Classify triangle by sides
Write a function that classifies a triangle based on three side lengths.
Two Sum with Dict
Implement the classic Two Sum problem: return indices of two numbers that add up to a target using a dict.
Stack class
Implement a Stack class with push, pop, peek, is_empty, and size.
Event emitter basics
Implement an EventEmitter class with subscribe/emit/unsubscribe functionality.
Rectangle class
Implement a Rectangle class with properties, methods, and special methods for basic geometry and comparison.
Queue class (list-based)
Implement a Queue class with enqueue, dequeue, peek, is_empty, and is_full methods using a list.
Abstract Base Class
Create an abstract Shape class and implement Rectangle and Circle subclasses with area and perimeter.
Union Find Class
Implement a UnionFind class with find and union operations supporting path compression and union by size.
Async Context Manager Lifecycle
Build an async context manager class that tracks acquisition and ensures cleanup.
Custom iterator class
Implement a custom iterator class that repeatedly yields elements from a list up to a given number of times.
Context Manager Class
Implement a context manager class that measures execution time and sets duration, with None if an exception occurred.
File Open Context Manager
Create a class that acts as a context manager for opening a virtual file in memory.
Lookahead Validation
Write a regex-based function to check if a password meets length and character class requirements.
Binary Search Tree Class
Build a BinarySearchTree class and a sequence runner that executes a list of operations.
Keys and Rooms
A classic graph traversal challenge: check if all rooms are reachable from room 0 using keys found in visited rooms.
Min Heap Class
Build a MinHeap class with push, pop, peek, and size methods that maintain a valid min-heap.
Showing 16 challenges · easy
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.