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28

Find Number Of Islands

Difficulty: MEDIUM
Contributed By
Avg. time to solve
34 min
Success Rate
60%

Problem Statement

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.

Input Format :
``````The first line of input contains two integer values, 'N' and 'M', separated by a single space. They represent the 'rows' and 'columns' respectively, for the two-dimensional array/list.

The second line onwards, the next 'N' lines or rows represent the ith row values.

Each of the i-th row constitutes 'M' column values separated by a single space.
``````
Output Format :
``````The only line of output prints the number of islands present in the 2-dimensional array.
``````
Note :
``````You are not required to print anything explicitly, it has already been taken care of. Implement the function and return the desired output.
``````
Constraints :
``````1 <= N <= 10^3
1 <= M <= 10^3
0 <= ARR[i][j] <= 1

Time limit: 1sec
``````
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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