Easy

Quiz

#463 Island Perimeter

APPROACH

Given a row x col binary matrix grid (1 = land, 0 = water) with exactly one island (a connected group of land cells, no interior lakes, fully surrounded by water), compute and return the perimeter of that island. Each cell is a unit square.

Example 1:

Input: grid = [[0,1,0,0],[1,1,1,0],[0,1,0,0],[1,1,0,0]]

Output: 16

Explanation: The perimeter is the 16 yellow stripes in the image above.

Example 2:

Input: grid = [[1]]

Output: 4

Example 3:

Input: grid = [[1,0]]

Output: 4

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What is the optimal approach for this problem?