// language C with STL(C++)
// 剑指32-II
// https://leetcode-cn.com/problems/cong-shang-dao-xia-da-yin-er-cha-shu-ii-lcof/
/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
vector<vector<int>> levelOrder(TreeNode* root) {
vector<vector<int>> ans;
if(root ==NULL)
return ans;
queue<TreeNode*> q1,q2;
q2.push(root);
int level = 1;
while(!empty(q2)){
vector<int> niude;
while(!empty(q2)){ // 把q2中的元素移到q1中
q1.push(q2.front());
q2.pop();
}
//然后处理q1中的元素
TreeNode* temp;
while(!empty(q1)){
temp = q1.front();
q1.pop();
niude.push_back(temp->val);
if(temp->left)
q2.push(temp->left);
if(temp->right)
q2.push(temp->right);
}
ans.push_back(niude);
}
return ans;
}
};