Given a 2–d matrix , which has only 1’s and 0’s in it. Find the total number of connected sets in that matrix.

Explanation:

Connected set can be defined as group of cell(s) which has 1 mentioned on it and have at least one other cell in that set with which they share the neighbor relationship. A cell with 1 in it and no surrounding neighbor having 1 in it can be considered as a set with one cell in it. Neighbors can be defined as all the cells adjacent to the given cell in 8 possible directions ( i.e N , W , E , S , NE , NW , SE , SW direction ). A cell is not a neighbor of itself.

/*CODE*/

#include<stdio.h>
#define SIZE 1010
void disable_connected(int i, int j);
int matrix[SIZE][SIZE]={0};

main()
{
int t,size,i,j,k,num_connected=0;

    scanf("%d",&t);
    while(t)
    {
        t--;
        num_connected = 0;
        scanf("%d",&size);
        for(i=0;i<=size+1;i++)
        {
            matrix[0][i] = matrix[size+1][i]= matrix[i][0] = matrix [i][size+1] = 0;
        }
        for(i=1;i<=size;i++)
        {
            for(j=1;j<=size;j++)
            {
                scanf("%d",&matrix[i][j]);
            }
        }

        for(i=1;i<=size;i++)
        {
            for(j=0;j<=size;j++)   
            {
                if(matrix[i][j] == 1)
                {
                    disable_connected(i,j);
                    num_connected++;
                }
            }
        }
        printf("%d\n",num_connected);
    }

return 0;
}

void disable_connected(int i, int j)
{
int p,q;
       
    matrix[i][j] = 2;
    for(p=i-1;p<=i+1;p++)
    {
        for(q=j-1;q<=j+1;q++)
        {
            if(matrix[p][q] == 1)
            {
                matrix[p][q] =2;
                disable_connected(p,q);
            }
        }
    }

return ;
}