108. Convert Sorted Array to Binary Search Tree c++

1、题目：点击打开链接

2、给定一个数组，将其转换为一个平衡二叉查找树

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

3、代码16ms：

/** * 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) {        if(nums.empty())            return NULL;        int len=nums.size();        int mid=(len-1)/2;        TreeNode* treeNode=NULL;        Bst(treeNode,nums,0,len-1);        return treeNode;    }    void Bst(TreeNode* &treeNode,vector<int>& nums,int left,int right){        int mid=(left+right)/2;        //cout<<"l="<<left<<" r="<<right<<endl;        treeNode=new TreeNode(nums[mid]);        if(left<=mid-1)            Bst(treeNode->left,nums,left,mid-1);        if(mid+1<=right)            Bst(treeNode->right,nums,mid+1,right);    }};