int BSTree<DataType, KeyType>::countHelper(BSTreeNode *parent) const
{
if(parent == NULL)
{
return 0;
}
return countHelper(parent->left) + countHelper(parent->right) + 1;
}
int countNumbersWithUniqueDigits(int n) {
if (n == 0) return 1;
std::function<int(int)> countHelper = [&](int k) -> int {
if (k == 1) return 10;
if (k > 10) k = 10;
int num = 9;
for (int i = 0; i < (k-1); ++i)
num *= (9-i);
return num + countHelper(k-1);
};
return countHelper(n);
}
int BST::countHelper(Node *node){
if(node == NULL){
return 0;
}
else return 1+countHelper(node->left)+countHelper(node->right);
}
int BSTree<DataType, KeyType>::getCount() const
{
return countHelper(root);
}
//Count nodes in a BST
int BST::count(){
return countHelper(root);
}
