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Python Coding
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925 challenges 556 easy 323 medium 46 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

Math & Number Theory easy

Happy number check

Implement a function that returns True if a number is happy, False otherwise.

Bit Manipulation easy

Count Set Bits

Implement a function that returns the number of set bits (1s) in the binary representation of a non-negative integer.

bit-manipulation binary counting

Bit Manipulation easy

Find Rightmost Set Bit

Implement a function that returns the 1-indexed position of the rightmost set bit of a positive integer, or 0 if none.

bitwise bit-manipulation integer

Bit Manipulation easy

Isolate Rightmost Set Bit

Given an integer, return a number with only its rightmost set bit set.

bit-manipulation bitwise algorithms

Bit Manipulation easy

Set kth Bit

Implement a function that sets the kth bit (0-indexed) of a non-negative integer to 1 and returns the result.

bit-manipulation bits integer

Bit Manipulation easy

Brian Kernighan count

Implement a function that counts set bits using Brian Kernighan's efficient algorithm.

bit-manipulation integers counting

Bit Manipulation easy

Clear Rightmost Set Bit

Write a function clear_rightmost_set_bit that accepts a non-negative integer and returns the integer with its rightmost set bit cleared.

bitwise bit manipulation integers

Bit Manipulation easy

Subset XOR sum

Given a list of integers, compute the bitwise XOR of each non-empty subset and return the sum of those XOR totals.

xor bitwise subsets

Bit Manipulation easy

Check kth bit

Implement a function that checks whether the k-th bit of a non-negative integer is set (1) or not (0).

bit-manipulation bitwise integer

Bit Manipulation easy

Even Parity Bit

Given an integer, return the even parity bit (0 or 1) that makes the total count of set bits even.

bitwise parity bits

Graphs & Graph Algorithms easy

Clique Detection

Given an undirected graph and a list of vertices, check if every pair of distinct vertices in the list is connected by an edge.

graphs cliques adjacency-matrix

Recursion & Backtracking easy

Power set from set

Write a function to return the power set of a given list of distinct elements.

recursion subsets combinations

Matrix & 2D Arrays easy

Valid Sudoku Board

Determine if a 9x9 Sudoku board is valid by checking rows, columns, and 3x3 sub-boxes.

matrix set validation

Matrix & 2D Arrays easy

Valid Sudoku Validator

Determine if a given 9x9 Sudoku board is valid by checking rows, columns, and 3x3 boxes.

matrix validation set

Showing 25–38 of 38 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.