Grokking the Coding Interview: Patterns for Coding Questions
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Problem Challenge 1 (easy)
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Problem Statement

You are given a 2D matrix containing only 1s (land) and 0s (water).

An island is a connected set of 1s (land) and is surrounded by either an edge or 0s (water). Each cell is considered connected to other cells horizontally or vertically (not diagonally).

There are no lakes on the island, so the water inside the island is not connected to the water around it. A cell is a square with a side length of 1.

The given matrix has only one island, write a function to find the perimeter of that island.

Example 1

Input: matrix =

Image

Output: 14

Explanation: The boundary of the island constitutes 14 sides.

Example 2

Input: matrix =

Image

Output: 12

Explanation: The boundary of the island constitute 12 sides.

Try it yourself

Try solving this question here:

Python3
Python3
. . . .

.....

.....

.....

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