Class Method Factory
Create a class method factory that dynamically adds methods to a class based on a mapping of names to behaviors.
Longest Consecutive Sequence
Given an unsorted list of integers, find the length of the longest consecutive elements sequence in O(n) time.
Union Find Class
Implement a UnionFind class with find and union operations supporting path compression and union by size.
Context Manager Class
Implement a context manager class that measures execution time and sets duration, with None if an exception occurred.
Match Credit Card Pattern
Write a function that validates a credit card number string against a set of formatting rules.
Power set size
Compute the size of the power set of a given sequence.
Happy number check
Implement a function that returns True if a number is happy, False otherwise.
Count Set Bits
Implement a function that returns the number of set bits (1s) in the binary representation of a non-negative integer.
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.
Isolate Rightmost Set Bit
Given an integer, return a number with only its rightmost set bit set.
Bit Mask Permissions
Implement helper functions to compose bit masks and check permission bits using bitwise operators.
Set kth Bit
Implement a function that sets the kth bit (0-indexed) of a non-negative integer to 1 and returns the result.
Brian Kernighan count
Implement a function that counts set bits using Brian Kernighan's efficient algorithm.
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.
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.
Check kth bit
Implement a function that checks whether the k-th bit of a non-negative integer is set (1) or not (0).
Even Parity Bit
Given an integer, return the even parity bit (0 or 1) that makes the total count of set bits even.
Partition Equal Subset
Determine whether a given list of positive integers can be partitioned into two subsets with equal sum.
Target Sum Subsets
Write a function that counts the number of subsets of a list of positive integers that sum exactly to a target.
Word Break DP
Implement a function to check if a string can be segmented into space-separated dictionary words.
Count subsets with sum
Given a list of integers and a target sum, count how many subsets of the list sum to the target.
Subset Sum Exists
Given a list of positive integers and a target sum, return whether some subset adds up exactly to the target.
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.
Open the Lock BFS
Implement a BFS solution to find the minimum number of turns needed to open a 4-wheel lock, avoiding a set of deadends.
Showing 25–48 of 60 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.