leetcode

0 class Solution {

1 public:

2 vector<vector<int>> levelOrder(TreeNode *root) {

3 if (!root) return {};

4

5 vector<vector<int>> res;

6 queue<TreeNode *> q;

7

8 q.push(root);

9 for (int lvl = 0; !q.empty(); lvl++) {

10 res.push_back(vector<int>());

11 for (int t = q.size(); t > 0; t--) {

12 TreeNode *root = q.front();

13 q.pop();

14 res[lvl].push_back(root->val);

15 if (root->left) q.push(root->left);

16 if (root->right) q.push(root->right);

17 }

18 }

19 return res;

20 }

21 };