leetcode : same tree or symmetric tree

key: use queue

 usage:  queue<node*> myq; myq.push(); myq.front(); myq.pop()

 bool isSameTree(TreeNode *p, TreeNode *q) {
        queue<TreeNode*> myq;
        myq.push(p);
        myq.push(q);
        while(!myq.empty()){
            TreeNode *t1 = myq.front();
            myq.pop();
            TreeNode *t2 = myq.front();
            myq.pop();
            if(t1 == NULL && t2 == NULL) continue;
            if(t1 == NULL || t2 == NULL) return false;
            if(t1->val != t2->val ) return false;
       
            myq.push(t1->left);
            myq.push(t2->left);
            myq.push(t1->right);
            myq.push(t2->right);
        }
        return true;
    }