Unbounded Knapsack
Given item weights and values with unlimited copies, find the maximum total value that fits in a knapsack capacity.
Partition Equal Subset
Determine whether a given list of positive integers can be partitioned into two subsets with equal sum.
Target Sum Subsets
Write a function that counts the number of subsets of a list of positive integers that sum exactly to a target.
Coin Change Minimum
Given coin denominations and a target amount, compute the minimum number of coins needed or -1 if impossible.
Coin Change Ways
Count the number of distinct combinations of coins that sum to a target amount.
Perfect Squares Sum
Given a positive integer n, return the least number of perfect squares (e.g., 1, 4, 9, 16, ...) that sum to n.
Integer Break Product
Given a positive integer n, break it into at least two positive integers that sum to n and maximize their product.
Word Break DP
Implement a function to check if a string can be segmented into space-separated dictionary words.
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.
Paint House Colors
Given a cost matrix, compute the minimum total cost to paint all houses with no two adjacent houses having the same color.
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.
Longest Arithmetic Subsequence
Given a list of integers, return the length of the longest arithmetic subsequence (constant difference) within it.
Create Maximum Number
Given two arrays of digits and an integer k, merge them to form the largest number of length k.
Shortest Unsorted Continuous Subarray
Given an array of integers, return the length of the shortest contiguous subarray whose sorting makes the whole array sorted.
Ugly Number II
Given an integer n, return the nth ugly number using an efficient dynamic programming approach.
Unique Paths in a Grid
Count distinct paths in an m x n grid moving only down or right.
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.
Minimum Falling Path Sum
Compute the minimum falling path sum in an n x n matrix by moving down or diagonally each step.
Derangement count
Implement a function to count derangements of n items using the classic recurrence.
Shortest Common Supersequence
Given two strings, return any shortest supersequence that contains both as subsequences.
Interleaving string
Given three strings s1, s2, and s3, check if s3 is formed by interleaving s1 and s2 while preserving the order of each input string.
Count subsets with sum
Given a list of integers and a target sum, count how many subsets of the list sum to the target.
Showing 577–600 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.