#include <stdio.h>
#define True 1
#define False 0
#define K 6

int count;

typedef struct node {
   struct node *left, *right;
} NODE;

int bin_tree_isom( NODE *r1, NODE *r2 )
{
   count += 2;
   if ( r1 == NULL && r2 == NULL )
      return True;
   count += 2;
   if ( r1 == NULL || r2 == NULL )
      return False;
   return ( bin_tree_isom( r1 -> left, r2 -> left ) &&
            bin_tree_isom( r1 -> right, r2 -> right ) );
}

void main()
{
   int i;
   NODE *r1, *r2, *ptr1, *ptr2;
   r1 = ( NODE * ) calloc( 1, sizeof( NODE ) );
   r2 = ( NODE * ) calloc( 1, sizeof( NODE ) );
   ptr1 = r1;
   ptr2 = r2;
   for ( i = K - 1; i > 0; i-- ) {
      ptr1 = ptr1 -> left = ( NODE * ) calloc( 1, sizeof( NODE ) );
      ptr2 = ptr2 -> left = ( NODE * ) calloc( 1, sizeof( NODE ) );
   }
/* r2 -> right = ( NODE * ) calloc( 1, sizeof( NODE ) ); */
   count = 0;
   if ( bin_tree_isom( r1, r2 ) )
      printf( "Trees are isomorphic\n" );
   else
      printf( "Trees are not isomorphic\n" );
   printf( "count = %d\n", count );
}