// Input a 2-dimensional matrix of size 5x5 from the user and print the number of
// 0-regions in the matrix. Also for each region, print the coordinates of any one
// cell inside it. Assume that the user inputs only 0's and 1's. Also assume that
// the top-left cell is (0,0).
// Author:rahule@cse.iitk.ac.in

#include<stdio.h>
int a[5][5];	//the matrix declared globally..
void mark(int,int);
main()
{
  int i,j;
  printf("\nenter the matrix\n");
  for(i=0;i<5;i++)
  {
    printf("\n");
    for(j=0;j<5;j++)
    {
      printf("(%d,%d) :",i,j);
      scanf("%d",&a[i][j]);
      printf("  ");
    }
  }
  
  printf("\nthe 0 regions in the matrix are.\n");
  for(i=0;i<5;i++)
    for(j=0;j<5;j++)
    {
      if(a[i][j]==0)	//if (i,j) is 0,mark all o cells reachable from it as -1
      {
	printf("(%d,%d), ",i,j);
	mark(i,j);
      }
    }
     printf("\n");
    

}
void mark(int i,int j)
//mark all the cells with 0 reachable from (i,j) as -1.
{
 
  a[i][j]=-1;	//mark (i,j) as -1
  if(j<4 && a[i][j+1]==0)	//if LHS cell of (i,j) is also 0,call the mark funtion recursively for it
    mark(i,j+1);
  
  if(i<4 && a[i+1][j]==0)	//if the cell bellow (i,j) is also 0,call the mark funtion recursively for it
    mark(i+1,j);
  
  if(j>0 && a[i][j-1]==0)	//if the RHS cell of (i,j) is also 0,call the mark funtion recursively for it
    mark(i,j-1);
  
  if(i>0 && a[i-1][j]==0)	//if the cell above (i,j) is also 0,call the mark funtion recursively for it
    mark(i,j+1);
}