【Leetcode108】关关刷题日记65–Convert Sorted Array to Binary Search Tree

class Solution {public:
    TreeNode* dfs(int l, int r, vector<int>& nums)
    {
        if(l<=r)
        {
            TreeNode* root;
            root=new TreeNode(nums[(l+r)/2]);
            root->left=dfs(l, (l+r)/2-1 ,nums);
            root->right=dfs((l+r)/2+1, r, nums);
            return root; 
        }
        else
            return nullptr;
    }

    TreeNode* sortedArrayToBST(vector<int>& nums) {
       return dfs(0, nums.size()-1, nums);
    }};