Garbage Collection Hint
Write a function that predicts when an object is garbage collected based on reference counting.
Delete Old Records
Filter a list of records by removing those with a date older than a given cutoff date.
Delete Middle Node
Implement a function that deletes a given non-tail node from a singly linked list in O(1) time.
Design Skip List Lite
Implement a simplified skip list supporting insert, search, and delete with O(log n) average complexity.
Delete duplicates sorted II
Given a sorted list, remove duplicates in place so each element appears at most twice, returning the new length.
Yield from delegation
Implement a generator that flattens nested iterables of any depth using `yield from`.
Non-greedy quantifier
Implement a function that uses a non-greedy regex to extract the shortest substring between two delimiters.
Delete and Earn
Given an array of integers, find the maximum points you can earn by repeatedly deleting a number and all its adjacent values.
Delete Node in BST
Implement a function that deletes a key from a binary search tree and returns the new root.
Network Delay Time
Given a directed weighted graph and a starting node, find the minimum time for a signal to reach all nodes, or -1 if unreachable.
Capacity to Ship Packages
Given package weights and days allowed, compute the smallest ship capacity that can deliver all packages in order within the given days.
Showing 1–11 of 11 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.