Given an array where elements are sorted in ascending order, convert it to a height balanced BST.
https://oj.leetcode.com/problems/convert-sorted-array-to-binary-search-tree/
/**
* Definition for binary tree
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
TreeNode *sortedArrayToBST(vector<int> &num) {
return buildTree(num, 0, num.size() -1);
}
TreeNode *buildTree(std::vector<int> &num, int start, int end)
{
if (start > end) {
return NULL;
}
int mid = (end + start) / 2;
TreeNode *root = new TreeNode(num[mid]);
root->left = buildTree(num, start, mid -1);
root->right = buildTree(num, mid + 1, end);
return root;
}
};