Prime Factorization
Return a sorted list of prime factors of a positive integer, including repeated factors.
Shortest Unsorted Continuous Subarray
Given an array of integers, return the length of the shortest contiguous subarray whose sorting makes the whole array sorted.
Search Insert Position
Return the index where a target should be inserted into a sorted list to maintain order.
Upper Bound Binary Search
Write a function that returns the index of the first element greater than a target in a sorted list.
Find Indices of Target in Sorted List
Given a sorted list and a target, return the indices of its first and last occurrence, or [-1, -1] if absent.
First Bad Version
Implement a function to find the first bad version in a sorted range using binary search.
Two Sum Sorted
Given a 1-indexed sorted array and a target, return the two indices that add up to the target.
Squares of Sorted Array
Implement a function that returns a sorted list of squares for a given non-decreasing integer array.
Customers Never Order
Given Customers and Orders tables, return the names of customers with no orders, sorted alphabetically, or None if all have ordered.
Showing 25–33 of 33 challenges · easy
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.