//return a pointer to the node with the least value in root

//for the selected descriminator

BinNode<E>* findmin(BinNode<E>* root,

int discrim, int currdis) const

{

//discrim: discriminator key used for minimum search

//currdis: current level (mod D)

if (root == NULL) return NULL;

BinNode<E>* minnode = findmin(root->left(), discrim,

(currdis+1)%D);

if (discrim != currdis) //if not at discrim's level

{ //we must search both subtrees

BinNode<E>* rightmin =

findmin(root->right(), discrim, (currdis+1)%D);

//check if right side has smaller key value

minnode = min(minnode, rightmin, discrim);

} //now minnode has the smallest value in children

return min(minnode, root, discrim);

}