Max of a variable-length list
Implement a function that returns the maximum value from a list of numbers without using max().
Max of three numbers
Implement a function that returns the maximum of three numbers using comparisons.
Argmax along axis
Write a function that returns index positions of the maximum values along rows or columns of a 2D list.
Jump Game Minimum Jumps
Given an array of non-negative integers where each element is the maximum jump length, compute the minimum jumps to reach the last index.
Maximum subarray (Kadane)
Find the contiguous subarray with the largest sum.
Sliding window maximum
Return the maximum of each window of size k as it slides across an array.
Running Maximum
Implement a function that returns a list where each element is the largest value seen so far.
Partition Array
Implement a function that finds a contiguous partition of a list into k groups, minimizing the maximum sum of the groups.
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.
Largest Rectangle in Histogram
Given an array of bar heights, compute the largest rectangle that can be formed by consecutive bars.
Online Stock Span
Implement StockSpanner.next(price) that returns the maximum number of consecutive days (including today) with price <= current price.
Rate Limit Decorator
Implement a decorator that enforces a maximum number of calls per second for any function.
Maximum XOR Pair
Implement max_xor_pair(nums) that returns the maximum XOR value obtainable by pairing any two numbers in the given list.
Kadane Variant: Maximum Product Subarray
Implement max_product_subarray(nums) that returns the maximum product of any contiguous subarray.
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.
House Robber
Given a list of house values, return the maximum sum you can rob without robbing two adjacent houses.
Unbounded Knapsack
Given item weights and values with unlimited copies, find the maximum total value that fits in a knapsack capacity.
Buy Sell Stock with Cooldown (DP)
Given daily stock prices, compute the maximum profit you can achieve if you must wait one day after selling before buying again.
Create Maximum Number
Given two arrays of digits and an integer k, merge them to form the largest number of length k.
Cherry Pickup Maximum
Given a grid with cherries, find the maximum cherries you can collect using two paths from top-left to bottom-right.
Maximal square matrix
Given a 2D binary matrix of 0s and 1s, find the side length of the largest square containing only 1s.
Delete and Earn
Given an array of integers, find the maximum points you can earn by repeatedly deleting a number and all its adjacent values.
Maximum depth of tree
Implement max_depth(root) to return the maximum depth of a binary tree.
Maximum Width of a Binary Tree
Given the root of a binary tree, compute its maximum width (the maximum number of nodes in any level, counting null positions).
Showing 1–24 of 47 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.