(N叉树 递归) leetcode 590. N-ary Tree Postorder Traversal

Given an n-ary tree, return the postorder traversal of its nodes' values.

For example, given a 3-ary tree:

Return its postorder traversal as: [5,6,3,2,4,1].

Note:

Recursive solution is trivial, could you do it iteratively?

---------------------------------------------------------------------------------------------------------------------------------

和leetcode589. N-ary Tree Preorder Traversal类似。用递归会简单些

C++代码：

/*
// Definition for a Node.
class Node {
public:
    int val;
    vector<Node*> children;

    Node() {}

    Node(int _val, vector<Node*> _children) {
        val = _val;
        children = _children;
    }
};
*/
class Solution {
public:
    vector<int> postorder(Node* root) {
        vector<int> vec;
        helper(root,vec);
        return vec;
    }
    void helper(Node* root,vector<int> &vec){
        if(!root) return;
        for(Node *cur:root->children){
            helper(cur,vec);
        }
        vec.push_back(root->val);
    }
};