N-Queens Solutions
Implement a function to count the number of distinct ways to place n queens on an n×n board.
Palindrome Partitioning Minimum Cuts
Given a string, return the minimum number of cuts needed such that every substring in the partition is a palindrome.
Egg Drop Puzzle
Given k eggs and n floors, compute the minimum number of attempts required in the worst case to find the highest safe floor.
Create Maximum Number
Given two arrays of digits and an integer k, merge them to form the largest number of length k.
Remove invalid parentheses
Given a string with parentheses and letters, return all valid strings after removing the minimum number of invalid parentheses.
Remove K Digits to Form the Smallest Number
Given a non-negative integer as a string, remove exactly k digits to form the smallest possible integer without leading zeros.
Patching Array
Given a sorted array of positive integers and a target n, find the minimum number of patches to make every number from 1 to n representable as a subset sum.
Subarrays with K different ints
Count the number of contiguous subarrays that contain exactly K distinct integers.
Showing 8 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.