108. Convert Sorted Array to Binary Search Tree

dfs的簡單題, 但還是沒有很習慣

class Solution {
public:
    TreeNode* sortedArrayToBST(vector<int>& nums) {
        if(nums.size() == 0)
            return nullptr;
        int mid = nums.size() / 2;
        TreeNode *cur = new TreeNode(nums[mid]);
        vector<int> left (nums.begin(), nums.begin() + mid);
        vector<int> right(nums.begin() + mid + 1, nums.end());
        cur->right = sortedArrayToBST(right);
        cur->left = sortedArrayToBST(left);
        return cur;
    }
};