Practice Arena

Python Coding
Challenges

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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

Lists & Arrays medium

Flatten nested list

Yield every integer from an arbitrarily nested list, depth-first.

recursion generators

Data Structures & Algorithms medium

AST Visitor Lite

Implement a depth-first traversal of a simplified AST and return identifier names in order.

trees traversal ast

Iterators & Generators easy

Yield from delegation

Implement a generator that flattens nested iterables of any depth using `yield from`.

generators yield delegation

Iterators & Generators easy

Flatten Nested List Iterator

Implement a class that iterates over all integers in a nested list structure in depth-first order.

iterator generator flatten

Iterators & Generators easy

Graph DFS Generator

Implement a generator function that performs a depth-first traversal of a graph without recursion.

generators dfs graph

Trees & Binary Trees easy

Maximum depth of tree

Implement max_depth(root) to return the maximum depth of a binary tree.

binary-tree recursion depth

Trees & Binary Trees easy

Minimum Depth of Tree

Given a binary tree, compute the minimum depth from the root to the nearest leaf node.

binary-tree depth traversal

Trees & Binary Trees medium

Binary tree left side view

Given a binary tree, return the leftmost node's value at each depth, from top to bottom.

binary-tree levels bfs

Showing 1–8 of 8 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.