Pathlib Operations: File Path Basics
Practice using pathlib to manipulate file paths and extract components.
Stack Trace Sanitizer
Implement a function that rewrites traceback file paths to basenames only.
Extract file extensions
Implement a function that extracts the extension from a filename according to standard rules.
Change directory manager
Implement a function that processes `cd` commands and returns the resulting absolute path.
Path Sum II All Paths
Return all root-to-leaf paths where the sum of node values equals a target.
Unique Paths in a Grid
Count the number of unique paths from the top-left corner to the bottom-right corner of a grid, moving only right and down.
Unique Paths with Obstacles
Given a 2D grid with obstacles, count the unique paths from top-left to bottom-right moving only down or right.
Unique Paths in a Grid
Count distinct paths in an m x n grid moving only down or right.
Cherry Pickup Maximum
Given a grid with cherries, find the maximum cherries you can collect using two paths from top-left to bottom-right.
All Paths from Source to Target
Given a directed acyclic graph, return all paths from node 0 to the last node.
Floyd-Warshall: All-Pairs Shortest Paths
Implement the Floyd-Warshall algorithm to find all-pairs shortest path distances in a directed graph with possibly negative weights but no negative cycles.
Rat in a Maze
Count the number of distinct paths a rat can take from top-left to bottom-right in a binary grid, moving down or right and avoiding walls.
Showing 1–12 of 12 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.