589. N-ary Tree Preorder Traversal.cpp

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

    Node() {}

    Node(int _val) {
        val = _val;
    }

    Node(int _val, vector<Node*> _children) {
        val = _val;
        children = _children;
    }
};
*/

class Solution {
public:
    vector<int>v;
    void pre(Node* root){
        if(!root)return;
        
        v.emplace_back(root->val);
        for(int i=0; i<root->children.size();i++){
            pre(root->children[i]);
        }
        
    }
    
    vector<int> preorder(Node* root) {
        pre(root);
        return v;
    }
};