/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
int res;
int findTilt(TreeNode* root) {
findSum(root);
return res;
}
int findSum(TreeNode* root) {
if (root == NULL) return 0;
int left = findSum(root->left);
int right = findSum(root->right);
res += abs(left - right);
return left + right + root->val;
}
};