Clamp a Number to a Range
Implement a clamp function that returns a value within a specified range.
Count down from n
Implement a function that returns a list from n down to 1.
Count Multiples in a Range
Given a start, end, and divisor, count how many integers in [start, end] are divisible by the divisor.
Range of values
Calculate the range (max minus min) of a list of numbers. Empty list returns 0.
Element-wise Clip
Implement a function that clips each element of a list to a specified range.
Min-Max Scaler: Fit and Transform
Implement a MinMaxScaler class that normalizes numeric data to a given range using fit and transform methods.
Parse range notation
Parse a comma-separated list of ranges and individual numbers, expanding each range into its full sequence.
Move Zeros to End
Rearrange a list by moving all zeros to the end while preserving the relative order of non-zero elements.
Find Duplicate Number
Given a list of n+1 integers in the range 1..n, find the one integer that appears more than once.
Rearrange Positives and Negatives
Write a function that rearranges a list in-place so all negative numbers come before non-negative numbers.
Wave sort array
Given a list of integers, reorder it into a wave pattern where elements alternate down-up, and return the new list.
Normalize Array to Zero-One Range
Implement a function that normalizes a list of numbers to the range [0,1] using min-max scaling.
Bucket Sort
Implement bucket sort to sort a list of floating-point numbers in the range [0,1).
Count of Range Sum
Count contiguous subarrays whose sum lies in a given inclusive range using an efficient divide-and-conquer algorithm.
Range-like generator
Implement a custom generator that yields numbers like Python's range but with flexible bounds.
Bitwise AND of a Range
Given a range [a, b], return the bitwise AND of all integers in that inclusive range without iterating over all numbers.
House Robber Circular
Solve the House Robber problem with houses arranged in a circle.
Derangement count
Implement a function to count derangements of n items using the classic recurrence.
Trim BST to range
Implement a function to trim a BST to only retain nodes with values in a given inclusive range.
Range Sum BST
Return the sum of all node values in a BST that lie within a given inclusive range [low, high].
Beautiful Arrangement Count
Count the number of permutations of 1..n such that for every index i, either i is divisible by the number at that position or the number is divisible by i.
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.
Value at index n
Return the value at zero-based index n or None if out of range.
Showing 1–24 of 28 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.