BST* bst_get_smallest(BST* bst) {
        while (bst != NULL && bst->left != NULL) {
            bst = bst->left;
        }
    return bst;
}


BST* rec_bst_remove(BST **bst, int ele) {
    BST* curNode = *bst;
    BST* temp = curNode;

    if (ele < (*bst)->data) {
        (*bst)->left = rec_bst_remove(&(*bst)->left, ele);

    } else if (ele > (*bst)->data) {
        (*bst)->right = rec_bst_remove(&(*bst)->right, ele);

    } else {

        BST* dummy;

        //3 cases: 0 children, 1 child, 2 children
        //case 0 children:

        if ((*bst)->left == NULL && (*bst)->right == NULL) {
            bst_delete(&(*bst));
            return 0;
        }

            //case 1 child:

            // right child
        else if ((*bst)-> left == NULL && (*bst)->right != NULL) {
            dummy = *bst;
            *bst = (*bst)->right;
            free(dummy);
            dummy = NULL;
            return 0;

        }
            // left child
        else if ((*bst)-> left != NULL && (*bst)->right == NULL) {
            dummy = *bst;
            *bst = (*bst)->left;
            free(dummy);
            dummy = NULL;
            return 0;

        } else {

            //case 2 children

            int dummyVal;
            dummy = bst_get_smallest((*bst)->right);
            dummyVal = dummy->data;
            (*bst)->data = dummyVal;
            bst_remove(&(*bst)->right, dummyVal);


        }
    }
    return *bst;
}


int bst_remove (BST **bst, int ele) {

    if (!bst_contains(*bst, ele)) {
        return -1;
    }
    rec_bst_remove(bst, ele);
    return 0;
}