leetcode

0 class Solution {

1 int res = 0;

2

3 int rec(const TreeNode *root, int parent) {

4 if (!root) return 0;

5

6 const auto l = rec(root->left, root->val), r = rec(root->right, root->val);

7

8 res = max(res, l + r);

9 return root->val == parent ? max(l, r) + 1 : 0;

10 }

11

12 public:

13 int longestUnivaluePath(const TreeNode *root) {

14 rec(root, -1);

15 return res;

16 }

17 };