Problem
Given an array where elements are sorted in ascending order, convert it to a height balanced BST.
For this problem, a height-balanced binary tree is defined as a binary tree in which the depth of the two subtrees of every node never differ by more than 1.
Example
Given the sorted array: [-10,-3,0,5,9],
One possible answer is: [0,-3,9,-10,null,5], which represents the following height balanced BST:
0
/ \
-3 9
/ /
-10 5
Code
/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
static int var = [](){
std::ios::sync_with_stdio(false);
cin.tie(NULL);
return 0;
}();
class Solution {
public:
TreeNode* sortedArrayToBST(vector<int>& nums) {
return func(nums);
}
TreeNode* func(vector<int> nums){
if(nums.empty())
return NULL;
int mid = nums.size()/2;
TreeNode* root = new TreeNode(nums[mid]);
vector<int> left_temp(nums.begin(),nums.begin()+mid);
root->left = func(left_temp);
vector<int> right_temp(nums.begin()+mid+1,nums.end());
root->right = func(right_temp);
return root;
}
};
Result
108. Convert Sorted Array to Binary Search Tree.png
