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Strings coding challenges
Practise strings with 36 coding challenges, from easy to hard. Every challenge runs in your browser with instant tests, an AI review of your code and community solutions to compare.
Easy · 30 Medium · 3 Hard · 3
Skills you'll practise: String splittingCountingCharacter checksRecordsValidationBase casesBoolean flagsBuilder patternCapitalizationCase normalizationCharacter mappingCharacter replacement
- Python · C++ · C#
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- AI code review
- Community solutions
- 226
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- 2
- Solutions shared
- 3
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All challenges
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Hard
Minimum Window Substring
Find the shortest piece of text containing all required characters.
You'll learn
Grow and shrink windowsFrequency maps
No solutions yet
Hard
Word Break
Decide whether text can be split into dictionary words.
You'll learn
Prefix DPString segmentation
No solutions yet
Medium
Recursive Palindrome
Check a palindrome recursively, ignoring case and punctuation.
You'll learn
Base casesString cleaning
No solutions yet
Hard
Find Many Patterns in Text
For each requested pattern, decide whether it appears as a contiguous substring anywhere in the shared text.
You'll learn
Substring searchPreprocessing
No solutions yet
Easy
Roman Numeral Value
Convert a Roman numeral to a number.
You'll learn
Symbol-to-value mapsSubtractive rules
No solutions yet
Easy
Character Frequency
Count how often each character appears.
You'll learn
Frequency tablesCounting
No solutions yet
Medium
Readability Grade
Estimate the school grade needed to read a text.
You'll learn
Text analysisFormulas
No solutions yet
Easy
First Unique Character
Find the first character that appears only once.
You'll learn
Hash mapsCounting
No solutions yet
Easy
Password Rules Check
Check a password against simple strength rules.
You'll learn
ValidationBoolean flags
No solutions yet
Easy
Every Other Character
Keep the characters at even positions.
You'll learn
String indexingSteps
No solutions yet
Easy
DNA to RNA Transcription
Build an RNA string by replacing every DNA character with its partner.
You'll learn
Character mappingTranslation tables
No solutions yet
Easy
Palindrome String
Check whether text reads the same forwards and backwards.
You'll learn
Two pointersEarly exit
No solutions yet
Easy
Acronym Generator
Create an acronym from the first letter of every word, in uppercase.
You'll learn
String parsingWord splitting
No solutions yet
Easy
Title Case
Capitalize the first letter of every word.
You'll learn
String methodsCapitalization
No solutions yet
Easy
Word Tile Score
Add the tile values for every letter in a word.
You'll learn
Letter scoresSumming with a map
No solutions yet
Easy
Pangram Check
A pangram contains every English letter at least once.
You'll learn
Letter setsCase normalization
No solutions yet
Easy
Reverse a String
Return the characters of a string in reverse order.
You'll learn
Reverse iterationSlicing
No solutions yet
Easy
Anagram Check
Check whether two phrases use the same letters.
You'll learn
SortingFrequency counts
No solutions yet
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