Sliding window maximum
Return the maximum of each window of size k as it slides across an array.
LRU cache decorator
Implement @lru_cache(maxsize=N) for unary functions using OrderedDict.
Largest Rectangle in Histogram
Given an array of bar heights, compute the largest rectangle that can be formed by consecutive bars.
Largest Area Histogram Matrix
Given a binary matrix, compute the largest rectangle area consisting entirely of 1s.
Create Maximum Number
Given two arrays of digits and an integer k, merge them to form the largest number of length k.
Cherry Pickup Maximum
Given a grid with cherries, find the maximum cherries you can collect using two paths from top-left to bottom-right.
Minimum Cut
Given an undirected graph in adjacency-list form, return the size of the minimum edge cut that disconnects the graph.
Swim in Rising Water
Find the minimum time needed to swim from the top-left to the bottom-right of a grid where water level rises and you can only move to cells with elevation ≤ current time.
Index of maximum value
Return index of largest value (first on tie).
Showing 1–9 of 9 challenges · hard
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.