leetcode

0 class Solution {

1 public:

2 TreeNode *reverseOddLevels(TreeNode *root) {

3 static vector<TreeNode *> vec(8192);

4 queue<TreeNode *> q({root});

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

6 for (int k = q.size() - 1; k >= 0; k--) {

7 vec[k] = q.front();

8 q.pop();

9 if (vec[k]->left) q.push(vec[k]->left);

10 if (vec[k]->right) q.push(vec[k]->right);

11 }

12 if (lvl % 2 == 0) continue;

13 int i = 0, j = (1 << lvl) - 1;

14 while (i < j)

15 swap(vec[i++]->val, vec[j--]->val);

16 }

17 return root;

18 }

19 };