C++ 108. 将有序数组转换为二叉搜索树

class Solution {
public:
    TreeNode* sortedArrayToBST(vector& nums) {
        return binary(nums, 0, nums.size() - 1);
    }

    TreeNode* binary(vector& nums, int left, int right){
        if(left > right){
            return nullptr;
        }         

        int mid = (left + right) / 2;
        TreeNode* root = new TreeNode(nums[mid]);
        root -> left = binary(nums, left, mid - 1);
        root -> right = binary(nums, mid + 1, right);
        return root;
    }
};