text: Calculate size of vertex cover when root is not part of it
code: int size_excl = 0 ; if ( root -> left ) size_excl += 1 + vCover ( root -> left -> left ) + vCover ( root -> left -> right ) ; if ( root -> right ) size_excl += 1 + vCover ( root -> right -> left ) + vCover ( root -> right -> right ) ;