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Find Number Of Islands
MEDIUM
34 mins
64 upvotes
Arrays
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Find Number Of Islands

Contributed by
Ankit Kharb
Medium
yellow-spark
0/80
Avg time to solve 34 mins
Success Rate 60 %
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64 upvotes

Problem Statement

You are given a 2-dimensional array/list having N rows and M columns, which is filled with ones(1) and zeroes(0). 1 signifies land, and 0 signifies water.

A cell is said to be connected to another cell, if one cell lies immediately next to the other cell, in any of the eight directions (two vertical, two horizontal, and four diagonals).

A group of connected cells having value 1 is called an island. Your task is to find the number of such islands present in the matrix.

Detailed explanation ( Input/output format, Notes, Constraints, Images )
Sample Input 1 :
4 5
0 1 1 0 0
1 0 0 1 0
0 0 1 0 0
1 0 0 0 1
Sample Output 1 :
3
Explanation For Sample Input 1 :
The first island of connected 1s is signified by: {0, 1}, {0, 2}, {1, 0}, {1, 3}, {2, 2}.

The second island being: {3, 0}.

The third island being: {3, 4}.
Sample Input 2 :
4 4
1 0 0 1
0 1 1 0
0 1 1 0
1 0 0 1
Sample Output 2 :
1
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