Practice Arena

Python Coding
Challenges

Write real Python in the browser. Instant feedback. From beginner to expert.

875 challenges 536 easy 303 medium 36 hard

All Easy Medium Hard

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

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

Number of Islands in a Matrix

Count the number of distinct islands (connected groups of 1s) in a 2D binary matrix.

Matrix & 2D Arrays medium

Regions Cut by Slashes

Given a grid of slashes, count the number of connected regions formed by the slashes and the grid borders.

grid dfs union-find

Showing 3 challenges · medium · Matrix & 2D Arrays

Matrix & 2D Arrays — Python coding challenges

What you will find here

This page lists matrix & 2d arrays challenges — real Python problems you solve in the browser IDE with instant test feedback. Each challenge includes a clear brief, starter code, and automated checks.

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.