Binary Tree Zigzag Traversal

#include <bits/stdc++.h> 
/*************************************************************

    Following is the Binary Tree node structure

    class BinaryTreeNode
    {
    public :
        T data;
        BinaryTreeNode<T> *left;
        BinaryTreeNode<T> *right;

        BinaryTreeNode(T data) {
            this -> data = data;
            left = NULL;
            right = NULL;
        }
    };

*************************************************************/

vector<int> zigZagTraversal(BinaryTreeNode<int> *root)
{
    if(!root) return {};

    queue<BinaryTreeNode<int>*>q;
    q.push(root);
    bool leftToRight=true;
    vector<int>ans;

    while(!q.empty())
    {
        int size=q.size();
        vector<int>temp(size);

        for(int i=0;i<size;i++)
        {
            BinaryTreeNode<int>* node=q.front();
            q.pop();
            int ind=(leftToRight) ? i : size-i-1;

            temp[ind]=node->data;

            if(node->left)
            {
                q.push(node->left);
            }
            if(node->right)
            {
                q.push(node->right);
            }
        }
        leftToRight=!leftToRight;

        for(auto it:temp)
        {
            ans.push_back(it);
        }
    }
    return ans;
}