Ukiut nunarput, n-ary tree-p imaq nunamut tunngasut, sisamatut postorder traversal-imi atorneqatigut nodes-i ilisarnitsi.

Nary-Tree input serialization-i ukiut nunarput, level order traversal-imut atuakkiortut. Children-i gruppi null torneqatigalugu ilisserneqartut.

C++-imi solution-i:
```cpp
class Solution {
public:
    vector<int> postorder(Node* root) {
        vector<int> result;
        if (!root) return result;
        
        stack<Node*> s;
        s.push(root);
        
        while (!s.empty()) {
            Node* node = s.top();
            s.pop();
            result.push_back(node->val);
            
            for (Node* child : node->children) {
                s.push(child);
            }
        }
        
        reverse(result.begin(), result.end());
        return result;
    }
};
```
Ilisarnitsi C++-p kingornatigut postorder-traversali n-ary tree-mut:

```
class Node {
public:
    int val;    
    vector<Node*> children;

    Node() {}

    Node(int _val) {
        val = _val;
    }

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

vector<int> postorder(Node* root) {
    vector<int> result;
    if (root == nullptr) {
        return result;
    }

    // Traverse all the children
    for (Node* child : root->children) {
        vector<int> childValues = postorder(child);
        result.insert(result.end(), childValues.begin(), childValues.end());
    }

    // Append the value of the root
    result.push_back(root->val);
    return result;
}
```