Convert Sorted Array to Binary Search Tree

Convert Sorted Array to Binary Search Tree

Total Accepted: 61516 Total Submissions: 173462 Difficulty: Medium

Given an array where elements are sorted in ascending order, convert it to a height balanced BST.

/**
* Definition for a binary tree node.
* struct TreeNode {
*     int val;
*     TreeNode *left;
*     TreeNode *right;
*     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
TreeNode* sortedArrayToBST(vector<int>& nums,int start,int end){
if(end <= start) return NULL;
int mid = start + (end-start)/2;
TreeNode* root = new TreeNode(nums[mid]);
root->left = sortedArrayToBST(nums,start,mid);
root->right = sortedArrayToBST(nums,mid+1,end);
return root;
}
TreeNode* sortedArrayToBST(vector<int>& nums) {
int nums_size = nums.size();
return sortedArrayToBST(nums,0,nums_size);
}
};

Next challenges: (M) Course Schedule (M) Count Univalue Subtrees (M) Verify Preorder Sequence in Binary Search Tree