Maximum Running Time of n Computers
Use binary search to maximize the running time for n computers with batteries.
Magnetic Force Packages
Given basket positions and k balls, find the largest possible minimum distance between any two balls.
Minimum Speed to Arrive on Time
Given commute distances and a time limit, compute the minimum integer speed so you arrive on time.
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.
Lower Bound Binary Search
Implement binary search to find the first index where an element is not less than a given target.
Upper Bound Binary Search
Write a function that returns the index of the first element greater than a target in a sorted list.
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.
Rotated Array Search II
Implement a function to search for a target in a rotated sorted array with possible duplicates.
Kth Smallest in Sorted Matrix
Implement kth_smallest(matrix, k) to return the kth smallest element in a row- and column-sorted square matrix.
Search 2D Matrix
Given a sorted 2D matrix with sorted rows and first element of each row greater than last of previous, find target efficiently.
First Bad Version
Implement a function to find the first bad version in a sorted range using binary search.
Book Allocation: Minimize Maximum Pages
Implement a function that returns the minimized maximum pages when allocating a list of books to k students.
Minimum Days to Make Bouquets
Given bloomDay per flower, find the minimum day to make m bouquets each needing k adjacent flowers.
Nth Magical Number
Given three integers n, a, b, return the nth positive integer that is divisible by either a or b.
Find k Closest Elements to Target
Return exactly k elements from a sorted list that are closest to a given target, preserving order.
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.
Container With Most Water
Given an array of heights, find the maximum area between two vertical lines that can hold water.
Trapping Rain Water
Given an array of non-negative integers representing an elevation map, compute how much water it can trap after raining.
Best Time to Buy and Sell Stock
Given a list of daily stock prices, determine the maximum profit achievable by buying on one day and selling on a later day.
Sort Colors (Dutch National Flag)
Implement the Dutch National Flag algorithm to sort an array of 0, 1, 2 in one pass.
Longest Substring Without Repeating Characters
Implement a function that returns the length of the longest substring without repeating characters.
Minimum Window Substring
Implement a sliding window algorithm to find the minimum window substring containing all characters of a given pattern.
Character Replacement Window
Given a string and a number k, find the length of the longest substring that can be made uniform by replacing at most k characters.
Permutation in String
Determine if any permutation of a shorter string appears as a contiguous substring in a longer string using an efficient sliding window.
Showing 721–744 of 925 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.