s4553711
4/29/2017 - 3:03 PM

563.cpp

/**
 * 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;
    }
};