// *& is reference to pointer, similar to double pointer(**)
BSTNode* build_bst(ListNode *&head, int start, int end)
{
// terminate condition
if (start > end) return NULL;
int mid = start + (end - start) / 2;
// traverse to the left first
BSTNode *leftChild = build_bst(head, start, mid-1);
BSTNode *parent = new BSTNode(head->m_Data);
head = head->m_Next;
BSTNode *rightChild = build_bst(head, mid+1, end);
parent->left = leftChild;
parent->right = rightChild;
return parent;
}
BSTNode* convert_sorted_list(ListNode *head)
{
int len = 0;
ListNode *curr = head;
// find the length of the list
while(curr != NULL) {
curr = curr->m_Next;
len++;
}
return build_bst(head, 0, len-1); //both start and end is inclusive
}
void test()
{
node_t* root = build_bst(30);
node_t* head = tree_to_list(root);
while (head != NULL)
{
printf("%d ", head->data);
head = head->right;
}
printf("\n");
}
void ahnentafel_fill(struct ahnentafel_t* bs, iter_t iter, void* opaque)
{
for (int i = 0; i < bs->size; i++)
bs->array[i] = *(iter(opaque));
build_bst(bs);
}
