Practice Arena

Python Coding
Challenges

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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

Palindrome check

Return True if the string reads the same forwards and backwards (ignoring case and non-alphanumeric).

strings two-pointer

Lists & Arrays easy

Remove duplicates (sorted)

Return a sorted list with duplicates removed.

arrays two-pointer

Lists & Arrays easy

Merge two sorted arrays

Merge two sorted arrays into one sorted array.

arrays merge two-pointer

Lists & Arrays easy

Move Zeros to the End

Reorder a list in-place, pushing all zeros to the end while preserving the order of non-zero numbers.

lists in-place two-pointer

Lists & Arrays easy

Move Zeros to End

Rearrange a list by moving all zeros to the end while preserving the relative order of non-zero elements.

list in-place two-pointer

Lists & Arrays easy

Rearrange Positives and Negatives

Write a function that rearranges a list in-place so all negative numbers come before non-negative numbers.

in-place two-pointers partition

Two Pointers & Sliding Window easy

Longest Substring Without Repeating Characters

Implement a function that returns the length of the longest substring without repeating characters.

strings sliding-window two-pointers

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.