Leetcode 之Convert Sorted Array to Binary Search Tree（54）

TreeNode* sortedArrayToBST(vector<int> &num)
{
return sortedArrayToBST(num.begin(), num.end());
}
template<typename RandomAccessIterator>
TreeNode* sortedArrayToBST(RandomAccessIterator first, RandomAccessIterator last)
{
const auto length = distance(first, last);
if (length <= 0)return nullptr;

auto mid = first + length / 2;
TreeNode *root = new TreeNode(*mid);
root->left = sortedArrayToBST(first, mid);
root->right = sortedArrayToBST(mid, last);

return root;
}