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Python Coding
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467 challenges 330 easy 120 medium 17 hard

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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

Python Basics easy

Absolute Difference of Two Integers

Compute the absolute difference between two integers, regardless of order.

absolute difference math

Python Basics easy

Set symmetric difference

Write a function that returns the elements found in exactly one of two sets, sorted ascending.

sets symmetric-difference sorting

Python Basics easy

Absolute Difference

Implement a function that returns the absolute difference between two numbers.

absolute value arithmetic function

Lists & Arrays easy

Difference of Consecutive Elements

Given a list of numbers, return a new list where each element is the difference between consecutive elements.

list iteration math

Lists & Arrays easy

Difference of Two Lists

Write a function that returns items in list a that are not in list b, preserving order and duplicates.

lists difference counting

Dicts & Sets easy

Pair with difference K

Count unordered index pairs with absolute difference exactly K, handling duplicates correctly.

dictionary set counting

Dicts & Sets easy

Symmetric Difference

Write a function that computes the symmetric difference of two lists, returning a sorted list of unique elements.

sets set-operations symmetric-difference

Data Structures & Algorithms easy

Count pairs with given difference

Count how many unordered pairs in a list have a given absolute difference using an efficient approach.

hash map counting arrays

Dynamic Programming medium

Longest Arithmetic Subsequence

Given a list of integers, return the length of the longest arithmetic subsequence (constant difference) within it.

dp subsequence hashmap

Showing 9 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.