leetcode

0 class Solution {

1 public:

2 string smallestFromLeaf(const TreeNode *root) const {

3 queue<pair<const TreeNode *, string>> q;

4 q.emplace(root, "");

5

6 string res(16, 'z');

7 while (!q.empty()) {

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

9 auto [root, s] = q.front();

10 q.pop();

11 s += 'a' + root->val;

12

13 if (root->left) q.emplace(root->left, s);

14 if (root->right) q.emplace(root->right, s);

15

16 if (!root->left && !root->right) {

17 reverse(begin(s), end(s));

18 res = min(res, s);

19 }

20 }

21 }

22

23 return res;

24 }

25 };