Medium

Quiz

#200 Number of Islands

APPROACH

Given an m x n 2D binary grid grid which represents a map of '1's (land) and '0's (water), count and return the number of distinct islands.

An island is a group of '1' cells connected horizontally or vertically. The entire border of the grid is surrounded by water.

Example 1:

Input: grid = [

["1","1","1","1","0"],

["1","1","0","1","0"],

["1","1","0","0","0"],

["0","0","0","0","0"]

]

Output: 1

Example 2:

Input: grid = [

["1","1","0","0","0"],

["0","0","1","0","0"],

["0","0","0","1","1"]

]

Output: 3

1 of 4

1:00

What is the optimal approach for this problem?