Practice Arena

Python Coding
Challenges

Write real Python in the browser. Instant feedback. From beginner to expert.

467 challenges 330 easy 120 medium 17 hard

All Easy Medium Hard

All Python Basics Strings & Text Lists & Arrays Dicts & Sets Functions & Closures OOP & Classes Data Structures & Algorithms Advanced Python Iterators & Generators Decorators & Context Managers Error Handling & Exceptions Regular Expressions Math & Number Theory Bit Manipulation Dynamic Programming Trees & Binary Trees Graphs & Graph Algorithms Recursion & Backtracking Greedy Algorithms Binary Search Two Pointers & Sliding Window Stacks & Queues Heaps & Priority Queues Linked Lists Matrix & 2D Arrays Datetime & Time Calculations Data Formats & Parsing SQL & SQLite Numpy & Vectorized Computing Cryptography & Hashing

Strings & Text easy

Stack Trace Sanitizer

Implement a function that rewrites traceback file paths to basenames only.

strings regex parsing

OOP & Classes easy

Stack class

Implement a Stack class with push, pop, peek, is_empty, and size.

OOP stack data-structures

Data Structures & Algorithms easy

Valid parentheses

Return True if brackets in the string close in the correct order.

Data Structures & Algorithms easy

Previous Smaller Element

Find the nearest previous index with a smaller value for every element in an array.

arrays stack monotonic-stack

Graphs & Graph Algorithms easy

Cycle Detection in a Directed Graph

Use DFS with a recursion stack to detect cycles in a directed graph.

graph dfs cycle

Stacks & Queues easy

Balanced brackets in string

Check if a string of brackets is properly balanced using a stack-based approach.

stack string parsing

Stacks & Queues easy

Next Greater Element

Return a list where each position holds the next greater element to the right, or -1 if none exists.

stack arrays monotonic stack

Showing 7 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.