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Python Coding
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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

Data Structures & Algorithms hard

Longest increasing subsequence

Return the length of the longest strictly increasing subsequence.

dp binary-search LIS

Dynamic Programming medium

Longest Common Subsequence

Given two strings, compute the length of the longest subsequence common to both.

dynamic-programming strings lcs

Dynamic Programming medium

Longest Palindromic Subsequence

Compute the length of the longest palindromic subsequence in a given string.

strings dp subsequence

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 4 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.