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
Dressing UpRead an odd height H and print a bow tie of H rows where each side widens as rows approach the middle.	Easy2	ImplementationSimulation+1	No attempts yet	1s	128 MB	Judgeable
Shift LettersFor each test case, rotate the letters of a word right by n positions and print the result in a fixed sentence format.	Easy2	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
AnagramsGiven two lowercase words, decide whether one can be rearranged into the other, and print the result with the words.	Easy2	StringHash map+1	No attempts yet	1s	128 MB	Judgeable
StringCollapse every run of identical consecutive letters in a lowercase string into a single letter and print the result.	Easy2	StringImplementation	No attempts yet	1s	128 MB	Judgeable
NonogramGiven a grid of black and white squares, print the lengths of the consecutive black blocks in each row and then each column.	Easy2	ImplementationArray+2	No attempts yet	1s	1024 MB	Judgeable
Hidden Roman NumeralsFind which of the twelve Roman numerals from 1 to 12 appear as substrings of a given string over {I,V,X}.	Easy2	StringImplementation+1	No attempts yet	1s	1024 MB	Judgeable
Counting SheepCount how many words in each list match the string "sheep" exactly, case-sensitive, and print the count per list with blank lines between cases.	Easy2	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
EntropyRead one line of text, count how often each character appears, and print the Shannon entropy rounded to three decimals.	Easy2	Hash mapMath+2	No attempts yet	1s	128 MB	Judgeable
ExpressionGiven N, build a fully parenthesized NAND (Sheffer stroke) expression for the carry-out bit by iterating a fixed string concatenation rule.	Easy2	StringImplementation+2	No attempts yet	1s	128 MB	Judgeable
Programming Contest PasswordsFor each test case, read a word list and participant index sequences, then print each password formed by concatenating the indexed words.	Easy2	ImplementationArray+1	No attempts yet	1s	128 MB	Judgeable
Stacked BowlsGiven a string of parentheses, compute the total stack height where the first bowl adds 10 and each following bowl adds 5 if it matches the previous direction or 10 if it differs.	Easy2	StringSimulation+1	No attempts yet	1s	128 MB	Judgeable
Jumbled WordsFor each line of lowercase words, keep the first and last letter of every word and reverse the letters in between.	Easy2	StringImplementation	No attempts yet	1s	128 MB	Judgeable
MP3 SongsRead several lists of tune names and print each list sorted alphabetically while ignoring case and keeping input order for ties.	Easy2	SortingString+1	No attempts yet	1s	128 MB	Judgeable
How Many Distinct LettersFor each line until the terminator '#', count how many distinct alphabet letters appear, ignoring case and non-letters.	Easy2	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
DivisibilityGiven a base-62 string, decide whether the number it represents is divisible by 61.	Easy2	MathNumber theory+1	No attempts yet	1s	128 MB	Judgeable
JokeCount how many times the substring 'joke' appears in the input text, with line breaks treated as part of the text.	Easy2	StringImplementation	No attempts yet	2s	128 MB	Judgeable
Huffman TreeGiven Z characters and arity N, decode the stored digit string into the per-character encoding.	Easy2	TreeString+1	No attempts yet	3s	128 MB	Judgeable
A Cat on a KeyboardGiven a text, replace each character with the keyboard row number (1 to 5) where its key sits.	Easy2	StringImplementation	No attempts yet	1s	128 MB	Judgeable
Ant NamesGiven up to 100 lowercase names, print the maximum number of distinct letters found in any single name.	Easy2	StringImplementation+1	No attempts yet	1s	128 MB	Judgeable
Rhyming VersesCount pairs of lines with the same number of vowels and identical last k letters ignoring spaces.	Easy2	StringImplementation	No attempts yet	1s	512 MB	Judgeable
Hidden NumberSum every maximal run of digits in a word of letters and digits, ignoring leading zeros.	Easy2	StringImplementation	No attempts yet	1s	256 MB	Judgeable
Caesar CipherDecode a Caesar-shifted uppercase message by matching its most frequent letter to the given original letter.	Easy2	StringArray+1	No attempts yet	1s	512 MB	Judgeable
KaraokeCount the starting positions where the next K characters of the song string are all vowels.	Easy2	Sliding windowString	No attempts yet	2s	128 MB	Judgeable
Palindrome ColoringSplit each A/B string into the fewest palindromic subsequences and output that count.	Easy2	StringTwo pointers	No attempts yet	1s	128 MB	Judgeable
Molar MassThe program parses each formula of C, H, O, and N with optional atom counts and prints its molar mass using the given weights.	Easy2	StringImplementation	No attempts yet	1s	128 MB	Judgeable
Careless AdditionAdd two integers digit by digit from the right with no carries and print the column sums in order.	Easy2	ImplementationString	No attempts yet	1s	128 MB	Judgeable
DecryptionCount the letters in each sentence ignoring spaces and print the most frequent one, or ? on a tie.	Easy2	ArrayString	No attempts yet	1s	128 MB	Judgeable
War GameGiven each opponent row of archers, lancers, and riders with cyclic strengths, output the shortest row that beats every soldier in meeting order.	Easy2	StringImplementation	No attempts yet	1s	128 MB	Judgeable
Addition in Different BasesAdd two numbers of up to 1000 digits in bases 1 to 35, including unary base 1, and print each equation with its sum in the same base.	Easy2	ImplementationString+1	No attempts yet	1s	128 MB	Judgeable
Air speed of a fully laden swallowYou group messy swallow flight records by subspecies and compute two average speeds for each group.	Easy2	ImplementationString+1	No attempts yet	1s	128 MB	Judgeable
Pig LatinConvert each word to Pig Latin by moving leading consonants to the end and appending ay.	Easy2	StringSimulation	No attempts yet	1s	128 MB	Judgeable
Wh yr mouth out with s**pReplace the middle two letters of every four-letter run whose first and last letters match the given list, scanning each line left to right with no overlap.	Easy2	StringSimulation	No attempts yet	1s	128 MB	Judgeable
Word LadderDecide for each test case whether every consecutive word pair has equal length and differs in exactly one letter.	Easy2	StringImplementation	No attempts yet	1s	128 MB	Judgeable
Morse CodeDecode each test case of five space-separated Morse codes into five uppercase letters or digits.	Easy2	Hash mapString	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
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
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
Easy EncryptionEach letter becomes its two-digit code and each digit gains a # prefix while other characters stay unchanged.	Easy2	StringImplementation	No attempts yet	1s	128 MB	Judgeable
Length and Frequency of SentencesCount the words in each of N sentences and report how often each length occurs in ascending order.	Easy2	StringHash map+1	No attempts yet	1s	128 MB	Judgeable
Form GuideParse home and away scorelines into win, draw, and loss marks, print the overall, home, and away form strings, and report the longest run of each mark.	Easy2	ImplementationString	No attempts yet	1s	128 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
Mingyun's PasswordFind the word whose reverse also appears in the list and print its length and middle letter.	Easy2	StringBrute force	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
Finding NemoPrint Found for each input line before EOI when the letters n, e, m, o appear in order ignoring case, else Missing.	Easy2	String	No attempts yet	1s	256 MB	Judgeable