Window Iterator
Implement a generator that yields consecutive windows of a given size from any iterable.
Shortest Common Supersequence
Given two strings, return any shortest supersequence that contains both as subsequences.
Letter Tile Possibilities
Given a string of letter tiles, count the number of distinct non-empty sequences that can be formed using any non-empty subset in any order.
Validate Stack Sequences
Given two sequences of distinct integers, verify whether the second sequence is a valid pop order for a stack given the first sequence as push order.
Showing 1–4 of 4 challenges
Guide: free Python coding challenges
Practice Python by solving problems
PythonSkillset challenges are hands-on coding exercises from beginner to advanced. Open a challenge, read the problem, write Python in the split-pane editor, and run tests with Pyodide — no install required.
How to use the arena
- Pick a category — basics, algorithms, strings, and more
- Open a challenge, read the statement, and edit the starter code
- Run tests, fix failures, then try a related quiz or tutorial lesson
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.