leetcode589. N 叉树的前序遍历(java & python3)

简单题重拳出击 还是看了题解 太久没搞树了 忘了 无语 和前序遍历一样

java：

class Solution {
    public List preorder(Node root) {
        List res = new ArrayList<>();
        goodnight(root, res);
        return res;
    }
    public void goodnight(Node root, List res){
        if(root == null){
            return ;
        }
        res.add(root.val);
        for(Node num : root.children){
            goodnight(num, res);
        }
    }
}

python3:

class Solution:
    def preorder(self, root: 'Node') -> List[int]:
        res = []
        def goodnight(node : 'Node'):
            if root is None:
                return
            res.append(node.val)
            for num in node.children:
                goodnight(num)
        goodnight(root)
        return res