递归会超时,调了半天都是只能通过自测,还是老老实实层序遍历吧

class Solution {
public:
    TreeNode* Mirror(TreeNode* pRoot) {
        // write code here
        TreeNode* tmp;
        TreeNode* node;
        queue<TreeNode*> que;
        if(pRoot!=NULL) que.push(pRoot);
        while(!que.empty()){
            for(int i=0;i<que.size();i++){
                node=que.front();
                que.pop();
                tmp=node->left;
                node->left=node->right;
                node->right=tmp;
                if(node->left) que.push(node->left);
                if(node->right) que.push(node->right);
            }
        }
        return pRoot;
    }
};