Candy Distribution
Compute the minimum total candies needed so that every child gets at least one and children with higher ratings than neighbors get more candies.
Job Sequencing with Deadlines and Profits
Given jobs with deadlines and profits, choose a subset that maximizes profit while meeting deadline constraints.
Gas Station Circuit
Given gas and cost arrays for a circular route, determine the starting gas station index that allows a full loop, or -1 if none exists.
Jump Game Reachable
Given an array of non-negative integers where each element is the maximum jump length, determine if you can reach the last index.
Non-overlapping Intervals
Given a list of intervals, return the minimum number of intervals to remove to make the rest non-overlapping.
Search in Rotated Array
Implement an efficient search in a rotated sorted array using modified binary search.
Find Minimum in Rotated Sorted Array
Implement a function that finds the minimum element in a rotated sorted array of distinct integers in O(log n) time.
Koko Eating Bananas
Given piles of bananas and hours, find the minimum integer eating speed Koko needs to finish all piles within H hours.
Capacity to Ship Packages
Given package weights and days allowed, compute the smallest ship capacity that can deliver all packages in order within the given days.
Kth Missing Positive
Given a strictly increasing array and an integer k, return the k-th positive integer that is missing from the array.
Binary Search on Answer: Find the Minimal Maximum Subarray Sum
Implement a function that finds the minimal possible maximum subarray sum when splitting an array into at most k contiguous subarrays.
Book Allocation: Minimize Maximum Pages
Implement a function that returns the minimized maximum pages when allocating a list of books to k students.
Minimum Limit of Balls in a Bag
Given an array of bag sizes and a number of allowed splits, find the minimum possible maximum bag size.
Sort Colors (Dutch National Flag)
Implement the Dutch National Flag algorithm to sort an array of 0, 1, 2 in one pass.
Count Nice Subarrays
Given an array of integers, count the number of contiguous subarrays that contain exactly k odd numbers.
Reverse Pairs Count
Implement a function to count reverse pairs in an array efficiently.
Three Sum
Given an array of integers, return all unique triplets that sum to zero.
Binary Subarray with Sum
Given a binary list and a goal sum, count the number of subarrays that add up to that goal.
Subarray product less than K
Count contiguous subarrays where the product of all elements is strictly less than a target K.
Boats to Save People – Two Pointer
Implement a function that returns the minimum number of boats needed to rescue everyone, given a weight limit and each boat carrying at most two people.
Trapping Rain Water (Two Pointers)
Given an array of non-negative integers representing elevation heights, compute how much water can be trapped after rain.
Four Sum
Find all unique quadruplets in an array that sum to a given target.
Count Nice Subarrays
Count subarrays that contain exactly k odd numbers.
Daily Temperatures
Given a list of daily temperatures, return for each day how many days until a warmer temperature appears.
Showing 25–48 of 62 challenges · medium
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.