Decode Ways
Count the number of ways to decode a numeric string into letters using the mapping A=1 to Z=26.
Catalan number
Implement a function that returns the nth Catalan number using dynamic programming.
Lucas Sequence
Implement a function to compute the n-th Lucas number using iteration or recursion with memoization.
Max Profit from Selling Twice
Compute the maximum profit that can be achieved by completing at most two buy-sell transactions on a given price array.
Bell number
Implement a function to compute the Bell number B(n) using dynamic programming.
Min cost climbing stairs
Compute the minimum total cost to reach the top of a staircase, given you can climb 1 or 2 steps at a time.
0/1 Knapsack
Implement the classic 0/1 Knapsack dynamic programming solution to maximize value under a weight capacity.
Coin Change Ways
Count the number of distinct combinations of coins that sum to a target amount.
Showing 8 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.