mean

class Solution {
public:
    int mean(Node* root, int key) {
        Node* less = NULL;
        Node* greater = NULL;

        while (root != NULL) {
            if (root->data == key) {
                less = root;
                greater = root;
                break;
            }
            else if (root->data > key) {
                greater = root;
                root = root->left;
            }
            else {
                less = root;
                root = root->right;
            }
        }

        int lessVal = (less != NULL) ? less->data : -1;
        int greaterVal = (greater != NULL) ? greater->data : -1;

        return ceil((lessVal + greaterVal) / 2.0);
    }
};