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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

Lists & Arrays medium

Find Duplicate Number

Given a list of n+1 integers in the range 1..n, find the one integer that appears more than once.

arrays hash-set duplicates

Data Structures & Algorithms medium

Find Peak Element

Implement a function that returns the index of any peak element in an integer array.

arrays search binary-search

Trees & Binary Trees medium

Delete Node in BST

Implement a function that deletes a key from a binary search tree and returns the new root.

binary-search-tree tree-traversal recursion

Graphs & Graph Algorithms medium

A* Pathfinding Heuristic

Implement A* search on a 2D grid to find the shortest path length between two cells.

search heuristic shortest-path

Binary Search medium

Search in Rotated Array

Implement an efficient search in a rotated sorted array using modified binary search.

binary-search arrays search

Binary Search medium

Interpolation Search

Implement interpolation search in Python on a sorted list of integers.

search sorted-array binary-search

Binary Search medium

Ternary Search

Implement ternary search to locate the maximum of a discrete unimodal function.

ternary-search binary-search unimodal

Showing 7 challenges · medium

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.