Unique Paths with Obstacles
Given a 2D grid with obstacles, count the unique paths from top-left to bottom-right moving only down or right.
Triangle Minimum Path
Compute the minimum path sum from top to bottom of a triangle given as a list of lists.
Maximal square
Given a 2D binary matrix of 0s and 1s, compute the area of the largest square containing only 1s.
Longest Common Subsequence
Given two strings, compute the length of the longest subsequence common to both.
Longest Palindromic Subsequence
Compute the length of the longest palindromic subsequence in a given string.
Edit Distance (Levenshtein Distance)
Implement the classic edit distance algorithm to find the minimum number of single-character edits required to transform one string into another.
0/1 Knapsack
Implement the classic 0/1 Knapsack dynamic programming solution to maximize value under a weight capacity.
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.
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.
Create Maximum Number
Given two arrays of digits and an integer k, merge them to form the largest number of length k.
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.
Showing 49–72 of 148 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.