Longest Harmonious Subsequence
Given a list of integers, find the length of the longest harmonious subsequence where the difference between maximum and minimum values is exactly 1.
Longest increasing subsequence
Return the length of the longest strictly increasing subsequence.
Longest Common Subsequence
Given two strings, compute the length of the longest subsequence common to both.
Longest Palindromic Subsequence
Compute the length of the longest palindromic subsequence in a given string.
Longest Arithmetic Subsequence
Given a list of integers, return the length of the longest arithmetic subsequence (constant difference) within it.
Shortest Common Supersequence
Given two strings, return any shortest supersequence that contains both as subsequences.
Minimum Window Subsequence
Given strings s and t, return the minimum window substring of s that contains t as a subsequence, or empty string if none exists.
Showing 1–7 of 7 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.