LevelxLevel Alternate

class Solution {
public:
    vector<vector<int>> zigzagLevelOrder(TreeNode* root)
    {
        vector<vector<int>> zigzag;
        vector<int> temporal;
        bool valor = true, cambio = true;
        if(root==NULL)
        {
            return zigzag;
        }
        int posicion = 0;
        stack<TreeNode*> s;
        queue<TreeNode*> q;
        q.push(root);
        while(!q.empty()||!s.empty())
        {
            if(valor)
            {
                temporal.push_back(q.front()->val);
                if(q.front()->left!=NULL)
                {
                    s.push(q.front()->left);
                }
                if(q.front()->right!=NULL)
                {
                    s.push(q.front()->right);
                }
                q.pop();
                if(q.empty())
                {
                    valor = false;
                }

            }
            else
            {
                temporal.push_back(s.top()->val);
                if(s.top()->left!=NULL)
                {
                    q.push(s.top()->left);
                }
                if(s.top()->right!=NULL)
                {
                    q.push(s.top()->right);
                }
                s.pop();
                if(s.empty())
                {
                    valor = true;
                }
            }
            if(cambio!=valor)
            {
                cambio = !cambio;
                zigzag.push_back(temporal);
                temporal.clear();
                posicion++;
            }
        }
        return zigzag;
    }
};