Iterative Recursive Boundary Level Traversal of Binary Tree

recursive_boundary.cpp

class Solution {
public:

    void traverseLeft(Node* root, vector<int> &ans){
        if(!root or (!root->left and !root->right)) return;
        ans.push_back(root->data);
        if(root->left) traverseLeft(root->left, ans);
        else traverseLeft(root->right, ans);
    }
    void traverseLeaf(Node* root, vector<int> &ans){
        if(!root) return;
        if(!root->left and !root->right){
            ans.push_back(root->data);
            return;
        } 
        traverseLeaf(root->left, ans);
        traverseLeaf(root->right, ans);
    }
    void traverseRight(Node* root, vector<int> &ans){
        if(!root or (!root->left and !root->right)) return;
        if(root->right) traverseRight(root->right, ans);
        else traverseRight(root->left, ans);
        ans.push_back(root->data);
    }
    vector <int> boundary(Node *root)
    {
        if(!root) return {};
        vector<int> ans;
        ans.push_back(root->data);
        traverseLeft(root->left, ans);
        traverseLeaf(root->left, ans);
        traverseLeaf(root->right, ans);
        traverseRight(root->right, ans);
        return ans;
    }
};