Driver code
int main ( ) { struct Node * root = newNode ( 5 ) ; root -> left = newNode ( 1 ) ; root -> right = newNode ( 6 ) ; root -> left -> left = newNode ( 3 ) ; root -> right -> left = newNode ( 7 ) ; root -> right -> right = newNode ( 4 ) ; check ( root ) ? printf ( " YES " ) : printf ( " NO " ) ; return 0 ; }