Run-length encoding
Compress consecutive identical characters, e.g. 'aaabbc' → 'a3b2c1'.
Longest common prefix
Find the longest common prefix among a list of strings.
Integer to Roman
Convert a positive integer to its Roman numeral representation.
Zigzag string conversion
Encode a string in zigzag order across numRows rows, then read row by row.
Find all anagrams
Return all starting indices where any anagram of a given word appears as a substring.
Substring Anagrams
Return all start indices in a string where a substring of length k is an anagram of a pattern string.
Longest Palindrome Substring
Given a string s, return the longest substring that reads the same forwards and backwards.
Simplify Path
Implement a function that simplifies a Unix-style absolute file path to its canonical form.
Minimum Remove Valid Parentheses
Given a string with parentheses and letters, remove the fewest parentheses to make it valid.
Custom Sort String
Given a string s and an order string, reorder s so that characters that appear in order come first in that order, and all other characters are appended in stable original order.
Change directory manager
Implement a function that processes `cd` commands and returns the resulting absolute path.
Parse key-value lines
Parse structured key-value lines into a dictionary with support for quoted values and escaped characters.
Additive number sequence
Check whether a given digit string can be partitioned into a valid additive sequence where each term is the sum of the previous two.
Showing 1–13 of 13 challenges · medium · Strings & Text
Strings & Text — Python coding challenges
What you will find here
This page lists strings & text challenges — real Python problems you solve in the browser IDE with instant test feedback. Each challenge includes a clear brief, starter code, and automated checks.
Challenges vs tutorials and quizzes
Challenges test what you can build under constraints. For guided teaching, use our Python tutorials. For quick checks, try quizzes or copy snippets from code samples.