Longest Consecutive Sequence
Given an unsorted list of integers, find the length of the longest consecutive elements sequence in O(n) time.
Context manager timer
Implement a Timer context manager that records elapsed seconds.
Retry decorator
Implement @retry(times=3) that retries a function on exception.
Memoize with TTL
Implement a decorator that caches function results for a limited time, returning cached values within the TTL and recomputing after expiry.
Rate Limit Decorator
Implement a decorator that enforces a maximum number of calls per second for any function.
Profile time decorator
Create a decorator that tracks how many times a function is called and its cumulative execution time.
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.
Rotting Oranges Time
Given a grid of fresh, rotten, and empty cells, compute the minimum minutes until all fresh oranges rot, or -1 if some are unreachable.
Showing 8 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.