leetcode

0 class Solution {

1 public:

2 vector<string> binaryTreePaths(TreeNode *root) {

3 if (!root) return {};

4

5 vector<string> res;

6 stack<pair<TreeNode *, string>> st;

7 st.push({root, to_string(root->val)});

8 while (!st.empty()) {

9 TreeNode *root = st.top().first;

10 string s = st.top().second;

11 st.pop();

12 if (!root->left && !root->right)

13 res.push_back(s);

14 else {

15 s += "->";

16 if (root->left) st.push({root->left, s + to_string(root->left->val)});

17 if (root->right) st.push({root->right, s + to_string(root->right->val)});

18 }

19 }

20 return res;

21 }

22 };