Number of Islands
Given a 2D grid of '1' (land) and '0' (water), count the number of islands surrounded by water.
Max Area of Island
Given a 2D grid of 0s and 1s, find the maximum area of a connected group of 1s.
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.
Number of Islands in a Matrix
Count the number of distinct islands (connected groups of 1s) in a 2D binary matrix.
Shortest Path in Binary Matrix
Compute the shortest path length from top-left to bottom-right in a binary matrix using 8-directional moves.
Largest Plus Sign
Compute the largest possible plus sign of 1s in an n x n grid with some cells set to 0.
Shift 2D Grid
Implement a function to shift a 2D grid right by k positions, flattening the grid and wrapping elements.
Word Search Matrix
Given a 2D board and a word, determine if the word can be formed by sequentially adjacent cells (horizontally or vertically), without reusing cells.
Pacific Atlantic Flow
Given a height matrix, return all cells from which water can flow to both the Pacific and Atlantic oceans.
Regions Cut by Slashes
Given a grid of slashes, count the number of connected regions formed by the slashes and the grid borders.
Showing 1–10 of 10 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.