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Python Coding
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467 challenges 330 easy 120 medium 17 hard

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All Python Basics Strings & Text Lists & Arrays Dicts & Sets Functions & Closures OOP & Classes Data Structures & Algorithms Advanced Python Iterators & Generators Decorators & Context Managers Error Handling & Exceptions Regular Expressions Math & Number Theory Bit Manipulation Dynamic Programming Trees & Binary Trees Graphs & Graph Algorithms Recursion & Backtracking Greedy Algorithms Binary Search Two Pointers & Sliding Window Stacks & Queues Heaps & Priority Queues Linked Lists Matrix & 2D Arrays Datetime & Time Calculations Data Formats & Parsing SQL & SQLite Numpy & Vectorized Computing Cryptography & Hashing

Data Structures & Algorithms medium

Shortest Path in Binary Matrix

Implement BFS to find the shortest path length from (0,0) to (n-1,n-1) in an n x n binary matrix, moving through 0 cells in 8 directions.

bfs grid shortest-path

Dynamic Programming easy

Unique Paths in a Grid

Count the number of unique paths from the top-left corner to the bottom-right corner of a grid, moving only right and down.

dynamic-programming grid counting

Dynamic Programming medium

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.

dynamic-programming grid 2d-array

Graphs & Graph Algorithms medium

A* Pathfinding Heuristic

Implement A* search on a 2D grid to find the shortest path length between two cells.

search heuristic shortest-path

Matrix & 2D Arrays medium

Number of Islands

Given a 2D grid of '1' (land) and '0' (water), count the number of islands surrounded by water.

matrix graph bfs

Matrix & 2D Arrays medium

Max Area of Island

Given a 2D grid of 0s and 1s, find the maximum area of a connected group of 1s.

grid dfs connected-components

Matrix & 2D Arrays medium

Rotting Oranges Time

Given a grid of fresh, rotten, and empty cells, compute the minimum minutes until all fresh oranges rot, or -1 if some are unreachable.

bfs grid simulation

Showing 7 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.