Practice Arena

Python Coding
Challenges

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

925 challenges 556 easy 323 medium 46 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

Matrix & 2D Arrays medium

Search a 2D Matrix II

Implement an efficient search for a target in a matrix where each row and each column is sorted in ascending order.

matrix binary-search search

Matrix & 2D Arrays easy

Diagonal Traverse Matrix

Implement a function that returns all elements of a matrix in diagonal zigzag order.

matrix traversal array

Matrix & 2D Arrays medium

Regions Cut by Slashes

Given a grid of slashes, count the number of connected regions formed by the slashes and the grid borders.

grid dfs union-find

SQL & SQLite easy

Customers Never Order

Given Customers and Orders tables, return the names of customers with no orders, sorted alphabetically, or None if all have ordered.

sql sqlite join

SQL & SQLite easy

Cumulative Sum SQL

Write a SQL query to compute cumulative sales totals per product ordered by sale date.

sql window-functions running-total

Numpy & Vectorized Computing medium

Reverse vector order

Return elements in opposite order.

vectors arrays numpy-style

Showing 73–78 of 78 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.