leetcode

0 class Solution {

1 public:

2 bool hasPathSum(TreeNode *root, int targetSum) {

3 if (!root) return false;

4

5 stack<pair<TreeNode *, int>> st;

6 st.push(make_pair(root, 0));

7 while (!st.empty()) {

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

9 int val = st.top().second + root->val;

10 st.pop();

11

12 if (val == targetSum && !root->left && !root->right) return true;

13

14 if (root->left) st.push(make_pair(root->left, val));

15 if (root->right) st.push(make_pair(root->right, val));

16 }

17 return false;

18 }

19 };